Anthocyanins affect glutathione S‐transferase activity in human HepG2 cells

Abstract

Anthocyanins (ANTH) may act as antioxidants either directly or by increasing the activities of antioxidant enzymes and raising glutathione (GSH) concentration. Previous studies in our lab showed that rats consuming blueberry ANTH fractions had increased liver glutathione S‐transferase (GST) activity. Subsequent studies in HT‐29 colon cells showed that ANTH increase GST activity at low doses (< 10 μmol/L). The aim of this study was to examine possible protective mechanism(s) of ANTH by determining the effects of malvidin (MAL) and delphinidin (DEL) on antioxidant enzyme activity, cell viability and oxidative stress in human hepatocellular carcinoma (HepG2) cells. HepG2 cells were incubated in 75 cm2 flasks with 0, 5, or 10 μmol/L MAL or DEL for 24 h at 37°C, 95% CO2, 5% air, followed by incubation with 0–200 μM tert‐butyl hydroperoxide (t‐BOOH) for 2 h. Activity of GST was then assessed. t‐BOOH significantly (p = .049) increased GST activity above the control. ANTH increased GST activity (p=.058) above the control, with MAL having a greater effect (54%–84%) than DEL (29%). ANTH did not oppose the effects of t‐BOOH on GST activity. While t‐BOOH reduced cell viability, pre‐incubation with ANTH returned viability to that of the control. Further studies will examine the effects of MAL and DEL on glutathione peroxidase and glutathione reductase activities, GSH concentration and lipid peroxidation. Funding: GA‐AES.