Five daucane-type sesquiterpenes isolated from the roots of <i>Ferula songarica</i> Pall. ex Schult. and their anti-gastric cancer activity

Two new daucane-type sesquiterpenes (1–2) and three known compounds (3–5) were isolated from the dried roots of Ferula songarica Pall. ex Schult., their structures were elucidated through comprehensive 1D and 2D NMR spectroscopy, high-resolution electrospray ionisation mass spectrometry (HR-ESI-MS), experimental and calculated (ECD) spectra, and other complementary methods. The MTT assay was employed to evaluate its in vitro antitumor activity. The results indicated that compounds 1, 3 and 4 exhibited potent cytotoxicity against gastric cancer cells with IC50 values of 14.27 ± 0.4 μM, 18.71 ± 1.2 μM and 21.83 ± 3.4 μM, respectively. Compound 2 displayed moderate inhibition with an IC50 value of 45.66 ± 1.9 μM.