INHIBITION OF SOME KEY ENZYMES LINKED TO DIABETES BY ANNONA SENEGALENSIS LEAF EXTRACT IN VITRO
INHIBITION OF SOME KEY ENZYMES LINKED TO DIABETES BY ANNONA SENEGALENSIS LEAF EXTRACT IN VITRO
No Thumbnail Available
Date
2018-09
Authors
AUWAL, IBRAHIM
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Annona senegalensis Pers (Annonaceae) known as Wild Custard Apple is locally used in treatment of diabetes in Nigeria. This study was aimed at investigating the possible compounds present in the leaf extracts of A. senegalensis and their inhibitory potentials on the activities of α-amylase, α-glucosidase and aldose reductase. The leaf sample was extracted sequentially in n-hexane, ethyl acetate and ethanol and the effect of the extracts on the activities of some enzymes was tested. The most active extract was further fractionated using column chromatography and the fractions obtained were used to determine the inhibitory activities of some enzymes to find the most active fraction. The possible bioactive compounds were determined by Gas Chromatography Mass Spectroscopy (GC-MS). Ethanol extract had significantly higher (p<0.05) inhibitory activities with lower IC50 values against the activities of α-amylase: 204.04±6.38 μg/ml, α-glucosidase: 97.91±2.40 μg/ml and aldose reductase: 119.58±12.85 μg/ml compared to other extracts. The most active fraction-F from the ethanolic extract had significantly higher (p<0.05) α-amylase and α-glucosidase inhibitory activities with IC50 values 237.14±31.19 μg/ml and α-88.25±0.59 μg/ml respectively while fraction-B had higher aldose reductase inhibitory activity with IC50 value 83.18±0.03μg/ml. The kinetics of the enzymes’ activities of the fraction-F is a competitive inhibitor for α-amylase with Vmax: 27.03μmol/min, Km: 0.24% and ki: 8.46μg/ml and non-competitive inhibitor for α-glucosidase Vmax: 1.10 μmol/min, Km: 3.7 mmol/L, and ki: 1.26μg/mL. Phenolic compounds were found in fraction-F. 1, 2-Benzenedicarboxylic acid butyl octyl ester, 1, 2-Benzenedicarboxylic acid, bis (2-methylpropyl) ester, Hexadecanoic acid, methyl ester and Methyl 9-methyltetradecanoate were found in fraction-F. The data of this study suggest that A. senegalensis possess inhibitory activities on against α-amylase, α-glucosidase and aldose reductase activities; and therefore could be attributed to the presence of compounds identified
Description
A THESIS SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES, AHMADU BELLO UNIVERSITY, ZARIA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE AWARD OF A MASTER DEGREE IN BIOCHEMISTRY DEPARTMENT OF BIOCHEMISTRY FACULTY OF LIFE SCIENCES AHMADU BELLO UNIVERSITY, ZARIA NIGERIA
Keywords
INHIBITION,, KEY ENZYMES LINKED,, DIABETES,, ANNONA SENEGALENSIS,, LEAF EXTRACT,, VITRO,