Biliary excretion of metabolites of baicalin, and baicalein in rats.
作者:Ken-ichi ABE、Osamu INOUE、Eizaburo YUMIOKA
DOI:10.1248/cpb.38.208
日期:——
Biliary excretion of metabolites of baicalin, present in Scutellariae Radix, was investigated using rats. The bile of rats administered baicalin orally was shown to montain five major metabolites, which were identified as baicalein 6-O-β-glucopyranuronoside (M1), 6-O-methyl-baicalein 7-O-β-glucopyranuronoside (oroxylin A 7-O-β-glucuronide (M2)), baicalein 7-O-β-glucopyranuronoside (M3), 6-O-β-glucopyranuronosyl-baicalein 7-O-sulfate (M4), and baicalein 6, 7-di-O-β-glucopyranuronoside (M5) on the basis of chemical and spectroscopic evidence.The bile of rats treated with baicalein also contained the above metabolites. Slower biliary excretion of the metabolites after baicalin administration suggested that it was absorbed as baicalein after hydrolysis in the gastrointestinal tract.The total cumulative amounts of the five metabolites excreted in the bile during 30 h after oral administration of baicalin and that of baicalein were approximately 54% and 40% of hte doses, respectively. In addition the bilary metabolites of both drugs were shown to be mainly composed of M5 and M4, which have high polarity and large molecular weight.
研究使用大鼠探讨了黄芩苷(存在于黄芩根中的化合物)的代谢物的胆汁分泌。口服黄芩苷的大鼠胆汁中发现了五种主要代谢物,分别被鉴定为:黄芩6-O-β-葡萄糖醛酸苷(M1)、6-O-甲基黄芩7-O-β-葡萄糖醛酸苷(或称黄芩A 7-O-β-葡萄糖醛酸(M2))、黄芩7-O-β-葡萄糖醛酸苷(M3)、6-O-β-葡萄糖醛酸基黄芩7-O-硫酸盐(M4),以及黄芩6,7-二-O-β-葡萄糖醛酸苷(M5),这些都是基于化学和光谱证据进行鉴定的。用黄芩苷处理的大鼠胆汁中也含有上述代谢物。黄芩苷给药后代谢物的胆汁排泄速度较慢,表明其在胃肠道水解后作为黄芩被吸收。口服黄芩苷后30小时内,胆汁中排出的五种代谢物的总累积量约为剂量的54%,而黄芩的总累积量约为40%。此外,两个药物的胆汁代谢物主要由M5和M4组成,它们具有较高的极性和大分子量。