In the pursuit of highly active specialized metabolites from endemic plants, Centaurea papposa (Coss.) Greuter, an endemic plant in Algeria and Tunisia, was investigated and afforded eleven sesquiterpene lactones (1-11). Cytotoxic evaluation of these compounds using the in vitro MTT assay on three human cancerous cell lines (HeLa, SK-MEL-28 and HepG2), revealed that isolates 4, 8 and 9 (IC50 ≤ 10 μM) could be potential anti-cancer drugs for cervical cancer according to the National Cancer Institute. Further evaluation of the in vitro anti-inflammatory activity showed that compounds 1 and 4 inhibited the TNF-α induced ICAM-1 expression in HMEC-1 endothelial cells at a maximum of 21% and 2% of the control (IC50 values 21.9 and 5.7 μM, respectively). The Michael reactions of the α-methylene-γ-lactone ring seem to be responsible for the strong activity, while no toxicity was observed in the HMEC-1 cells in all the range of tested concentrations (6.25-50.0 µM).
Keywords: Asteraceae; Centaurea papposa; I-CAM-1; MTT; Sesquiterpene lactones; anti-inflammatory; cytotoxic.