A synergistic combination of Phyllanthus emblica and Alpinia galanga against H2O2-induced oxidative stress and lipid peroxidation in human ECV304 cells

A combination of ethanolic extract of Phyllanthus emblica fruits and ethanolic extract of Alpinia galanga rhizomes at a ratio of 7:3 (PE-AE (7:3)) exhibited synergistic antioxidant activities against DPPH, ABTS+, and superoxide anion (O2−) radicals with Combination Indices (CIs) of 0.692 ± 0.048, 0.802 ± 0.033, and 0.840 ± 0.023, respectively. At concentrations of 20 and 50 µg/mL, the PE-AE (7:3) showed a significant decrease in intracellular reactive oxygen species against H2O2-induced oxidative stress in an endothelial cell line (ECV304) in dose-dependent manner, as well as an increase in cell survival. In addition, The PE-AE (7:3) at 50 µg/mL was as potent as quercetin at 10 µg/mL in the inhibition of H2O2-induced lipid peroxidation. The combinations of ellagic acid and hydroxycinnamic derivatives which attributed to synergistic antiradicals enhanced cytoprotective activity. This first report on synergistic combination of PE and AE has the potential to develop as new nutritional antioxidants.