Contamination of Asian herbal drugs : Need for its critical evaluation

Herbal drugs have been used as remedies for the treatment of large number of humans, ailments since ancient times as the traditional medicine system; India has a glorious past, having first documented record of fully developed medical science known as Ayurveda written by several ancient Rishi’s. Major groups of indigenous system of medicine are based on herbal drugs. A survey made by WHO indicated that about 80% of the world population relies on herbal drugs. Herbal drugs are becoming more popularized and important even in the developednations with hope of their non-toxicity and may play a role of substitute to overcome the problems of multi drug resistant pathogens. Cultivation of drug plants has been started in large scale without considering the land quality and in certain cases irrigation with waste water. Application of different fungicides, pesticides in that specific field or in neighboring fields may be directly deposited superficially or may be absorbed by the plant system. Therefore in the present situation possibilities of the Asian herbal drugs, contaminated with large number of toxic components cannot be ignored which may severely hurt human life in place of healing or curing.These contaminants may be either alone or in combination and may be originated intrinsically, extrinsically and deliberately. Certain contaminants may be highly toxic and may cause severe adverse effect in the human system. Some of the important contaminants are the heavy metals like lead, arsenic, cadmium, mercury, copper and pesticides. Adulteration of modern drugs to enhance drug potency and heterogenous microbial population including human pathogens may contaminate both raw and powdered herbal drugs. Among these contaminants, microbial contamination seems more severe and may be due to their dual action on the drug i.e. utilization of medicinally important chemical components as nutrients and in certain cases by producing certain mycotoxins, which may be even carcinogenic under certain conditions . Critical evaluation of both raw and powdered herbal drugs for contaminants is the urgent need of the time in order to provide safety measures in herbal health care medicine