Anti-tumour screening of Brazilian plants

Organic and aqueous extracts of 145 Brazilian plants (538 extracts) from 34 families were evaluated for anti-tumour activity against the human tumour cell lines HT29 and NCI-H460. Of the extracts tested, 117 (22%) demonstrated cytotoxicity against one or both of the cell lines at a concentration of 100 mug/ml.. Of special interest are the families Anacardiaceae, Annonaceae, Asteraceae, Celestraceae, Leguminosae (Fabaceae), Meliaceae and Myrtaceae, which contain a high proportion of active species. On the basis of these results we are further examining the cytotoxic species, with the objective of isolating and identifying the active phytochemicals. These results also confirm the continuing importance of natural product screening models, alongside targeted drug development, in the discovery of new anti-neoplastic pharmacophores.