Screening of Panamanian medicinal plants for brine shrimp toxicity, crown gall tumor inhibition, cytotoxicity and DNA intercalation

Crude extracts from 20 Panamanian plants used in traditional medicine have been screened for brine shrimp toxicity, tumor inhibition, DNA-intercalation and cytotoxicity tests in a clonogenic assay in V79 suspension culture gassed with air or nitrogen. Of the 20 plant extracts, 8 (40%) proved active in DNA intercalation. The most active were the methanol extracts of Bidens pilosa (root), Jatropha curcas (leaf), Pereskia bleo (whole plant), Isertia hypoleuca (leaf), Cyperus luzulae (root), Vernonia patens (leaf and stem), Alibertia edulis (stem) and Justicia graciliflora (aerial parts). Sixteen (80%) of the 20 methanol plant extracts were active in potato disc tumor inhibition assay; Cyperus luzulae (root), Justicia graciliflora (aerial parts), Pereskia bleo (whole plant) and Vernonia patens (leaf and stem) being the most active. Cytotoxicity in the clonogenic assay was observed only in three plant extracts: Cyperus luzulae, Piper auritum and Psychotria correae, whereas high brine shrimp toxicity (LC(50) < 100 p.p.m.) was observed in 13 (65%) of the 20 plant extracts tested. These results appear to show a good correlation between the three bioassays: brine shrimp toxicity, tumor inhibition and DNA intercalation. The latter bioassay is rapid, economical, and can be used in activity guided fractionation of plant extracts.