Study on chemical constituents of herbal formula Er Miao Wan and GC-MS based metabolomics approach to evaluate its therapeutic effects on hyperuricemic rats

Hyperuricemia strongly correlates with an increased risk of the development of gout, and cardiovascular and kidney diseases, etc. Er Miao Wan (EMW) is a classical traditional Chinese medicine (TCM) formula extensively used for the treatment of hyperuricemia and gout. However, the global components and action mechanism of the formula are still unknown. Here, the chemical constituents of EMW extract were identified by ultra-high performance liquid chromatography quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF/MS) and gas chromatography-mass spectrometry (GC-MS). A total of 24 alkaloids, 15 organic acids, 4 terpenoids, 3 lactones, 3 glycosides, 46 volatile constituents and 3 other compounds were tentatively identified from the EMW extract. Additionally, based on the hyperuricemic rat model induced by long-term high-fructose feed, a GC-MS based metabolomics approach was conducted to holistically assess the mechanism of EMW. Principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA) were applied for screening differential metabolites. A total of 21 metabolites that markedly changed in hyperuricemic rats were identified. Further univariate analysis showed that 9 differential metabolites among them were profoundly reversed by EMW intervention. Metabolic pathway analysis revealed that the variations of these metabolites were mainly associated with glycerolipid metabolism, amino acid metabolism, primary bile acid metabolism, taurine and hypotaurine metabolism and purine metabolism. It was inferred that EMW possibly induced its anti-hyperuricemic effect through restoring multiple disturbed pathways to the normal state. This study could assist with elucidating the potential mechanisms of EMW.