Biological and anticancer activity of selected natural products

Cancer continues to be one of the major causes of death worldwide. In recent years, the concept of cancer chemoprevention and treatment with natural occurring agents has evolved greatly. In this review work the biological activity and protective effects against cancer of some  natural products - coffee, caffeic acid, caffeic acid phenethyl ester ( CAPE), chlorogenic acid, quercetin and curcumin are presented. It seems that the most natural products with anticancer activity act as strong antioxidants and/or modify the activity of one or more protein kinases involved in cell cycle control. The results of in vitro and in vivo studies showed that some of them may be useful as potential chemotherapeutic or chemopreventive anticancer drugs or adjuvants in complex anticancer therapy.