Activity of Piperaceae extracts and fractions in the control of Phytomonas serpens/Atividade de extratos e fracoes de Piperaceae no controle de Phytomonas serpens

Protozoa of the genus Phytomonas are harmful parasites to several agricultural crops of economic importance. Due to their recognized biological activity, crude extracts of Piper aduncum, P. crassinervium, P. hispidum, and P. amalago leaves, were tested using the microdilution plate technique to assess the antiparasitic potential against Phytomonas serpens. Results showed that the ethanolic crude extract of P. crassinervium and P. amalago presented the best inhibitory concentration for 50% of the cells (I[C.sub.50], 16.5 [micro]g [mL.sup.-1] in chloroform phase, and 18 [micro]g [mL.sup.-1] in aqueous phase, respectively, after 48 h treatment. Cytotoxicity analyses were performed using the colorimetric method of sulforhodamine-B in LLCM[K.sub.2]mammalian cells. The chloroform phase of P. crassinervium was subjected to the fractionation process, in which the ethyl acetate and dichloromethane fractions obtained better I[C.sub.50] values. Scanning electron microscopy (SEM) images showed alterations in the cell membrane of the treated parasites. The data obtained indicate a potential antiparasitic effect of the Piper species analyzed against P. serpens, being considered promising candidates for formulations of bioproducts to control the parasite. Key words: antiparasitic activity, medicinal plants, Piper, Trypanosomatid, Phytomonas. Protozoarios do genero Phytomonas sao parasitas prejudiciais a varias culturas agricolas de importancia economica. Devido a sua atividade biologica reconhecida, extratos brutos de folhas de Piper aduncum, P. crassinervium, P. hispidum e P. amalago, foram testadas pela tecnica de microdiluicao em placa para avaliar o seu potencial antiparasitario contra Phytomonas serpens. Os resultados mostraram que o extrato bruto etanolico de P. crassinervium e P. amalago apresentaram as melhores concentracoes inibitorias para 50% das celulas (I[C.sub.50], 16,5 [micro]g [mL.sup.-1] na fase cloroformio e 18 [micro]g [mL.sup.-1] na fase aquosa, respectivamente, apos 48 h de tratamento. Analises de citotoxicidade foram realizadas atraves do metodo colorimetrico da sulforodamina-B, em celulas de mamiferos LLCMK2. A fase cloroformio de P crassinervium foi submetida ao processo de fracionamento, no qual as fracoes acetato de etila e diclorometano obtiveram melhores valores de I[C.sub.50] Imagens de microscopia eletronica de varredura (MEV) mostraram alteracoes na membrana celular dos parasitas tratados com fase aquosa de P. amalago. Os dados obtidos indi