INVESTIGATION OF IN VITRO AND IN VIVO ANTIOXIDANT ACTIVITIES OF FLAVONOID EXTRACT FROM ABELMOSCHUS MANIHOT (L.) MEDIC FLOWER

An increasing number of natural antioxidants from medicinal plants have been shown safe and effective to human health. Abelmoschus manihot (L.) Medic flower is a traditional medicine with high flavonoid content. In this study we investigated the antioxidant activities of total flavonoid extract from A. manihot (L.) Medic flowers (TFAE) in vivo and in vitro and explored the expression of antioxidant genes in mice. In the in vitro assay, the scavenging activities of TFAE were evaluated against DPPH radical superoxide radical hydroxyl radical. Meanwhile, ferric reducing antioxidant power and inhibiting lipid peroxidation of TFAE were investigated. In the in vivo assay, male Kunming mice were randomly divided into six groups (n = 10/group): (1) Normal control, (2) GAL (D-galactose) model, (3) GALA (positive control, GAL+ ascorbic acid), (4) GALL (GAL + 40 mg total flavonoid of TFAE/kg body weight), (5) GALM (GAL + 80 mg total flavonoid of TFAE/kg body weight), (6) GALH (GAL + 160 mg total flavonoid of TFAE/kg body weight). After 42 days, protective effects of TFAE were determined by biochemical studies and Real-time PCR. TFAE had strong scavenging activities against DPPH radical (IC50 = 7.98 mu g/ml), superoxide anion radical (IC50 = 14.96 mu g/ml), hydroxyl radical (IC50 = 129.02 mu g/ml) and high ferric reducing antioxidant power (A(700nm) = 2.32) compared to ascorbic acid. However, the inhibiting of lipid peroxidation was lower than that of BHA. GAL-induced mice that were administered TFAE showed significant elevation in serum and liver activities of antioxidant enzymes (CAT, GPx, SOD) and T-AOC whereas reduction in MDA production in a dose-dependent manner compared with mice in GAL model group. Furthermore, the mRNA expression of antioxidant genes also increased in TFAE treatment groups significantly. These results suggested that TFAE exhibited antioxidant activities possibly regulated through antioxidant genes expression. TFAE may represent a potential natural source for reducing the risk of diseases and preventing aging.