Didunyemi OM
The objective of this study was to investigate comparatively the inhibitory potency and mode of inhibition of aqueous leaf extracts of Acalypha wilkesiana ‘green’ (A.w.g) and Acalypha wilkesiana ‘red’ (A.w.r) on alpha glucosidase from Saccharomyces cerevisiae and alpha amylase from Aspergillus oryzae with a view to establishing the better antidiabetic plant. This study employed para-nitrophenylglucopyranoside (PNPG) and starch as substrates while Acarbose was used as reference. We also qualitatively screened for important phytochemicals as well as the phenolic contents of the extracts. The extracts contained alkaloid, flavonoid, saponin, tannin, steroid, carotenoid and terpenoid while anthraquinone was absent. Aqueous extract of A.w.r had the higher total phenolics (total phenol: 35.75±3.39mgGAE/g and total flavonoid: 350.63±5.01mgQE/g). A.w.r expressed the higher inhibitory effect against alpha glucosidase and alpha amylase with IC50 values of 85.6μg/ ml and 75.6μg/ml respectively in a near competitive fashion while the A.w.g exhibited mixed non-competitive inhibition of alpha amylase and alpha glucosidase. We can therefore deduce from this study that aqueous extract of Acalypha wilkesiana ‘red’ is a more potent inhibitor of alpha amylase and alpha glucosidase.
Keywordsα-glucosidase; α-amylase; Total phenol; Flavonoids
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