BackgroundApis mellifera venom, which has already been recommended as an alternative anti-inflammatory treatment, may be also considered an important source of candidate molecules for biotechnological and biomedical uses, such as the treatment of parasitic diseases.MethodsAfricanized honeybee venom from Apis mellifera was fractionated by RP-C18-HPLC and the obtained melittin was incubated with promastigotes and intracellular amastigotes of Leishmania (L.) infantum. Cytotoxicity to mice peritoneal macrophages was evaluated through mitochondrial oxidative activity. The production of anti- and pro-inflammatory cytokines, NO and H2O2 by macrophages was determined.ResultsPromastigotes and intracellular amastigotes were susceptible to melittin (IC50 28.3 μg.mL−1 and 1.4 μg.mL−1, respectively), but also showed mammalian cell cytotoxicity with an IC50 value of 5.7 μg.mL−1. Uninfected macrophages treated with melittin increased the production of IL-10, TNF-α, NO and H2O2. Infected melittin-treated macrophages increased IL-12 production, but decreased the levels of IL-10, TNF-α, NO and H2O2.ConclusionsThe results showed that melittin acts in vitro against promastigotes and intracellular amastigotes of Leishmania (L.) infantum. Furthermore, they can act indirectly on intracellular amastigotes through a macrophage immunomodulatory effect.
A necessidade de encontrar novas drogas eficazes no combate microbiano tem aumentado a cada dia e estimulado a busca de novos compostos naturais com atividades biológicas. Neste trabalho, realizaram-se estudo fitoquímico e análises microbiológicas com os extratos etanólicos das espécies (jurema-preta) Mimosa tenuiflora (Wild) Poiret e (juremabranca) Piptadenia stipulacea (Benth) Ducke, frente a linhagens de bactérias patogênicas. O pó da casca do caule de ambas as espécies foi submetido à avaliação bromatológica e determinados os teores de Matéria Seca, Matéria Mineral, Proteína Bruta, Fibra em Detergente Neutro e Energia Bruta. Os resultados para a prospecção química indicaram a presença de taninos e outros compostos fenólicos, bem como a presença de saponinas em ambos os extratos. Os extratos das duas espécies demonstraram que mais de uma parte das plantas possui atividade antimicrobiana. A composição bromatológica da casca do caule de jurema-preta e jurema-branca apresentou teores diferenciados para as variáveis avaliadas.
BackgroundAmerican visceral leishmaniasis is caused by the intracellular parasite Leishmania (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 of Crotalus durissus terrificus venom fractions on promastigote and amastigote forms of Leishmania (L.) infantum chagasi.MethodsPhospholipase A2 (PLA2) and a pool of peptide fraction (<3 kDa) were purified from Crotalus venom. Furthermore, promastigotes and peritoneal macrophages of mice infected by amastigotes were exposed to serial dilutions of the PLA2 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).ResultsMTT assay for promastigotes showed IC50 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 PLA2 and peptide by MTT assay, respectively. In peritoneal macrophages infected by Leishmania (L.) infantum chagasi amastigotes, the PLA2 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 H2O2 production by macrophages but only PLA2 was able to stimulate NO production.ConclusionWe have demonstrated the in vitro leishmanicidal activity of the PLA2 and peptide fraction of Crotalus 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.
Objective: To evaluate the antimicrobial and ant-adherent in vitro activity of tannins isolated from Anacardium occidentale Linn. (Cashew) on dental biofilm bacteria. Material and Methods: Streptococcus mutans ATCC 25175, Streptococcus mitis ATCC 903, Streptococcus sanguis ATCC 15300, Streptococcus oralis ATCC 10557, Streptococcus salivarius ATCC 7073 and Lactobacillus casei ATCC 9595 samples were used in this study. The tests were performed by the solid medium dilution method to determine the Minimum Inhibitory Concentration (MIC). The Minimum Inhibitory Concentration of Adherence (MICA) of bacteria to glass was determined in the presence of 5% sucrose. As a positive control, 0.12% chlorhexidine gluconate was used. The substances were tested at concentrations of 1:1 (pure solution) up to 1:512. Data were analyzed using descriptive statistics and the SPSS software, version 15.0. Results: Tannins isolated from Anacardium occidentale Linn. (cashew) formed inhibition halos ranging from 11 to 17 mm in diameter and were capable of inhibiting the growth of bacteria tested at concentrations of 1:4 (S mutans), 1:16 (S mitis), 1:8 (S sanguis), 1:4 (S oralis), 1:8 (S salivarius) and 1:2 (L casei). The tannin solution was effective in inhibiting the adherence of microorganisms to glass, and its effect on Streptococcus sanguis (1:512) and Lactobacillus casei (1:512) stood out, showing ant-adherent effect at all concentrations tested. Conclusion: Tannin isolates produced in vitro antimicrobial and ant-adherent activity on dental biofilm-forming bacteria and can be considered as an alternative treatment in infectious processes in clinical dentistry.
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