Two new 2"-ethyl-furanoflavones named fistulaflavones A and B together with six known furanoflavones were isolated from the stems of Cassia fistula. The structures were elucidated by spectroscopic methods including extensive 1D, 2D NMR and high resolution electrospray ionization mass spectrometry (HRESIMS) techniques, and comparison with literature data. All the compounds were evaluated for their cytotoxicity against five human tumor cell lines. One of the compounds showed potent cytotoxicity against SHSY5Y and MCF7 cells with IC50 values of 2.7 and 2.6 µmol L-1, respectively.
Cassia fistula; 2"-ethyl-furanoflavones; furanoflavones; cytotoxicity
