Enhancement of polyphenol bio-activities by enzyme reaction

Using beta-glucosidase to hydrolyze glycosides into aglycones, the present study attempted to improve the bio-activity of the extract from mulberry leaves. When varying the ethanol fraction, pH,and temperature of the extract, the optimum conditions for the enzyme reaction were identified as a 10% ethanol fraction in the extract, pH 5.0, and 40 C temperature. Under these optimum conditions, the enzyme reaction produced a remarkable increase in the anti-oxidation and tyrosinase inhibition activities of the extract by as much as 219.5% and 230.9%, respectively. This improved bio-activity of the extract was due to the hydrolysis of the glycoside polyphenols rutin, isoquercitrin, and astragalin into the aglycone polyphenols quercetin and kaempferol. Furthermore, the enzymatic hydrolysis of the extract by beta-glucosidase also produced some additional benefits that are critical factors for the skin absorption of bio-active ingredients, including an improved hydrophobicity (239.41%) and reduced mean molecular weight (from 387.3 to 291.4), resulting in a significantly enhanced skin permeability (513%). (C) 2008 Elsevier B.V. All rights reserved.