Metabolism of Eriocitrin in the Gut and its Regulation on Gut Microbiota in Mice. Metabolism of Eriocitrin in the Gut and its Regulation on Gut Microbiota in Mice

Eriocitrin, found in lemon fruit, has shown a wide range of biological properties. Herein, to evaluate the intestinal metabolic profile of eriocitrin in colon, the flavonoids in mice colon contents were identified by ultra performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS), and a total of 136 flavonoids were found, including eriocitrin and its six metabolites (eriodictyol, homoeriodictyol, hesperetin, eriodictyol-3'-O-glucoside, hesperetin-7-O-glucoside and eriodictyol-7-O-(6''-O-galloyl) glucoside). Mice colon contents were used for 16S rDNA gene sequencing and gas chromatography-mass (GC-MS). Resultu showed that eriocitrin significantly alters the beta diversity of the gut microbiota, the probiotics such as Lachnospiraceae_UCG_006 were significantly enriched, and the production of butyrate, valerate and hexanoate in the colon pool of short-chain fatty acids (SCFAs) were significant increased. The spearman's association analysis performed some intestinal bacteria may be involved in the metabolism of eriocitrin. Collectively, our results preliminarily suggesting the metabolism of eriocitrin in the gut, demonstrate alterations of eriocitrin on gut microbiota, which warrants further investigation to determine its potential use in food and biomedical applications. Overall design: Six-week-old male Institute of Cancer Research (ICR) mice (n=12) were randomly divided into eriocitrin treatment and control group (6 males per group). After 2-weeks of feeding, mice were abrosiaed with CO2 asphyxiation after 12h fasting, and colon faeces of mice were collected and stored at -80℃ until later microbial analysis.

圣草枸橼苷（Eriocitrin）广泛存在于柠檬果实中，已被证实具备多种生物学活性。本研究为解析圣草枸橼苷在结肠内的肠道代谢谱，采用超高效液相色谱-电喷雾电离串联质谱（UPLC-ESI-MS/MS）对小鼠结肠内容物中的黄酮类物质进行鉴定，共检出136种黄酮类化合物，包括圣草枸橼苷及其6种代谢产物：圣草酚（eriodictyol）、高圣草酚（homoeriodictyol）、橙皮素（hesperetin）、圣草酚-3'-O-葡萄糖苷（eriodictyol-3'-O-glucoside）、橙皮素-7-O-葡萄糖苷（hesperetin-7-O-glucoside）以及圣草酚-7-O-(6''-O-没食子酰)葡萄糖苷（eriodictyol-7-O-(6''-O-galloyl) glucoside）。
研究人员以小鼠结肠内容物为样本开展16S rDNA基因测序与气相色谱-质谱（GC-MS）分析。结果显示，圣草枸橼苷可显著改变肠道菌群的β多样性，毛螺菌科_UCG_006（Lachnospiraceae_UCG_006）等益生菌的丰度显著升高，且结肠内短链脂肪酸（SCFAs）库中的丁酸、戊酸与己酸含量均显著提升。通过斯皮尔曼关联分析发现，部分肠道菌群可能参与圣草枸橼苷的代谢过程。
综上，本研究结果初步证实了圣草枸橼苷在肠道内的代谢过程，并揭示了其对肠道菌群的调控作用，该发现为进一步探究其在食品与生物医学领域的应用潜力提供了依据。
实验设计：将12只6周龄的雄性ICR（Institute of Cancer Research）小鼠随机分为圣草枸橼苷处理组与对照组，每组6只。饲喂2周后，小鼠经12小时禁食后采用CO₂窒息法处死，收集结肠粪便样本并保存于-80℃环境中，以待后续微生物组学分析。