Regioselective formation of quercetin 5-O-glucoside from orally administered quercetin in the silkworm, Bombyx mori
Regioselective formation of quercetin 5-O-glucoside from orally administered quercetin in the silkworm, Bombyx mori
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DOI：
10.1016/j.phytochem.2007.11.009
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发表时间：
2008-03-01
期刊：
影响因子：
3.8
通讯作者：
Nakamura, Masatoshi
中科院分区：
文献类型：
--
作者：
Hirayama, Chikara;Ono, Hiroshi;Nakamura, Masatoshi
一些家蚕品种的茧，家蚕，已被证明含有5-O-葡萄糖基化的黄酮类化合物，这不是天然存在于其宿主植物，桑葚（桑树）的叶子。因此，饲料黄酮类化合物可以在这种昆虫的生物转化。在本研究中，我们发现，在蚕饲料中富含黄酮醇槲皮素，槲皮素5-O-葡萄糖苷是中肠组织中的主要代谢产物，而槲皮素5，4 '-二-O-葡萄糖苷是血淋巴和丝腺中的主要成分。中肠的UDP-葡萄糖基转移酶（UGT）可以将葡萄糖转移到槲皮素的每个羟基上，优先形成5-O-葡萄糖苷，而如果脂肪体或丝腺的酶提取物与槲皮素5-O-葡萄糖苷和UDP-葡萄糖一起孵育，则主要产生槲皮素5，4 '-二-O-葡萄糖苷。这些结果表明，膳食槲皮素口服吸收后，作为槲皮素的首过代谢产物，在中肠的5-OP位置被葡萄糖基化，然后在脂肪体或丝腺的4 '-O位置被葡萄糖基化。5-O-葡萄糖基化类黄酮保留在昆虫的生物活性，因为总的自由基清除能力的几个组织口服给药后增加槲皮素。(c)2007爱思唯尔有限公司保留所有权利。
The cocoons of some races of the silkworm, Bombyx mori, have been shown to contain 5-O-glucosylated flavonoids, which do not occur naturally in the leaves of their host plant, mulberry (Morus alba). Thus, dietary flavonoids could be biotransformed in this insect. In this study, we found that after feeding silkworms a diet rich in the flavonol quercetin, quercetin 5-O-glucoside was the predominant metabolite in the midgut tissue, while quercetin 5,4'-di-O-glucoside was the major constituent in the hemolymph and silk glands. UDP-glucosyltransferase (UGT) in the midgut could transfer glucose to each of the hydroxyl groups of quercetin, with a preference for formation of 5-O-glucoside, while quercetin 5,4'-di-O-glucoside was predominantly produced if the enzyme extracts of either the fat body or silk glands were incubated with quercetin 5-O-glucoside and UDP-glucose. These results suggest that dietary quercetin was glucosylated at the 5-OP position in the midgut as the first-pass metabolite of quercetin after oral absorption, then glucosylated at the 4'-O position in the fat body or silk glands. The 5-O-glucosylated flavonoids retained biological activity in the insect, since the total free radical scavenging capacity of several tissues increased after oral administration of quercetin. (c) 2007 Elsevier Ltd. All rights reserved.