Ligustrum lucidum – noxious weed or useful osteoporosis treatment?

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It’s a Saturday in early February in NZ, and the warm summer days linger on. Trying to retain some of the holiday vibe, we pack a picnic and togs and head out with some friends to Cornwallis Beach, on Auckland’s west coast.

On the way, as we drive up through Glen Eden and Titirangi, I find it difficult not to comment on the frequent appearance of Glossy Privet (Ligustrum lucidum) trees, on road and garden verges including an alarming number of indentations into adjacent native bush. Prominent this time of year with their creamy-yellow flower clusters amidst a dark green foliage background, they remind me of the Elder trees whose flowers used to similarly draw my attention every summer when I lived in the UK.

Unlike Elder in the UK, however, Glossy Privet is not native to New Zealand, and just like hundreds of other clever plant species, has become so well colonised here it is classed as a ‘noxious’ plant. It is, in fact, according to the NZ Plant Conservation Network(1), New Zealand’s most invasive introduced tree, as the dark purple brown berries make a tasty treat for our large bird population who then excrete the seeds far and wide. Not only around Auckland, but on a drive back from Gisborne to Auckland in January, I again couldn’t help but notice the large number of these trees in numerous locations throughout the 500km journey.

While my frequent comments concerning this tree to family or other fellow passengers over the past couple of years may seem obsessive, my fascination with it stems from the fact that it is also highly medicinal. In its native China, the small fruits of Glossy Privet (Nu-Zhen-Zi) are commonly used to strengthen bones, and it is an ingredient of many herbal formulae for the treatment of osteoporosis.  Osteoporosis is a condition characterised by low bone mass and micro-architectural deterioration of bone tissues leading to increased bone fragility. It is the leading cause of bone fractures in older adults, and is increasing in prevalence in both women and men, as populations age(2).

Several scientific papers have appeared in recent years supporting Glossy Privet’s beneficial effects in osteoporosis. These include increased circulation levels of vitamin D (1,25-dihydroxyvitamin D3) and improved calcium balance in mature female rats(3,4). Higher bone mineral density and positive effects on bone microstructure, have also been reported following its administration to young male and female growing rats(5-7). As optimising peak bone mass during early life is a key preventive action against osteoporosis, these findings collectively suggest that regular intake of Glossy Privet may well have a preventive effect against this debilitating condition in humans.

In Asian traditional medicine Glossy Privet is also used to treat menopausal problems, blurred vision, tinnitus, rheumatic pains, palpitations, backache and insomnia(8). Other traditional applications supported by recent scientific studies include protection against liver toxins(9, 10), and inhibition of the Hepatitis C (HCV) virus(11).

In China, as with other medicinal herbs, Glossy Privet fruits are sometimes used as an adjunct in cancer therapy (12). Researchers have reported enhanced sensitivity of human colorectal carcinoma cells to the chemotherapy drug doxorubicin(13). Inhibition of the mutagenic activities of benzo(a)pyrene(14) and aflatoxin B1(12) suggest cancer chemopreventive properties, and laboratory studies implicate potential applications in the treatment of human hepatocellular(15) and brain(16) cancer. Animal studies also suggest a possible therapeutic role in diabetes, including protective effects against diabetes-related reproductive deficits(9, 17, 18), and high fat diet-induced obesity(19).

There is clearly potential merit in further evaluating potential therapeutic applications of the fruits of this tree, now found throughout New Zealand and endemic in many other countries. Research to date strongly suggests a significant opportunity for medical herbalists and other clinicians, researchers, health funding providers and conservation agencies, to collaborate to further investigate such medicinal applications. Harvesting its berries and processing these into a prophylactic as well as treatment for osteoporosis alone, would reduce its spread and help protect New Zealand’s precious environment with less use of chemical control measures. This would at the same time also help to reduce Pharmac’s spending on biphosphonates and other osteoporosis treatments, thus potentially enabling more funding towards expensive new generation cancer drugs.

Refs:

  1. New Zealand Plant Conservation Network, www.nzpcn.org.nz
  2. Cawthon PM et al, Ther Adv Musculoskelet Dis 2016; 8(1):15-27
  3. Zhang YZ et al, J Econ Entomol. 2008;101(4):1146-51.
  4. Dong Xl et al, Menopause. 2010;17(6):1174-81.
  5. Feng X et al, Calcif Tissue Int. 2014; 94(4):433-41.
  6. Lyu Y et al, J Bone Miner Metab 2014; 32(6):616-626.
  7. Rasmussen PL, Phytonews 40, ISSN 1175-0251, Phytomed Medicinal Herbs Ltd, November 2014.
  8. Gao L et al, Nat Prod Res 2015; 29(6):493-510.
  9. Yim TK et al, Phytother Res 2001; 15(7):589-592.
  10. Gao D et al, Phytother Res 2009; 23(9):1257-1262.
  11. Kong L et al, Antiviral Res 2013; 98(1):44-53.
  12. Wong BY et al, Mutat Res 1992; 279(3):209-216.
  13. Zhang JF et al, Integr Cancer Ther 2011; 10(1):85-91.
  14. Niikawa M et al, Mutat Res 1993; 319(1):1-9.
  15. Hu B et al, Oncol Rep 2014; 32(3):1037-1042.
  16. Jeong JC et al, Phytother Res 2011; 25(3):429-434.
  17. Feng SL et al, Asian J Androl 2001; 3(1):71-73
  18. Zhang Y et al, J Ethnopharmacol 2014; 158, PtA:239-245.
  19. Liu Q et al, Nat Prod Commun 2014; 9(10):1399-1401
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Herbal Medicine Past and Future

Herbal medicine or the use of plants as medicines, is the oldest form of medicine in the world. If the history of all human medicine was condensed into a relative 1 year timeframe, use of drugs (individual chemical entities) as primary medicine for health ailments has only been around for the past 2 minutes, herbs for the past 364 days and 58 minutes.

P1060966Known as Phytotherapy in Europe (‘phyto’ being the latin word for plant), and Botanical medicine in North America, the use of aerial parts, leaves, flowers, seeds, roots and barks of small (‘herbaceous’) plants, trees or mushrooms (fungi) to alleviate and prevent health complaints in humans and animals, is still the most often used medicine globally. Plants produce a large number of diverse chemicals (phytochemicals) to enable them to survive in their particular environment, just as human physiology has evolved to develop a wide range of biochemical compounds to help us cope with the many challenges of daily life. These phytochemicals help the plant cope with the stresses of drought, pest infestation, predator attack, nutritional deficits and much more. It is therefore not surprising that when taken in a balanced or whole plant part form by humans, they can help enhance our resistance to a range of illnesses.

Use of food as medicine is a growing trend in modern societies, and with the proliferation of so called ‘functional foods’ and ‘dietary supplements’ including capsules or tablets containing well known foods such as beetroot, garlic and turmeric, whether a particular product is in fact a food or a medicine or both, is often a challenge for consumers and regulators.

These hazy boundaries between foods and herbal medicines, reinforce the fact that not only is herbal medicine the most natural, accessible, safest and most easily assimilated form of medicine available, but also that as with a healthy plant-rich diet, it has a huge illness preventive potential. Preventative actions against a wide range of serious and increasingly common medical conditions have been shown from a growing body of research published in peer-reviewed scientific journals. Not only can a healthier diet have a major impact on health outcomes and the cost of modern day healthcare, but so too can prophylactic herbal medicine.

This simple fact, is something that should be properly digested by doctors, pharmacists and other healthcare professionals, as well as insurers, health policy analysts and politicians. The pharmaco-economics of a largely drug and hospital care-based health service is becoming increasingly expensive and unaffordable, and government efforts to encourage more ‘self-care’ by its population, should be cautiously congratulated. It is, however, a shame that due to a lack of recognition of the now compelling case for herbal medicine’s usefulness for a wide variety of common conditions, drugs continue to be used as a ‘first line’ therapy by much of the population, with resulting outcomes that are sometimes less than optimal. Limitations exist with many drug-focussed treatments in psychiatry, autoimmune diseases and cancer, and the increasing proliferation of ‘superbugs’ for which antibiotics and antiviral drugs are ineffective, is cause for alarm.

Apart from favourable clinical trial results, growing concerns about drug adverse effects and costs, aging populations and more emphasis on wellness and disease preventive approaches, have seen herbal medicine’s popularity grow substantially in recent years. As a country, New Zealand is extremely well positioned to take advantage of this global trend, and has an ability to grow, process, and manufacture, a wide range of herbal medicines. Our unique combination of geographical, soil and climatic attributes enables us to grow plants that are premium quality, something the world outside of New Zealand is increasingly appreciative of.  This combined with our agriscientific know how, health research capabilities and innovative food & beverage industry sectors, provides the potential to apply our greatest asset (that we are an ideal country to grow things in), to producing herbal medicines that are among the best quality in the world. This would make a valuable and cost-effective contribution to the health of our population, and that of other countries through development of a sizeable export industry.

Echinacea FieldHorticulture has much more long term potential to provide a sustainable and profitable return on agricultural investment than the dairy industry, and it is encouraging to see that fruit exports increased by 20% to reach $2 billion in the year ending June 2015 (www.stats.govt.nz). The fact that organically grown and processed products better care for the health of agricultural workers and our precious soil and environment, have optimal beneficial effects on end users, and attain a premium in export markets, is however, largely unrecognised. It is a shameful reflection on our farming practices and policies that New Zealand is trailing other countries in terms of the percentage of agricultural land that is certified organic.

The virtual absence of appropriate regulations for the local natural health product industry, and ongoing delays with their introduction, is also of concern. As with other export-focussed agricultural sectors of our economy, in order to achieve further establishment of a world class reputation, a regulatory environment that is current best practice and internationally recognised, is absolutely imperative.

Phil dispensingFinally, the obvious fact that as with drugs certain herbs may not be safe when made readily available for consumers to purchase and self-medicate with, should be better recognised by both consumers and regulators. A small number of herbs should therefore only be prescribed by well-trained medical herbalists following an individual consultation where they can make a valuable contribution to treatment, in a similar manner to drugs which can only be prescribed by medical specialists or suitably qualified health professionals.

It is clear that in this rapidly changing world herbal medicine has a huge potential to play a major role in the future health as well as economic and environmental wellbeing of New Zealanders. However, as with other industry sectors that have proven successful for our country in recent decades, this potential will take longer to develop or not be fully achieved, unless government takes an integrative, forward thinking and strategic approach to their policy setting and dealings with the industry, to help foster its further fruition.

Phil Rasmussen