Abstract
A new rosane-type diterpenoid (1) along with nine known diterpenoids (2-10), were isolated from the dried roots of Euphorbia nematocypha. The absolute configuration was elucidated from spectroscopic (nuclear magnetic resonance, high-resolution electrospray ionization mass spectrometry, and electronic circular dichroism) and optical-rotation analyses. Cytotoxicity and the ability to scavenge 2,2-diphenyl-1-picrylhydrazyl radicals were determined. Compound 1 showed remarkable cytotoxicity against human cancer cell lines (HeLa, CT26, and HCC 1806) in vitro. The interaction between compound 1 and proteins of ribosomal S6 kinase was revealed using molecular docking and provided valuable insights into the cytotoxic mechanism of action of compound 1. The latter could be developed as a pharmaceutical agent in the future.