New 6-O-acyl isoflavone glycosides from soybeans fermented with Bacillus subtilis (natto). I. 6-O-succinylated isoflavone glycosides and their preventive effects on bone loss in ovariectomized rats fed a calcium-deficient diet.
Three new 6-O-acylated isoflavone glycosides were isolated from soybeans fermented with Bacillus subtilis (natto) and identified as daidzein 7-O-beta-(6''-O-succinyl)-D-glucoside (1), genistein 7-O-beta-(6''-O-succinyl)-D-glucoside (2), and glycitein 7-O-beta-(6''-O-succinyl)-D-glucoside (3) on the basis of spectral data and chemical transformations. During fermentation, the content of the isoflavone glycosides first decreased and then increased, whereas the corresponding 6''-O-succinyl derivatives first accumulated and then decreased, in either soybeans or soybean cooking solution. These changes suggest that enzymatic interconversion of isoflavone glycosides and the corresponding 6''-O-succinylated derivatives occurs in these media during fermentation. The 6-O-succinylated isoflavone glycosides 1, 2 and 3 accounted for 4.8, 7.2 and 0.6%, respectively, of the total isoflavones in commercial fermented soybeans (Japanese natto). Oral administration of 1 or 2 alone for 4 weeks at a dose of 50 mg/kg/d prevented bone loss in ovariectomized (ovx) rats fed a calcium-deficient diet, being as effective as the positive controls, daidzin and genistin, respectively. Compound 1 seems to be proestrogenic, like daidzin, which suppresses bone resorption to prevent bone loss after ovariectomy by directly acting on bone sites, while 2 appears to have a different mechanism of action, like that of genistin.
Toda
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T
Fujicco Co., Ltd., Kobe, Japan.
Uesugi
T
T
Hirai
K
K
Nukaya
H
H
Tsuji
K
K
Ishida
H
H
D000818:Animals; D001412:Bacillus subtilis / Q000378:metabolism*; D001835:Body Weight / Q000187:drug effects; D002118:Calcium / Q000172:deficiency*; D002136:Calcium, Dietary / Q000494:pharmacology; D002851:Chromatography, High Pressure Liquid; D005260:Female; D005285:Fermentation; D006027:Glycosides / Q000096:biosynthesis / Q000302:isolation & purification / Q000494:pharmacology*; D006801:Humans; D007529:Isoflavones / Q000138:chemical synthesis / Q000302:isolation & purification / Q000494:pharmacology*; D009929:Organ Size / Q000187:drug effects; D015663:Osteoporosis, Postmenopausal / Q000188:drug therapy* / Q000473:pathology; D010052:Ovariectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D013025:Glycine max / Q000737:chemistry*; D016339:Spectrometry, Mass, Fast Atom Bombardment; D013055:Spectrophotometry, Infrared
D002136:Calcium, Dietary; D006027:Glycosides; D007529:Isoflavones; D002118:Calcium