ICAM-1 bioassay for the evaluation of sesquiterpene lactones from Calea and Centaurea spp.

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.

Publication History

Article published online:
13 December 2021

• References

• 1 Grafakou et al, 2020. Nat Prod Res, under revision.
• 2 Padilla-Gonzalez et al., 2016. Crit Rev Plant Sci, 5, 18-37.