Antioxidant activities of sea buckthorn leaf tea extracts compared with green tea extracts

The polyphenol, flavonoid, and ascorbic acid contents of sea buckthorn leaf tea extracts, along with antioxidant activities, were compared with green tea extracts under different extraction conditions. Sea buckthorn leaf tea and green tea were extracted using water (SW, GW) and ethanol at room temperature (SE, GE), respectively, and at 80°C (SWH, GWH, SEH, and GEH, respectively). GEH, GWH, SE, and SEH contained more antioxidant compounds and higher activities, and SWH, SEH, GWH, and GEH had elevated antioxidant enzyme activity levels in H2O2-treated RAW264.7 cells. Cells treated with SWH and SEH showed elevated expression of nuclear factor (erythroid-derived 2)-like 2 and maintained the cell glutathione (GSH)/glutathione disulfide (GSSG) ratio at levels similar to H2O2-untreated controls.