1. Introduction
Plants as natural medicines to benefit humans have a long history and ancient civilization,
particularly in some nations such as India, China, Egypt, and Greece. The majority of world
populations still rely on plant based medicine because of several reasons such as long history of
safe use, affordability and easy availability. The growing interest in drugs of plant origin may
also be due to several other reasons such as a large section of world's population does not have
access to conventional pharmacological treatment and side effects and other problems of
synthetic drugs due to incorrect use. Natural product remains a prolific source of discovery of
new drugs from the ancient Vedic period.