Inhibitory Effect of the Stem Bark Extracts of Albizia chevalieri Harms on the Activity of Alpha-glucosidase Obtained from Aspergillus niger

Abstract

The aim of the current study is to evaluate the inhibition of α-glucosidase activity by stem bark extract of Albizia chevalieri. The activity of alpha glucosidase was assayed in vitro using 50 mM acetate buffer pH 6.0 (prepared from acetic acid and sodium acetate) and various concentration of maltose (0.5 mM to 10 mM). Five test tubes, labeled TA – TE, each containing 1.5 ml of acetate buffer, 0.5 ml of alpha glucosidase and 0.5 ml of a known concentration of plant extract and control tubes (CA – CE) were assessed for Alpha glucosidase activity. The results showed that hexane, ethyl acetate and methanol extracts inhibited α-glucosidase activity. The results further indicated that the extracts act by competitive inhibition with inhibition constant of 232 mg/ml, 157 mg/ml and 67 mg/ml for hexane, ethyl acetate and methanol extracts, respectively. The value for the inhibition constants shows that there is a strong binding of the enzyme to the inhibitor as the polarity of solvent increases. The inhibitory activity of Albizia chevalieri may be due one or more of the phytochemicals present in the extracts.