Abstract
Higher plants are the major source of crude drugs used in herbal therapy. Adulteration in crude drug material has necessitated scientific characterization of plant drugs, which is based primarily on morphological, anatomical and physico-chemical characters studied through microscopy and some analytical techniques. These criteria are helpful in isolating the adulterants from the actual drug, but fail to deliver when the very botanical identity of a plant drug is controversial, and several different plant species are used under a single drug name. This article suggests how to face this situation and overcome the problems likely to occur. Quantification of active ingredients in plant tissues is the only dependable way to identify the actual drug out of the different species in use. However, the amount of active ingredients in plants, responsible for the therapeutic efficacy of those plants, may vary with plant genotype and the habitat ecology, regulated largely by soil characters and agro-climatic conditions. Even within the individual plant, concentration of active ingredients often varies with plant parts/organs, stage of plant development and status of plant nutrition. Besides, degradation of environment may not only affect the quantity, but even the composition of the secondary metabolites produced. This situation may alter the chemical properties, and hence the degree of therapeutic effectiveness of these bioactive compounds. Thus, a careful estimation of active ingredients, taking all the above-said situations into account, may decide which species should be regarded as the actual drug, which as an alternative drug and which as the non-drug (if the amount of the ingredient in question is just negligible). It may also indicate which plant organ should preferably be used and what should be the proper stage for harvesting. Further, environmental degradation may have a far-reaching influence on the therapeutic potential of medicinal plants and may also necessitate a re-fixing of drug doses, keeping in view the overall impact of environmental degradation on the active ingredients of these plants on one hand, and on the resistance level/immune system of human beings on the other.