Phytoestrogens are a class of plant produced polyphenolic compounds with diphenolic structure, which is similar to 17β-estradiol. These phytoestrogens preferentially bind to estrogen receptors, however, with weak affinity. Recently, many studies have found that these phytoestrogens can be transformed by gut microbiota through novel enzymatic reactions into metabolites with altered bioactivity. Recent studies have also implied that these metabolites could possibly modulate the host gut ecosystem, gene expression, metabolism and the immune system. Thus, isolating gut microbes capable of biotransforming phytoestrogens and characterizing the novel enzymatic reactions involved are principal to understand the mechanisms of beneficial effects brought by gut microbiota and their metabolism on phytoestrogens, and to provide the theoretical knowledge for the development of functional probiotics. In the present review, we summarized works on gut microbial biotransformation of phytoestrogens, including daidzin (isoflavone), phenylnaringenin (prenylflavonoid), lignans, resveratrol (stilbene) and ellagitannins. We mainly focus on gut bacterial isolation, metabolic pathway characterization, and the bidirectional interaction of phytoestrogens with gut microbes to illustrate the novel metabolic capability of gut microbiota and the methods used in these studies.

植物雌激素是一类植物产生的具有双酚结构的多酚化合物，类似于17β-雌二醇。这些植物雌激素优先结合雌激素受体，但是亲和力较弱。最近，许多研究发现这些植物雌激素可以通过新的酶促反应被肠道菌群转化为具有改变的生物活性的代谢产物。最近的研究还暗示，这些代谢物可能会调节宿主肠道生态系统，基因表达，代谢和免疫系统。因此，分离能够生物转化植物雌激素的肠道微生物并表征涉及的新型酶促反应是了解肠道微生物及其代谢对植物雌激素的有益机理的主要原理，并为功能性益生菌的发展提供理论知识。在本综述中，我们总结了植物雌激素对肠道微生物的生物转化，包括大豆苷（异黄酮），苯基柚皮苷（异戊烯类黄酮），木脂素，白藜芦醇（（）和鞣花单宁。我们主要关注肠道细菌的分离，代谢途径表征以及植物雌激素与肠道微生物的双向相互作用，以说明肠道菌群的新型代谢能力以及这些研究中使用的方法。