Serial Review J. Clin. Biochem. Nutr., 40, 82–91, March 2007 Recent Advances in Indian Herbal Drug Research Guest Editor: Thomas Paul Asir Devasagayam Chemopreventive Herbal Anti-Oxidants: Current Status and Future Perspectives Rachana Patel, Rachana Garg, Suvarna Erande, and Girish B. Maru* Advanced Centre for Treatment Research and Education in Cancer (ACTREC), Tata Memorial Centre (TMC), Kharghar, Navi-Mumbai-410 208, India Received 19 September, 2006; Accepted 8 December, 2006 Summary Cancer chemoprevention is fast becoming a lucrative approach for controlling cancer. Carcinogenesis being a complex multi-step, multi-factorial process, a number of chemopreventive interventions can be employed. These strategies are generally directed against two broad events of carcinogenesis viz., initiation and promotion/progression. Anti- initiation interventions principally involve inhibition of carcinogen activation, scavenging of free radicals and reactive carcinogen metabolites along with enhanced detoxification of carcinogens by modulating cellular metabolism. Anti-promotion strategies involve attenuation of enhanced cellular proliferation along with induction of cellular apoptosis and differentiation. Dietary agents or herbal anti-oxidants due to low toxicity and relative safety are promising chemopreventive agents. These agents after emerging successful through a series of in vitro and in vivo assays enter clinical trials. Many dietary compounds have emerged as promising chemopreventive agents in empirical experiments. However, in clinical trials these compounds have met with limited success. This emphasizes the need for further detailed research on the mechanisms of observed chemoprevention and choice, dose, duration and bioavailability of chemopreventive agent used. Complex issues such as choice and nutritional status of target population, genetic variation, gene-environment interactions and relevance of biomarkers analyzed also warrant further research and analyses. Key Words: carcinogenesis, herbal antioxidant, screening assays, chemoprevention, current status Introduction Majority of human cancers are caused, mediated or modified by exogenous/endogenous environmental factors. Epidemio- logical studies have successfully demonstrated that certain well-defined exposures (e.g. tobacco, alcohol, ionizing radi- *To whom correspondence should be addressed. Tel: 91-22-27405022 Fax: 91-22-27405085 E-mail: gmaru@actrec.gov.in 82 ation, occupational carcinogens and viruses etc.) increase the risk of cancers at specific sites, which have also been supported by in vivo experimental studies. A few associations like tobacco use and oral cancer have been established to be causative while for many other associations, their role in causation of cancer still remains to be established. Further, the identification of specific causative factors and evaluation of their relative importance has proved to be rather difficult since majority of cancers result from complex interactions between environmental and host factors [1]. Efforts to eliminate known human carcinogens like tobacco from the environment