A Review on Phytochemicals from Some Medicinal Plants of Bangladesh

Natural products, especially those derived from higher plants, have attracted scientists from ancient time because of their potential therapeutic values. Drug development from natural sources showed that natural products or natural product-derived drugs comprised about 28% of all new chemical entities launched to the market. These are originated from terrestrial plants, microbes, marine organisms, etc. However, until recently an insignificant part of the plants has been scientifically evaluated for their medicinal properties. Bangladesh is a rich repository of medicinal plants, many of which are widely used in the Ayurvedic, Unani, herbal and other traditional systems of medicines. In our laboratory, we have extensively investigated over 48 medicinal plants and several microbial strains that have resulted in the isolation and characterization of 133 compounds, including 33 new molecules. Terpenoids, alkaloids, flavonoids and glycosides were the major classes of constituents. The crude extractives and several purified molecules demonstrated statistically significant inhibition of growth of microorganisms. On the other hand, usnic acid obtained from the lichen, Parmelia kamtschandalis, demonstrated even better of inhibition of microbial growth as compared to the standard antimicrobial agents, whereas dehydroaltenusin extracted from a Streptomyces sp. exhibited significant HIV-inhibitory activity