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.
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