Because oxidative stress is involved in the pathogenesis of various chronic diseases and the aging process, antioxidants that can increase the intrinsic antioxidant potency are proposed as desirable therapeutic agents to counteract oxidative stress-related diseases. NF-E2-related factor-2 (Nrf2) is a transcription factor that regulates important antioxidant and phase II detoxification genes, and therefore, the molecule that regulates nuclear translocation of Nrf2 and the induction of antioxidative proteins is thought to be a promising candidate as acytoprotective agent for oxidative stress. In the present study, we show that isoorientin (luteolin 6-C-${eta}$-D-glucoside)obtained from the leaves of Sasa borealis upregulates and activates Nrf2, and has protective ability against oxidative damage caused by reactive oxygen intermediates in HepG2 cells. Issorientin induces increase in the level of antioxidant enzyme proteins, especially NQO1, and the cytoprotective and antioxidative effecxts of isoorientin are PI3K/Akt pathway-dependent Together with direct radical scavenging activity, the novel effect of isoorientin on the regulation of antioxidative gene expression provides attractive strategy to prevent diseases associated with oxidative stress and attenuate the progress of the diseases.