Discovery of rearranged eudesmane-type sesquiterpenes from Artemisia tournefortiana.

Six undescribed sesquiterpenes artetourneforin F-K (1-6), along with six known compounds (7-12), were isolated from Artemisia tournefortiana. Their structures were established by 1D and 2D NMR spectroscopic data, HRESIMS, ECD, and quantum chemical calculations. Artetourneforin F-K (1-6) represented a rare 4,5-seco undescribed skeleton in natural sesquiterpenes, and a plausible biosynthetic pathway was proposed. The X-ray crystal structures of compounds 7 and 8 were reported for the first time. Compound 9 showed extremely significant anti-inflammatory and cytotoxicity activity against HeLa cell lines with IC50 values of 0.87 ± 0.05 μM and 4.02 ± 0.15 μM, respectively. In the anti-vitiligo activity test, compounds 8 and 10 demonstrated activity in promoting melanogenesis in B16F10 cells. Compound 8 exhibited significant cytotoxicity against the HT29 and MCF7 cell lines, with IC50 values of 6.40 ± 0.41 and 10.18 ± 0.49 μM, respectively.