In vitro comparative assessment of the inhibitory effects of single and combined spices against glucose-synthesizing enzymes

Abstract

Purpose: To assess the individual and synergistic inhibitory activities of five (5) tropical spices, viz, Zingiber officinale Rosc., Xylopia aethiopica (Dun.) A. Rich, Piper guineense Schum & Thonn, Myristica fragrans Houtt. and Allium sativum L. against glucose hydrolysing enzymes.Methods: In vitro assessment of the alpha-amylase and alpha-glucosidase inhibitory activities of cold water, hot water, ethanol and aqueous-ethanol extracts of each of the five spices and their combination was investigated using enzymatic protocols. Acarbose was used as the standard.Results: Only four extracts showed strong inhibition against alpha-glucosidase and weak inhibition against alpha-amylase. Going by their half-maximal inhibitory concentrations (IC50), the combined spices exhibited the best concurrent inhibitory activity against both hydrolysing enzymes (665.83 ± 27.50 μg/mL for alpha-glucosidase) and (1166.86 ± 14.70 μg/mL for alpha-amylase).Conclusion: The findings from this study demonstrate the enhanced antihyperglycemic potentials of the combined spices compared to the individual spices for the management of diabetes. Keywords: Hyperglycemia, Diabetes, Alpha-amylase, Alpha-glucosidase, Zingiber officinale, Xylopia aethiopica, Piper guineense, Myristica fragrans, Allium sativum, Spices