Screening of in vitro prebiotic potentials and bioactive properties of ethanol and water extracts of four Centaurea L. species.

The lactic acid bacteria, a key probiotic group, is influenced by prebiotics that are critical for maintaining microbiota health. This study evaluated the in vitro prebiotic potential of water and ethanol extracts from Centaurea virgata, Centaurea macrocephala, Centaurea depressa, and Centaurea solstitialis on Lactiplantibacillus plantarum and Limosilactobacillus fermentum. The water extract of C. virgata exhibited the highest prebiotic activity score. Extracts significantly improved probiotic survival in simulated gastric and bile fluids compared to controls. The antioxidant activity of bacteria incubated with extracts surpassed that of controls, and cell surface hydrophobicity, vital for epithelial adhesion, was enhanced. Probiotic strains metabolized phenolic compounds in extracts to varying degrees. Ethanol extract of C. depressa showed the highest phenolic content, while its water extract had the highest flavonoid content. These in vitro findings suggest that Centaurea extracts may exhibit prebiotic-like effects, supporting further exploration for potential use in synbiotic development.