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.