Sesquiterpenes, flavonoids, shikimic acid derivatives and pyrrolizidine alkaloids from Senecio kingii Hook

[Display omitted] •Twenty-four compounds were isolated from Senecio kingii.•Thirteen compounds are new natural products, including seven sesquiterpene lactone (3, 5, 6, 8–11) and six shikimic acid derivatives (13–18).•The molecular structure of 3 was confirmed by single-crystal X-ray diffraction.•Compounds 3, 9, 18 and 25 showed a strong insect antifeedant activity. Twenty-four compounds including eleven eremophilanolides (1–11), one eremophilane (13), five shikimic acid derivatives (14–18), six flavonoids (19–24), and the macrocyclic unsaturated pyrrolizidine alkaloid integerrimine (25) were isolated from Senecio kingii, an endemic species from the Magallanes Region (Chile). Compounds 3, 5, 6, 8–11 and 13–18 have not been previously reported as natural products. Their molecular structures were determined by NMR spectroscopic analysis and comparison with published NMR data. An X-ray-analysis of compound 3 has been performed. Their insecticidal and antifungal activities were tested, being compound 3 the strongest insect antifeedant. Compounds 6, 9 and 18 were moderate antifungals.