Deglycosylation of flavonoid and isoflavonoid glycosides by human small intestine and liver beta-glucosidase activity.
Flavonoid and isoflavonoid glycosides are common dietary phenolics which may be absorbed from the small intestine of humans. The ability of cell-free extracts from human small intestine and liver to deglycosylate various (iso)flavonoid glycosides was investigated. Quercetin 4'-glucoside, naringenin 7-glucoside, apigenin 7-glucoside, genistein 7-glucoside and daidzein 7-glucoside were rapidly deglycosylated by both tissue extracts, whereas quercetin 3,4'-diglucoside, quercetin 3-glucoside, kaempferol 3-glucoside, quercetin 3-rhamnoglucoside and naringenin 7-rhamnoglucoside remained unchanged. The Km for hydrolysis of quercetin 4'-glucoside and genistein 7-glucoside was approximately 32+/-12 and approximately 14+/-3 microM in both tissues respectively. The enzymatic activity of the cell-free extracts exhibits similar properties to the cytosolic broad-specificity -glucosidase previously described in mammals.
Department of Biochemistry, Institute of Food Research, Colney, Norwich, UK.
A J
AJ
Day
M S
MS
DuPont
S
S
Ridley
M
M
Rhodes
M J
MJ
Rhodes
M R
MR
Morgan
G
G
Williamson
D002457:Cell Extracts; D002474:Cell-Free System; D020843:Chamomile; D003600:Cytosol / Q000201:enzymology; D044950:Flavanones; D005419:Flavonoids / Q000378:metabolism*; D019833:Genistein / Q000378:metabolism; D005942:Gluconates / Q000494:pharmacology; D006027:Glycosides / Q000378:metabolism*; D006031:Glycosylation; D006801:Humans; D007294:Inositol / Q000031:analogs & derivatives / Q000494:pharmacology; D007421:Intestine, Small / Q000201:enzymology*; D007529:Isoflavones / Q000378:metabolism; D007783:Lactones; D008099:Liver / Q000201:enzymology*; D009822:Oils, Volatile / Q000378:metabolism; D010946:Plants, Medicinal; D011794:Quercetin / Q000031:analogs & derivatives / Q000378:metabolism; D012431:Rutin / Q000378:metabolism; D013656:Taurocholic Acid / Q000494:pharmacology; D001617:beta-Glucosidase / Q000037:antagonists & inhibitors / Q000378:metabolism*
D002457:Cell Extracts; D044950:Flavanones; D005419:Flavonoids; D005942:Gluconates; D006027:Glycosides; D007529:Isoflavones; D007783:Lactones; D009822:Oils, Volatile; D007294:Inositol; D013656:Taurocholic Acid; D012431:Rutin; C004742:daidzein; D011794:Quercetin; D019833:Genistein; D001617:beta-Glucosidase; C005273:naringenin; C080613:spiraeoside; C011423:conduritol epoxide; C010730:beta-glucono-1,5-lactone