Abstract Background: Wasp venoms constitute a molecular reservoir of new pharmacological substances such as peptides and proteins, biological property holders, many of which are yet to be identified. Exploring these sources may lead to the discovery of molecules hitherto unknown. This study describes, for the first time in hymenopteran venoms, the identification of an enzymatically inactive phospholipase A2 (PLA2) from the venom of the social wasp Polybia occidentalis. Methods: P. occidentalis venom was fractioned by molecular exclusion and reverse phase chromatography. For the biochemical characterization of the protein, 1D and 2D SDS-PAGE were performed, along with phospholipase activity assays on synthetic substrates, MALDI-TOF mass spectrometry and sequencing by Edman degradation. Results: The protein, called PocTX, was isolated using two chromatographic steps. Based on the phospholipase activity assay, electrophoresis and mass spectrometry, the protein presented a high degree of purity, with a mass of 13,896. 47 Da and a basic pI. After sequencing by the Edman degradation method, it was found that the protein showed a high identity with snake venom PLA2 homologues. Conclusion: This is the first report of an enzymatically inactive PLA2 isolated from wasp venom, similar to snake PLA2 homologues.

Background Mosquitoes are important vectors of several diseases, including malaria and dengue, and control measures are mostly performed using chemical insecticides. Unfortunately, mosquito resistance to commonly applied insecticides is widespread. Therefore, a prospection for new molecules with insecticidal activity based on Amazon biodiversity using the anuransLeptodactylus knudseni andPhyllomedusa vaillantii was performed against the mosquito speciesAnopheles darlingi and Aedes aegypti.Methods The granular secretion from anuran skin was obtained by manual stimulation, and lethal concentrations (LCs) for larvicidal and adulticidal tests were calculated using concentrations from 1-100 ppm. The skin secretions from the anuran species tested caused significant mortality within the first 24 hours on adults and larvae, but differed within the mosquito species.Results The skin secretions from the anuran species tested caused significant mortality within the first 24 hours on adults and larvae, but differed within the mosquito species. The calculated LC50 of L. knudseni skin secretions against An. darlingiwas 0.15 and 0.2 ppm for adults and larvae, respectively, but much higher for Ae. aegypti, i.e., 19 and 38 ppm, respectively. Interestingly, the calculated LCs50 of P. vaillantii against both mosquito species in adults were similar, 1.8 and 2.1 ppm, respectively, but the LC50 forAn. darlingi larvae was much lower (0.4 ppm) than forAe aegypti (2.1 ppm).Conclusions The present experiments indicate that skin secretions from L. knudseni and P. vaillantii contain bioactive molecules with potent insecticide activity. The isolation and characterization of skin secretions components will provide new insights for potential insecticidal molecules.

The Piper species chemistry has been widely investigated and the phytochemical analyses have led to the isolation of a number of active compounds like alkaloids, terpenes and flavones among others. The aim of this study was to evaluate the leishmanicidal activity of 2-[1-hydroxy-3-phenyl-(Z,2E)-2-propenylidene]-4-methyl-4-cyclopentene-1,3-dione (DCPC), a cyclopentenedione derivative isolated from the roots of Piper carniconnectivum C. DC., Piperaceae. Leishmanicidal activity against Leishmania amazonensis promastigotes was assessed, and the risk to host cell was assessed by measuring the cytotoxicity to peritoneal macrophages from BALB/c mice in vitro. L. amazonensis promastigotes and host macrophages were cultured in the presence of 100, 50, 25, 12.5 and 6 µg/mL of the cyclopentenedione derivative for up to 96 h. At the end of this period, the inhibitory concentrations (IC50) were compared with those from untreated cultures. The IC50 for promastigotes was 4.4 µg/mL after 96 h of treatment with the derivative. The 50% cytotoxic concentration (CC50) against murine peritoneal macrophages was 129 µg/mL. These results indicate that DCPC is a promising molecule for the development of leishmanicidal drugs.

O presente trabalho descreve a atividade do extrato etanólico (EE) dos frutos de Combretum leprosum, do triterpeno 3β, 6β, 16β-triidroxilup-20(29)-eno (1) e seus derivados sintéticos (1a-1d), sobre promastigotas de Leishmaniaamazonensis. O EE apresentou atividade leishmanicida e o valor de IC50 foi de 24,8 µg mL-1. Já o triterpeno 3β, 6β, 16β-trihidroxilup-20(29)-eno (1), na concentração de 5,0 µg mL-1, apresentou uma potente ação inibitória sobre a proliferação das promastigotas (IC50 = 3,3 µg mL-1). Entre os derivados sintéticos, apenas 1b e 1d apresentaram atividade contra as promastigotas (IC50 = 3,48 µg mL-1e 5,8 µg mL-1, respectivamente). Por outro lado, o derivado sintético 1a não apresentou atividade sobre as promastigotas de L. amazonensis. O EE, (1) e os derivados sintéticos 1a-1d não apresentaram efeito citotóxico sobre macrófagos peritoneais de camundongos. Estes resultados fornecem evidencias de que o extrato etanólico e o lupano isolado de C. leprosum possui atividade contra promastigotas de L. amazonensis, podendo ser utilizados como ferramentas no estudo de novas drogas leishmanicidas.

This paper describes the activity of the ethanolic extract (EE), obtained from the fruits of Combretum leprosum, the triterpene 3β, 6β, 16β-trihydroxylup-20(29)-ene (1) and its synthetic derivatives 1a-1d on Leishmania amazonensis promastigotes. The EE displayed leishmanicidal activity and the IC50 was 24.8 mg mL-1. However, the triterpene 3β, 6β, 16β-trihydroxylup-20(29)-ene (1), at a concentration of 5.0 mg mL-1, showed a potent inhibitory activity on promastigotes proliferation (IC50 = 3.3 mg mL-1). Among the synthetic derivatives, only (1b) and (1d) were active against promastigotes (IC50 = 3.48 mg mL-1and 5.8 mg mL-1, respectively). Moreover, the synthetic derivative 1a showed no activity on promastigotes of L. amazonensis. EE, (1) and the synthetic derivatives 1a-1d showed no cytotoxic effect on mice peritoneal macrophages. These results provide evidence that the ethanolic extract and the lupane isolated from C. leprosum was active against promastigotes of L. amazonensis, and may be used as a tool in the studies of new antileishmanial drugs.

A atividade leishmanicida do ácido 3,4,5-trimetoxi-dihidrocinâmico (TMPP) isolado do extrato hidroalcoólico de frutos de Piper turbeculatum Jacq. amazônica foi testado em ensaios in vitro utilizando formas promastigotas de Leishmania amazonensis. O TMPP foi utilizado em culturas de L. amazonensis nas concentrações de 1600 a 6,25 µg/mL. A viabilidade celular das formas promastigotas foi observada em 24, 48, 72 e 96 h para cálculo da CI50. O TMPP apresentou efeito leishmanicida dose dependente para as formas promastigotas de L. amazonensis apresentando CI50 de 145 µg/mL.

Leishmanicidal activity of the 3-(3,4,5-trimethoxyphenyl) propanoic acid (TMPP) isolated from EtOH extracts of the Amazonian Piper turbeculatum Jacq. fruits was evaluated in vitro using Leishmania amazonensis promastigotes. The TMPP was assayed at concentrations of 1600 to 6.25 µg/mL for 24, 48, 72 and 96 h. Promastigotes viability was analyzed and the IC50 of TMPP was 145 µg/mL.