Category: Herbal Medicine

Bird Flu – an increasing risk to animal and human health

On By HerbBlurbIn Animal health, Animal husbandry, antimicrobial, antiviral herbs, Biosecurity, Herbal Medicine, Infection management, Plant MedicineLeave a comment

by Phil Rasmussen

Aotearoa New Zealand has in the past two weeks detected its first cases of bird flu, a highly contagious strain of the H5N1 influenza A virus, that can spread rapidly in birds(1). This came less than a month after the first case of H5N1 bird flu was detected in Australia.

Waterfowl such as ducks, geese and swans and shorebirds are the natural reservoir of all known influenza A viruses. First detected in poultry in China in 1996, the H5N1 avian influenza virus has evolved into a significant global public health hazard, primarily owing to its high pathogenicity and potential for interspecies transmission. Extensive genetic diversification has occurred since 2005, including the formation of hundreds of genotypes following reassortment with other avian influenza A viruses.  Highly pathogenic H5N1 avian influenza (HPAI) A virus has spread widely through many regions of the world, causing infections of numerous terrestrial, seabird, shorebird, and migratory wild bird species(2). Since 1997, multiple outbreaks of avian influenza in domestic poultry have occurred, and the current 2.3.3.4.4b clade of H5N1 which emerged in 2020, has now become widespread(3, 4).

Migratory birds are the most likely pathway for the virus to come here, as Aotearoa is a seasonal home to several species who migrate from and travel between here and far away places including the Antarctic, other islands in the Pacific, Australia, China, Alaska, Siberia, and northern Asia. The first case was a wild brown skua found on Petone Beach in Lower Hutt.

Efforts to protect some of our already threatened native bird species such as kākāpō, takahē, tūturuatu (shore plover), kakī (black stilt) and kākāriki karaka (orange-fronted parakeet) by vaccination and isolation are underway.  The second bird confirmed to have bird flu here was a native kāhu or swamp harrier hawk, which doesn’t bode well given many of these species are already vulnerable. While vaccination may help save some, it has obvious limitations and only gives around 6 months of protection, therefore additional control measures are urgently needed.

Other biosecurity measures are now being implemented by the Ministry of Primary Industries, Department of Conservation and poultry farmers(5, 6). This includes PSE protection measures, moving chickens indoors, and lockdowns.  As has occurred overseas, it seems likely that New Zealand poultry farms will at some stage become affected by this virus, potentially leading to the deaths of many millions of birds.

Potential transmission to dairy cows

Highly pathogenic H5N1 influenza was first detected in dairy cows in Texas in March 2024. The virus then disseminated rapidly, causing widespread outbreaks in dairy cattle across the United States(7, 8, 9, 10). Over 1000 herds in at least 19 states have been affected to date(11, 12).

Most cattle recovered in two to three weeks with supportive care, but the impact of the virus on dairy cattle varied from nonclinical to severe clinical signs and death. Up to 20% of each herd in the U.S. outbreaks developed clinical disease with symptoms such as reduced milk production, thicker colostrum-like milk, reduced appetite, lethargy, fever and dehydration. This lead to substantial economic losses(9, 12).  

At first, many American dairy producers did not report clinical signs in their cows or test for the virus. Cats and peridomestic birds on many affected farms died from viral exposure. A number of dairy workers showed signs of conjunctivitis, which was confirmed to be due to H5N1(12).

This represents a significant expansion in the mammalian host range of highly pathogenic H5N1.  Genomic analysis and epidemiological investigation suggests a reassortment event in wild bird populations preceded a single wild bird-to-cattle transmission episode. The movement of asymptomatic or presymptomatic cattle also likely played a role in the spread of HPAI within the United States dairy sector(7).

While infectious virus is detected in milk following mammary infection, unpasteurised milk ingestion by calves doesn’t seem to cause overt disease(13). However, the risk to humans from drinking raw (unpasteurised) milk from infected cows remains unknown, and virologists in the US have advised against this.  American authorities have confirmed that pasteurization inactivated the virus in dairy products and showed that it was very rarely detected in beef from affected cows.

Two years later, the U.S. outbreak of the H5N1 influenza virus in cattle appears to be waning, easing fears that it could cause long-lasting damage to the dairy industry or mutate into a human pandemic form. However, it remains a problem in some states, and efforts to eliminate it entirely face formidable challenges.  The mechanisms of transmission within and between dairy herds also remains a critical question that has yet to be fully answered(13, 14). American virologists have advocated strongly for precautions to be taken by dairy or poultry farm workers, and that those with backyard birds, chickens or pigeons, should also be careful. Keeping dogs and cats away from dead birds,  is also recommended(15).

The persistence of the H5N1 virus in U.S. dairy cattle and the fact it has adapted to infect another key mammalian species, coupled with its broad and unprecedented host range, are alarming developments. It also presents a public health threat due to the establishment of distinct transmission chains linking wild birds, cattle, the environment, and humans.

This is highly relevant to our situation here in Aotearoa New Zealand, given that the dairy industry is our largest export earner, and is based largely on outdoor grazing. While the U.S. outbreak has to date been confined to that country, the risk of transmission of bird flu from wild or migratory birds to cattle as occurred in the U.S., appears very real. If highly pathogenic H5N1 become established in dairy cows here, it could have serious biosecurity, public health and economic consequences. Measures to increase surveillance, develop animal vaccines and treatment agents, enhance farm biosecurity, and continue to ensure dairy product safety, should be considered. Incorporation of a medicinal plant programme, could also make a valuable contribution as part of these measures.

Risk to Humans

While primarily affecting avian species, H5N1 has repeatedly breached species barriers, infecting mammals including seals, dolphins, seals, foxes, otters and cattle(16). As with the SARS-1 and SARS-2 (Covid-19) viruses, which originated from viruses in birds and bats, H5N1 also has the potential to infect humans.

The first known human infection with a highly pathogenic H5N1 influenza A virus appeared in China in 1997. Between 2003 and 2017, the WHO documented an additional 862 human cases, mainly from southeast Asia and Egypt, with a mean annual case fatality rate of 56%(17).

Human cases fell after 2016, but H5N1 clade 2.3.4.4b viruses then appeared in Europe and spread rapidly to the Americas. Human infections of this genotype have been relatively rare to date, and until the US dairy outbreak, mostly occurred in those with unprotected exposure to sick birds. Many instances of poultry workers being infected have been reported(18).

Since the start of the USA dairy outbreak, the H5N1 virus spread from dairy cattle to cats, mice, peridomestic birds, species such as skunks and raccoons, as well as humans.  Between March 2024 and May 2025,  70 human cases of highly pathogenic H5N1 were reported in the United States, although it is likely that the true number of cases was considerably more(12). Of these 41 were exposed to dairy cows, 24 to commercial poultry, two to backyard poultry and three had an unidentified source of exposure. All sequenced viruses were clade 2.3.4.4b. Overall, 62 cases (89%) reported eye redness, 32 (46%) fever and 29 (41%) respiratory symptoms; 54 of 67 cases (81%) reported receiving antiviral treatment. Most illnesses were mild; however, four patients were hospitalized. Of the hospitalized patients, three had pneumonia and one died(19).

While evolution of the virus to a strain capable of rapid human-to-human transmission hasn’t occurred as yet, history and science tell us that such a worrying development remains possible.

The 1918-1920 so-called Spanish flu (which actually began in the U.S.), was caused by a highly lethal strain of the H1N1 subtype of the influenza A virus, which likely originated in birds, before adapting in humans. This was an RNA virus that spread incredibly fast worldwide, ultimately infecting an estimated one-third of the global population and causing the deaths of an estimated 20 to 30 million people(20, 21). Despite our understanding of viral transmission and public health measures now being better than they were in 1918, the potential for an epidemic or pandemic is a concern.

Several outbreaks of bird flu have occurred since 2005, when H5N1 in birds was described as “public health enemy number 1”, and likely to lead to a global pandemic. At that time, highly pathogenic H5N1 influenza A viruses were spreading relentlessly across the globe, causing widespread death in poultry, substantial economic loss to farmers, and infections reported in more than 300 people with a very high mortality rate of 60%(22). As it happened, Covid-19 pipped it at the post, but that didn’t mean that the risk of a future H5N1 pandemic went away.

Detection of the D1.1 genotype primarily circulating in wild birds, was reported in dairy cows in early 2025. Unlike the B3.13 virus circulating in cattle, this has been associated with severe disease in humans, and resulted in two deaths(17, 23). The co-circulation of B3.13 and D1.1 viruses in dairy cows increases the risk of reassortment and viral evolution to a more virulent strain. Genotype D1.1 has now also been detected in domestic cats.

However humans have some residual or existing immunity to H5N1 through our long term exposure to other influenza viruses such as H1N1(24).  Studies in ferrets and using human organoids suggest that currently available seasonal influenza vaccines may confer some degree of protection against H5N1. To what extent however, is as yet unknown(24, 25).

It is hard to know how close we are to the H5N1 virus evolving to become much more virulent in humans. However, reassortment in particular, when co-infection with two viruses occurs (such as a dairy farm worker already with influenza, picking up H5N1), presents a possible mechanism of increased virulence developing.

Some useful phytomedicines

Medicinal plants, having being the mainstay of how humans and animals have treated themselves when unwell throughout virtually all of history, deserve much more attention for their potential value in dealing with H5N1.

In 2005, with a previous version of H5N1 circulating in many bird species around the globe and fears mounting of this triggering a human pandemic, I researched the history of infectious viral diseases and what was known about the H5N1 strains at the time(26, 27).

Below is a reproduction of part of an article I wrote on Avian Influenza in November 2005, for a practitioner publication produced by a company I founded and was then managing. While an update is now called for, much of the information provided is still highly relevant to the current H5N1 situation here in Aotearoa New Zealand.

Avian Influenza Update; excerpts from an article by Phil Rasmussen & edited by Noeline Jonkers, in Phytonews 23, published by Phytomed Medicinal Herbs Ltd, November 2005:

Echinacea:

Echinacea has been shown in animal studies to impart protection against mortality from various viruses(28,29), and several clinical trials have shown beneficial effects of Echinacea during the treatment of colds and influenza(30-34).

Increased numbers of circulating white blood cells, monocytes, neutrophils and natural killer (NK) cells, and the phagocytotic abilities of these, are the principle immunological changes associated with Echinacea root usage. These effects are all a reflection of enhancement of the non-specific immune response, whereby the body’s ability to maintain immunosurveillance against a variety of potential viral or bacterial pathogens or spontaneous-developing tumours, is increased.  This aspect of the immune response is quite different to that of the specific immune system as provoked by vaccination, whereby production of specific disease-related antibodies and a subsequent immune response occurs.

Certain of the above effects of Echinacea may at first seem counterproductive during the acute stage of an established H5N1 infection, in which much of the immune system could well be over-activated as described earlier. While activation of innate immune mechanisms such as NK cell activity is useful in the early immune response to most types of influenza(35,36), excessive enhancement of NK cell activity during the acute stage of a H5N1 infection, could perhaps be associated with a theoretical worsening of lung function(37).

At this point however, it is perhaps important to recognise that Echinacea root exhibits pharmacological actions better summarised as being immunomodulatory and anti-inflammatory rather than simply immunostimulant. Its use by experienced practitioners for autoimmune conditions such as asthma and eczema, is also due to its perceived actions as a modulator or regulator of a poorly functioning overall immune system. Additionally, while activation of several inflammatory as well as anti-inflammatory cytokines has been shown for Echinacea both in vitro and in vivo, the specific actions and potencies in this regard vary depending on the type of Echinacea product concerned.

Anti-inflammatory effects of Echinacea root are well established from both its traditional use to treat snake bites and major abscesses, as well as modern pharmacological studies(38-41). Recent studies have also shown that Echinacea alkamides produce a dual modulatory rather than simple stimulant effect on TNF-a expression in humans(42). These and other effects of Echinacea on gene expressions indicate a broad spectrum anti-inflammatory and immunomodulatory response(43), including reduced expression of IL-1β, IL-8 and TNF-α.  Such effects could be helpful during the acute stages of H5N1 infection.

While speculative, modulation of TNF-a and other cytokine expression by Echinacea could therefore be useful in a situation of H5N1 infection during which TNF-α and cytokine production in general, is dysregulated. In addition to these anti-inflammatory and immunomodulatory effects, antioxidant actions by Echinacea could also be helpful during this situation(44).

However, while adequate doses of a good quality Echinacea preparation have been shown to enhance the capability of the body’s immune system to combat existing upper respiratory tract infections, whether such effects would occur to help hasten elimination of a virulent H5N1 infection, remain unknown.

The question also arises as to whether Echinacea is best used as a possible preventative agent to optimise immune defences ready for when an avian influenza pandemic occurs, rather than a treatment when an individual infection has occurred. Optimising immunosurveillance and activity of the non-specific immune system against such a virulent pathogen, while less likely to ensure complete protection than appropriate vaccination, may prevent such a virulent and life-threatening response to its presence.

Other phytomedicines:

Shikimic acid is a phenolic acid compound used as a key starting material in the manufacture of oseltamivir, and found in many plants including Chinese Star Anise (Illicium verum)(45). While this and other shikimic acid rich plants have been increasingly sought after since fears of a pandemic escalated, little evidence exists that shikimic acid itself or plants containing it, could be useful.

American ginseng (Panax quinqefolium) root has a protective effect against winter influenza in institutionalised older adults (see Phytonews 20(46)). More recently, a preventative effect against winter colds has been reported following daily use for 4 months, in a Canadian study involving 323 subjects aged 18-65 years of age(47). A higher immune response from influenza vaccination, has also been produced by concurrent administration of the closely related Panax ginseng(48).

The popular Chinese herb Astragalus membranaceous, traditionally used to help manage viral infections such as the common cold, has also shown some evidence of immune stimulation and antiviral effects(49-51).

Elderflower (Sambucus nigra) is generally used for its diaphoretic and decongestant properties, particularly during hay fever as well as catarrh and fever associated with the common cold or influenza. A clinical trial has found elderberry to have in vitro antiviral effects and reduce the duration and severity of influenza symptoms(52), and possible immunostimulant properties have been reported(53).

The root of Ginger (Zingiber officinale) has immunomodulatory(53) and antiviral properties(55-57), which along with its anti-inflammatory actions, may be useful. The fungus Reishi (Ganoderma lucidum), has established immunomodulatory effects and enhances innate immunity by activating NF-kappaB(58).

Olive leaf (Olea europaea) has become popular over recent years as an alleged treatment for winter influenza, although little published research has appeared until recently(59).

Propolis, the resinous material manufactured by bees from plants and rich in flavonoids, shows in vitro activity against various viruses(60,61), and has proven immunomodulatory and anti-inflammatory effects including down-regulation of inflammatory cytokine production(62,63).

Various plants contain compounds which act as neuraminidase inhibitors in vitro in the same manner as oseltamivir. The best studied of these is 5,7,4”-trihydroxy-8-methoxyflavone(64,65), a flavone closely related to baicalin and baicalein and found in roots of the popular Chinese herb Baical Skullcap (Scutellaria baicalensis), as well as aerial parts of the well-known European Skullcap (Scutellaria lateriflora).

A study just reported using a Chinese formula containing a large amount of baicalin in a pre-clinical animal model of endotoxin-induced lung injury, found a marked reduction in elevated plasma levels and the expressions of several inflammatory cytokines, in lung tissues. The formulation itself (San-Huang-Xie-Xin-Tang), as well as baicalin alone, also reduced plasma concentrations of IL-1b, TNF-α, and expressions of other cytokines associated with lung injury and lethality(66).

This study as well as another finding in vitro antiviral activity against SARS coronavirus for baicalin(66), provides strong support for a potential role for baicalin-containing phytomedicines  in the treatment of acute H5N1 infection. The well-established anti-inflammatory, antioxidant and antimicrobial activities of Baical Skullcap(68), would seem to make further research on this phytomedicine in particular, highly justified.

Other neuraminidase inhibitors include resveratrol (found in red grapes) and emodin derivatives, anthraquinone compounds found in Aloe vera and a number of other laxative phytomedicines(69). The strong laxative effects of these would probably be major limitations to their clinical usefulness at this stage. As for all such compounds, considerations of bioavailability and dosage of each of these herbal medicines that would be required for significant activities need to be made.

With excessive inflammation in the lungs being increasingly related to the virulence of  H5N1, treatment of infected patients with anti-inflammatory drugs or herbal medicines may in some cases be useful. However while the use of corticosteroids together with antiviral medication has been reported to confer clinical benefits in some cases of SARS(70), clinical trials are lacking and such steroid therapy has been linked with residual lung damage following treatment. There nevertheless remains a theoretical potential role for anti-inflammatory phytomedicines or phytochemicals such as curcumin, a key constituent of the cheap spice Turmeric, which is a significant inhibitor of TNF and could help reduce the adverse effects of excessive cytokine release.

While in all cases it is at this stage conjectural as to whether these or other various natural treatments would be helpful during an H5N1 pandemic, the seriousness of the situation now arising warrants a systematic evaluation of these and other herbal medicines as possible alternative or adjunctive treatments to anti-viral drug or vaccine therapy. 

July 2026 Update:

Significantly, each of the aforementioned herbs as well as the propolis made by bees using plant phytochemicals, are already being grown or can easily be grown here in Aotearoa and their production scaled up rapidly, provided the required commitment and funding support to do so, is provided.

One of these, Scutellaria baicalensis (Baical Skullcap) is a widely used medicinal plant in Asia, and one of the species that I am participating in growing trials with, involving a landowner group here in Aotearoa New Zealand. I recommended this species for the trials based upon the huge amount of scientific evidence for its effectiveness in many human health conditions, my clinical experience with using it in hundreds of patients, its growing global demand, our need to strengthen our medicine security and diversify our rural economies, and a view it would grow very well in our country.  Early results from these trials have been promising.

As I summarised in blogs in April and October last year, Baical skullcap has recently been shown to possess potential applications for animal health in addition to its well-established benefits to treat human illnesses including infectious and neurological diseases, inflammatory and allergic conditions and cancer(71, 72). A study published last year by Chinese researchers also found an extract of the stems and leaves of Baical skullcap to offer promise in helping farmers to manage respiratory tract pathogens in laying hens.(73)

Supplementation of chickens vaccinated against the H5N1 avian influenza virus with oral extracts from Astragalus and Ginseng (two other species which are being trialed or cultivated here in Aotearoa), has been shown to increase their antibody production and immune response. This suggests their potential also as adjunctive treatments, to protect chickens against this virus(74).  Researchers in Thailand recently screened some Asian medicinal plant extracts and found ethanolic extracts of turmeric root as well as the leaf of guava (Psidium guajava), to have good in vitro activity against the H5N1 influenza virus(75).

A call to Action

Highly pathogenic avian influenza (HPAI) H5N1 continues to pose a serious threat to global health due to its increasing geographic spread, expanding host range including recent mammalian infections, and relatively high mortality in human cases.

The potentially devastating impact of this highly pathogenic H5N1 virus on our native birds as well as poultry industry, and risk of spread to the dairy industry, calls for urgent steps from the government and industry sectors and stakeholders.  The propensity of this strain of H5N1 to mutate, and potentially into a form more easily transmissible between humans, is a reason for concern. To effectively manage highly pathogenic avian influenza, a comprehensive, collaborative and forward thinking programme that invokes the principals of a One Health perspective involving all stakeholders, is recommended.

Despite the availability of vaccines and antivirals for seasonal influenza, effective prophylactic and treatment options for H5N1 remain limited.  Several drugs show promise in preclinical studies, but clinical data specifically for H5N1 is lacking.

Fortunately, compelling research suggests that several medicinal plants could make a valuable contribution as part of these management efforts, many of which we can easily grow here. Incorporating some of these into longer term farm management practices would also have other sustained benefits for our important animal based agricultural economy, as well as our resilience as a food producing nation, and protection of our rich native species biodiversity.

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  73. Wang X, Wu S, Guo N, Yu F et al, Scutellaria baicalensis stem and leaf combat chicken-derived respiratory bacterial infection. Microb Pathog. 2025 May;202:107439. 
  74. Abdullahi AY, Kallon S, Yu X, Zhang Y, Li G. Vaccination with Astragalus and Ginseng Polysaccharides Improves Immune Response of Chickens against H5N1 Avian Influenza Virus. Biomed Res Int. 2016;2016:1510264.
  75. Sornpet B, Potha T, Tragoolpua Y, Pringproa K. Antiviral activity of five Asian medicinal pant crude extracts against highly pathogenic H5N1 avian influenza virus. Asian Pac J Trop Med. 2017 Sep;10(9):871-876.

Baical Skullcap – additional uses for aerial parts

On By philrasmIn Antibiotic Resistance, antimicrobial, Herbal Medicine, UncategorizedLeave a comment

Baical Skullcap

Scutellaria baicalensis (known as Baical skullcap or Huangqin) is an important plant medicine in China, Russia, Mongolia, Korea and Japan.  It is a prominent constituent in a large number of Traditional Chinese Medicine formulations used to treat numerous disease conditions. These include allergic diseases, respiratory tract infections, pneumonia, colitis, hepatitis, dementia, Parkinson’s disease and cancer.

Scutellaria baicalensis is botanically related to Scutellaria lateriflora (commonly known as Skullcap or American Skullcap in western Herbal Medicine), best known for its anxiolytic and sedative properties.  However, the root of Baical skullcap is the plant part traditionally used, whereas for American Skullcap it is the aerial parts (leaves and stems).

Over 50 compounds have been isolated and identified from Baical skullcap, including flavonoids, terpenoids, volatile oils and polysaccharides. Flavonoids including baicalein and its metabolite baicalin and wogonin, are key active phytochemicals.  These occur in highest levels within the root, and virtually all research on this impressive plant has involved use of root-derived preparations.

Research on aerial parts

While not well known, other parts of Baical skullcap, are also sometimes used for therapeutic purposes.

Improved cognition in vascular dementia and in animal models of Alzheimer’s disease, and prevention of cerebral ischaemia reperfusion injury, have previously been reported in rats following administration of concentrated flavonoid extracts made from stems and leaves of Scutellaria baicalensis (1-5). While required dosages were large, favourable results using these animal models for common age-related conditions are encouraging. They also highlight potential applications in both veterinary and human medicine, for parts of the plant normally regarded as waste products from root farming operations. These have a different phytochemistry to the root, with the flavonoid scutellarin being predominant.

Poultry industry applications

The poultry industry is a huge global operation, but as it has grown and poultry farms become larger, challenges in relation to animal health and husbandry have also increased.

Most chicken farms around the world still rely heavily on regular use of antibiotics for disease prevention and control, and sometimes also to promote growth. However, such widespread use can lead to deposition of antibiotic residues in the soil and waterways, and the promotion of microbial mutations and antibiotic resistance. These are serious consequences for the environment, animal and human health(6).  Since 2006, the European Union has banned the use of antibiotics as growth promoters in farm animals. Their use in Australia and New Zealand, is also now limited to sick animals only.

Bacterial and viral infections nevertheless remain challenging for poultry farmers, and can lead to substantial losses in laying hens or in those farmed for meat.  Despite improvements in housing and management practices in recent years, infections such as salmonella or bird flu remain a constant threat.

A recent study by Chinese researchers, has now found the normally discarded tops of Baical skullcap to offer promise in helping farmers to manage respiratory tract pathogens in poultry.

Recent research

The study, conducted by agricultural researchers and veterinarians in Beijing, investigated the effects of an ethanolic extract of the stems and leaves of Scutellaria baicalensis, on respiratory symptoms in diseased laying hens.

Three groups of 60 diseased laying hens were randomly selected. One group was given a diet supplemented with dried Baical skullcap stem and leaf powder, another with a hydroethanolic extract of the stem and leaf, and one the usual diet only, for a period of 12 days.

After the 12 day supplementation period, hens given the Baical skullcap extract had a marked improvement in respiratory tract symptoms such as coughing, a runny nose and labored breathing. Subsequent biopsies revealed a significant improvement in lung tissue lesions and inflammation. Baical skullcap supplementation was also associated with a significant upward trend in the egg production rate starting 3 days after supplementation commenced, as well as improvements in egg quality(7).

Previous work

Earlier work in Europe found a combination of turmeric and baical skullcap given as a feed additive to chickens decreased gut inflammation and improved the health of chickens with the pathogen Salmonella enteritidis(8). Salmonella is a serious pathogen in chickens which can affect both meat and egg production and quality.

Another recent Chinese study found a combination of baical skullcap with flowers of Lonicera japonica (Japanese honeysuckle, a noxious weed in Aotearoa New Zealand)(9), to mitigate the negative effects of Clostridia perfringens infection in chickens. This is another gastrointestinal pathogen causing reduced growth and mortality in poultry, also normally treated with antibiotics. Mechanisms of action were related to improvement in intestinal barrier function, leading to a positive influence on the growth performance of challenged birds(10).

Economic and environmental benefits

Potential applications to develop animal feed products containing readily available and cheap or free plant materials to manage chicken diseases naturally rather than through agrichemicals, are made apparent by this recent research.

While above ground parts of medicinal plants where the root is harvested are usually returned to the land in the form of mulch or as some form of compost, an ability to utilize these also to produce valuable medicines, is preferential.

The area of commercial cultivation of Baical skullcap in China alone is currently more than four times that of all Aotearoa New Zealand apple and pear orchards combined. This in itself speaks to the market potential of farming for the highly medicinal root.  With additional poultry industry applications being revealed for plant parts generally regarded as a waste byproduct, the case for increased research to further develop a sustainable and profitable scaled up medicinal plant cultivation industry here, continues to strengthen.

Refs:

  1. Cao Y, Liang L, Xu J, Wu J, Yan Y, Lin P, Chen Q, Zheng F, Wang Q, Ren Q, Gou Z, Du Y. The effect of Scutellaria baicalensis stem-leaf flavonoids on spatial learning and memory in chronic cerebral ischemia-induced vascular dementia of rats. Acta Biochim Biophys Sin (Shanghai). 2016 May;48(5):437-46.
  2. Zhao S, Kong W, Zhang S, Chen M, Zheng X, Kong X. Pretreatment with scutellaria baicalensis stem-leaf total flavonoid prevents cerebral ischemia-reperfusion injury. Neural Regen Res. 2013 Dec 5;8(34):3183-92. doi: 10.3969/j.issn.1673-5374.2013.34.002.
  3. Zhang H, Liu QQ, Ding SK, Li H, Shang YZ. Flavonoids From Stems and Leaves of Scutellaria Baicalensis Georgi Improve Composited Aβ-Induced Alzheimer’s Disease Model Rats’ Memory and Neuroplasticity Disorders. Comb Chem High Throughput Screen. 2023;26(8):1519-1532. 
  4. Ma S, Xu CC, Dong YC, Li CX, Shang YZ. Scutellaria Baicalensis Georgi Stem and Leaf Flavonoids Ameliorate the Learning and Memory Impairment in Rats Induced by Okadaic Acid. Comb Chem High Throughput Screen. 2025;28(2):263-277
  5. Wang X, Xie Y, Bayoude A, Zhang B, Yu B. Discovering the Q-marker of scutellaria baicalensis against viral pneumonia integrated chemical profile identification, pharmacokinetic, metabolomics and network pharmacology. J Ethnopharmacol. 2025 Jan 31;340:119232.
  6. Rasmussen PL, ‘Antibiotics and their effects on Plants. www.herbblurb.com July 27, 2017.
  7. Wang X, Wu S, Guo N, Yu F, Xu X, Wang X, Yu X, Liu X, Dong H. Scutellaria baicalensis stem and leaf combat chicken-derived respiratory bacterial infection. Microb Pathog. 2025 May;202:107439. 
  8. Varmuzova K, Matulova ME, Gerzova L, Cejkova D, Gardan-Salmon D, Panhéleux M, Robert F, Sisak F, Havlickova H, Rychlik I. Curcuma and Scutellaria plant extracts protect chickens against inflammation and Salmonella Enteritidis infection. Poult Sci. 2015 Sep;94(9):2049-58.
  9. Rasmussen PL, ‘Honeysuckle and other useful weeds surrounding us. www.herbblurb.com January 24, 2019.
  10. Li S, Zhang K, Bai S, Wang J, Zeng Q, Peng H, Lv H, Mu Y, Xuan Y, Li S, Ding X. Extract of Scutellaria baicalensis and Lonicerae flos improves growth performance, antioxidant capacity, and intestinal barrier of yellow-feather broiler chickens against Clostridium perfringens. Poult Sci. 2024 Jul;103(7):103718.

PROMISING NEW FINDINGS FOR ROSEMARY

On By HerbBlurbIn Anti-inflammatory, antimicrobial, antioxidant, cancer, Herbal Medicine, Plant MedicineLeave a comment

The leaves and sprigs of Rosemary (Rosmarinus officinalis), have been widely used in food preparation and preservation and also for many medicinal purposes, almost as far back as human history began. As a popular plant that is easy to use and often readily accessible, its reputation as a meat preserver and an alleged hair restorer, are fairly well known in herbal folklore.

As with other long-esteemed herbaceous plants, rosemary’s diverse medicinal capabilities and their relevance to the needs of a modern-day world are being increasingly validated by modern research.  Rosemary is now known to have some powerful pharmacological actions, including antioxidant, hepatoprotective, anti-cancer, antimicrobial and potential antidepressant activities(1).

Further possible medicinal uses for this well-known plant have now emerged, following results from recent research.

Preservative actions have long been assigned to rosemary, and scientific evidence supporting an antimicrobial application is very encouraging(2,3). An ethanolic rosemary extract was recently reported to have promising antibacterial activity against different pathogenic bacteria, with particularly good activity against Klebsiella pneumoniae(4). The essential oil of rosemary also exhibits powerful bactericidal (bacteria killing) and anti-biofilm activity against Staphylococcus aureusand Staphylococcus epidermidis(5), common causes of infections such as UTI’s and those from medical devices such as catheters.

Another study by veterinarian researchers recently, found that rosemary essential oil improved the motility of sperm collected from roosters, during its storage at 4 degrees C. These benefits were particularly seen when low concentrations of 8.7 and 87 ug/ml of rosemary essential oil were used. This suggests potential uses in animal fertilisation, and in human fertility clinics and procedures(6). With declining rates of sperm counts and motility, anything that gives sperm a greater chance of successfully fertilising an egg, can only be a good thing. As such it is conceivable that humans (or prehumans) may become exposed to this remarkable herb even before conception itself in the future!

Rosemary also has a reputation for helping prevent cancer, and application of rosemary or its phenolic acid constituents carnosol and ursolic acid were first shown to inhibit skin cancer formation in 1994(7).  Such actions have since been extended to other forms of cancer cells, including most recently the growth of human colon adenocarcinoma(8), and three other gastrointestinal cancer cell lines(9).

Benefits on heart health are also associated traditionally with regular ingestion of this herb, and recent studies on rodents have provided some support for this.  Pre-treatment with an aqueous rosemary extract protected mice against cardiotoxicity and hepatotoxicity(10). Supplementation of the diet of rats with 0.02% rosemary for three months improved diastolic function, and reduced the degree of hypertrophy after a heart attack (myocardial infarction). These effects were associated with improved energy metabolism and decreased oxidative stress(11). Rosmarinic acid has also shown a cardioprotective effect against myocardial infarction and arrhythmia in rats(12).

Collectively, these recent studies support further investigations into the potential use of rosemary as adjuvant therapy with other cardiac drugs in those at risk of a heart attack, or to be taken immediately following such life-threatening cardiac events.

Finally, rosemary is also used in traditional medicine to alleviate rheumatic and abdominal pain. In a rat model of painful diabetic neuropathy, rosemary extract improved hyperglycemia, hyperalgesia and motor deficit(13). Triterpene constituents of an ethanolic extract also reduce abdominal pain in mice(14). These findings suggest rosemary may have analgesic and neuroprotective effects in painful diabetic neuropathy as well as abdominal pain in humans. Rosmarinic acid is likely to contribute to these effects, as other recent studies found it effective in a rat model of neuropathic pain(15-17). Analgesic properties have also previously been reported for rosemary essential oil (18).

Rosmarinic acid is a highly valued phenolic compound found not only in Rosemary, but also in many other well-known plants in the Lamiaceae and Boraginaceae families, such as Sage, Lemon balm, and Perilla (Perilla frutescens). Potentially beneficial pharmacological properties of this natural compound include anticancer, anti-angiogenic, anti-inflammatory, antioxidant, and antimicrobial activities(19,20). This has lead to increasing demands for it from the pharmaceutical industry. As a result, methods to chemically synthesise rosmarinic acid or produce it by biotechnological methods, are now being actively explored(19).

Beyond rosmarinic acid, however, the cumulative research into the diverse pharmacological actions of the reliable rosemary, show that other phenolic acids, triterpenoids, essential oil and other constituents, also seem to make powerful contributions to its many potential medicinal uses.

 

References:

  1. Andrade JM et al, Future Sci OA. 2018 Feb 1;4(4):FSO283.
  2. Ahn J et al, Food Microbiol. 2007 Feb;24(1):7-14
  3. Nieto G et al, Medicines (Basel).2018 Sep 4;5(3).
  4. Javed H 1stal, Pam J Pharm Sci 2018; 31(3):933-939.
  5. Jardak M et al, Lipids Health Dis. 2017 Oct 2;16(1):190.
  6. TouaziL et al, Vel World 2018; 11(5):590-597.
  7. Huang lT et al, Cancer Res.1994 Feb 1;54(3):701-8.
  8. Jaksevicius A, et al, Nutrients. 2017 Sep 21;9(10).
  9. Karimi N, Gastroenterol Hepatol Bed Bench. 2017 Spring;10(2):102-107.
  10. Hamed H et al, Appl Physiol Nutr Metab.2018 Apr 9. doi: 10.1139/apnm-2017-0786. [Epub ahead of print]
  11. Murino Rafacho BP, PLoS One. 2017 May 11;12(5):e0177521
  12. Javidanpour S et al, 2017 Dec;51(11-12):911-923.
  13. Rasoulian B et al, J Physiol Sci 2018; May 12 (epub ahead of print).
  14. Martinez AL et al, J Ethnopharmacol 2012; 142(1):28-34.
  15. Rahbardar GM et al, Biomed Pharmacother. 2017 Feb;86:441-449
  16. Rahbardar MGet al 2018 Feb 1;40:59-67
  17. Di Cesare Mannelli L et al,Sci Rep. 2016 Oct 7;6:34832.
  18. Raskovic A, et al, Eur Rev Med Pharmacol Sci. 2015 Jan;19(1):165-72.
  19. Swamy MK et al, Appl Micriobil Biotechnol 2018.
  20. Shekarchi M et al, Pharmacognosy Mag 2012; 8(29):37-41.

WITHANIA: A USEFUL ADJUNCT WITH ANTIPSYCHOTIC MEDICATIONS

On By HerbBlurbIn Anxiety, Herbal Medicine, insomnia, Plant Medicine, Stress, withania1 Comment

Antipsychotic drugs are strong medicines, and while they can successfully alleviate symptoms of psychosis and prevent relapse of schizophrenia and related conditions, like all drugs they are not without side effects.

There are two types of antipsychotics, older generation ones such as chlorpromazine or haloperidol developed in the 1960s, and so called ‘atypical’ antipsychotics such as olanzapine, clozapine and quetiapine developed in the 1990s, with a different side effect profile. While atypical newer generation antipsychotics are less likely than older generation ones to produce the extrapyramidal or Parkinson’s disease-like side effects, they can cause weight gain and precipitate or worsen metabolic syndrome or diabetes, and both types increase the risk of sudden cardiac death. Over-use and mis-use of antipsychotics is also of growing concern in the elderly(1).

Despite these risks, in a world in which the incidence and predominance of mental health conditions is rising, prescribing rates for antipsychotic drugs are increasing. Nearly seven million Americans take antipsychotic medications, and a recent study revealed a 49% rise in the use of anti-psychotic drugs by New Zealanders between 2008 and 2015. New Zealanders are now 60% more likely to be prescribed such drugs than Australians, with one in 36 New Zealand adults, or 2.81% of the population, being prescribed antipsychotic medication in 2015(2).

This recent New Zealand study also suggests that in a significant and probably increasing number of cases, these strong prescription-only drugs are being used to help with stress and associated sleep problems, rather than for their primary indication for conditions such as schizophrenia and bipolar disorders. Such ‘off label’ uses for prescription-only antipsychotics such as olanzapine, is something that has landed pharmaceutical companies in court in the U.S., in a number of prominent cases.

Herbal medicine offers an array of potential treatments for insomnia and stress-related conditions(3). One of the most suitable of these is Withania somnifera (Withania), known as Ashwagandha in India. The roots of Withania have a subtle but powerful nervous system and adrenal tonic action which insulates the nervous system from stress, enabling it to be better prepared to respond appropriately to the ‘fight or flight’ response. Many studies now support its applications for stress-associated anxiety conditions, including several human clinical trials(3).

Another possible application for Withania became apparent recently, through an American clinical trial where it was used as an adjunctive treatment alongside antipsychotic drug treatment in patients with schizophrenia(4). A total of 66 patients who had recently experienced an exacerbation of their schizophrenia symptoms, were given Withania or placebo alongside their usual antipsychotic drug medications, for a 12 week period. Outcomes were change from baseline to end of treatment on the “Positive and Negative Syndrome Scale” (PANSS), which measures total, positive, negative, and general symptoms of schizophrenia, and indices of stress and inflammation.

Patients given Withania were significantly more likely to achieve at least 20% improvements in PANSS negative, general, and total symptom scores, but not positive symptom scores, compared to those assigned to placebo. They also showed a significant improvement in stress scores compared to placebo. Additionally, only two of the Withania-treated subjects required an increase in their antipsychotic drug dosage, whereas nine of the placebo-assigned subjects either had their antipsychotic drug dosage increased or had a second antipsychotic drug added. These improvements were first noted at 4 weeks, and continued through the 12-week study period.

This is not the first time that Withania has been shown to be useful when taken alongside antipsychotic drugs. A one month clinical trial involving 30 schizophrenia patients with metabolic syndrome who had taken second generation antipsychotics for more than 6 months, found that adding Withania to their normal antipsychotic medication reduced serum triglycerides and fasting blood glucose, thus improving these metabolic syndrome symptoms(5).

Apart from Withania, clinical trials have shown appropriate doses of other high quality herbal medicines to benefit patients receiving antipsychotic drugs. Ginkgo was found to both increase the response rate to haloperidol when taken alongside it for 12 weeks(6), and to reduce the incidence of extrapyramidal side effects(7, 8). Similar effects have also been reported using Ginkgo alongside olanzapine(9).

Another U.S. study has shown American Ginseng (Panax quinquefolium) to have positive effects on memory function in individuals with schizophrenia, and to reduce the occurrence of extrapyramidal symptoms in patients on antipsychotic medications(10).

While underlying reasons for the high and increasing level of antipsychotic drug use in New Zealand and other countries should be further examined and addressed, clinical trials suggest that adjunctive herbal medicines such as Withania, Ginkgo and American ginseng, can play a role to help reduce some of the adverse events, and improve their response rates. Larger and longer term trials, are warranted.

References:
1. Bjerre LE; Canadian Fam Physician 2018; 64(1):17-27
2. Wilkinson S, Mulder RT. NZ Med J 2018 Aug 17; 131(1480):61-67.
3. Rasmussen PL, Feb 2017; Why Herbs should be the first choice of treatment for acute    anxiety. http://www.herbblurb.com
4. Chengappa KNR et al, J Clin Psychiatry 2018 Jul 10;79(5).
5. Agnihotri AP et al, Indian J Pharmacol 2013; Jul-Aug;45(4):417-8
6. Zhang XY et al, Psychopharmacology 2006; 188(1):12-17.
7. Zhang XY et al, J Clin Psychiatry 2001; 62(11):878-883.
8. Chen X et al, Psychiatry Res 2015; 228(1):121-127.
9. Atmaca M et al, Psychiatry Clin Neurosci 2005; 59(6):652- 656.
10. Chen EY et al, Phytother Res. 2012 Aug;26(8):1166-72

Herbs and Cancer

On By HerbBlurbIn Antibiotic Resistance, cancer, Environment, Herbal MedicineLeave a comment

A diagnosis of cancer is a highly stressful experience and increasingly, a common reason for people to consult a medical herbalist. With ongoing environmental exposures to carcinogenic agents, genetic predispositions and aging populations, this is likely to continue in coming decades.

Pharmaceutical company expenditure on research into new cancer drugs far outweighs that spent on developing new antibiotics or antidepressants, and advances in diagnosis, surgery, chemotherapy, radiotherapy and other cancer treatments, continue to be made. These can be expensive however, and waiting lists unacceptably long, in an increasingly stressed healthcare system. Also, conventional medicine is not always effective in the treatment of cancer and in many patients, its adverse effects and a relatively poor risk versus benefit rationale, are reasons for exploring herbal and other natural treatments.

Consequently, there is a huge amount of material on the subject available online, in magazines and books, including websites offering cancer cures through expensive clinic programmes, or ‘ready to take’ products that are heavily marketed. Soon after informing friends, colleagues and family, newly diagnosed patients tend to be inundated with suggestions and recommendations to take a wide range of ‘herbal remedies’, ‘dietary supplements’, ‘superfoods’ and other ‘alternative treatments’, several promising a cure, and strongly advocating against conventional treatments.  Care should be taken with all of these.

It’s fairly well known that a large percentage of chemotherapeutic drugs for cancer and leukaemia treatment are molecules identified and isolated from plants or their synthetic equivalents or close derivatives. Research on herbs has led to the development of anti-cancer drugs such as vincristine, vinblastine, paclitaxel, docetaxel, etoposide, teniposide and more.

These are however, strong and individual chemicals found in or derived from plants, they are not the plants themselves. It is inappropriate to extrapolate from the anticancer effects of large doses of these drugs (often given by injection rather than orally), and to claim that a plant extract from which chemotherapy drugs have been developed will also exhibit significant anticancer properties. Also, successful traditional uses of most of these plants for the treatment (as opposed to prevention) of cancer in humans is in fact poorly established. Finally, the likelihood of something that kills cancer cells in vitro (in laboratory cultures) doing the same thing when taken orally by human patients, is actually pretty low, just as the diabetes drug insulin is poorly absorbed when taken orally, and needs to be administered by injection.

Of more relevance from a scientific evidence-based perspective, are herbs and natural products that show useful outcomes (efficacy) when used in studies involving rats and mice (rodents). We now know that the mouse and human genomes are approximately 85% identical, meaning that if something works in mice, it has a reasonable chance of also working in humans. A 2005 Canadian study that found daily oral ingestion of Echinacea purpurea root from the age of 6 weeks until death from natural causes (‘old age’) reduced the incidence of spontaneous tumours and prolonged the life expectancy of mice, is therefore highly relevant(1, 2). This type of study should be given more prominence than claims that oral administration of Madagascar periwinkle (Catharanthus roseus, the source of the anti-cancer drugs vincristine and vinblastine), can help fight cancer.

The best contribution that most herbs make is in fact related to their preventive effects against human cancers, just as a diet rich in vegetables and low in or excluding red meat is now well established to do the same. Well-known herbs and spices such as ginger, garlic, turmeric, rosemary, nasturtium and watercress, are just some for which compelling evidence now exists as to their prophylactic properties. Incorporating these and many others into the diet or taking as a tonic on a regular basis, is likely to help reduce the likelihood of developing many different types of cancer.

When it comes to management of patients with a cancer diagnosis, one of the most promising contributions that herbs can make, is as adjunctive treatments to be taken alongside the anti-cancer drugs and other conventional interventions that modern medicine now has available. Evidence from a large number of animal studies and a growing number of human clinical trials, now strongly supports this approach, key outcomes being to help increase the chances of achieving remission, and/or reduce the likelihood of treatment-related adverse effects such as infertility and fatigue. Sadly, however, most of my cancer patients don’t come to see me until either after they have undergone chemotherapy, or where it is no longer an option, and a small number firmly opt against conventional treatment. This is perfectly their right and completely understandable, but may not have been their decision if they had been informed of the valuable contribution an individualised concurrent herbal treatment regimen can sometimes make.

It is in fact a reflection of the widespread lack of acknowledgement and appropriate regulation of highly trained medical herbalists, that most people’s view of virtually all herbs and herbal products, is that they are only things to be sourced from ‘over the counter’ (OTC) or internet outlets. This is a far cry from their view of drugs, where when suffering from most debilitating or serious conditions, the prescribing expertise of a medical practitioner or specialist such as an oncologist, is sought prior to embarking upon drug treatments.

While proactive selfcare should be actively encouraged as the best preventive approach to cancer and other illnesses. However, once cancer is diagnosed, while herbs are rarely a magic cure, seeking the best professional advice rather than relying on google apps or recommendations from those not trained in herbal medicine, is highly recommendable.

 

Refs:

 

  1. Brousseau M, Miller Enhancement of natural killer cells and increased survival of aging mice fed daily Echinacea root extract from youth. Biogerontology. 2005;6(3):157-63.

 

  1. Miller Echinacea: a miracle herb against aging and cancer? Evidence in vivo in mice.

Evid Based Complement Alternat Med. 2005 Sep;2(3):309-14.

 

 

Valerian –  favourable effects on cognitive function

On By HerbBlurbIn Anxiety, Dementia, Herbal Medicine, insomnia, StressLeave a comment

Valerian (Valeriana officinalis) root is well known for its applications in anxiety or insomnia, for which it has been used for thousands of years. Its anti-anxiety (anxiolytic) and sedative effects are mainly attributed to modulation and enhancement of the neurotransmitter GABA (gamma amino butyric acid), which prevents overstimulation of neurons implicated in anxiety and seizure disorders such as epilepsy. Behavioural studies in mice and clinical trials in humans are now expanding our understanding of this notable herb, and revealing other potential applications of relevance to modern day health gaps and needs.

One of these was a behavioural study in aged mice using a water maze performance test, reflective of spatial memory and the ability to cope with stress(1). Administration of valerian or valerenic acid improved the preferential exploration of new objects in a test of object recognition, and enhanced escape latency, swimming speeds, platform crossings, and a spatial preference for the target quadrant. These changes were accompanied by reduced blood levels of the stress-induced adrenal hormone corticosterone, and increased growth of nerve cell precursors (neuroblasts). The results suggest Valerian may help performance in stressful situations and moderate some of the less desirable neurological and physiological changes associated with becoming elderly, such as reduced cognitive function and confidence. This suggests adaptogenic (improved stress-coping ability) and possible nootropic (cognitive enhancing) properties for Valerian.

Other studies reporting anticholinesterase (cholinergic enhancement) activity, thought to be a mechanism of anti-dementia effects, and nerve growth stimulation by various Valerian iridoid and sesquiterpenoid constituents, further support such actions(2, 3).

Potential benefits of Valerian on cognitive function in patients undergoing certain forms of surgery, have also been revealed in a recent clinical trial(4).  Surgery is a stressful event, particularly so for patients with cardiovascular disease undergoing coronary artery bypass surgery. The trial involved 61 patients aged 30-70 years who underwent elective coronary artery bypass graft surgery using cardiopulmonary bypass. Patients received either one valerian capsule containing 530 mg valerian root extract (1,060 mg/daily), or a placebo capsule twice daily for 8 weeks. Cognitive brain function was evaluated prior to surgery then at 10 days and 2 months post surgery, using a test known as “Mini Mental State Examination (MMSE)”.

Following Valerian treatment, the mean MMSE score dropped from 27.03 in the preoperative period to 26.52 at the 10th day, then increased to 27.45 at the 60th day. This return to a normal MMSE was greater than that measured in the placebo group, in which the mean MMSE score fell from 27.37 at  baseline to 24 at day 10, and increased only slightly to 24.83 on the 60th day. This clinical trial provides evidence that Valerian may prevent early postoperative cognitive dysfunction after coronary artery bypass surgery. Given the high burden on the healthcare system and patients of such surgical procedures, further investigations using adjunctive Valerian in this and other forms of surgery, are warranted.

While unlike most sedative drugs Valerian shows little signs of impeding performance or producing an unwanted hangover effect the next day, until recently no study has specifically investigated these potential adverse effects.  Outcomes from a placebo-controlled clinical trial by Californian researchers in which participants received a dose of either 1600mg valerian or placebo then underwent a driving simulator, field sobriety and other tests of visual reactions and performance, are therefore of interest(5). No significant differences were recorded between groups in the simple visual reaction test or sleepiness scales, standardised field sobriety test total and individual test failure rates. This suggests a single dose of 1600mg valerian is unlikely to impair driving performance, in the way that alcohol or sedative drugs are known to do.

Finally, it is noted that Valerian’s reputation as a useful medicine in humans has attracted the attention of U.S. biotechnology researchers recently, who in a quest for new anti-anxiety agents have genetically engineered a strain of the E coli bacteria, to produce substantial quantities of the valerenic acid precursor valerenadiene(6, 7).

 

Refs:

  1. Nam SM et al, Exp Gerontol. 2013;48(11):1369-77
  2. Chen HW et al, 2016;110:142-9.
  3. Dong FW et al, Phytochemistry 2015; 118: 51-60.2015
  4. Hassani S et al, Psychopharmacology (Berl). 2015;232:843-50
  5. Thomas K, Accid Anal Prev 2016; 92:240-244.
  6. Nybo SE et al, J Biotechnol. 2017 Nov 20;262:60-66. doi: 10.1016/j.jbiotec.2017.10.004. Epub 2017 Oct 5.
  7. Ricigliano V et al, Phytochemistry 2016; 125:43-53.

Medicinal Uses of Nasturtium

On By HerbBlurbIn Herbal Medicine, Immunity, Plant Medicine, UncategorizedLeave a comment

With spring upon us, the New Zealand countryside and our gardens are rich with budding and flowering plants, many of them normally regarded as weeds, but in fact highly medicinal.

One of these is Nasturtium (Tropaelum majus; Indian cress), a plant with water lily like circular leaves and bright yellow, orange and red flowers which is native to South America but established in many warmer areas of New Zealand and Australia. While it can certainly be very weedy in some situations, it also makes a useful plant on the edges of the vegetable garden to attract bees and other beneficial insects. It can also act as a decoy by attracting cabbage white butterflies and drawing these pests away from brassicas.

What many people don’t realise, however, is that all parts of Nasturtium are edible, with its leaves and flowers making a decorative, peppery addition to salads, and the fruits when pickled with vinegar serving as a tasty alternative to capers. It also has outstanding antioxidant activity due to its rich content of phenolic compounds, including anthocyanin and vitamin C. Like many ‘weeds’ readily available in the New Zealand environment, Nasturtium is also a highly medicinal plant.

Traditionally it was used to help ward off and treat various infections, particularly those affecting the lungs and the urinary tract. The pungent compounds known as isothiocyanates found in all parts of nasturtium and roots of horseradish (Armoracia rusticana), have powerful and fairly broad spectrum antibacterial activities particularly against Haemophilus influenza and Moraxella catarrhalis, a common cause of middle ear infection (otitis media) and sinusitus in children(1). These isothiocyanates have also recently been reported to have good activity against both developing and mature biofilms of Pseudomonas aeruginosa, a bacterial pathogen associated with many serious human illnesses(2). Importantly also, they have also been shown to be well absorbed into the bloodstream following oral ingestion of nasturtium in humans(3).

Nasturtium was used in folk medicine as a remedy against scurvy, and can be used as a natural, warming remedy to help the body overcome and prevent the common cold and influenza. It was also used traditionally to treat muscular pain, and it’s antimicrobial properties extend to its use as a topical treatment for bacterial infections and minor scrapes and cuts.

Possible applications in the prevention or treatment of various cancers are also likely, due to conversion of a key constituent glucotropaeolin to benzyl isothiocyanate, within the body. This compound, formed also from isothiocyanates found in brassica (cruciferous) vegetables, exhibits anticancer activity against cultured lung, breast, liver, prostate, brain, melanoma, oral & ovarian cancer cells in vitro, and prevents chemically induced carcinogenesis in rodents(4-10).

Potential benefits in fluid retention, hypertension and other cardiovascular conditions, have been suggested by Brazilian research showing diuretic, hypotensive and lipid-lowering activities for a hydroethanolic extract in rats(11-13). Angiotensin converting enzyme (ACE) inhibition was implicated as a possible mechanism for these effects, in a similar manner to how ACE inhibitor drugs work to help manage hypertension and other cardiovascular conditions(14). Unlike many other conventional diuretic drugs, however, no unwanted effects on urinary calcium or potassium excretion seem to occur, suggesting valuable potassium and calcium-sparing properties. These findings indicate possible applications also to help prevent osteoporosis, which is supported by another Brazilian study in menopausal rats(13).

Nasturtium may also be useful to help prevent or manage obesity, according to findings from a Korean study published in the June 2017 issue of the journal Food and Nutrition Research(15). The study investigated the effects of a nasturtium ethanolic extract on a mouse cell line with adipocyte-like characteristics, used in research on adipose (fat) tissue. Treatment of cells with nasturtium extract produced a concentration-dependent reduction in lipid accumulation, and inhibited the expression of various proteins associated with differentiation of fat cells. This suggests potential usefulness also, in the prevention and treatment of obesity.

With these compelling research findings, incorporation of nasturtium into the diet or herbal treatments of a range of human conditions common in the 21st century, should overtake our view of it simply as a bothersome weed.

References:

  1. Conrad A et al, Drug Res (Stuttg). 2013 Feb;63(2):65-8.
  2. Kaiser SJ et al, 2017 Jun;119:57-63.
  3. PPlatz S et al, Mol Nutr Food Res. 2016 Mar;60(3):652-60..See comment in PubMed Commons below
  4. Wattenberg LW. J Natl Cancer 1977 Feb;58(2):395-8.
  5. Hecht SS et al. J Nutr. 1999 Mar;129(3):768S-774S.
  6. Cho HJ et al, Int J Mol Sci 2016 Feb 22; 17(2):264
  7. Shang HS et al, Environ Toxicol 2016 Dec; 31(12):1751-1760.
  8. Yeh YT et al. Food Chem Toxicol. 2016 Nov;97:336-345.
  9. Zhu M et al J Cancer. 2017 Jan 15;8(2):240-248.
  10. Lai KC et al, Int J Oncol. 2017 Sep;51(3):832-840.
  11. Gasparotto Junior A et al. J Ethnopharmacol. 2009 Apr 21;122(3):517-22.
  12. Gasparotto Junior A et al. J Ethnopharmacol. 2011 Mar 24;134(2):210-5.
  13. Barboza LN et al, Evid Based Complement Alternat Med 2014; 2014:958291.
  14. Gasparotto Junior A et al J Ethnopharmacol. 2011 Mar 24;134(2):363-72. (2011a)
  15. Kim GC et al,.Food Nutr Res. 2017 Jun 14;61(1):1339555.

 

Antibiotics and their effects on Plants

On By HerbBlurbIn Antibiotic Resistance, Antimicrobial chemicals, Environment, Herbal Medicine, PesticidesLeave a comment

Soil bacteria and fungi are a rich source of natural antibiotics, but the prevalence of human-made antibiotics and antibiotic resistance genes in soils, is an emerging concern. Antibiotics are widely used to promote livestock growth in modern non-organic agriculture, with poultry, cattle and pigs, being regularly treated with these antibacterial drugs. Millions of kilograms of antibiotics are released into the environment annually, much in the excrement of grazing animals, or through application of manure to agricultural fields(1). Discharge of human waste into waterways and the use of contaminated irrigation water or sewerage sludge to fertilise crops in many countries, is also a contributory cause. As a result, a higher level of antibiotic resistance is now apparent in conventional agricultural versus natural forest soils(2).

Soil and water-containing antibiotics constitute a potential route of human exposure to antibiotic resistance genes through their uptake by plants(3-8).  Uptake by plants can also have other effects, such as the accumulation of nitrofuran-type antibiotics in the edible parts of spring onions, and the subsequent metabolism of these into genotoxic and potentially carcinogenic hydrazine-containing metabolites(9).

The other consideration is the effects these human-made antibiotics have on the soil or plants themselves.  With human and animal health being intrinsically connected to that of plants and soil, and increasing research showing the many symbiotic and complex relationships between living organisms and their environment, effects of human-made antibiotics on plant health, should also be considered.

The high level of contamination with antibiotic residues and transferable resistance genes in pig manure applied to soil, has been shown to change the antibiotic resistant gene reservoir of the plant microbiome(10).  Carrots and lettuce can uptake amoxicillin and tetracycline(4), and tetracycline residues have toxic effects on both root and stems of germinating lettuce seedlings(11).  Oxytetracycline residues from cattle manure have also been shown to affect the diversity and type of nitrogen-fixing soil bacteria communities(12).

A recent European study has shown that even small amounts of antibiotics can have a range of potentially negative effects on plant traits(13). The comprehensive study examined the effects of three antibiotics (penicillin, tetracycline and sulfadiazine), on germination and growth of four plant species. These included two cultivated species (rapeseed, Brassica napus and common wheat, Tricicum aestivum), and two non-crop (herb) species (Shepherd’s purse, Capsella bursa-pastoria and Common Windgrass, Apera spicaventi). In farmland fertilised with manure containing antibiotic concentrations as typically found in agricultural soils, various effects on the plants were observed.

Main effects were delayed germination or reduced plant biomass. These effects varied markedly depending on the plant species concerned, but were most pronounced in the two herb species, particularly by penicillin and sulfadiazine. This suggests that different antibiotics could potentially affect the prevalence and types of species, and the diversity of natural plant communities near agricultural fields. Furthermore, these species-specific responses may not only alter the competitive abilities and makeup of the plant community, but also have secondary effects on other species such as pollinating and herbivorous insects(13).

Petrochemical residues and the use of non-organic agricultural pesticides and insecticides, are also starting to come under the spotlight as likely contributors to multi-drug antibiotic resistance among soil bacteria. A recent Chinese study has demonstrated that petrochemical residue -polluted soils were more than 15 times more likely than less-contaminated ones, to contain antibiotic resistance genes. This strong association of soil pollution with polycyclic aromatic hydrocarbons, suggests these may also be contributing to the growing amounts of antibiotic resistant genes in human-impacted environments(14).

In non-organic agriculture, soil bacteria can be continuously exposed to synthetic pesticides at sub-lethal concentrations, and a recent Indian study has found that insecticide-contaminated soil may have contributed to development of resistance to a range of different antibiotics, by several Bacillus species(15).

Silver nanoparticles are also now widely used in antibacterial products, and these inevitably discharge into aquatic environments and have been shown to affect the nitrogen cycle in phytoplankton and aquatic plant life(16).

Antimicrobial chemicals such as triclosan and triclocarban, which are used in some liquid soaps and toothpastes, can take a long time to break down in the environment and have been shown to have detrimental effects on aquatic organisms, and potentially contribute to antimicrobial resistance(17-19).

Soil and plant health are pivotal to the health of the planet and all its living organisms, and antibiotic drugs have saved many millions of lives. However, the widespread use of antibiotics in non-organic agricultural production systems particularly those involving animals, should be curtailed.

Refs:

  1. Popova IE et al, J Environ Sci Health B 2017; 52(5):298-305.
  2. Popowska M et al, Antimicrob Agents Chemother 2012; 56(3):1434-1443.
  3. Grote M. et al, Landbauforschung Volkenrode 2007; 57: 25-32.
  4. Azanu D et al, Chemosphere 2016; 157:107-114.
  5. Rahube TO et al, Can J Microbiol 2016; 62(7):600-7.
  6. Pan M et al, J Agric Food Chem 2014; 62:11062-11069.
  7. Kang DH et al, J AGric Food Chem 2013; 61:9992-10001.
  8. Kumar K et al, J Environment Qual 2005; 32:2082-2085.
  9. Wang Y et al, J Agric Food Chem 2017; 65(21):4255-4261.
  10. Wolters B et al, Appl Microbiol Biotechnol 2016; 100(21):9343-9353.
  11. Pino MR et al, Environ Sci Pollut Res Int 2016; 23(22):22530-22541.
  12. Sun J et al, Bioresour Technol 2016; 801-807, epub May 21.
  13. Minden V et al, AoB Plants 2017; 9(2):plx020.
  14. Chen B et al, Environ Pollut 2017; 220(Pt B):1005-1013.
  15. Rangasamy K et al, Microb Pathog 2017; 103:153-165.
  16. Jiang HS et al, Environ Pollut 2017; 223:395-402.
  17. Falisse E et al, Aquat Toxicol 2017; 189:97-107.
  18. McNamara PJ, Levy SB. Antimicrob Agents Chemother 2016; 60(12):7015-7016.
  19. Tremblay Louis, Environmental toxicologist, Cawthron Institute, Nelson, New Zealand Herald, 23 June 2017.

Mānuka and Myrtle Rust

On By HerbBlurbIn Antifungal, Biosecurity, Environment, Herbal Medicine, Manuka, Myrtle Rust, Organic Medicine, Pathogen, Plant MedicineLeave a comment

Last week I attended a two day workshop organised by scientists at Plant and Food Research Ltd and Massey University in Palmerston North, to discuss a range of recent scientific and biosecurity developments, concerning Mānuka (Leptospermum scoparium), an important plant in New Zealand’s natural environment and economy. As with the two day Hui on ‘Mānuka and More’ in Ruatoria and Te Araroa in November last year, this was an excellent event in which more than 30 scientists working actively on Mānuka research presented on a diverse range of subjects and discussed where there could be gaps in our knowledge or research needs for this plant. While Mānuka Honey and essential oil are currently the main two medicinal products produced from Mānuka, numerous other therapeutic applications and potential contributions to preserving our environment, are found within this plant.

Jacqui Horswell and colleagues from the Institute of Environmental Science and Research, have shown that Mānuka and other myrtaceaeous plants seem to be capable of killing the faecal bacterial pathogen Enterobacter coli (E. coli), by enhancing the die-off of this and other pathogenic organisms that pass through their root systems. A field trial involving riparian planting of Mānuka is just getting going, to see whether laboratory results extend to helping to reduce animal effluent flows into a polluted lake. A lake which was once pristine and a treasured swimming area, but in recent years has changed into a green and dirty waterway due largely to dairy industry runoff, has been selected for this trial.

Hayley Ridgway from Lincoln University presented some interesting findings concerning novel and potentially useful mycorrhizae (fungi) and endophytic bacteria associated with the roots of Mānuka, some of which I wrote about in my previous blog. Inoculation of Mānuka plants with different mycorrhizae causes significant alterations in their growth rates and essential oil composition, highlighting the complex inter-relationships between microbes associated with Mānuka, and its production of phytochemicals including some with bioactive properties.

Other presentations were made on experiences to date involving plantations of Mānuka which have been established at a number of North Island sites in recent years. Challenges include site access, weeds, pests, and the relative attractiveness of different genetic lines to bees. A comment made by one of the presenters that while humans have had multiple generations of experience with cultivation and enhancing performance characteristics of crops such as wheat and rice, our experience with Mānuka plantations spans less than 10-15 years to date.

The hottest topic at the workshop, however, was the recent finding of isolated outbreaks of Myrtle Rust (Austropuccinia psidii) in New Zealand nursery and garden grown specimens of Mānuka and the native tree, Ramarama (Lophomyrtus bullata). This pathogenic fungi originated from Brazil where it causes guava rust, but spread internationally into North America in the 1880’s, and was first reported in Australia in 2010.  Australia is home to around half of the world’s Myrtaceae (Myrtle family) plant species, including Eucalyptus (850 species), Melaleuca (176 species) and Callistemon species.

Outbreak of Myrtle rust has had a devastating effect on much of the east coast as well as other areas of Australia, where it has resulted in ecosystem collapse for certain plant species. To date it has only been found in isolated locations in Northland, Waikato, Bay of Plenty and Taranaki, although it is widespread on Raoul Island in the Kermadec group, about 1,100km to the north-east of New Zealand.

Myrtle rust spores can easily spread across large distances by wind, or via insects, birds, people, or machinery, and it is thought the fungus arrived in New Zealand carried by strong winds and significant weather events from Australia.

The Myrtle Rust Strategic Science Advisory Group is working hard to assess and try to ameliorate the widespread environmental, economic, social and cultural impacts this plant pathogen could have on New Zealand. Apart from Mānuka and Ramarama, other indigenous Myrtaceae species such as Pohutakawa (Metrosideros spp) and Swamp Maire (Syzygium maire), are under risk. Priorities including acceleration of scientific research into the biology of the pandemic strain detected here, pathways of spread, surveillance, management, exploring plant susceptibility and resistance, and coordinating and communicating a management plan that has widespread engagement by communities, scientists, industry and Maori stakeholders and landowners, councils and government.

The Ministry for Primary Industries (MPI) and the Department of Conservation (DOC), with the help of local iwi, the nursery industry, and local authorities are running an operation to determine the scale of the situation and to try and contain and control myrtle rust in the areas it has been found. However, emergence of the infection and appearance of the distinctive yellow or brown leaf discolouration may not become fully apparent until the spring, and a better assessment of the number of infection sites and their extent, may not be possible until then.

The arrival of Myrtle Rust in New Zealand means that the task of collecting and storing seed of New Zealand indigenous Myrtaceae including Mānuka, has now become urgent. The NZ Indigenous Flora Seed Bank (NZIFSB), a collaborative project between Massey University, AgResearch, Landcare and the Department of Conservation, with support from the NZ Plant Conservation Network and the Millennium Seedbank at Kew in the UK, was established in 2013. NZFISB has been doing some really valuable work to collect and store seeds aimed at preserving a wide range of biodiversity within New Zealand native plant species. More than 130 volunteer seed collectors have been trained to date, and plans are underway to extend this and the level of community participation, to try to better protect our native plants for generations to come.

Refs:

http://www.nzpcn.org.nz/page.aspx?conservation_seedbank

http://www.mpi.govt.nz/protection-and-response/responding/alerts/myrtle-rust/

Antimicrobial Endophytes in Echinacea, Olive and Manuka

On By HerbBlurbIn Antibiotic Resistance, Antifungal, Dermal Health, Herbal Medicine, Immunity, Organic Medicine, Plant Medicine1 Comment

While plants are being extensively explored for new therapeutic properties and pharmacological activities, the communities of live fungi and bacteria known as endophytes that live between living plant cells, are also now being regarded as having many useful potential medicinal applications. Ironically, in recent years it is these microorganisms associated with plants rather than plants themselves, which seem to be receive much research interest.

Endophytes are microorganisms that live within a plant for at least part of their life cycles, without causing apparent disease or infections in the plant. Different endophytes seem to have affinities for particular plants, with which they have distinctive and cherished but complex interactions while each of them grows. They are for instance known to sometimes enhance host growth and nutrient gain, improve the plant’s ability to tolerate various types of stressors, and enhance the its resistance to insects and pests. The rrelationships that these bacteria and fungal communities have with their host plant varies from symbiotic to parasitic, to bordering on pathogenic.
Some very unusual and valuable bioactive substances are sometimes produced by these endophytes, such as alkaloids, phenolic acids, quinones, steroids, saponins, tannins, and terpenoids, and these are increasingly being recognized as sources of novel compounds which may help to maintain or solve not only the plant’s health challenges, but can also have applications in human and animal health problems.
Over the past few decades, some highly medicinal compounds produced by endophytic microbes lead to novel drug development. These include Taxol (paclitaxol), a complex diterpene alkaloid produced by the endophyte Metarhizium anisopliae found in the bark of the Pacific Yew (Taxus brevifolia) tree, and one of the most promising anticancer agents ever developed. Also streptomycin, an antibiotic produced from the bacterial endophyte Streptomyces.

Other endophytes possess antibacterial activities which may be useful in treating various infections, and in a world where antibiotic resistance is becoming a major public health threat, these are obviously of great interest. Exploring and bioprospecting these for potential antimicrobial compounds may well yield valuable new natural products or drugs to help in the fight against resistant organisms(1,2,3,4).

It now seems that bacterial communities colonizing Echinacea purpurea contribute to its well-known immune enhancing activity(5). American researchers have reported that Echinacea’s stimulating activity on monocytes (a type of white blood cell involved in engulfing and destroying harmful microbes), could be solely if not partially accounted for by the activities and prevalence of Proteobacteria, a family of bacteria found in the bacterial community associated with this medicinal plant.
A screen of 151 different endophytic bacteria isolated from three different compartments of Echinacea purpurea, revealed that several bacteria isolated from the roots are strong inhibitors of Burkholderia cepacia complex bacteria, a serious threat particularly in immune-compromised cystic fibrosis patients(6). One of these bacterial strains also showed antimicrobial effects against Acinetobacter baumannii, a pathogenic bacteria mainly associated with hospital-acquired infections, and Klebsiella pneumoniae, also increasingly incriminated in hospital infections(7). Interestingly, the type of bacteria and their antimicrobial effects varied considerably, according to which part of the plant (root, stem, leaves etc) they were associated with. This has resemblances to different plant parts of Echinacea having different phytochemical and thus pharmacological activities, such as Echinacea roots being richest in alkylamides and thus anti-inflammatory activities.

Endophytic fungi including Penicillium commune and Penicillium canescens (related to the Penicillium notatum mould from which the first antibiotic penicillin originated), have also been isolated from the leaves of olive (Olea europaea) trees, and several of these have also shown antibacterial as well as antifungal activities in recent work(8).

Finally, a rich endophyte community has recently been identified by Lincoln University researchers for the New Zealand native plant Manuka (Leptospermum scoparium). A total of 192 culturable bacteria were recovered from leaves, stems and roots, including some showing activity against the bacterial pathogen, Pseudomonas syringae pv. actinidiae(9), otherwise known by Kiwifruit growers as Psa. With Psa being a serious risk to the health of the Kiwifruit vine, it could be that these endophytic bacteria found within Manuka will make a useful contribution to ensuring the future health of the Kiwifruit industry.
While very few of all of the world’s plants have had their complete complement of endophytes studied, these are just three well established medicinal plants from which some highly active cohabitating bacteria and fungi have been sourced. Undoubtedly this area of research will receive much more attention due to growing concerns about antibiotic resistance, as there would seem to be a huge opportunity to find new and interesting endophytes among the wealth of different plants growing not only in soil, but also in waterways and oceans.
Refs:
1. Alvin A et al, Microbiol Res 2014; 169(7-8)L483-495.
2. Martinez-Klimova E et al, Biochem Pharmacol 2016; Oct 27.
3. Kealey C et al, Biotechnol Lett 2017; Mar 8 (epub ahead of print)
4. Tanwar A et al, Microbiol Path 2016;101:76-82
5. Haron MH et al, Planta Med 2016; 82(14):1258-1265.
6. Chiellini C et al, Microbiol Res 2017; 196:34-43.
7. Presta L et al, Res Microbiol 2017; 168(3):293-305.
8. Malhadas C et al, World J Microbiol Biotechnol 2017; 33(3):46.
9. Wicaksono WA et al, PLoS One 2016; 11(9):e0163717.