Protective effects of sweet orange (Citrus sinensis) peel and their bioactive compounds on oxidative stress

► HD, HT, NT, and TT were present in water extracts of sweet orange peel (WESP). ► WESP and their bioactive compounds protected HepG2 cell death induced by t-BHP. ► Phenolic bioactive compounds in WESP contributed to inhibition of oxidative stress. ► The protective mechanism of WESP is maintenance of the normal redox status of cells.