Hydrolysis of flavonoid glycosides by propolis β-glycosidase

Flavonoids generally occur as O-glycosides with sugars bound in nature, while aglycones and their derivatives are the main flavonoids in propolis. The objective of this work was to study the propolis beta-glycosidase activities toward flavonoid beta-glycosides and their conjugated forms. beta-Glycosidase was extracted from propolis, incubated with Favonoid glycosides, and analysed for aglycone formation by HPLC. The results demonstrated that glucose conjugates were rapidly hydrolysed, but not conjugates with other sugars, i.e. rutin and naringin. The rate and extent of deglycosylation depends on the structure of the Favonoid and the position of the sugar substituitions. Quercetin 3-O-glucoside had the highest percent of hydrolysis, while quercetin 7-O-glucoside was the least hydrolysed. The K-m values for hydrolysis of apigenin 7-glucoside and luteolin-7-O-glucoside were 13 mu M and 20 mu M, respectively.