Abstract
BACKGROUND: Centaurea sinaica DC (Asteraceae) is traditionally used in treating various ailments, yet its phytochemical composition and cytotoxic potential remain underexplored. OBJECTIVE: To isolate and identify the major metabolites from the methanolic extract of C. sinaica aerial parts and evaluate their cytotoxic activity against selected human cancer cell lines. RESULTS: Six known compounds were isolated and identified: chlorohyssopifolin A (1), cirsiliol (2), isovitexin (3), isoorientin (4), kaempferol-3-O-glucoside (5), and rutin (6), based on physical, chemical, and spectral analyses (¹H and ¹³C NMR). Cytotoxic evaluation using the sulforhodamine B assay revealed that chlorohyssopifolin A exhibited the highest activity with IC₅₀ values of 4.8 ± 0.6 µM (SKOV-3), 6.8 ± 0.5 µM (MCF-7), and 0.6 ± 0.1 µM (PC-3). Cirsiliol showed moderate cytotoxicity against PC-3 (IC₅₀ = 18.5 ± 1.6 µM), while the remaining compounds were inactive. CONCLUSION: Centaurea sinaica is a promising source of bioactive metabolites. Chlorohyssopifolin A displayed potent and selective cytotoxicity, particularly against prostate cancer cells, warranting further in-vivo and mechanistic studies.