About 61% of new drugs developed between 1981 and 2002 were based on natural products and they have been very successful, especially in the areas of infectious disease and cancer.[4]
Recent trends, however, show that the discovery rate of active novel chemical entities is declining.[5]
Natural products of higher plants may give a new source of antimicrobial agents with possibly novel mechanisms of action.[6,7]
The effects of plant extracts on bacteria have been studied by a very large number of researchers in different parts of the world.[8]
Much work has been done on ethnomedicinal plants in India.[9]