Comprehensive phenolic profiling and biological evaluation of <i>Centaurea glastifolia</i> L. (Asteraceae)

The present investigation focused on the comprehensive analysis of the phenolic profile of <i>Centaurea glastifolia</i> L. (Asteraceae) and the assessment of its diverse biological activities. Utilising LC-MS/MS, the phytochemical composition of the 70% methanol extract of <i>Centaurea glastifolia</i> (CG-ME) was thoroughly elucidated, revealing the presence of 30 distinct phytochemical compounds. Notably, major phenolic constituents identified in the extract included quinic acid, chlorogenic acid, luteolin-7-<i>O</i>-glucoside, kaempferol-3-<i>O</i>-glucoside, luteolin, and apigenin-7-<i>O</i>-glucoside. The antioxidant, antibacterial, antiproliferative, and cytotoxic activities of CG-ME were investigated. The CG-ME exhibited a moderate capacity for scavenging DPPH radicals (IC₅₀: 50.05 ± 1.58 µg/mL) and FRAP (63.96 ± 0.39 mg TE/g extract), indicating a moderate level of antioxidant activity. Moreover, CG-ME demonstrated significant antiproliferative effects (GI₅₀: 1.10 and 1.30 µg/mL) on cancer cells (C6 and HTC cancer cell lines, respectively) while displaying low cytotoxicity towards normal cells (LC₅₀: >1000 µg/mL). In terms of antibacterial activity, CG-ME was found to be inactive against tested both Gram-positive and Gram-negative bacterial strains (MIC > 500 µg/mL). The extracts had a promising antiproliferative effect on C6, HeLa, and HT29 cancer cell lines with a less cytotoxic effect (10.5-14.2%) against normal cells.