Objective To explore the antioxidant activity and molecular mechanism of the typical flavonoid apigenin and its glycoside compounds in Dendrobium officinale.Methods The antioxidant activities of apigenin and its glycoside compounds were assessed using the DPPH free radical scavenging assay, and their effects on the expression of antioxidant proteins in HepG2 cells were examined by Western blot.Results Vitexin exhibited significantly stronger antioxidant activity than apigenin and New Zealand vitexin Ⅱ, with an IC₅₀ value for DPPH radical scavenging of 43.48 mmol/L. MTT assays confirmed that apigenin (20 μmol/L), vitexin, and New Zealand vitexin Ⅱ (80 μmol/L) were non-toxic to HepG2 cells. In normal HepG2 cells, 5 μmol/L apigenin significantly upregulated the expression of the antioxidant proteins Nrf2 and NQO1 compared with its glycoside compounds. In the t-BHP-induced oxidative stress model, apigenin significantly alleviated oxidative damage by promoting nuclear translocation of Nrf2, activating the expression of NQO1, HO-1, and Nrf2, enhancing SOD activity, and increasing GSH content.Conclusion The flavonoid apigenin in D. officinale exerts significant antioxidant effects by activating the Nrf2 signaling pathway.