Cytotoxicity of abietane diterpenoids from Salvia multicaulis towards multidrug-resistant cancer cells.

Abstract Diterpenoids salvimulticanol (1) and salvimulticaoic acid (2) together with known diterpenoid (3–6) were isolated from Salvia multicaulis. Structures were elucidated by spectroscopic techniques including HRESIMS as well as 1D-, and 2D-NMR. In-vitro cytotoxicity was assayed against human cancer cell lines. As several metabolites exhibited activity against drug-resistance lines, compounds were screened against a panel of human drug-sensitive and multidrug-resistant cancer lines. A proposed biosynthetic pathway for these new diterpenoids (1 – 2) as well as the cytotoxic structure-activity relationship of all identified compounds were discussed. Compound 1 and 6 showed the most potent cytotoxicity with IC 50 11.58 and 4.13 towards leukemia cell lines CCRF-CEM and CEM-ADR5000, respectively. Graphical abstract Unlabelled Image [ABSTRACT FROM AUTHOR]