RESUMO
The chemical investigation of the leaves and stem bark of Acacia polyacantha (Fabaceae) led to the isolation of a new oleanane-type triterpenoid saponin named polyacanthoside A 1 together with fifteen known compounds. Their structures were established from spectral , mainly HRESIMS, 1D NMR and 2D NMR and by comparison with literature data. The cytotoxicity of compound 1 and the analogues 8 as well as doxorubicin was determined in a panel of 9 cancer cell lines including sensitive and drug resistant phenotypes. Unlike the analogue 8, compound 1 as well as doxorubicin displayed cytotoxic effects in all the 9 tested cancer cell lines with IC50 values ranged from 8.90 µM (towards CCRF-CEM leukemia cells) to 35.21 µM (towards HepG2 hepatocarcinoma cells) for compound 1 and from 0.02 µM (towards CCRF-CEM leukemia cells) to 66.83 µM (against CEM/ADR5000 leukemia cells) for doxorubicin.