多糖广泛存在于草本植物中，具有多种活性，特别是具有免疫调节作用和改善代谢紊乱的作用。然而，其潜在机制还没有被很好地诠释。功能代谢组学越来越多地被用于通过鉴定具有特定功能的代谢产物来研究多糖对宿主的系统性影响。本研究采用功能代谢组学策略，探讨黄芪多糖（Astragalus polysaccharide, APS）代谢获益的潜在机制。在为期8 周的高脂肪饮食（high-fat diet, HFD）喂养的肥胖小鼠中测定了APS的作用。然后，进行基于气相色谱-飞行时间质谱（gas chromatography-time-of-flight mass spectrometry, GC-TOFMS）的非靶向代谢组学分析血清和肝组织，并进行基于液相色谱- 串联质谱（liquid chromatography-tandem mass spectrometry, LC-MS/MS）的靶向代谢组学分析。使用体外和体内代谢紊乱模型测试了代谢产物的潜在功能。我们的结果首次证实了APS对肥胖小鼠的代谢益处。然后，代谢组学分析显示，补充APS 可逆转HFD 诱导的代谢变化，并确定2-羟基丁酸（2-hydroxybutyric acid, 2-HB）是APS活性的潜在功能性代谢产物，该代谢物被HFD显著降低，并被APS逆转。进一步研究表明，2-HB可抑制油酸（oleic acid, OA）诱导的甘油三酯（triglyceride, TG）累积。还发现其可刺激肝细胞中脂质降解蛋白的表达和3T3-L1 细胞中的TG脂解。此外，在高脂肪和高蔗糖（high-fat and high-sucrose, HFHS）喂养的小鼠中发现2-HB可降低血清TG并调节参与脂质降解的蛋白质。总之，我们的研究表明，APS的代谢
益处至少部分归因于2-HB 的产生，2-HB 在体外和体内均可调节脂质代谢。我们的结果同样证实，功能代谢组学在研究植物多糖系统益处的潜在机制方面是切实可行的。

Polysaccharides are widely present in herbs with multiple activities, especially immunity regulation and metabolic benefits for metabolic disorders. However, the underlying mechanisms are not well understood. Functional metabolomics is increasingly used to investigate systemic effects on the host by identifying metabolites with particular functions. This study explores the mechanisms underlying the metabolic benefits of Astragalus polysaccharides (APS) by adopting a functional metabolomics strategy. The effects of APS were determined in eight-week high-fat diet (HFD)-fed obese mice. Then, gas chromatography–time-of-flight mass spectrometry (GC–TOFMS)-based untargeted metabolomics was performed for an analysis of serum and liver tissues, and liquid chromatography–tandem mass spectrometry (LC–MS/MS)-based targeted metabolomics was performed. The potential functions of the metabolites were tested with in vitro and in vivo models of metabolic disorders. Our results first confirmed the metabolic benefits of APS in obese mice. Then, metabolomics analysis revealed that APS supplementation reversed the HFD-induced metabolic changes, and identified 2-hydroxybutyric acid (2-HB) as a potential functional metabolite for APS activity that was significantly decreased by a HFD and reversed by APS. Further study indicated that 2-HB inhibited oleic acid (OA)-induced triglyceride (TG) accumulation. It was also found to stimulate the expression of proteins in lipid degradation in hepatocytes and TG lipolysis in 3T3-L1 cells. Moreover, it was found to reduce serum TG and regulate the proteins involved in lipid degradation in high-fat and high-sucrose (HFHS)-fed mice. In conclusion, our study demonstrates that the metabolic benefits of APS are at least partially due to 2-HB generation, which modulated lipid metabolism both in vitro and in vivo. Our results also highlight that functional metabolomics is practical for investigating the mechanism underlying the systemic benefits of plant polysaccharides.