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Wednesday, August 27, 2014

Problems with the Usage of Medicinal Plants in Traditional Medicine

Plants, plant parts and plant products and produce of all descriptions, particularly those with medicinal properties, are invariably used as principal components or ingredients of various traditional medicines. The number of plants with medicinal properties include in the material medica of traditional medicine in the South East Asian subcontinent at present stands at about 2000 (R.N. Chopra et al. 1958, Indigenous Drugs of India). More than 500 of such medicinal plants have so far been enlisted as growing in Bangladesh (M. Yusuf et al, 1994, Medicinal Plants of Bangladesh). This number of the indigenous medicinal plants is in the increase with the discovery and introduction of newer plants every day. In the traditional systems at the present time almost every plant and herb growing in Bangladesh has ascribed to it some medicinal virtue and is used as either principal therapeutic agent or as necessary associate (excipient) in medicinal preparations to increase the potency of the principal ingredients. Although uses of some of these plants are based on individual experience or isolated cases of their beneficial effects. This is how the number of medicinal plants have multiplied without sufficient scientific or clinical proof of their therapeutic properties. At the same time it is also true that, while the employment of a large number of the currently used medicinal plants would appear to have been based on empirical evidence handed down from generation to generation, many of these plants have been recommended as efficacious drugs after being clinically tried by the practising physicians. 

Medicinal Plants
However, due to the introduction of a large number of plants into traditional medicine based on only empirical evidence, many of these so-called medicinal plants are now found to be therapeutically useless. In this regard blurs have been created in the field of traditional medicine vide these introductions. Their continued use in traditional medicine is now justified by arbitrarily calling them as necessary associates (excipients) of the active ingredients. Of course, inability to correctly identify the recommended medicinal plants on the part of their present day users may also be responsible for so many listed medicinal plants turning out to be medicinally inactive.
Establishment of correct identity of the medicinal plants used in traditional medicines is a serious problem, because they are too many in number and too varied in character and the process of identification is long, tedious and laborious. In addition to these, there are other difficulties which have to be surmounted. No standard methods of identification and proper scientific descriptions of the recommended medicinal plants have been recorded in the older publications. Many of the plants mentioned in the old records baffle and defy proper recognition and identification as the descriptions recorded in them are so scanty and vague that one cannot be certain from these descriptions whether the specimens used currently are the particular plants recommended earlier.
Moreover, in many cases medicinal plants are often referred to by using only their local or native names with incomplete or unscientific descriptions. This results in a great deal of confusion. Many vegetable drugs are sold in the market under various names and different drugs under the same name. It so happens sometimes that entirely different herbs are sold in different parts of a country under exactly the same name and a particular plant is known by different names in different parts of the same country.
This predicament of identification of medicinal plants has further been aggravated by the lack of trained manpower and absence of proper facilities in the traditional medicine manufacturing firms. These firms mainly depend for the supply of their crude drugs on ordinary, sometimes illiterate, drug dealers in the market who do not have any formal training or education for identification of the medicinal plants they collect or supply. They identify these plants in the natural habitats or commercial consignments by organoleptic means entirely relying on their past experience and familiarity with most of the medicinal plants used in traditional medicines. This method of identification is not always reliable, because there are many plants with different identities which look alike in their apparent morphological characters. This is particularly true in cases of closely related plants. Another issue with these unskilled collectors of plants is in their selection of the specific plant parts. As is well knows each plant has specific areas where its medicinal properties are potent. These collectors often collect the wrongly identified parts of the genuine plant or the same part of a wrongly identified similar plant. Thus, there exist much room for mislabelled crude drugs. In fact, the majority of the vegetable drugs available in the local market of Bangladesh or supplied to the manufacturers by the dealers are invariably either heavily adulterated or entirely replaced by cheap and worthless substitutes, either deliberately or un-deliberately.
Furthermore, it has been seen that the problem of mislabelled plants or plant parts does not end with the plant collectors or dealers. Many manufacturers of traditional medicines, even when equipped with the right medicinal plants, out of ignorance, use the wrong parts of these medicinal plants when preparing medicines. Thereby, the therapeutic quality of the preparation is reduced or becomes completely useless for the specific indications. These shortcomings on the part of the collectors and suppliers and manufacturers of traditional medicines and lack of proper expertise and facilities seriously affect the quality and potency of the finished product.

Reference: The Medicinal Plants of Bangladesh by Abdul Ghani. ISBN: 984-512-348-1

Origins of Medicinal Plants

Eclipta alba medicinal plant
The history of the use of medicinal plants for alleviating diseases had its origin in the activities of the most primitive man of the remote past. Illness, physical discomfort, injuries, wounds and fear of death had forced early man to use any natural substance that he could lay his hands on, without any resistance, for relieving the pains and sufferings caused by these abnormal conditions and for preserving his health against disease and death. Plants growing in his environment were such a group of natural substances to which the early man turned his attention for these purposes. In fact, in his long struggle to achieve mastery over the powerful forces of nature, man has always turned to plants for help, and that no just for medicine but for food, shelter, clothing and weapons as well. 

Selection of the medicinal plants by early man, without any prior knowledge about them, was largely based on intuition, guesswork or trial and error. Curiosity and search for food had contributed considerably to his knowledge about the plants and their virtues. Superficial resemblance between a specific plant part and the affected organ or some symptoms of the ailment had also guided the animals’ instinctive discrimination between toxic and palatable plants might also have helped primitive man in choosing those plants which were beneficial from nutritive and medicinal standpoints. Furthermore, the healing powers of some plants were undoubtedly discovered by accident. Thus, by a combination of these processes there are gradually developed a considerable knowledge of medicinal plants which was transmitted from one generation to another at first orally and later in written form as papyri, baked clay tablets, parchments, manuscripts, herbals and finally printed herbals, pharmacopoeias and other works. 

As far as records go, it appears that Babylonians (about 300 years BC) were aware of a large number of medicinal plants and their properties. Some of the plants they used are still in use in almost the same manner and for the same purpose. As evident from the Papyrus Ebers (written in about 1500 BC), the ancient Egyptians possessed a good knowledge of the medicinal properties of hundreds of plants. Many of the present day important plant drugs like henbane (Hyoscyamus spp.), mandrake (Mandragora officinarum), opium (latex of Papaver somniferum fruit), pomegranate (Punica granatum), castor oil (oil of Ricinus communis seeds) aloe (juice of Aloe spp.), onion (Allium cepa) and many others were in common use in Egypt about 4500 years ago. 

The earliest mention of the medicinal use of plants in the Indian subcontinent is found in the Rig Veda (4500 – 1600 BC), which noted that the Indo-Aryans used the Soma plant (Amanita muscaria, a narcotic and hallucinogenic mushroom) as a medicinal agent. The Vedas made many references to healing plants including sarpagondha (rauvolfia serpentine), while a comprehensive Indian Herbal, the Charaka Samhita, cites more than 500 medicinal plants. 

The earliest known Chinese pharmacopoeia, the Pen Tsao, appeared around 1122 BC attributed to the legendary emperor Shen Nung, this authoritative work described the use of Chaulmoogra oil (from the seeds of Hydnocarpus kurzii) to treat leprosy. Among its many other listings are hemp (Cannabis sativa), opium, rhubarb (rhizome of Rheum spp.) and aconite (Aconitum napellus). It also first recorded the uses of Ephedra species.