Effect of stigmasterol and 5β-hydroxysitostanol isolated from microalgae Navicula incerta on apoptosis in human hepatoma HepG2 cells

Abstract

Marine microalgae are the primary producers of the marine ecosystem and they produce large array of metabolic products. Therefore, marine microalgae is used in different fields of application including live stock feed, oceanic life raising feed, cosmetic ingredient and nutraceutical. Besides, recently many ongoing research have focused on producing biomass fuel using microalgae. However, there are less reports in use of microalgae on isolating active metabolites. Therefore, this study has focused on investigating the apoptosis inductive effects of active compounds isolate from marine microalgae Navicula incerta extracts. Stigmasterol and 5β-hydroxysitostanol, belonging to the sterol group were isolated from the methanol : dichloromethane (1:1) extract of Navicula incerta. There are several reports on anti-cancer effects of plant sterols on breast cancer and prostate cancer, but no reports on liver cancer. Thus, we investigated the apoptosis inductive effects of stigmasterol and 5β-hydroxysitostanol on hepatocarcinoma cells HepG2. According to the results obtained stigmasterol induce the apoptosis on HepG2 cell via intrinsic pathway by down regulating Bcl-2 and extrinsic pathway by upregulating caspase-8, 9 and FASL. On the other hand, the apoptosis inductive effects of 5β-hydroxysitostanol was not prominently seen. In conclusion, we can conclude that the stigmasterol isolated from marine microalgae shows potent apoptosis inductive effects and could be developed as a anti-cancer therapeutic against liver cancer.