Mechanisms of Anticancer Activity of Sulforaphane from Brassica oleracea in HEp-2 Human Epithelial Carcinoma Cell Line

Sulforaphane (SFN) an isothiocyanate formed by hydrolysis of glucosinolates found in Brassica oleraceaeis reported to possess anticancer and antioxidant activities. In this study, we isolated SFN from red cabbage(Brassica oleraceae var rubra) and evaluated the comparative antiproliferative activity of various fractions(standard SFN, extract and purified SFN) by MTT assay in human epithelial carcinoma HEp -2 and and Verocells. Probable apoptotic mechanisms mediated through p53, bax and bcl-2 were also examined. The SFN fractionwas collected by HPLC, enriched for its SFN content and confirmed. Expression of apoptosis-related proteinswas detected by western blotting and RT PCR. Results showed that Std SFN and purified SFN concentrationfound to have closer IC50 which is equal to 58.96 microgram/ml (HEp-2 cells), 61.2 microgram/ml (Vero cells)and less than the extract which is found to be 113 microgram/ml (HEp-2 cells) and 125 microgram/ml (Verocells). Further studies on apoptotic mechanisms showed that purified SFN down-regulated the expression ofbcl-2 (antiapoptotic), while up-regulating p53 and Bax (proapoptotic) proteins, as well as caspase-3. This studyindicates that purified SFN possesses antiproliferative effects the same as Std SFN and its apoptotic mechanismin HEp-2 cells could be mediated through p53 induction, bax and bcl-2 signaling pathways.