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BioMed Research International
Volume 2013 (2013), Article ID 527570, 6 pages
http://dx.doi.org/10.1155/2013/527570
Research Article

Modes of Inhibition of α-Amylase and α-Glucosidase by Aqueous Extract of Morinda lucida Benth Leaf

1Department of Biochemistry, Lagos State University, PMB 0001, LASU Post Office, Lagos, Nigeria
2Department of Chemistry, Lagos State University, PMB 0001, LASU Post Office, Lagos, Nigeria

Received 16 April 2013; Revised 1 October 2013; Accepted 11 October 2013

Academic Editor: Jude M. Przyborski

Copyright © 2013 M. I. Kazeem et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Diabetes mellitus is a metabolic disorder of glucose metabolism. The management of blood glucose level is the hallmark in the treatment of this disease. This may be achieved through the use of oral hypoglycemic drugs such as biguanides, insulin secretagogues, and α-glucosidase inhibitors. The purpose of the present study was to investigate the inhibitory effect of Morinda lucida leaf extracts on the activities of α-amylase and α-glucosidase. This was performed using α-amylase from Aspergillus oryzae and α-glucosidase from Saccharomyces cerevisiae. Aqueous extract of Morinda lucida gave the highest percentage yield (9.99%) of the plant out of the three extracts (compared to acetone and ethanolic extracts) and possesses the highest inhibitory activity against α-amylase (IC50 value of 2.30 mg/mL) and α-glucosidase (IC50 value of 2.00 mg/mL). Kinetic analysis revealed that the aqueous extract of this plant leaf inhibited the α-amylase competitively but displayed mixed noncompetitive mode of inhibition towards α-glucosidase. It can be concluded that aqueous extract of Morinda lucida exhibited the best inhibitory activity on the two enzymes studied and the presence of phytochemicals like flavonoids, saponins, and tannins may have contributed greatly to the inhibitory activity of the plant extract.