Anti-oxidant, anti-glycant, and inhibitory activity against α-amylase and α-glucosidase of selected spices and culinary herbs

Aqueous and methanol extracts of dry sage, rosemary, basil, parsley, chili, garlic and onion were analyzed to investigate their anti-oxidant and anti-glycant activities and in vitro inhibitory potential against enzymes involved in glycemic regulation. The aqueous extracts of rosemary and sage were the richest in phenolic compounds and showed the highest ability in binding iron and inhibiting DPPH, superoxide radicals and advanced glycation end-product production, lipid peroxidation, and the activity of a-glucosidase and a-amylase. On the other hand, the methanol extracts of both these Labiatae were less efficient than those of garlic, onion, parsley and chili in scavenging hydroxyl radicals. As far as protein glycation is concerned, methanol extracts were more effective in inhibiting the production of Amadori compounds and the aqueous ones in preventing advanced glycation endproduct formation. Therefore these spices may be preventive not only against cardiovascular diseases but also type 2 diabetes.