Antiproliferative constituents from the aerial parts of Chrysophthalmum montanum (DC.) Boiss

Three undescribed sesquiterpene lactones (1-3), 1β,4β-dihydroxy-guaia-10(14),11(13)-dien-8α,12-olide (1), 4α, 6α-dihydroxy-9β,10β-epoxy-1βH-guaia-11(13)-en-8α,12-olide (2), and 4α,9β-dihydroxy-6α-acetoxy-1βH-guaia-10(14),11(13)-dien-8α,12-olide (3), as well as a known sesquiterpene lactone, (4α,5α,8β,10α)-4,10-dihydroxy-1,11(13)-guaiadien-12,8-olide (4), along with a lignan, pinoresinol (5), a flavonoid, chrysosplenol C (6), and two triterpenes, a mixture of isomers, taraxasterol acetate and Ψ-taraxasterol acetate (7a/7b), and a mixture of isomers taraxasterol and Ψ-taraxasterol (8a/8b) were isolated from the aerial parts of Chrysophthalmum montanum (DC.) Boiss. The structures of 1-6, 7a/7b, and 8a/8b were established on the basis of spectroscopic evidence, such as MS, NMR, UV, and IR spectroscopy. All isolated compounds, except for 5 and 8a/8b, were assayed for their antiproliferative activities against three human cancer cell lines, i.e. cervical (HeLa), breast (MCF-7), and lung (A549), and a normal human lung cell line (BEAS-2B) using MTT method. Compounds 1, 4, and 6 showed significant inhibitory effects on cancer cell growth at 20 μg/mL concentration, with cell viability ranging from 53 to 64 % against MCF-7 cell line. In addition, compounds 4, and 6 exhibited cytotoxicity against HeLa cancer cell line with the viability of approximately 64 %. In conclusion, compounds 1, 4, and 6 may serve as leads for further research towards the development of anticancer agents.