Isothiocyanates as promising chemopreventive and antioxidant agents

In the last decades, mounting evidence from mechanistic studies of cancer helped to develop new promising chemopreventive agents. On the basis of the mechanism through which they exert anticancer effects, chemopreventive agents can be divided into two groups: antimutagenic and antiproliferative. Antimutagens reduce formation of mutagens or carcinogens thereby preventing DNA damage. For instance, reactive oxygen species scavenging and alteration in carcinogen metabolism (through suppression of phase I enzymes or enhancement of phase II detoxifying enzymes) represent antimutagenic effects. Alternatively, chemopreventive agents may exert antiproliferative effects via induction of cell cycle arrest or apoptosis, inhibition of angiogenesis, induction of terminal differentiation, and inhibition of oncogene activity or DNA synthesis. A lot of chemopreventive compounds exist in vegetables or fruits that are consumed by humans on a daily basis. Among these, isothiocyanates (ITCs) present in different plant families such as Cruciferae have gained much attention because of their potential anticarcinogenic properties in culture models as well as in animal models. In this study we evaluated the ability of sulforaphane and 4 (rhamnopyranosyloxy)benzyl ITC (RBITC)-containing Moringa oleifera extract to protect cultured human lymphocytes from genotoxicity induced by three different agents: ethyl methanesulfonate, an alkylating agent, hydrogen peroxide, an oxidizing agent, and mitomycin C, which acts as both an alkylating and an oxidizing agent. In order to understand the mechanisms of action of sulforaphane and Moringa oleifera extract, the cultures were treated before, during, and after treatment with the mutagens. We also explored the involvement of apoptosis in the anti-genotoxic activity of sulforaphane and Moringa oleifera extract.