Sesquiterpene lactones (SLs) are highly active specialized metabolites, with well-known
cytotoxic, anti-inflammatory, anti-microbial activities etc. This project unveiled
that SLs isolated from endemic Calea and Centaurea spp. are strong inhibitors of the TNF-α induced ICAM-1 expression on endothelial
HMEC-1 cells, in a dose-dependent manner, comparably to parthenolide used as positive
control (Figure 1). The expression of the surface molecule ICAM-1 is triggered by
cytokines and leads to endothelial adhesion and generation of intracellular signals
on the endothelial cells during the inflammation process [1]. The lactone ring is essential for the mechanism of action of the strong inhibitors
in comparison to the lower inhibitory potential of compounds lacking the α,β-unsaturated
lactone moiety. The samples were firstly subjected to MTT viability test on HMEC-1
cells, in order to exclude any false positive results. No toxicity was observed, although
Michael reactions usually also involve non-specific toxicity [2].
Further exploration of the SLs may offer a novel therapeutic approach to cope with
inflammatory diseases.
