Category: Plant Medicine

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 supportfurther 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 Lamiaceaeand Boraginaceaefamilies, 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 Get 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. HuangMT 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 Set 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

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.

 

Manuka 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 Manuka (Leptospermum scoparium), an important plant in New Zealand’s natural environment and economy. As with the two day Hui on ‘Manuka 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 Manuka 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 Manuka Honey and essential oil are currently the main two medicinal products produced from Manuka, 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 Manuka 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 Manuka 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 Manuka, some of which I wrote about in my previous blog. Inoculation of Manuka plants with different mycorrhizae causes significant alterations in their growth rates and essential oil composition, highlighting the complex inter-relationships between microbes associated with Manuka, and its production of phytochemicals including some with bioactive properties.

Other presentations were made on experiences to date involving plantations of Manuka 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 Manuka 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 Manuka 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 Manuka 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 Manuka, 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 MedicineLeave a 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.