Enzymatic preparation of kaempferol from green tea seed and its antioxidant activity.
Among the flavonols in green tea, kaempferol has many biological activities but kaempferol of plant origin is too expensive to be used in commercial products. Recently, we confirmed that green tea seed (GTS) contained a reasonable amount of kaempferol glycoside. After conducting structure analysis, two kaempferol glycosides were identified, kaempferol-3-O-[2-O-beta-D-galactopyranosyl-6-O-alpha-L-rhamnopyranosyl]-beta-D-glucopyranoside (compound 1) and kaempferol-3-O-[2-O-beta-D-xylopyranosyl-6-O-alpha-L-rhamnopyranosyl]-beta-D-glucopyranoside (compound 2), respectively. Also, a commercially useful method for kaempferol preparation was suggested by enzymatic hydrolysis using these two flavonoids. After several enzyme reactions were performed for the complete bioconversion of compounds 1 and 2 to kaempferol, we found that the optimum enzyme combination was reaction with beta-galactosidase and hesperidinase. Finally, we produced pure kaempferol with over 95% purity. We also compared the antioxidant effect of these two GTS flavonoids and its aglycone, kaempferol. Kaempferol is a more efficient scavenger of 1,1-diphenyl-2-picrylhydrazyl radicals and a better inhibitor of xanthine/xanthine oxidase than the two glycosides.
Park
Jun Seong
JS
Skin Research Institute, AMOREPACIFIC R&D Center, Yongin-si, Gyeonggi-do 449-729, Korea. superbody@amorepacific.com
Rho
Ho Sik
HS
Kim
Duck Hee
DH
Chang
Ih Seop
IS
D000975:Antioxidants / Q000494:pharmacology*; D028241:Camellia sinensis / Q000737:chemistry*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016166:Free Radical Scavengers; D006026:Glycoside Hydrolases / Q000378:metabolism; D006868:Hydrolysis; D044949:Kaempferols / Q000302:isolation & purification* / Q000494:pharmacology*; D012639:Seeds / Q000737:chemistry*; D014969:Xanthine Oxidase / Q000037:antagonists & inhibitors; D001616:beta-Galactosidase / Q000378:metabolism
D000975:Antioxidants; D004791:Enzyme Inhibitors; D016166:Free Radical Scavengers; D044949:Kaempferols; C006552:kaempferol; D014969:Xanthine Oxidase; D006026:Glycoside Hydrolases; C023307:hesperidinase; D001616:beta-Galactosidase