Cytotoxic Activities and QSAR Studies of Diterpenoid Isosteviol Derivatives as Anti-Esophageal Agents

The cytotoxicity of isosteviol and its twenty derivatives on three human tumor cell lines (ECA-109, MCF-7 and B16-F10) were evaluated. The results demonstrated that ECA-109 was the most sensitive cell line which was exposed to the compound (VI) with the lowest IC50 value of 1.30 ± 0.11 μM. By quantitative structure–activity relationship (QSAR) technique, the obtained cytotoxicity data were further utilized to respectively generate the statistically reliable HQSAR model (q2 = 0.828, r2 = 0.941, $$r_{{{\text{pred}}}}^{{\text{2}}}$$ = 0.849) and topomer CoMFA model (q2 = 0.608, r2 = 0.919, $$r_{{{\text{pred}}}}^{{\text{2}}}$$ = 0.747), which could provide the guidelines for the further development of novel and potent anti-esophageal agent.