Two previously undescribed isoflavones, erysacleuxin C (1) and erysacleuxin D (2), together with seven known compounds (3–9), were isolated and identified from the EtOAc extract of the twigs of Erythrina sacleuxii Hua (Leguminosae). The structures of the isolated compounds were determined on the basis of their spectroscopic and spectrometric data. Evaluation of their cytotoxicity against the human cancer HeLa-S3 cell lines indicated IC50 values of 130.4, 54.9 and 73.9 µM for erysacleuxin C (1), erysacleuxin D (2) and butin (9), respectively. Keywords: Erythrina sacleuxii, Leguminosae, Isoflavone, Erysacleuxin C, Erysacleuxin D, Cytotoxicity
