Chemical quality profile and bioactivities of "Hongyin" tea, a purple-budded cultivar from eastern Guangdong

This study systematically analyzes the chemical composition and bioactivities of the "Hongyin" tea cultivar, represented by the purple-budded tea tree from eastern Guangdong, providing a scientific basis for the upgrading of the local tea industry and the development of new germplasm resources. By integrating sensory analysis, physicochemical testing, wide-target metabolomics, network pharmacology, and high-fat diet (HFD) mouse models, this research reveals for the first time the unique chemical characteristics of HY: low caffeine, high GCG, rich in anthocyanins, and abundant in unsaturated fatty acids (UFA-oxylipids). The low caffeine, high antioxidant capacity, anti-obesity, and intestinal barrier protection properties of HY position it as a promising candidate for the functional tea consumption market. Metabolomics analysis revealed that HY is rich in oxylipins derived from linoleic acid (LA) and α-linolenic acid (ALA), which regulate inflammation, lipid metabolism, and cell survival through PPAR, GPR120, and PI3K-Akt/STAT3 signaling pathways. Additionally, HY enhances the gut microbiota diversity, promotes beneficial bacteria, and restores intestinal barrier function, further supporting its anti-inflammatory and cardiometabolic protective effects. Experimental results indicate that HY provides significant protection against obesity, liver damage, and intestinal injury in HFD mice. In conclusion, "Hongyin" tea exhibits a unique chemical profile with low caffeine and high levels of GCG, anthocyanins, and unsaturated fatty acids, alongside multidimensional bioactivities including anti-obesity, hepatoprotective, anti-inflammatory, and microbiota-modulating effects. These findings provide biochemical and system-level evidence for its application in metabolic health and intestinal homeostasis, offering substantial market potential and practical value.