7,8‐dihydroxyflavone displayed antioxidant effect through activating HO‐1 expression and inhibiting caspase‐3/PARP activation in RAW264.7 cells

Abstract

AbstractFlavonoids, which contain a benzo‐γ‐pyrone (C6–C3–C6) skeleton, have been reported to exhibit effective antioxidant ability. This study aimed to compare the antioxidant activities of 7,8‐dihydroxyflavone (7,8‐DHF) and 7‐hydroxyflavone (7‐HF) in H2O2, lipopolysaccharide (LPS), or tert‐butyl hydroperoxide (t‐BHP)‐induced RAW264.7 cells, respectively. The antioxidant capacities of 7,8‐DHF and 7‐HF were firstly evaluated by 2,2‐azinobis‐3‐ethyl‐benzothiazoline‐6‐sulphonic acid (ABTS), 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. Then, reactive oxygen species (ROS), super oxide dismutase (SOD), and malondialdehyde (MDA) productions in H2O2, LPS, or t‐BHP‐induced RAW264.7 cells were tested and compared, respectively. Finally, the antioxidant mechanisms of 7‐HF and 7,8‐DHF were initially investigated by western blot. Our results showed that 7,8‐DHF possessed stronger free‐radical scavenging capacity than 7‐HF. Both 7,8‐DHF and 7‐HF suppressed MDA production and ROS accumulation, improved the activity of SOD in H2O2, LPS, or t‐BHP‐induced RAW264.7 cells, respectively. And 7,8‐DHF exerted a better antioxidant effect than 7‐HF, especially in t‐BHP‐induced oxidative stress. Mechanically, 7,8‐DHF prevented the activation of poly ADP‐ribosepolymerase and caspase‐3, meanwhile markedly upregulated the expression of HO‐1 protein in t‐BHP‐induced oxidative stress. These results suggested that 7,8‐DHF might serve as a potential pharmaceutical drug against oxidative stress injury.