Teng Zeng-Hui, Zhou Si-Yuan, Yang Run-Tao, Liu Xin-You, Liu Ren-Wang, Yang Xi, Zhang Bang-Le, Yang Jing-Yue, Cao Da-Yong, Mei Qi-Bing
Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, Shaan'xi 710032, China.
Biol Pharm Bull. 2007 Sep;30(9):1628-33. doi: 10.1248/bpb.30.1628.
Emodin has numerous biochemical and pharmacological activities, though information about its intestinal absorption and first-pass metabolism is scarce. The purpose of this study was to evaluate intestinal absorption and metabolism of luminally administered emodin in an isolated rat small intestine using the method of LC/MS/MS. About 22.55% of the administered emodin appeared at the vascular side, chiefly as free emodin (12.01%), but some emodin glucuronide (8.69%) and sulfate (1.84%) were also detected. Free glucuronide (5.23%) and sulfate (1.08%) moieties were found in the luminal perfusate. This model serves as a valuable tool for understanding intestinal handling of emodin, and our results confirm absorption and first-pass metabolism of emodin in the rat small intestine. Phase II metabolic enzymes such as glucuronyl transferase or sulfate transferase may also play an important role in the first-pass metabolism of emodin in the small intestine, which may ultimately reduce the bioavailability (and thus the efficacy) of orally administered emodin.
大黄素具有多种生化和药理活性，不过关于其肠道吸收和首过代谢的信息却很少。本研究的目的是采用液相色谱/串联质谱法评估在离体大鼠小肠中经肠腔给予大黄素后的肠道吸收和代谢情况。给予的大黄素约22.55%出现在血管侧，主要以游离大黄素形式存在（12.01%），但也检测到一些大黄素葡萄糖醛酸苷（8.69%）和硫酸酯（1.84%）。在肠腔灌流液中发现了游离葡萄糖醛酸苷（5.23%）和硫酸酯（1.08%）部分。该模型是了解大黄素肠道处理情况的一个有价值的工具，我们的结果证实了大黄素在大鼠小肠中的吸收和首过代谢。Ⅱ相代谢酶如葡萄糖醛酸转移酶或硫酸转移酶可能在大黄素在小肠的首过代谢中也起重要作用，这可能最终降低口服大黄素的生物利用度（进而降低其疗效）。
