Gradient ethanol extracts of Coreopsis tinctoria buds: Chemical and in vitro fermentation characteristics

Coreopsis tinctoria buds grow at high altitudes and have unique medicinal and health effects. This study focused on the chemical components of gradient ethanol extracts of Coreopsis tinctoria buds and their impact on the gut microbiota and its metabolites. UPLC-Q-Exactive-MS results disclosed the presence of 24 distinct chemicals in the extracts, marein, and quercetin-3-β-D-glucoside as the predominant antioxidants. Furthermore, the anhydrous ethanol extract (EtOH-EX) and 80 % (w/w) ethanol extract (80 % EtOH-EX) showed the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis-(3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) free radical scavenging capacity, and the water extract (Water-Ex) showed excellent bile acid binding capacity. Besides, simulated fermentation of the extracts increased short-chain fatty acids and the abundance of gut-friendly bacteria like Bifidobacteria, especially in the Water-EX group. Correlation analysis revealed that the key microbiota on metabolites production. In conclusion, the extracts derived from Coreopsis tinctoria buds exhibit a spectrum of bioactivities, viewing them as flexible options for applications across food and pharmaceutical products.