Food Research Laboratories, Mitsui Norin. Co., Ltd., 223-1 Miyabara, Fujieda-shi, Shizuoka, 426-0133, Japan,
Arch Microbiol. 2014 Oct;196(10):681-95. doi: 10.1007/s00203-014-1006-y. Epub 2014 Jun 20.
Two intestinal bacterial strains MT4s-5 and MT42 involved in the degradation of (-)-epigallocatechin (EGC) were isolated from rat feces. Strain MT4s-5 was tentatively identified as Adlercreutzia equolifaciens. This strain converted EGC into not only 1-(3, 4, 5-trihydroxyphenyl)-3-(2, 4, 6-trihydroxyphenyl)propan-2-ol (1), but also 1-(3, 5-dihydroxyphenyl)-3-(2, 4, 6-trihydroxyphenyl)propan-2-ol (2), and 4'-dehydroxylated EGC (7). Type strain (JCM 9979) of Eggerthella lenta was also found to convert EGC into 1. Strain MT42 was identified as Flavonifractor plautii and converted 1 into 4-hydroxy-5-(3, 4, 5-trihydroxyphenyl)valeric acid (3) and 5-(3, 4, 5-trihydroxyphenyl)-γ-valerolactone (4) simultaneously. Strain MT42 also converted 2 into 4-hydroxy-5-(3, 5-dihydroxyphenyl)valeric acid (5), and 5-(3, 5-dihydroxyphenyl)-γ-valerolactone (6). Furthermore, F. plautii strains ATCC 29863 and ATCC 49531 were found to catalyze the same reactions as strain MT42. Interestingly, formation of 2 from EGC by strain MT4s-5 occurred rapidly in the presence of hydrogen supplied by syntrophic bacteria. Strain JCM 9979 also formed 2 in the presence of the hydrogen or formate. Strain MT4s-5 converted 1, 3, and 4 to 2, 5, and 6, respectively, and the conversion was stimulated by hydrogen, whereas strain JCM 9979 could catalyze the conversion only in the presence of hydrogen or formate. On the basis of the above results together with previous reports, the principal metabolic pathway of EGC and EGCg by catechin-degrading bacteria in gut tract is proposed.
从大鼠粪便中分离到两株参与 (-)-表没食子儿茶素（EGC）降解的肠道细菌菌株 MT4s-5 和 MT42。菌株 MT4s-5 被初步鉴定为 Adlercreutzia equolifaciens。该菌株不仅将 EGC 转化为 1-(3,4,5-三羟基苯基)-3-(2,4,6-三羟基苯基)丙-2-醇（1），还转化为 1-(3,5-二羟基苯基)-3-(2,4,6-三羟基苯基)丙-2-醇（2）和 4'-去羟基 EGC（7）。肠埃希氏菌（Eggerthella lenta）的模式菌株（JCM 9979）也被发现能将 EGC 转化为 1。菌株 MT42 被鉴定为 Flavonifractor plautii，能同时将 1 转化为 4-羟基-5-(3,4,5-三羟基苯基)戊酸（3）和 5-(3,4,5-三羟基苯基)-γ-戊内酯（4）。菌株 MT42 还能将 2 转化为 4-羟基-5-(3,5-二羟基苯基)戊酸（5）和 5-(3,5-二羟基苯基)-γ-戊内酯（6）。此外，发现 F. plautii 菌株 ATCC 29863 和 ATCC 49531 能够催化与菌株 MT42 相同的反应。有趣的是，在提供的氢的存在下，MT4s-5 菌株从 EGC 快速生成 2。JCM 9979 菌株也在氢或甲酸盐的存在下形成 2。MT4s-5 菌株分别将 1、3 和 4 转化为 2、5 和 6，氢能刺激转化，而 JCM 9979 菌株仅能在氢或甲酸盐的存在下催化转化。基于上述结果以及以前的报告，提出了肠道中儿茶素降解菌代谢 EGC 和 EGCg 的主要途径。
