Original scientific paper

https://doi.org/10.2478/acph-2014-0025

Anti-oxidative activity and inhibition of key enzymes linked to type 2 diabetes(α-glucosidase and α-amylase) by Khaya senegalensis

MOHAMMED AUWAL IBRAHIM ; School of Life Sciences, University of KwaZulu-Natal (Westville Campus), Durban, 4000 South Africa; Department of Biochemistry, Ahmadu Bello University, Zaria, Nigeria
NEIL ANTHONY KOORBANALLY ; School of Chemistry and Physics, University of KwaZulu-Natal (Westville Campus), Durban, 4000 South Africa
MD. SHAHIDUL ISLAM ; School of Life Sciences, University of KwaZulu-Natal (Westville Campus), Durban, 4000 South Africa

Abstract

This study evaluated the in vitro anti-oxidative activity of Khaya senegalensis extracts and inhibitory effects of some solvent fractions on α-glucosidase and α-amylase activities. The stem bark, root and leaf samples of the plant were sequentially extracted with ethyl acetate, ethanol and water and then tested for anti-oxidative activity. Our findings revealed that the ethanolic extract of the root had the highest anti-oxidative activity. Solvent-solvent fractionation of the root ethanolic extract yielded a butanol fraction that showed higher anti-oxidative activity than other fractions. Furthermore, the butanol fraction had significantly higher (p < 0.05) α-glucosidase and α-amylase inhibitory activities with IC50 values of 2.89 ± 0.46 and 97.51 ± 5.72 μg mL–1, respectively. Enzyme kinetic studies indicated that the butanol fraction is a non-competitive inhibitor for α-glucosidase with an inhibition binding constant Ki of 1.30 μg mL–1 and a competitive inhibitor of α-amylase with a Ki of 7.50 μg mL–1. GC-MS analysis revealed that the butanol fraction contained two chromones, p-anilinophenol and 3-ethyl-5-(3-ethyl-(3H)-benzothiazol-2-ylidene)-2-(p-tolylvinylamino)-4-thiazolidinone.Data obtained in the study suggest that the butanol fraction derived from the ethanolic extract of K. senegalensis root possessed excellent anti-oxidative as well as α-glucosidase and α-amylase inhibitory activities while chromones and/or p-anilinophenol could be the main bioactive compounds responsible for the observed activities.

Keywords

Khaya senegalensis (Meliaceae); type-2 diabetes; α-glucosidase; α-amylase; oxidative stress

Hrčak ID:

121069

URI

https://hrcak.srce.hr/121069

Publication date:

30.9.2014.

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