Isolation of a human intestinal bacterium that transforms mangiferin to norathyriol and inducibility of the enzyme that cleaves a C-glucosyl bond
Isolation of a human intestinal bacterium that transforms mangiferin to norathyriol and inducibility of the enzyme that cleaves a C-glucosyl bond
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DOI：
10.1248/bpb.28.1672
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发表时间：
2005-09-01
影响因子：
2
通讯作者：
Hattori, M
中科院分区：
文献类型：
--
作者：
Sanugul, K;Akao, T;Hattori, M
C-葡萄糖苷的C-葡萄糖键一般耐酸和酶水解。许多C-葡萄糖苷被人体肠道细菌分解。我们从人类粪便细菌的混合物中分离出了参与芒果苷(2-beta-D-glucopyranosyl-1，3，6，7-tetrahydroxyxanthone)，C-葡萄糖基黄原酮代谢的特定细菌。厌氧类杆菌MANG将芒果苷转化为苷元去甲三醇，暗示着C-葡萄糖键的断裂。然而，B.sp.只有在芒果苷存在的情况下，芒果才能以剂量和时间依赖的方式裂解C-葡萄糖基。RNA和蛋白质合成的抑制剂，如利福平和氯霉素，分别阻止了裂解，这表明裂解C-葡萄糖的酶是由芒果苷诱导的。相反，芒果苷在任何条件下都不影响细菌α-葡萄糖苷酶和β-葡萄糖苷酶的活性。有效的葡萄糖苷酶抑制剂如1-脱氧野生霉素和葡萄糖内酯不能改变无细胞提取物中的C-葡萄糖基裂解。因此，C-葡萄糖基裂解酶与已知的裂解O-葡萄糖苷的葡萄糖苷酶有很大的不同。这是第一次描述一种特定的肠道细菌，它参与芒果苷的代谢，并产生一种新的和可诱导的C-葡萄糖裂解酶。
The C-glucosyl bond of C-glucosides generally tolerates acid and enzymatic hydrolysis. Many C-glucosides are cleaved by human intestinal bacteria. We isolated the specific bacterium involved in the metabolism of mangiferin (2-beta-D-glucopyranosyl-1,3,6,7-tetrahydroxyxanthone), C-glucosyl xanthone, from a mixture of human fecal bacteria. The anaerobic Bacteroides species named MANG, transformed mangiferin to the aglycone, norathyriol, suggesting cleavage of a C-glucosyl bond. However, B. sp. MANG cleaved C-glucosyl in a dose- and time-dependent manner only when cultivated in the presence of mangiferin. Cleavage was abolished by inhibitors of RNA and protein syntheses, such as rifampicin and chloramphenicol, respectively, indicating that the enzyme that cleaves C-glucosyl is induced by mangiferin. In contrast, mangiferin did not affect bacterial alpha- and beta-glucosidase activities under any conditions. The C-glucosyl-cleavage in cell-free extracts was not altered by potent glucosidase inhibitors such as 1-deoxynojirimycin and gluconolactone. Therefore, the C-glucosyl-cleaving enzyme substantially differs from known glucosidases that cleave O-glucosides. This is the first description of a specific intestinal bacterium that is involved in the metabolism of mangiferin and which produces a novel and inducible C-glucosyl-cleaving enzyme.