Diterpenoids from Roots of Salvia lachnocalyx; In-silico and In-vitro Toxicity against Human Cancer Cell Lines

Further investigations on phytochemical constituents of dichloromethane extract fromroots of Salvia lachnocalyx (S. lachnocalyx) led to the isolation and identification of eightknown diterpenoids from this plant for the first time. The chemical structures of the purifiedcompounds were elucidated using spectroscopic analyses including EI-MS, 1H and 13C NMR andby comparison of the resulting spectra with those reported in the literature. Then, the cytotoxicactivity of identified compounds was examined against two human cancer cell lines MCF-7(human breast adenocarcinoma) and K562 (human chronic myelogenous leukemia). Moleculardocking of promising cytotoxic compounds were performed by AutoDock Tools 1.5.4 programin the active site of Topoisomerase I. Eight known diterpenoids; 12-hydroxysapriparaquinone(1), 15-deoxyfuerstione (2), horminon (3), 7α-acetoxyroyleanone (4), 11β-hydroxymanoyloxide (5), microstegiol (6), 1-keto-aethiopinone (7) and 14-deoxycoleon U (8) were isolated ofdichloromethane extract from roots of salvia lachnocalyx. Compounds 2, 3, 6, and 8 showedcytotoxic activity against MCF-7 (human breast adenocarcinoma) and K562 (human chronicmyelogenous leukemia) cell lines with IC50 values in the range of 2.63-11.83 μg/mL. The inhibitionof” topoisomerase I” was suggested by molecular docking calculations as the mechanism ofcytotoxicity of the tested compounds. According to cytotoxic assay and docking results, it issuggested that compounds 2, 3, 6, and 8 have good potential as anticancer agents.