Estudo preliminar toxicológico, antibacteriano e fitoquímico do extrato etanólico das folhas de Jatropha mollissima (Pohl) Baill. (pinhão-bravo, Euphorbiaceae), coletada no Município de Tauá, Ceará, Nordeste Brasileiro / Toxicological, antibacterial, and phytochemical preliminary study of the ethanolic extract of Jatropha mollissima (Pohl) Baill (pinhão-bravo, Euphorbiaceae) leaves, collected in Tauá, Ceará, Northeastern Brazil

RESUMO A cada dia, cepas bacterianas estão tornando-se resistentes a diversos antibióticos, o que faz necessária a busca de novas substâncias eficazes para o tratamento de doenças. Desta forma, este trabalho reporta o estudo preliminar toxicológico, antibacteriano e fitoquímico do extrato etanólico das folhas de Jatropha mollissima (pinhão-bravo, Euphorbiaceae), coletada no Município de Tauá, Ceará, Nordeste Brasileiro. Inicialmente, realizou-se o teste de toxicidade do extrato contra Artemia salina. Na sequencia, foi realizado o ensaio antibacteriano contra quatro cepas bacterianas Gram-negativas (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Hafnia alvei ATCC 51873, Klebsiella pneumoniae ATCC 13883) e uma cepa Gram-positiva (Enterococcus faecalis ATCC 29212). Finalmente, fez-se a análise fitoquímica preliminar do extrato ativo para detecção das principais classes de metabólitos especiais. Como resultado, o extrato etanólico das folhas de J. mollissima se mostrou tóxico para Artemia salina, pois apresentou CL50 igual a 406,02 μg/mL. Quanto à ação antibacteriana, o extrato se mostrou ativo contra a bactéria Gram-positiva Enterococcus faecalis ATCC 29212, apresentando moderada atividade antibacteriana (halo de inibição igual a 7,03 mm). Evidenciou-se no extrato bioativo a presença de cumarinas, fenóis, taninos, flavonoides (flavonóis e flavanonas), alcaloides e esteroides, ambas as classes reportadas como antimicrobianos. Portanto, esse extrato tem potencial para ser usado na produção de fármacos contra infecções causadas por bactérias Gram-positivas. No entanto, as informações direcionam estudos futuros para o isolamento e identificação dos compostos bioativos, monitorados sob a ação antibacteriana mais expressiva.

ABSTRACT Each day, bacterial strains are becoming more resistant to various antibiotics, which requires the search for new effective substances for the treatment of diseases. Thus, this study reports the toxicological, antibacterial, and phytochemical preliminary study of the ethanolic extracts of Jatropha mollissima (pinhão-bravo, Euphorbiaceae) leaves, collected in Tauá, Ceará, Northeast of Brazil. Initially, we performed the toxicity testing of the extract against Artemia salina. Then, we conducted the antibacterial assay against four Gram-negative bacterial strains (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Hafnia alvei ATCC 51873, Klebsiella pneumoniae ATCC 13883), and one Gram-positive strain (Enterococcus faecalis ATCC 29212). Finally, we carried out the preliminary phytochemical analysis of the active extract to detect the main classes of special metabolites. As a result, the ethanolic extract of J. mollissima leaves was toxic to Artemia salina, because it presented LC50 equal to 406.02 µg/mL. Regarding antibacterial action, the extract was active against the Gram-positive bacteria Enterococcus faecalis ATCC 29212, with moderate antibacterial activity (inhibition zone equal to 7.03 mm). The bioactive extract had the presence of coumarins, phenols, tannins, flavonoids (flavanols and flavonones), alkaloids and steroids, both classes reported as antimicrobials. Therefore, this extract has the potential to be used in the production of drugs against infections caused by Gram-positive bacteria. However, these information require further studies for the isolation and identification of bioactive compounds, monitored under the more expressive antibacterial action.

Antiviral activities of extracts and phenolic components of two Spondias species against dengue virus

In recent years, the search for natural plant products to fight viral diseases has been increasing. In this work, two Spondias species, namely S. mombin and S. tuberosa, found in Ceará state (Brazil), and their main phenolic components were evaluated against dengue virus. In vitro antiviral tests were performed against type-2 dengue virus by the MTT method and standard cytopathic effect reduction assay in C6/36 cells. Cytotoxicity was also evaluated by MTT. The presence of phenolic compounds quercetin, rutin, and ellagic acid in plant extracts was characterized by HPLC analysis. Both Spondias species extracts and components were nontoxic to the cells whereas rutin and quercetin displayed relevant antiviral activity with IC50 of 362.68 µg/mL and 500 µg/mL, respectively.