Bioactivity of Fermented Green Coffee Bean Extract Containing High Chlorogenic Acid and Surfactin

Chlorogenic acid (CGA) is a major component of green coffee beans. Surfactin, a cyclic lipopeptide, is produced and secreted by Bacillus subtilis strains. In this study, bioactivities of fermented green coffee bean extract (FGCBE) and the individual compounds, CGA and surfactin. were compared in HepG2 cells. The concentration of surfactin and CGA in the FGCBE and non-fermented green coffee bean extract (NFGCBE) were determined to be 9.2 and 7.33 and 0.72 and 0.53 mg·mL^-1, respectively. The FGCBE contained about 20% and 26% more CGA and surfactin than the NFGCBE. Although CGA and surfactin exhibited cytotoxicity at concentrations more than 100 and 20 μg respectively, the FGCBE 50 containing CGA (460 μg·mL^-1) and surfactin (720 μg·mL^-1) effectively prevented cell death by oxidative stress and also strongly activated the proliferation of cells incubated with under 50 μM H₂O₂. The CGA and surfactin in FGCBE were 9.2 and 72 times higher than the CGA and surfactin compounds (50 and 10 μg·mL^-1). The relative proliferation of the FGCBE-treated cells also was 3.3 and 8.8 times higher than the CGA and surfactin compounds treated the oxidative stressed cells with 50 μM H₂O₂. These results suggest that the single compounds such as CGA and surfactin generally have cytotoxicity at low concentration of them but FGCBE contained them acted as strong antioxidants, activators of cell proliferation, inhibitors of cell apoptosis. Various bioactive compounds in fermented coffee bean also seem to help cell proliferation and decreasing of cytotoxicity by CGA and surfactin in coffee bean.