Variation of glucoraphanin metabolism in vivo and ex vivo by human gut bacteria.
Variation of glucoraphanin metabolism in vivo and ex vivo by human gut bacteria.
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DOI：
10.1017/s0007114511000274
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发表时间：
2011-08
影响因子：
3.6
通讯作者：
Lampe, Johanna W.
中科院分区：
文献类型：
--
作者：
Li, Fei;Hullar, Meredith A. J.;Beresford, Shirley A. A.;Lampe, Johanna W.
硫代葡萄糖苷是十字花科蔬菜中发现的植物化学物质，在人体肠道中被某些细菌代谢为具有生物活性的异硫氰酸酯（ITC）。在以前的十字花科蔬菜喂养研究中，已经观察到尿ITC排泄的显著个体差异。我们假设肠道微生物群落的个体差异有助于观察到的硫代葡萄糖酸盐代谢的变化，即，高ITC和低ITC排泄物之间的肠道微生物群组成不同。我们招募了23名健康的个体，并给他们喂食含有200克煮熟的西兰花的标准餐。餐后测定24小时尿ITC排泄量。ITC排泄量最高（n=5）和最低（n=5）的研究参与者提供粪便样本，用50 μM萝卜硫苷（西兰花中发现的主要硫代葡萄糖苷）进行离体细菌培养。当离体生长时，来自所选高ITC排泄物的粪便细菌能够比来自低排泄物的粪便细菌降解更多的萝卜硫苷（P=0.05）。然而，粪便和离体培养微生物群的细菌指纹显示，在细菌16S rRNA基因的末端限制性片段长度多态性分析中，高ITC排泄物和低ITC排泄物之间没有统计学显著差异。总之，离体粪便细菌的芥子油苷降解可能与体内细菌芥子油苷代谢能力有关，但可能与特定细菌种属没有直接联系，这可能是由于肠道微生物群的复杂性和功能冗余。
Glucosinolates, phytochemicals found in cruciferous vegetables, are metabolized to bioactive isothiocyanates (ITC) by certain bacteria in the human gut. Substantial individual variation in urinary ITC excretion has been observed in previous cruciferous-vegetable feeding studies. We hypothesized that individual differences in gut microbial community contribute to the observed variation in glucosinolate metabolism, i.e., gut microbiota composition between high- and low-ITC excreters differ. We recruited 23 healthy individuals and fed them a standardized meal containing 200 g cooked broccoli. 24-h urinary ITC excretion was measured after the meal. Study participants with the highest (n=5) and the lowest (n=5) ITC excretion provided fecal samples for ex vivo bacterial cultivation with 50 μM glucoraphanin, the major glucosinolate found in broccoli. When grown ex vivo, fecal bacteria from the selected high ITC excreters were able to degrade more glucoraphanin than those from the low excreters (P=0.05). However, bacterial fingerprints of fecal and ex vivo culture microbiota revealed no statistically significant differences between the high and low ITC excreters in terminal restriction fragment length polymorphism analysis of the bacterial 16S rRNA gene. In conclusion, glucosinolate degradation by fecal bacteria ex vivo may be associated with in vivo bacterial glucosinolate metabolism capacity but no direct link to specific bacterial species could be established, possibly due to the complexity and functional redundancy of the gut microbiota.