In vitro cytotoxic and anti-inflammatory activities of sesquiterpene lactones from Centaurea papposa (Coss.) Greuter

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).