Jacaranone analogs from Senecio scandens

Abstract

Bioassay-guided fractionation of the ethanolic extract of Senecio scandens led to the isolation of four new compounds 4, 5, 7, and 8, along with four known jacaranone analogs (1, 2, 3, 6). Their structures were elucidated on the basis of spectral and chemical evidence. Compound 7 was obtained as a tautomeric mixture of α/β-epimer. The cytotoxic activities of these compounds were evaluated. Among these, compounds 5 and 8 showed potent cytotoxicities. The benzoquinone derivative, jacaranone ethyl ester (1), was the major cytotoxic constituent in this plant with IC₅₀s at a range of 0.5–1.0 μg/ml against various tumor cell lines. The SAR of these jacaranone analogs (1–8), isolated from S. scandens, was also discussed.

Keywords:

• Senecio scandens
• Jacaranone analog
• tetrahydrojacaranone
• benzoquinone

Acknowledgements

The authors are thankful to the Beijing Municipal Science and Technology Commission of China for the financial support. We also thank Mr Hongyan Liu for her help with the cytotoxicity assay.