Laurus Nobilis Linn. Inhibits Polyol Pathway Enzymes: Strategy for Managing Diabetic Complications

Background: The rising incidence of diabetic complications necessitate the continuous search for safer, cheaper, and effective pharmacological agents. The polyol pathway is an underlying process implicated in the pathogenesis of diabetic complications. Inhibition of enzymes in the polyol pathway is a veritable means of ameliorating diabetic complications. Objective: This study evaluated the inhibitory potential of some spicy plants on the activities of polyol pathway enzymes (aldose reductase and sorbitol dehydrogenase). Methods: Aqueous extracts of Laurus nobilis (bay), Cinnamomum zeylanicum (cinnamon), Murraya koenigii (curry), Thymus vulgaris (thyme), and Curcuma longa (turmeric) were incubated with appropriate enzymes and substrates, and inhibition percentages were determined. Results: The results showed that bay extract had effective IC50 for the inhibition of both aldose reductase (174.87 μg/mL) and sorbitol dehydrogenase (37.08 μg/mL). It also revealed that bay extract inhibited aldose reductase and sorbitol dehydrogenase in a non-competitive and competitive manner, respectively. Conclusion: It is, therefore, concluded that bay extract effectively inhibited activities of polyol pathway enzymes and might contribute to the amelioration of diabetic complications.