Li Chun-Yu, Wang Hao-Nan, He Rong-Jing, Huang Jian, Song Li-Lin, Song Yun-Qing, Huo Peng-Chao, Hou Jie, Ji Guang, Ge Guang-Bo
Shanghai Frontiers Science Center of TCM Chemical Biology, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China.
Pharmacology and Toxicology Division, Shanghai Institute of Food and Drug Control, Shanghai 201203, China.
Food Funct. 2022 Mar 21;13(6):3318-3328. doi: 10.1039/d1fo03277a.
Bile salt hydrolases (BSHs), a group of cysteine-hydrolases produced by gut microbes, play a crucial role in the hydrolysis of glycine- or taurine-conjugated bile acids and have been validated as key targets to modulate bile acid metabolism. This study aims to discover one or more efficacious inhibitors against a BSH produced by (lsBSH) from natural products and to characterize the mechanism of the newly identified BSH inhibitor(s). Following screening of the inhibition potentials of more than 100 natural compounds against lsBSH, amentoflavone (AMF), a naturally occurring biflavone isolated from various medicinal plants, was discovered to be an efficacious BSH inhibitor (IC = 0.34 μM). Further investigation showed that AMF could strongly inhibit the lsBSH-catalyzed hydrolytic reaction in living gut microbes. Inhibition kinetic analyses demonstrated that AMF reversibly inhibited the lsBSH-catalyzed hydrolytic reaction in a mixed-inhibition manner, with an apparent value of 0.65 μM. Fluorescence quenching assays suggested that AMF could quench the fluorescence of lsBSH a static quenching procedure. Docking simulations suggested that AMF could be fitted into lsBSH at two distinct ligand-binding sites, mainly hydrophobic interactions and hydrogen bonding, which explained well the mixed inhibition mode of this agent. Animal tests showed that the hydrolytic activities of BSHs in mice feces could be significantly blocked by AMF. In summary, this study reports that AMF is a strong, naturally occurring inhibitor of lsBSH, which offers a promising lead compound to develop novel agents for modulating bile acid metabolism in the host targeting BSHs.
胆汁盐水解酶（BSHs）是一组由肠道微生物产生的半胱氨酸水解酶，在甘氨酸或牛磺酸共轭胆汁酸的水解中起关键作用，并且已被确认为调节胆汁酸代谢的关键靶点。本研究旨在从天然产物中发现一种或多种针对（lsBSH）产生的BSH的有效抑制剂，并表征新鉴定的BSH抑制剂的作用机制。在筛选了100多种天然化合物对lsBSH的抑制潜力后，发现从多种药用植物中分离出的天然双黄酮杨梅素（AMF）是一种有效的BSH抑制剂（IC = 0.34 μM）。进一步研究表明，AMF可以强烈抑制活肠道微生物中lsBSH催化的水解反应。抑制动力学分析表明，AMF以混合抑制方式可逆地抑制lsBSH催化的水解反应，表观 值为0.65 μM。荧光猝灭试验表明，AMF可以通过静态猝灭过程猝灭lsBSH的荧光。对接模拟表明，AMF可以在两个不同的配体结合位点与lsBSH结合，主要通过疏水相互作用和氢键，这很好地解释了该药物的混合抑制模式。动物试验表明，AMF可以显著阻断小鼠粪便中BSHs的水解活性。总之，本研究报道AMF是一种强大的天然lsBSH抑制剂，为开发以BSHs为靶点调节宿主胆汁酸代谢的新型药物提供了一个有前景的先导化合物。
