Abstract
Plants have been one of the major sources of medicines since the dawn of human civilization. The contribution of plant-derived drugs in modern times is still significant and much interest has been focused on exploiting the wide diversity of medicinal plants in both traditional systems of medicine and modern drug development. In this review, we assess three plants, namely Punica granatum L., Curcuma longa L. and Zingiber officinale Rosc., for their biological activities. Recent trends in phytochemical investigation and study of the pharmacological actions of all P. granatum components (juice, seeds, leaf, pericarp) suggest possible clinical application for the treatment and prevention of cancer and other diseases where chronic inflammation is believed to play an essential etiological role. C. longa extracts and active constituents have a potential role in the prevention of cancer and the management of infectious and chronic diseases. Z officinale extracts and active constituents have potent antioxidant, antiinflammatory, antimutagenic and antimicrobial activities, and some of them have shown anticancer activity in experimental models of carcinogenesis. Z officinale has also been found to be effective against pregnancy-induced and postoperative nausea and vomiting, and has proved useful for treating motion sickness and arthritis symptoms.