CaHMRI News CARIBBEAN HERBAL MEDICINE RESEARCH INSTITUTE April, 2010
Volume 2, Issue2
The “greening” of modern medicine New categories of food and drug products have entered the international market place. Some are called “health foods”, and others “botanicals”. Some are called nutraceuticals, and are the refined food extracts or preparations designed to provide specific health benefits. The use of herbal preparations has also increased worldwide. As a result of these actions today there is increasing attention being paid to promoting the responsible use of herbs and of herbal medicinal products. For example, spreading sound information about herbal products is a major activity of the American Herbal Pharmacopoeia (AHP). This body was formed in 1995 to produce documents called monographs, containing complete and critical reviews of the traditional medicine and modern scientific literature describing the identity, quality, efficacy and safety of “the most widely used” herbal medicinal agents. Documents of this kind are also published in other countries, such as the British Herbal Compendium, the German Commission E Monographs and the Indian Herbal Pharmacopoeia. An article is written below on the sorrel as a medicinal plant, which is partially based on the German Commission E Monographs. Such activities provide an indication of the current “greening” of modern conventional medicine. Writing in a 2009 issue of the journal known as Drugs, Professors Izzo and Ernst stated that “the efficacy and safety of herbal medicinal products can be tested in clinical trials much like synthetic drugs, yet numerous methodological and logistical problems exist. The therapeutic value of several herbal
medicines has been established; for many others this is not the case, often because the research has not been done”.
But there is dire need for more monographs concerned with medicinal and food plants which grow in the Tropics. This situation is reflected in the book “Herbal Products: Toxicology and Clinical Pharmacology”, edited by Tracy, T.S. and Kingston, R.L., which was published by Springer in 2007. This book is described as, “a comprehensive resource for objective clinical information about the potential uses, efficacy, and safety of herbal medicines”; but its contents are focused on the products of no more than eighteen medicinal plants.
Inside this issue: THE “GREENING” OF MOD-
THE SORREL AS A MEDICINAL PLANT?
THE INTERACTIONS BETWEEN
HERBAL MEDICINES AND CONVENTIONAL (CHEMICAL) DRUGS
Newsletter Title contâ€™d from page 1 No Caribbean herbal medicines seem to have been included in the book, except for those derived from garlic and ginger.
The Sorrel as a medicinal plant? SORREL TEA IS A MILD LAXATIVE WHEN TAKEN IN LARGE AMOUNTS, BECAUSE THE ACIDS ARE DIFFICULT TO BE
Among the German Commission E Monographs (Bisset, N.G. 1994), the sorrel plant is listed under the name as Hibisci flos. It is included as a drug (or the nutraceutical) product which comes from the calyx of Hibiscus sabdariffa L. The calyx is the protective layer that forms around the developing flower of the plant, and Hibiscus sabdariffa is the scientific name of the plant.
taken in large amounts, because the acids are difficult to be resorbed. The wine red colour of the sorrel is due to its anthocyanin constituents, which reach about one percent content in the calyx. Anthocyanins are the coloured glycosides of polyphenols of the flavonoid class. The anthocyanins in sorrel are mainly cyanidin glycosides and delphinidin glycosides.
Other botanical names or synonyms sometimes are used for the plant, such as Abelmoschus cruentus Bertol, and Sabdariffa rubra Kostel; and it belongs to the family known as Malvaceae. A botanist would describe it as a shrubby annual growing up to two metres high, with or without hairs on the stems, its leaves being deeply lobed, flowers solitary, and the calyx up to two centimetres long in flower, and increasing to become bright red in fruit.
The safety of sorrel as a widely consumed beverage is well-established. Its medicinal properties may be separated into three distinct categories. The first category defines those of its therapeutic uses which specifically are supported by good data derived from clinical trials with human volunteers. The second category describes those uses supported in traditional systems of medicine and sometimes documented in pharmacopoeias and compendia. Those uses described in the practices of folk medicine, but which are not supported by experimental or clinical data fall into the third category. We shall describe some of the attributes of sorrel which belong to the first category. There is some good data derived from good clinical trials which have been conducted with human volunteers taking sorrel teas.
Sorrel is most probably of African origin, but nowadays it is very widely distributed and cultivated in many tropical countries around the world, and not surprisingly, is known by several local names. Some of these common names are - Sour tea, Roselle, Red Sorrel, Lozey, Lal-ambari, Karkade, Jamaica Sorrel, Hibiscus, Guinea Sorrel and Florida Cranberry.
Sorrel (Hibiscus sabdariffa) www.rastaseed.com/â€Ś/2008/02/ rosella_sorrel.jpg
Numerous chemical constituents of the plant are known. It contains organic acids (1530% in the calyx) including citric acid, malic acid, and tartaric acid. Together with the pectins and flavonoids and other polyphenolic glycosides in the calyx, these acids give a pleasant and refreshing taste to sorrel drinks. Sorrel tea is a mild laxative when Page 2
Recent scientific reports suggest that daily consumption of sorrel tea, in an amount readily incorporated into the diet, lowers blood pressure in pre- and mildly hypertensive adults (McKay D.L. et al. 2010).Two anthocyanin constituents of the sorrel calyx have been shown to inhibit angiotensin converting enzyme (ACE) activity (Ojeda D. et al. 2010); and such an effect can be correlated with the hypotensive outcome.
Volume 2, Issue2 cont’d from page 2 As so often stated, further research is warranted related to the bioavailability and potential mechanism of action of sorrel teas as anti-hypertensive agents. (REFERENCES: 1. Bisset NG (Editor). 1994. Max Wichtl Herbal Drugs and Phytopharmaceuticals. (CRC Press, Boca Raton, Florida, USA); 2. McKay DL et al. 2010. Journal of Nutrition, 140 (2): 298-303; 3. Ojeda D et al. 2010. Journal of Ethnopharmacology, 127: 7-10).
The interactions between herbal medicines and conventional (chemical) drugs. The following introductory statements were made by Professors Izzo and Ernst in their 2009 paper in the journal Drugs, -- which was discussed above. “Approximately 38 million adults in the US (18.9% of the population) use herbs or other natural supplements, but only one-third tell their physician about this use. This lack of information, combined with the fact that herbal medicines are usually a mixture of many active ingredients, increases the likelihood of harm.” In the journal article, the possible interactions were critically reviewed between each of seven popular herbal medicines (ginkgo, St. Johns Wort, ginseng, garlic, echinacea, saw palmetto and kava) and conventional drugs. The authors found that “numerous interactions between herbal medicines and conventional drugs have been documented” in the biomedical literature. Garlic oil (of Allium sativum) can cause prolonged bleeding when taken with anti-coagulant (blood-thinning)
drugs, like warfarin. No interactions were reported for saw palmetto (Serenoa repens). Older adults have the highest per capita use of prescription (chemical) medications, and therefore are at the greatest risk of harmful herb-drug interactions.
“APPROXIMATELY 38 MILLION ADULTS IN THE US (18.9% OF THE POPULATION) USE
In their paper, Izzo and Ernst noted that “the study of herb-drug interactions is hindered by the nature of herbal medicines. Invariably (and by definition) these are not drugs with only one pharmacologically active constituent. Typically we are dealing with complex mixtures of dozens of potentially active principles. It seems obvious that this renders investigations of herb-drug interactions more complex than drug-drug interactions.”
HERBS OR OTHER NATURAL SUPPLEMENTS, BUT ONLY ONE-THIRD TELL THEIR PHYSICIAN ABOUT THIS USE.
The authors noted that current research into herb-drug interactions is intense, and that it is important that healthcare professionals are well informed about this fast-expanding field.
FUTURE ISSUES will include: *News from the TRAMIL network *Herbs for the cold season *Natural and Traditional medicine in Cuba *Legendary herbal aphrodisiacs *Poisonous plants
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