Ioku K, Pongpiriyadacha Y, Konishi Y, Takei Y, Nakatani N, Terao J
Osaka Kyoiku University, Japan.
Biosci Biotechnol Biochem. 1998 Jul;62(7):1428-31. doi: 10.1271/bbb.62.1428.
In order to evaluate the positional specificity for a glucoside group in the hydrolysis of flavonoid glucosides in the rat small intestine, beta-glucosidase activity was measured with the quercetin monoglucosides, quercetin-3-O-beta-D-glucopyranoside (Q3G), quercetin-4'-O-beta-D-glucopyranoside (Q4'G) and quercetin-7-O-beta-D-glucopyranoside (Q7G), as well as with quercetin-3-O-rutinoside (rutin) and p-nitrophenyl-beta-D-glucopyranoside (NPG) by using the HPLC technique. Enzymes were prepared from rat small intestinal mucosa of the duodenum, jejunum and ileum, among which the enzyme activity of the jejunum was highest for all the glycosides tested. Q4'G was the richest substrate for a beta-glucosidase solution among these glycosides, while rutin and NPG were both poor substrates. This suggests that dietary flavonoid glucosides are primarily hydrolyzed and liberated aglycones in the jejunum.
为了评估大鼠小肠中黄酮类糖苷水解时葡萄糖苷基团的位置特异性，采用高效液相色谱技术，用槲皮素单糖苷、槲皮素-3-O-β-D-吡喃葡萄糖苷（Q3G）、槲皮素-4'-O-β-D-吡喃葡萄糖苷（Q4'G）和槲皮素-7-O-β-D-吡喃葡萄糖苷（Q7G）以及槲皮素-3-O-芸香糖苷（芦丁）和对硝基苯基-β-D-吡喃葡萄糖苷（NPG）测定β-葡萄糖苷酶活性。酶是从大鼠十二指肠、空肠和回肠的小肠黏膜中制备的，在所测试的所有糖苷中，空肠的酶活性最高。在这些糖苷中，Q4'G是β-葡萄糖苷酶溶液最丰富的底物，而芦丁和NPG都是较差的底物。这表明膳食黄酮类糖苷主要在空肠中水解并释放出苷元。
