Koekemoer T.C., Rashed K., Mtshizana O., van de Venter M.
Department of Biochemistry and Microbiology, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa; Pharmacognosy Department, National Research Centre, Dokki, Giza, Egypt
Koekemoer, T.C., Department of Biochemistry and Microbiology, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa; Rashed, K., Pharmacognosy Department, National Research Centre, Dokki, Giza, Egypt; Mtshizana, O., Department of Biochemistry and Microbiology, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa; van de Venter, M., Department of Biochemistry and Microbiology, Nelson Mandela Metropolitan University, Port Elizabeth, South Africa
Postprandial hyperglycaemia is a major contributory factor in the development of diabetes which can be clinically targeted via a number of independent mechanisms such as the inhibition of postprandial glucose absorption and through potentiating glucose dependent insulin release. This study was carried out to evaluate antidiabetic effect of four Egyptian medicinal plants, Sonchus oleraceus, Lagerstroemia tomentosa, Diospyros virginiana, and Toona ciliate, and to investigate the phytoconstituents from the bioactive plant extracts. The results revealed that L. tomentosa leaves methanol 80% extract was the most effective inhibitor of carbohydrate digestion which showed strong inhibition against both alpha-amylase and alphaglucosidase. The relevance to mammalian alpha-glucosidase was confirmed using a rat intestinal maltase assay however the inhibitory activity was considerably weaker relative to the yeast enzyme. None of the extracts displayed any significant inhibition against DPP-iv, an additional target to regulate postprandial hyperglycaemia. Cytotoxicity screening against Chang liver cells did not reveal any significant toxicity suggesting a favourable safety profile. Phytochemical studies of methanol 80% extract of L. tomentosa leaves produced lupeol (1), corosolic acid (2), gallic acid (3), ellagic acid (4), apigenin (5), vitexin (6), apigenin 7-O-β-glucoside (7), and kaempferol 3-O-β- galactoside (8). These results gave scientific evidence that L. tomentosa leaves may provide anti-diabetic effect through the inhibition of postprandial glucose absorption.
alkaloid; alpha glucosidase; amylase; antidiabetic agent; apigenin; apigetrin; carbohydrate; corosolic acid; coumarin derivative; Diospyros virginiana extract; ellagic acid; flavonoid; gallic acid; kaempferol 3 galactoside; Lagerstroemia tomentosa extract; lupeol; methanol; plant extract; plant medicinal product; saponin; Sonchus oleraceus extract; tannin derivative; Toona ciliate extract; triterpene; unclassified drug; vitexin; antidiabetic activity; Article; controlled study; cytotoxicity test; Diospyros virginiana; drug identification; drug mechanism; drug screening; drug structure; Egypt; enzyme inhibition; glucose absorption; IC50; Lagerstroemia tomentosa; liver cell; medicinal plant; phytochemistry; plant leaf; Sonchus oleraceus; Toona ciliate