Journal of
Medicinal Plants Research

  • Abbreviation: J. Med. Plants Res.
  • Language: English
  • ISSN: 1996-0875
  • DOI: 10.5897/JMPR
  • Start Year: 2007
  • Published Articles: 3835

Full Length Research Paper

Inhibitory effects of five medicinal plants on rat alpha-glucosidase: Comparison with their effects on yeast alpha-glucosidase

Shai, L. J.1*, Magano, S. R.2, Lebelo, S. L.2 and Mogale, A. M.3
1Department of Biomedical Sciences, Tshwane University of Technology, Arcadia Campus, Private Bag X680, Pretoria, 0001, South Africa. 2Department of Life and Consumer Science, University of South Africa, Florida campus, South Africa. 3Department of Physiology, University of Limpopo, P. O. Medunsa, 0204, South Africa.
Email: [email protected]

  •  Accepted: 07 March 2011
  •  Published: 04 July 2011


The mammalian and yeast α-glucosidase inhibitory activities of Senna italica, Tinospora fragosa, Manilkara mochisia, Xanthocercis zambesiaca, Ozoroa cf. albicans, Peltophorum africanum, Cassia abbreviata were investigated using p-nitrophenyl glucopyranoside as a substrate. All the plant species tested had low inhibitory activity against rat intestinal α-glucosidase. The highest concentration of C. abbreviata resulted in no observable loss of rat intestinal α-glucosidase activity. At 2.5 mg/ml, X. zambesiaca managed only 25% inhibition of rat intestinal glucosidase activity. M. mochisia led to about 60% loss of activity at 5 mg/ml. On the other hand, all plant species tested had good inhibitory activity against Baker’s yeast α-glucosidase. These findings suggest that a chemical substance that inhibits yeast α-glucosidase activity will not necessarily inhibit mammalian α-glucosidase. The validatation of the antidiabetic activity of medicinal plant extracts, with the focus on the inhibition of carbohydrate-digesting enzymes, will require, in addition, investigation of mammalian enzymes. The antioxidant activity of these plant species was also investigated, with C. abbreviata and ascorbic acid as the positive controls. The IC50 values were estimated. P. africanum had good antioxidant activity with an IC50 value of 0.030 mg/ml, similar to the IC50 value resulting from the positive control, ascorbic acid.


Key words: Diabetes mellitus, α-glucosidase activity, antioxidant activity, plant extracts.