Quercetin‑3‑O‑α‑L‑rhamnopyranoside (QI) is derived from the leaves of Lindera aggregata (Sims) Kosterm. And exhibits multiple biological activities, including an antioxidant activity. However, the detailed molecular mechanism of its antioxidant activity remains unknown. The aim of the present study was to investigate the antioxidant activity of QI and the underlying molecular mechanism in human umbilical vein endothelial cells (HUVECs). An oxidative stress model was established in HUVECs using H2O2, and cells were then treated with different concentrations of QI. The results revealed that the exposure of HUVECs to QI protected these cells from H2O2‑induced damage. QI treatment also increased the activities of the antioxidant enzymes superoxide dismutase (SOD) and glutathione (GSH) in the cell culture medium. In addition, QI inhibited H2O2‑induced apoptosis by decreasing the expression levels of cleaved Caspase‑9 and poly(ADP‑ribose) polymerase. QI also inhibited the production of DNA fragments and reactive oxygen species induced by H2O2. Furthermore, QI decreased the oxidative stress by promoting the nuclear transfer of nuclear factor erythroid 2‑related factor 2 (Nrf2) and heme oxygenase‑1 by activating autophagy, and inhibited the competition of Bach1 from Nrf2. Finally, QI significantly improved the activities of T‑SOD and GSH, and decreased the content of malondialdehyde in the serum and heart tissue of aging rats. These data support the use of QI as a health supplement to alleviate oxidative stress or further development of this compound as an antioxidant drug.