Sesquiterpene lactones from the extracts of two Balkan endemic Laserpitium species and their cytotoxic activity

► Extracts of Laserpitium zernyi and Laserpitium ochridanum underground parts were analysed. ► In both extracts six known sesquiterpene lactones and latifolone were present. ► Five slovanolides, four being 2β-esterified were isolated from L. ochridanum. ► Cytotoxicity of extracts and lactones was tested in in vitro assays on two cell lines. ► The most active compounds: with unsaturated lactone ring and more esterified ones.