Widely Targeted Metabolomic Analysis of Two Chinese Traditional Herbal Imperial Chrysanthemum Teas and In Vitro Evaluation of Their Hyperglycemia and Inflammation Enzyme Inhibitory Activities

Imperial chrysanthemum teas 'Wuyuan Huangju' (WYHJ) and 'Jinsi Huangju' (JSHJ), dried from the flowers of <i>Chrysanthemum morifolium</i> cv. Huangju, are traditional and popular herbal teas in China. However, their metabolite profiles and bioactivities remain unclear. In this study, we aimed to comprehensively elucidate the non-volatile and volatile metabolites of these two imperial chrysanthemum teas and assess their antioxidant activities and inhibitory effects on hyperglycemia and inflammation enzymes. Thus, we employed a widely targeted metabolomics approach based on UPLC-ESI-MS/MS and GC-MS/MS to characterize metabolite profiles of the two teas. In total, 1971 non-volatile and 1039 volatile metabolites were explored, and among these, 744 differential non-volatiles (classified into 11 categories) and 517 differential volatiles (classified into 12 categories) were identified. Further, 474 differential non-volatiles were upregulated in WYHJ, particularly flavonoids, terpenoids, and phenolic acids. In contrast, JSHJ exhibited a greater number of upregulated differential volatiles compared to WYHJ, contributing primarily to its sweet, fruity, and floral aroma. The results of scavenging activities towards DPPH·, ABTS·⁺, OH·^-, and reducing power demonstrated that both imperial chrysanthemum teas, especially WYHJ, displayed high antioxidant capacity. We also noted that WYHJ exhibited stronger α-amylase, α-glucosidase, xanthine oxidase, and lipoxygenase inhibitory effects owing to its high active substance content. Therefore, this study provides insights into the metabolites of Chinese traditional medicinal herbal teas and highlights strategies for the comprehensive development and utilization of these traditional plant resources.