In vitro metabolism of pyripyropene A and ACAT inhibitory activity of its metabolites
作者:Daisuke Matsuda、Taichi Ohshiro、Masaki Ohtawa、Hiroyuki Yamazaki、Tohru Nagamitsu、Hiroshi Tomoda
DOI:10.1038/ja.2014.91
日期:2015.1
Pyripyropene A (PPPA, 1) of fungal origin, a selective inhibitor of acyl-CoA:cholesterol acyltransferase 2 (ACAT2), proved orally active in atherogenic mouse models. The in vitro metabolites of 1 in liver microsomes and plasma of human, rabbit, rat and mouse were analyzed by ultra fast liquid chromatography and liquid chromatography/tandem mass spectrometry. In the liver microsomes from all species, successive hydrolysis occurred at the 1-O-acetyl residue, then at the 11-O-acetyl residue of 1, while the 7-O-acetyl residue was resistant to hydrolysis. Furthermore, dehydrogenation of the newly generated 11-alcoholic hydroxyl residue occurred in human and mouse-liver microsomes, while oxidation of the pyridine ring occurred in human and rabbit liver microsomes. On the other hand, hydrolysis of the 7-O-acetyl residue proceeded only in the mouse plasma. These data indicated that the in vitro metabolic profiles of 1 have subtle differences among animal species. All of the PPPA metabolites observed in liver microsomes and plasma markedly decreased ACAT2 inhibitory activity. These findings will help us to synthesize new PPPA derivatives more effective in in vivo study than 1.
源于真菌的 Pyripyropene A(PPPA,1)是一种酰基-CoA:胆固醇酰基转移酶 2(ACAT2)的选择性抑制剂,在动脉粥样硬化小鼠模型中被证明具有口服活性。超快速液相色谱法和液相色谱/串联质谱法分析了 1 在人、兔、大鼠和小鼠肝脏微粒体和血浆中的体外代谢物。在所有物种的肝脏微粒体中,1 的 1-O- 乙酰基残基和 11-O- 乙酰基残基相继发生水解,而 7-O- 乙酰基残基则不能水解。此外,新生成的 11-乙醇羟基残基在人和小鼠肝脏微粒体中发生脱氢反应,而吡啶环在人和兔肝脏微粒体中发生氧化反应。另一方面,7-O-乙酰残基的水解只在小鼠血浆中进行。这些数据表明,1 的体外代谢特征在动物物种之间存在细微差别。在肝脏微粒体和血浆中观察到的所有 PPPA 代谢物都会明显降低 ACAT2 的抑制活性。这些发现将有助于我们合成在体内研究中比 1 更有效的新 PPPA 衍生物。