Role of ROS and COX-2/iNOS inhibition in cancer chemoprevention: a review

Since the times immemorial, our ancestors have been using medicinal plants or their parts for curing various ailments. The experiences of time have led to the strong system of medicine such as ayurveda. We have now moved to an age/era, where these therapies are now being tested scientifically. The knowledge about the medicinal plants in these ayurvedic scriptures can help us to unfold the mysteries related to the chronic diseases such as cancer. Several therapies are available for cancer prevention including radiation, chemotherapy, immunosuppression and surgery etc. but all these strategies have one or the other disadvantages. Natural plant products are the potential candidates for the cancer chemoprevention due to their antioxidant, anti-inflammatory and antitumor activities. From the time immemorial, plants have been the basis of traditional medicines and keep on to provide new remedies. Antioxidants are necessary for controlling degenerative reactions produced by reactive oxygen and nitrogen species in vivo. Increased intake of antioxidants in the form of fruits and vegetables may reduce the risk of cancer. It has been proposed that modulation of inflammatory mechanisms can be used for the cancer chemoprevention. The primary targets for modulation are cyclooxygenase (COX)-2 and nitric oxide synthase (iNOS). Thus, antioxidant, COX-2, iNOS represents a prime target for potential chemoprevention by phytochemicals. This review highlights various plants and their constituents explored for their antioxidant, COX-2 and iNOS inhibitory potential in various in vitro/in vivo assays and this knowledge can be exploited for the discovery of novel anticancer agents.