Grape pomace bioactivity from Brazilian wine industry: toxicity and antioxidant properties in human hepatocarcinoma cells (830.31)

Abstract

Wine industry produces large quantities of by‐products rich in bioactive compounds from grapes, which could be utilized for nutraceutical purposes. We aim to evaluate antioxidant activity (AC) and bioactivity of grape pomace extract from Brazilian wine industry in human hepatocarcinoma cells (HepG2). The content of bioactive compounds and AC of extracts were determined by ORAC, TEAC (ABTS•‐) and TRAP assays. Bioactivity was assessed on HepG2 and on normal human fibroblasts (BEAS). Cellular viability was accessed by MTT reduction and cellular antioxidant capacity (CAC) by dichlorofluorescein oxidation, under short‐, medium‐, and long‐term incubation periods. Total phenolics, flavonoids and anthocyanins of extracts where, respectively, (mean±SD) 473.8±52.4 mg GAE/100g, 147.5±2.77 mg CE/100g and 105.5±7.27 mg cyanidin3‐glycoside/100g. Extract AC was (mean±SD; µmol TE/g) 27.1±0.33, 9.33±6.74, 122.2±2.40. HepG2 viability reduced in a time‐ and dose‐dependent manner. Short‐term incubation had no effect whereas medium‐ and long‐term incubation induced, respectively, a 37% and a 75% reduction in viability. BEAS viability was not affected by the extract, regardless of time and concentration used. Interestingly, short‐term incubation promoted a dose‐response increase in HepG2 CAC, suggesting that decreased oxidative stress signals to decrease HepG2 proliferation. Taken together, wine industry by‐products present important antioxidant activity and potential selective anticancer and antiproliferative effects on HepG2 cells.Grant Funding Source: Supported by FAPERJ, CNPq, CAPES, EMBRAPA (Brazil)