Science reveals the magic in herbal cures

Recent studies have brought to light the science behind traditional herbal medicinal systems.

 
By Amit Mitra
Published: Sunday 07 June 2015

Science reveals the magic in herbal cures

-- SCIENTISTS the world over are agog at the discovery of flavonoids in tea by Michael Hertog of the National Institute of Public Health and Environmental Protection, at Bilthoven in the Netherlands. Hertog's discovery supports the belief held by most Chinese that tea is good for health. The East abounds with many such informal medical practices, but it is only recently that scientists are waking up to their beneficial properties.

Till recently, flavonoids -- essentially brightly coloured flower pigments -- were thought to aid the pollination process by attracting bees and butterflies. However, medical scientists now say that flavonoids are chemicals belonging to the class of anti-oxidants that prevent oxygen from binding to or reacting with a form of cholesterol called IDL. The oxygen-IDL combination sticks to blood vessels and clogs them, thereby impeding the flow of blood and leading to high blood pressure, or sometimes even a small tear in the heart muscle. Thus, by preventing oxygen from binding to IDL, flavonoids can reduce the risk of heart ailments.
Not all superstition The discovery of flavonoids in tea is just one example of the scientific processes that underlie a large number of traditional practices, many of which had hitherto been dismissed as superstition or quackery. The Chinese, who have a penchant for tea, have always held the beverage to be good for health. Another Chinese remedy, a decoction of kudzu root drunk with tea, is believed to cure dipsomaniacs.

In India, the use of plant-based products to cure disease -- the Ayurvedic system of medicine -- dates back to the Vedic period, c. 3000 BC. A sloka (stanza) in the Rig Veda says, "Let all the medicinal plants become sweet. Let all the trees become sweet." Similarly, a stanza in the Atharva Veda says, "Oh Saha Devi, the Goddess of all medicinal plants, we are touching you to cure our fevers and all our body ailments."

Apart from Ayurveda, Indians traditionally use many herbal remedies for every-day home cures (See box). Now scientists are waking up to the fact that many such beliefs have medical explanations. While some of the chemicals contained in these remedies have been derived, many more await the attention of researchers.

The northeastern states of India, which are home to many indigenous tribes, have a forest cover of almost 47 per cent and countless medicinal plants. Assam alone contributes nearly 3,000 species of plants, which are used in indigenous medicines. Small wonder then that medicinal practices abound in the region. But with the development of allopathy, increasing urbanisation and destruction of forests, many plant species are becoming extinct and unique medical traditions getting destroyed.

According to F Suchiang, a forest official in Meghalaya, one of the most popular plants in the region is Rauwolfia serpentina. The plant contains a chemical called reserpine, which reduces blood pressure, acts as a tranquiliser and is used locally as an antidote for snake bite. The berries of another plant, Solanum khasianum, yields disogenin from which various steroid hormones can be extracted. The tribals use S. khasianum as well as Castus specious to brew oral contraceptives.

Cure for leprosy
Local people in Nongpoh, near Shillong, and other parts of the Garo hills use oil from the seed of the Taragtogenus Kurtii plant to treat leprosy, which is prevalent in the area. The root of Rauwolfia canesence and the leaves of Tabernamontana coronaria are used to cure heart ailments. Suchiang says vinca leucoplasma, the active ingredient in a plant called Vinca rosea, effectively heals cuts and bruises. A decoction made from the leaves of Taxus racata is effective against cancer of the stomach and a truckload of these leaves can fetch a substantial amount in the market. Chirata, which grows in abundance in the Northeast, is rich in quinine sulphate -- an anti-malarial compound. The locals use the pulp of the fruit of the Indian Laburnum sinaru (seneru in the local language) as a purgative.

L F Ruse, a botanist who studied Northeastern flora between 1922 and 1935, reported on many medicinal plants used by the tribals. He referred to Parvifolia and Smilax ferox (called soh krot locally), the root of which are "ground and the extract mixed in water" to treat stomach disorders.

Ruse also reported some interesting cures for dog bite. A poultice made of the leaves and flowers of Rosa longicuspis tied over the wound was effective in treating bites by a mad dog, as was drinking a decoction made from the same ingredients. He talks of Khasi tribals using the leaves of Zanthoxylum khasianum on people bitten by mad dogs, of which there seems to have been an epidemic after World War I. For bites from a dog that was not mad, he reported an extract of the leaves and stem of Caesalpnia circlidocarpia, which the Khasis called dieng sia khwai, was useful.

Ruse found the Khasis used the leaves of Euonymous japonicus for cuts and bruises. The crushed leaves of Glouchidon Assamicum cure cattle of stomach ailments, while humans used the boiled roots of Rubus Moluccanus for stomach disorders. The extract of the fruits of a plant known locally as shiah-jaiur-cum (Zanthozylum acanthopodium) was given to cholera patients.

Were these remedies really foolproof? Scientists such as A C Ghosh, J C Sarma, N C Baruah and R K Mathur of the Centre for Scientific and Industrial Research, have isolated the active ingredients of some local herbal remedies. They report, for instance, that Clerodendron collebrokianum walp -- known as nephaphu in Assam, Arunachal Pradesh and Nagaland -- is widely used to control high blood pressure. The locals recommend 70 gm of boiled leaves and twigs twice daily, thrice a week for three months. Adverse effects are possible if used for longer durations.

The scientists made an extract from the leaves and twigs of C. collebrokianum walp with chloroform. Chromatography of the resultant gum, after evaporating the crude chloroform extract, led to the isolation of a mixture of unsaturated fatty acids and a sterol that lowers blood pressure.

They also found that an alcohol extract of the leaves of Bryophyllum calycinum salisb -- Pategoja in Assamese -- effectively dissolved kidney stones, perhaps because the leaves contain more than 10 per cent isocitric acid. Pategoja belongs to the family, Crassulaceae, and can be found widely in the Brahmaputra valley. The juice of its leaves, which has a sour taste, is used widely for urinary problems.

Ghosh and his associates report the roots of Plumbago zylanica linn -- a plant found widely in India -- ground and made into a thick paste with molasses, effectively cures piles because it contains quinone, commonly known as plumbagin.

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