RESUMO
Benzofurans are bioactive compounds isolated from the Asteraceae family. Benzofuran derivatives have been extensively studied because of their toxic effects on humans and animals. The phytotoxic activity of the benzofuran derivative (2R)-6-hydroxytremetone was studied on germination, seedling development, and cytotoxic and genotoxic effects on monocotyledoneous (onion and wheat) and dicotyledoneous (lettuce and tomato) species. Results of these assays demonstrated that (2R)-6-hydroxytremetone is a potent germination inhibitor of onion, lettuce, and tomato seeds. Germination reductions of approximately 80% were measured when seeds were exposed to 100 mg l(-1) of the compound, and showed considerably effects on the posterior development of the sprouts, including rootlets and hypocotyl elongations. Moreover, this benzofuran derivative also significantly reduced the root length and mitotic division of Allium cepa bulbs, although DNA damages were not observed. Our findings suggest that a mechanism of mitosis inhibition may play a role in the phytotoxic effects of plants producing these compounds.
Assuntos
Benzopiranos/toxicidade , Produtos Agrícolas/efeitos dos fármacos , Inibidores do Crescimento/toxicidade , Magnoliopsida/efeitos dos fármacos , Mitose/efeitos dos fármacos , Extratos Vegetais/toxicidade , Estruturas Vegetais/efeitos dos fármacos , Asteraceae/química , Benzopiranos/isolamento & purificação , Produtos Agrícolas/crescimento & desenvolvimento , Germinação/efeitos dos fármacos , Lactuca/efeitos dos fármacos , Lactuca/crescimento & desenvolvimento , Solanum lycopersicum/efeitos dos fármacos , Solanum lycopersicum/crescimento & desenvolvimento , Magnoliopsida/crescimento & desenvolvimento , Cebolas/efeitos dos fármacos , Cebolas/crescimento & desenvolvimento , Extratos Vegetais/química , Estruturas Vegetais/crescimento & desenvolvimento , Triticum/efeitos dos fármacos , Triticum/crescimento & desenvolvimentoRESUMO
The antimicrobial and cytotoxic activities of chloroform extracts from the weeds Centaurea tweediei and C. diffusa, and the main sesquiterpene lactones isolated from these species, onopordopicrin and cnicin, respectively, were assayed. Results show that the chloroform extracts from both Centaurea species possess antibacterial activities against a panel of Gram-positive and Gram-negative bacteria. Remarkable antibacterial activity against methicillin-resistant Staphylococcus aureus was also measured. Both the extracts and the purified sesquiterpene lactones show high cytotoxicity against human-derived macrophages. Despite this cytotoxicity, C. diffusa chloroform extract and cnicin are attractive candidates for evaluation as antibiotics in topical preparations against skin-associated pathogens.
