Angiotensin-converting enzyme inhibitory and antioxidant activities of enzymatically synthesized phenolic and vitamin glycosides

Amyloglucosidase from Rhizopus mould and beta-glucosidase from sweet almond were employed for the preparation of phenolic and vitamin glycosides of vanillin, N-vanillylnonanamide, DL-dopa, dopamine, curcumin, alpha-tocopherol (vitamin E), pyridoxine (vitamin B-6), ergocalciferol (vitamin D-2), thiamin (vitamin B-1) and riboflavin (vitamin B-2). Approx. 20 enzymatically prepared phenolic and vitamin glycosides were subjected to ACE (angiotensin-converting enzyme) inhibition activity measurements, and 14 glycosides were tested for antioxidant activities. Both phenolic and vitamin glycosides exhibited IC50 values for ACE inhibition in the 0.52 +/- 0.03-3.33 +/- 0.17 mM range and antioxidant activities ranging from 0.8 +/- 0.04 to 1.18 +/- 0.06 mM. Comparable ACE inhibition values were observed between free phenols and vitamin glycosides. However, antioxidant activities of glycosides were, in general, lesser than those of free phenols. Best IC50 value for ACE inhibition were observed for II-O-(D-fructofuranosyl)thiamin (0.52 +/- 0.03 mM), 3-hydroxy-4-O-(6-D-sorbitol)phenylalanine (0.56 +/- 0.03 mM), 4-O-(beta-D-glucopyranosyl)vanillin (0.61 +/- 0.03 mM), 4-O-(D-galactopyranosyl)vanillin (0.61 0.03 mM) and pyridoxine-D-glucoside (0.84 +/- 0.04 mM). Similarly, best IC50 values for antioxidant activity were observed for 1,7-O-(bis-beta-D-glucopyranosyl)curcumin (0.8 +/- 0.04 mM), 4-O-(beta-D-glucopyranosyl)vanillin (0.9 +/- 0.05 mM), 3-hydroxy-4-O-(beta-D-galactopyranosyl-(1' -> 4)beta-D-glucopyranosyl)phenylalanine (0.9 0.05 mM), 20-O-(D-glucopyranosyl)ergocalciferol (0.9 +/- 0.05 mM) and dopamine-D-galactoside (0.93 +/- 0.05 mM).