In vitro activity of phospholipase A2 and of peptides from Crotalus durissus terrificus venom against amastigote and promastigote forms of Leishmania (L) infantum chagasi

Background American visceral leishmaniasis is caused by the intracellular parasiteLeishmania (L.) infantum chagasi, and transmitted by the sand fly Lutzomyia longipalpis. Since treatment is based on classical chemotherapeutics with significant side effects, the search for new drugs remains the greatest global challenge. Thus, this in vitro study aimed to evaluate the leishmanicidal effect ofCrotalus durissus terrificus venom fractions on promastigote and amastigote forms of Leishmania (L.) infantum chagasi. Methods Phospholipase A 2 (PLA 2 ) and a pool of peptide fraction ( 3 kDa) were purified from Crotalusvenom. Furthermore, promastigotes and peritoneal macrophages of mice infected by amastigotes were exposed to serial dilutions of the PLA 2 and peptides at intervals varying between 1.5625 g/mL and 200 g/mL. Both showed activity against promastigotes that varied according to the tested concentration and the time of incubation (24, 48 and 72 h). Results MTT assay for promastigotes showed IC 50 of 52.07 g/mL for PLA2 and 16.98 g/mL for the peptide fraction of the venom. The cytotoxicity assessment in peritoneal macrophages showed IC50 of 98 g/mL and 16.98 g/mL for PLA 2 and peptide by MTT assay, respectively. In peritoneal macrophages infected by Leishmania (L.) infantum chagasi amastigotes, the PLA 2 stimulated growth of parasites, and at higher doses reduced growth by 23 %. The peptide fraction prevented 43 % of the intracellular parasite growth at a dose of 16.98 g/mL, demonstrating the toxicity of this dose to macrophages. Both fractions stimulated H 2 O 2 production by macrophages but only PLA 2 was able to stimulate NO production. Conclusion We have demonstrated the in vitro leishmanicidal activity of the PLA2 and peptide fraction ofCrotalus venom. The results encourage further studies to describe the metabolic pathways involved in cell death, as well as the prospecting of molecules with antiparasitic activity present in the peptide fraction of Crotalus durissus terrificus venom.

In vitro activity of phospholipase A 2 and of peptides from Crotalus durissus terrificus venom against amastigote and promastigote forms of Leishmania (L) infantum chagasi

Background American visceral leishmaniasis is caused by the intracellular parasiteLeishmania (L.) infantum chagasi, and transmitted by the sand fly Lutzomyia longipalpis. Since treatment is based on classical chemotherapeutics with significant side effects, the search for new drugs remains the greatest global challenge. Thus, this in vitro study aimed to evaluate the leishmanicidal effect ofCrotalus durissus terrificus venom fractions on promastigote and amastigote forms of Leishmania (L.) infantum chagasi. Methods Phospholipase A 2 (PLA 2 ) and a pool of peptide fraction (<3 kDa) were purified from Crotalusvenom. Furthermore, promastigotes and peritoneal macrophages of mice infected by amastigotes were exposed to serial dilutions of the PLA 2 and peptides at intervals varying between 1.5625 μg/mL and 200 μg/mL. Both showed activity against promastigotes that varied according to the tested concentration and the time of incubation (24, 48 and 72 h). Results MTT assay for promastigotes showed IC 50 of 52.07 μg/mL for PLA2 and 16.98 μg/mL for the peptide fraction of the venom. The cytotoxicity assessment in peritoneal macrophages showed IC50 of 98 μg/mL and 16.98 μg/mL for PLA 2 and peptide by MTT assay, respectively. In peritoneal macrophages infected by Leishmania (L.) infantum chagasi amastigotes, the PLA 2 stimulated growth of parasites, and at higher doses reduced growth by 23 %. The peptide fraction prevented 43 % of the intracellular parasite growth at a dose of 16.98 μg/mL, demonstrating the toxicity of this dose to macrophages. Both fractions stimulated H 2 O 2 production by macrophages but only PLA 2 was able to stimulate NO production. Conclusion We have demonstrated the in vitro leishmanicidal activity of the PLA2 and peptide fraction ofCrotalus venom. The results encourage further studies to describe the metabolic pathways involved in cell death, as well as the prospecting of molecules with antiparasitic activity present in the peptide fraction of Crotalus durissus terrificus venom.(AU)

Antimicrobial activity of Mimosa tenuiflora (Willd.) Poir. from Northeast Brazil against clinical isolates of Staphylococcus aureus / Atividade antimicrobiana de Mimosa tenuiflora (Willd.) Poir. do Nordeste do Brasil, contra isolados clínicos de Staphylococcus aureus

Mimosa tenuiflora is a native plant of Northeast Brazil where it is popularly known as ''jurema-preta'' and it is widely used in folk medicine. In this work the anti-Staphylococcus aureus activity of ethanol extract of M tenuiflora was evaluated by determination of minimum inhibitory concentration (MIC) of clinical isolates by the agar dilution method, and by time-kill assay using a reference strain. MIC values against 30 isolates were 0,18 mg/mL (16/30) or 0,36 mg/mL (14/30, and also the reference strain). In the reference strains, at concentrations up to 4x MIC, only bacteriostatic effect was observed, but at 8x MIC a fast bactericidal effect was observed.

A Mimosa tenuiflora é uma planta nativa da região Nordeste do Brasil onde é conhecida como jurema-preta sendo amplamente utilizada na medicina popular. No presente trabalho a atividade anti-Staphylococcus aureus do extrato etanólico da M. tenuiflora foi avaliada pela determinação da concentração inibitória mínima (CIM), pelo método da diluição em agar, em 30 isolados clínicos e pela cinética de inativação com a linhagem referência. Os valores da CIM foram 0,18 mg/mL em 16 isolados e 0,36 mg/mL nos demais, bem como na linhagem referência. A cinética de inativação mostrou apenas efeito bacteriostático nas concentrações do extrato até aquela correspondente a 4x CIM e um rápido efeito bactericida na concentração correspondente a 8x CIM.

Atividade anti-fúngica do neem e jurema-preta sobre cepas de Candida spp isolados de vacas com mastite subclínica no Estado de Pernambuco / Anti-fungal activity of neem and jurema-preta on samples of isolated Candida spp of cows with subclinical mastitis in the State of Pernambuco

O objetivo deste estudo foi avaliar a atividade anti-fungica (in vitro) do neem (Azadiracta indica A. Juss.) e de jurema preta (Mimosa tenuiflora (Wild) Poir.) sobre cepas de Candida spp. isoladas de casos de mastite subclínica em vacas no Estado de Pernambuco. As folhas do neem foram coletadas em árvores de fazendas do município de Patos-PB e a casca da jurema-preta foi coletada na UFCG, Campus de Patos e preparados extratos etanólicos. As amostras de Candida spp. foram coletadas de leite de vacas com mastite subclínica e semeadas em placas de Petri contendo ágar-base acrescido de 5 por cento de sangue desfibrinado de ovino Sabouraud. As placas foram incubadas em estufa bacteriológica a 37 ºC e a leitura foi realizada com 24 e 48 h. Os ensaios foram realizados em duplicata e o resultado final foi determinado pela média aritmética dos halos de inibição. A avaliação microbiológica destes ensaios demonstrou que o extrato da casca da jurema-preta apresentou atividade antifúngica bastante satisfatória sobre a levedura de C. albicans, proporcionando resultado superior aos obtidos com o extrato do neem e fluconazol.

The leaves of neem were collected on farms of the city of Patos-PB, and the bark of jurema-preta was collected in the UFCG - Campus of Patos-PB, and the extracts were prepared from the ethanol. The samples of Candida spp. were collected in milk of cows with subclinical mastitis and sown in plates of Petri containing agar-base 5 percent increased of de-fiber blood of sheep Sabouraud. The plates were incubated in bacteriological greenhouse 37 ºC and the reading was carried through with 24 and 48 h. The assays were carried through in duplicate and the final result was determined by the arithmetic mean of inhibition halos. The microbiological evaluation of these assays demonstrated that the extract from the bark of jurema-preta showed antifungal activity quite satisfactory on the yeast C. albicans, providing superior results to those obtained with the extract of neem and fluconazol.

Atividade biológica da jurema-preta (Mimosa tenuiflora (Wild) Poir. ) sobre Staphylococcus aureus isolado de casos de mastite bovina / Biological Activity of jurema preta (Mimosa tenuiflora (Wild) Poiret) on Staphylococcus aureus isolated of mastitis cattle

O objetivo deste estudo foi avaliar a sensibilidade do Staphylococcus aureus ao extrato da jurema-preta (Mimosa tenuiflora (Wild) Poir.). Foram isoladas 25 cepas de S. aureus de amostras de leite de vacas com histórico de mastite clínica e subclínica, submetidas ao teste de atividade antimicrobiana do extrato de M. tenuiflora. Os testes de sensibilidade in vitro foram realizados utilizando o método de difusão em meio sólido. Em seguida foram inoculados 50 μL do extrato nas seguintes diluições 1:1; 1:2; 1:4; 1:8; 1:16; 1:32; 1:64; 1:128; 1:256; 1:512. As placas foram incubadas a 37 °C, por um período de 24 a 48 h. Os ensaios foram realizados em triplicata. Observou-se halos de inibição entre 6 e 25 mm de diâmetro. O percentual de sensibilidade das amostras testadas foi distribuido em: 1:1 a 1:32 (100 por cento); 1:64 (92 por cento); 1: 128 (72 por cento); 1:256 (28 por cento); 1:512 (0 por cento). O estudo da M. tenuiflora sobre as amostras de S. aureus testadas demonstrou que a planta tem ação antimicrobiana.

The aim of this study was to evaluate the sensitivity of the S.aureus to the extract of Mimosa tenuiflora (Wild) Poir. (jurema-preta). Twenty five strains of S. aureus were isolated from milk samples with description of clinical and subclinical mastitis and submitted to antimicrobial activity test of the M. tenuiflora extract. The sensitivity in vitro tests were carried out using the agar difusion method (well diffusion method). After that, 50μL of the extract were inoculated in the following dilutions: 1:1; 1:2; 1:4; 1:8; 1:16; 1:32; 1:64; 1:128; 1:256; 1:512. The plates were incubated at 37 ºC during 24 and 48 h. The tests were made in triplicate. Halos of inhibition were observed between 6 and 25 mm of diameter. The percentage of sensitivity of the tested samples was distributed in: 1:1 to 1:32 (100 percent), 1:64 (92 percent); 1: 128 (72 percent); 1:256 (28 percent); 1:512 (0 percent). The study of M. tenuiflora on the tested S. aureus samples it demonstrated that the plant has antimicrobial action.