Key Laboratory of New Drug Delivery System of Chinese Materia Medica, Jiangsu Provincial Academy of Chinese Medicine, 100 Shizi Road, Nanjing 210028, China.
Molecules. 2011 Feb 1;16(2):1336-48. doi: 10.3390/molecules16021336.
Yinyanghuo (Herba Epimdii) is a traditional Chinese herb containing prenylated flavonoids as its active constituents. The aim of this study was to examine the significance of the intestinal hydrolysis of prenylated flavonoids by lactase phlorizin hydrolase (LPH), an enzyme at the brush border membrane of intestinal cells.
A four-site perfused rat intestinal model was used. The concentration of the flavonoids of interest and their metabolites in different intestinal segements were analyzed by HPLC, and the apparent permeabilities were calculated. A lactase phlorizin hydrolase inhibitor (gluconolactone) was employed to investigate the mechanism of the intestinal absorption, and the metabolites of the four flavonoids were identified using LC/MS/MS.
Diglycosides (icariin) or triglycosides (epimedin A, epimedin B, and epimedin C) were hydrolyzed rapidly in duodenum and jejunum producing one or two metabolites, while a monoglycoside (baohuoside I) was absorbed directly. When co-perfused with glucono-lactone, both the hydrolysis of diglycosides and triglycosides were significantly inhibited, with inhibition rates for icariin (62%, 50%, 40%, 46%), epimedin A, (55%, 26%, 21%, 14%); epimedin B (42%, 40%, 74%, 22%), and epimedin C (42%, 40%, 52%, 35%) in duodenum, jejunum, ileum, and colon, respectively. Also the metabolites of icariin, epimedin A, epimedin B, and epimedin C were identified as baohuoside I (one of two), sagittatoside A, sagittatoside B, and 2"-O-rhamnosylicariside II, respectively.
The results showed that lactase phlorizin hydrolase was a major determinant of the intestinal absorption of prenylated flavonoids present in Yinyanghuo.
淫羊藿（Epimdii 草）是一种传统的中国草药，其有效成分是类黄酮。本研究的目的是研究乳糖酶 - 根皮苷水解酶（LPH）对肠道细胞刷状缘膜中类黄酮的肠内水解的重要性。
使用四部位灌注大鼠肠道模型。通过 HPLC 分析不同肠段中感兴趣的类黄酮及其代谢物的浓度，并计算表观渗透率。使用乳糖酶 - 根皮苷水解酶抑制剂（葡萄糖酸内酯）来研究肠吸收的机制，并使用 LC/MS/MS 鉴定四种类黄酮的代谢物。
二糖苷（淫羊藿苷）或三糖苷（朝藿定 A、朝藿定 B 和朝藿定 C）在十二指肠和空肠中迅速水解，产生一种或两种代谢物，而单糖苷（宝藿苷 I）则被直接吸收。当与葡萄糖酸内酯共灌注时，二糖苷和三糖苷的水解均显著受到抑制，淫羊藿苷的抑制率分别为 62%、50%、40%、46%；朝藿定 A 为 55%、26%、21%、14%；朝藿定 B 为 42%、40%、74%、22%；朝藿定 C 为 42%、40%、52%、35%，分别在十二指肠、空肠、回肠和结肠中。此外，淫羊藿苷、朝藿定 A、朝藿定 B 和朝藿定 C 的代谢物分别鉴定为宝藿苷 I（两种之一）、箭藿苷 A、箭藿苷 B 和 2"-O-鼠李糖苷二氢芝麻素。
结果表明，乳糖酶 - 根皮苷水解酶是淫羊藿中存在的类黄酮肠内吸收的主要决定因素。
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