In Vitro α ‐Amylase and α ‐Glucosidase Inhibitory and Antioxidant Activities of the Crude Extract and Solvent Fractions of Hagenia abyssinica Leaves

Background . The leaves of Hagenia abyssinica have been used in the management of diabetes mellitus in Ethiopian folk medicine. Thus, this study is aimed at investigating the in vitro α ‐amylase and α ‐glucosidase inhibitory and antioxidant activities of the crude extract and solvent fractions of H. abyssinica leaves. Methods . The in vitro α ‐amylase and α ‐glucosidase inhibitory and antioxidant activities of the plant extract were assessed using 3,5‐dinitrosalicylic acid (DNSA), p‐nitro‐phenyl‐a‐D glucopyranoside (p‐NPG), and 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) assays, respectively. Each value of percent inhibition of α ‐amylase, α ‐glucosidase, and DPPH scavenging effect was presented as means ± SEM ( n = 3). Results . The α ‐amylase inhibitory activity of the crude extract and solvent fractions was found to be concentration‐dependent. The strongest activity was exhibited by the crude extract at the highest concentration with a percentage inhibition of 74.52% (IC 50 , 14.52 μ g/ml) followed by water fraction 68.24% (IC 50 , 16.31 μ g/ml), ethyl acetate fraction 61.57% (IC 50 , 18.73 μ g/ml), and chloroform fraction 56.87% (IC 50 , 21.57 μ g/ml) of H. abyssinica leaves. In the α ‐glucosidase inhibition assay, the maximum activity was exhibited by the aqueous fraction 62.54% (IC 50 , 11.67 μ g/ml) followed by ethyl acetate fraction 54.97% (IC 50 , 15.89 μ g/ml), crude extract 46.79% (IC 50 , >16.5 μ g/ml), and chloroform fraction 36.44% (IC 50 , >16.5 μ g/ml). In the antioxidant assay, the crude extract exhibited the highest antioxidant activity 86.36% (IC 50 , 10.25 μ g/ml) followed by water fraction 78.59% (IC 50 , 13.86 μ g/ml), ethyl acetate fraction 71.58% (IC 50 , 16.34 μ g/ml), and chloroform fraction 63.65% (IC 50 , 18.83 μ g/ml). Conclusion . This study has revealed that H. abyssinica leaves possess noticeable in vitro α ‐amylase and α ‐glucosidase inhibitory and antioxidant activities.