Enzymatic hydrolysis of green tea seed extract and its activity on 5α-reductase inhibition

Abstract

Two kaempferol glycosides were isolated from green tea seed extract (GTSE). After conducting a structure analysis, these two compounds were identified as kaempferol-3-O-[2-O-β-D-galactopyranosyl-6-O-α-L-rhamnopyranosyl] -β-D-glucopyranoside (compound 1) and kaempferol-3-0-[2-O-β-D- xylopyranosyl-6-0-α-L-rhanmopyranosyl]-β-D-glucopyranoside (compound 2). These two compounds were hydrolysed by o-glycolytic enzymes for the production of kaempferol. After performing several reactions, we found the optimum enzyme combination, a reaction with β-galactosidase and hesperidinase. Finally, we produced kaempferol of above 95% purity. The 5α-reductase inhibition activities of GTSE hydrolysate (GTSE-H) containing kaempferol were evaluated by the contact cell-based metabolic method using a stable HEK 293 cell line. GTSE-H showed a good inhibition effect on HEK 293 cell lines both type 1 and type 2 on 5α-reductase. Especially, GTSE-H inhibited type 2 with kaempferol content dependency. The results indicate that the inhibition activity of hydrolysate on 5α-reductase type 2 increases in accordance with kaempferol content.