Antioxidant and a-glucosidase inhibitory activity of Adina rubella Hance in vitro

Antioxidant activity of extracts from Adina rubella Hance (AR) was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and 2,2′-azino-bis (3-ethylbenzothiazoline)-6-sulphonic acid diamonium salt (ABTS) radical scavenge and ferric reducing antioxidant power assay (FRAP) with BHT (2,6-Di-tert-butyl-4-methyiphenol) as positive control, and α-glucosidase inhibitory activity assay of AR extracts with acarbose as positive control in vitro. DPPH radical scavenging activity was observed in ethyl acetate extract (AREA) and n-butanol extract (ARBU). Their IC50 values were 21.63 and 23.16 µg/mL, respectively, slightly weaker than that of BHT (IC50 = 18.71 µg/mL). ABTS radical scavenging activity of AREA (IC50 = 17.25 µg/mL) was higher than that of petroleum ether extract (ARPE) and ARBU (IC50 = 25.73 and 20.64 µg/mL, respectively), but they were weaker than that of BHT (IC50 = 7.72 µg/mL). Ferric reducing antioxidant power for ARPE, ARBU and TEAC values were 1649.6 ± 16.09 and 1734.27 ± 68.53 μmol TE/g, respectively, and was higher than that of BHT with TEAC value of 1581.68 ± 97.41 μmol TE/g. AREA (IC50 = 862.2 μg/mL ) had the best α-glycosidase inhibitory activity, followed by ARBU (IC50 = 924.9 μg/mL) and ARPE (IC50 = 994.0 μg/mL). Their inhibitory activity was higher than that of acarbose (IC50 = 1103.01 µg/mL) as positive control. Results indicated that antioxidant and α-glycosidase inhibitory activity of AREA were better than that ARPE and ARBU in vitro. Key words: Antioxidant activity, α-glucosidase inhibitory activity, Adina rubella Hance.