Formononetin and its glycoside ononin are bioactive isoflavones widely present in legumes. The present study investigated the pharmacokinetics, bioavailability, and in vitro absorption of formononetin and ononin. After an oral administration to rats, formononetin showed a higher systemic exposure over ononin. The oral bioavailability of formononetin and ononin were 21.8% and 7.3%, respectively. Ononin was more bioavailable than perceived, and its bioavailability reached 21.7% when its metabolite formononetin was taken into account. Both formononetin and ononin exhibited better absorption in large intestine segments than that in small intestine segments. Formononetin displayed a better permeability in all intestinal segments over ononin. Transport of formononetin across Caco-2 cell monolayer was mainly through passive diffusion, while ononin was actively pumped out by MRP2 but not P-gp. The results provide evidence for better understanding of the pharmacological actions of formononetin and ononin, which advocates more in vivo evaluations or human trials.

中文翻译：

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异黄酮Formononetin和Ononin的药代动力学和生物利用度及其在Ussing Chamber和Caco-2细胞模型中的体外吸收

Formononetin及其糖苷ononin是广泛存在于豆类中的生物活性异黄酮。本研究调查了formononetin和ononin的药代动力学，生物利用度和体外吸收。对大鼠口服后，formononetin的全身暴露量高于ononin。福莫奈汀和ononin的口服生物利用度分别为21.8％和7.3％。Ononin的生物利用度比想象的要高，并且考虑到其代谢物formononetin的生物利用度达到21.7％。Formononetin和ononin在大肠段的吸收均好于小肠段。Formononetin在所有肠段中的渗透率均优于ononin。Formononetin跨Caco-2细胞单层的转运主要是通过被动扩散，而ononin则是由MRP2主动抽出的，而不是由P-gp抽出的。这些结果为更好地了解formononetin和ononin的药理作用提供了证据，后者主张进行更多的体内评价或人体试验。