Cytotoxic activity and triterpenes content of nine Mexican species of Bursera.

The genus Bursera (Burseraceae) is considered an interesting source of antitumour compounds. This study aimed to evaluate the cytotoxic activity of the dichloromethane-soluble extracts from the bark of nine Mexican Bursera species. The chemical components of the extracts were determined by NMR and mass spectroscopy, whereas its cytotoxicity was tested using the sulphorhodamine (SRB) method on seven cell lines. Triterpenes and fatty acids were the most abundant components found in the extracts. A quantification by HPTLC - densitometry, showed that the species B. copallifera had the highest content of amyrins (287 µg/mg extract) followed by B. submoniliformis (159.5 µg/mg) and B. bicolor (156.5 µg/mg). Regarding cytotoxicicity, the species B. bicolor caused the highest growth inhibition (>90%) in colon (HCT-15) and lung (SK-LU1) lines; while B. fagaroides, B. grandifolia, B. morelensis, B. bicolor and B. linanoe were active in the SK-LU1cell line.