Biochemical, antioxidant, and antimicrobial characterization of endemic Ornithogalum yildirimlii

This study provides the first comprehensive evaluation of the antioxidant activity, antimicrobial potential, phenolic composition, and fatty acid profile of methanolic extracts from the aerial and bulb parts of the endemic Ornithogalum yildirimlii Kılıç. Antioxidant capacity was assessed using total phenolic content, FRAP, and DPPH radical scavenging assays. Phenolic constituents were identified by LC–MS/MS, fatty acids by GC–FID, and antimicrobial activity was tested against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Enterococcus faecalis, and Candida albicans. The aerial parts of O. yildirimlii contained higher total phenolic content (0.189 ± 0.003 mg GAE/g) and demonstrated stronger antioxidant activity, with FRAP value of 0.241651 µM Fe2+/g and DPPH IC50 of 2.157 ± 0.9009 mg/mL. They were also rich in resveratrol, hydroxycinnamic acid, and luteolin, along with oleic and palmitic acids as dominant fatty acids. In contrast, the bulbs exhibited higher levels of hydroxycinnamic and ellagic acids, with linoleic and palmitic acids prevailing. Notably, bulb extracts showed stronger antimicrobial effects, especially against E. coli (MIC: 0.001563 mg/mL) and P. aeruginosa (MIC: 0.003125 mg/mL). Overall, these findings highlight O. yildirimlii as a promising natural bioactive source.