Abstract INTRODUCTION: Snakebites represent a serious global public health problem, especially in tropical countries. In Brazil, the incidence of snakebites ranges from 19 to 22 thousand cases per 100000 persons annually. The state of Rondônia, in particular, has had an increasing incidence of snakebites. METHODS: A retrospective cross-sectional study on snakebites was conducted from January 2007 to December 2018. Brazil’s Information System for Notifiable Diseases was queried for all snakebites reported in Porto Velho, Ariquemes, Cacoal, and Vilhena. Data on land surface temperatures during the day and night, precipitation, and humidity were obtained using the Google Earth Engine. A Bayesian time series model was constructed to describe the pattern of snakebites and their relationship with climate data. RESULTS: In total, 6326 snakebites were reported in Rondônia. Accidents were commonly caused by Bothrops sp. (n=2171, 81.80%). Snakebites most frequently occurred in rural areas (n=2271, 85.5%). Men, with a median age of 34 years (n=2101, 79.1%), were the most frequent bitten. Moderate clinical manifestation was the most common outcome of an accident (n=1101, 41.50%). There were clear seasonal patterns with respect to rainfall, humidity, and temperature. Rainfall and land surface temperature during the day or night did not increase the risk of snakebites in any city; however, changes in humidity increased the risk of snakebites in all cities. CONCLUSION: This study identified the population exposed to snakes and the influence of anthropic and climatic factors on the incidence of snakebites. According to climate data, changes in humidity increased the risk of snakebites.

Abstract INTRODUCTION: Crotalus envenomations cause serious complications and can be fatal without appropriate treatment. Venom isoforms present and inter/intraspecific variations in the venom composition can result in different symptoms presented by bites by snakes from the same species but from different geographical regions. We comparatively evaluated the local and systemic effects caused by Crotalus durissus terrificus (Cdt), C.d. collilineatus (Cdcolli), and C.d. cascavella (Cdcasc) envenomation. METHODS: Venom chromatography was performed. Proteolytic, phospholipase, and LAAO activities were analyzed. Edema, myotoxicity, hepatotoxicity, nephrotoxicity, and coagulation alterations were evaluated. RESULTS: The venom SDS-PAGE analyses found the presence of convulxin, gyroxin, crotoxin, and crotamine in Cdt and Cdcolli venoms. Crotamine was not present in the Cdcasc venom. Cdt, Cdcollli, and Cdcasc venoms had no proteolytic activity. Only Cdcasc and Cdt venoms had phospholipase activity. LAAO activity was observed in Cdcolli and Cdcasc venoms. Cdcolli and Cdcasc venoms caused 36.7% and 13.3% edema increases, respectively. Cdt venom caused a 10% edema induction compared to those by other venoms. All venoms increased TOTAL-CK, MB-CK, and LDH levels (indicating muscle injury) and ALT, AST, GGT, and ALP levels (markers of liver damage) and were able to induce a neuromuscular blockade. Urea and creatinine levels were also altered in both plasma and urine, indicating kidney damage. Only Cdcolli and Cdcasc venoms increased TAPP and TAP. CONCLUSIONS: Together, these results allow us to draw a distinction between local and systemic effects caused by Crotalus subspecies, highlighting the clinical and biochemical effects produced by their respective venoms.

Abstract INTRODUCTION Brazil has the largest number of snakebite cases in South America, of which the large majority is concentrated in the Midwest and North. METHODS In this descriptive observational study, we assessed the epidemiological and clinical snakebite cases referred to the Centro de Medicina Tropical de Rondônia from September 2008 to September 2010. RESULTS We followed up 92 cases from admission until discharge, namely 81 (88%) men and 11 (12%) women, with a mean age of 37 years, and mainly from rural areas (91.3%). The snakebites occurred while performing work activities (63%) during the Amazon rainy season (78.3%). The vast majority of individuals presented from the Porto Velho microregion (84.7%). Approximately 95.6% of the snakebites were caused by snakes of the genus Bothrops, followed by two lachetics and two elapidics cases. Surgery was performed in 10 cases (9 fasciotomies in the lower limb and 1 amputation). No deaths were reported in this study, but 4 cases (4.3%) developed sequelae in the lower limb. CONCLUSIONS This study can contribute to a better understanding of envenomation in the state of Rondônia and thus can be useful for identifying real conditions that can increase the incidence of snakebites in this region. Moreover, the study results can serve as a basis for improving educational campaigns designed to prevent these types of snakebites, as well as for preserving snakes.

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.

Abstract Background: Cnidarians produce toxins, which are composed of different polypeptides that induce pharmacological effects of biotechnological interest, such as antitumor, antiophidic and anti-clotting activities. This study aimed to evaluate toxicological activities and potential as antitumor and antiophidic agents contained in total extracts from five cnidarians: Millepora alcicornis, Stichodactyla helianthus, Plexaura homomalla, Bartholomea annulata and Condylactis gigantea (total and body wall). Methods: The cnidarian extracts were evaluated by electrophoresis and for their phospholipase, proteolytic, hemorrhagic, coagulant, fibrinogenolytic, neuromuscular blocking, muscle-damaging, edema-inducing and cytotoxic activities. Results: All cnidarian extracts showed indirect hemolytic activity, but only S. helianthus induced direct hemolysis and neurotoxic effect. However, the hydrolysis of NBD-PC, a PLA2 substrate, was presented only by the C gigantea (body wall) and S. helianthus. The extracts from P. homomalla and S. helianthus induced edema, while only C gigantea and S. helianthus showed intensified myotoxic activity. The proteolytic activity upon casein and fibrinogen was presented mainly by B. annulata extract and all were unable to induce hemorrhage or fibrinogen coagulation. Cnidarian extracts were able to neutralize clotting induced by Bothrops jararacussu snake venom, except M. alcicornis. All cnidarian extracts were able to inhibit hemorrhagic activity induced by Bothrops moojeni venom. Only the C. gigantea (body wall) inhibited thrombin-induced coagulation. All cnidarian extracts showed antitumor effect against Jurkat cells, of which C. gigantea (body wall) and S. helianthus were the most active; however, only C. gigantea (body wall) and M. alcicornis were active against B16F10 cells. Conclusion: The cnidarian extracts analyzed showed relevant in vitro inhibitory potential over the activities induced by Bothrops venoms; these results may contribute to elucidate the possible mechanisms of interaction between cnidarian extracts and snake venoms.

Abstract This review discusses studies on the venom of Bothrops erythromelas published over the past 36 years. During this period, many contributions have been made to understand the venomous snake, its venom, and its experimental and clinical effects better. The following chronological overview is based on 29 articles that were published between 1979 and 2015, with emphasis on diverse areas. The complexity of this task demands an integration of multidisciplinary research tools to study toxinology. This science is in need of renewed conceptual and experimental platforms aimed at obtaining a profound understanding of the highly complex pathophysiology of snakebite envenoming and toxins isolated from snakes.

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.

Este trabalho relata o estudo químico de duas plantas medicinais da Amazônia: Philodendron scabrum K. krause (Araceae) e Vatairea guianensis Aubl. (Fabaceae). As composições dos óleos essenciais dos cipós de P. scabrum e dos frutos de V. guianensis, respectivamente, foram analisadas em CG-DIC e CG-EM. Os constituintes majoritários dos cipós de P. scabrum foram óxido de cariofileno (19,42%), α-copaeno (16,08%) e β-bisaboleno (10,01%); e nos frutos de V. guianensis foram o ácido (9Z)-octadecenoico (24,95%) e o ácido docosahexaenoico (24,17%). β-sitosterol e o alquilresorcinol 1-hexadecanoil-2,6-dihidroxibenzeno foram isolados do extrato etanólico dos cipós de P. scabrum; e do extrato etanólico dos frutos de V. guianensis, foram isoladas as antraquinonas crisofanol e fisciona. As determinações estruturais foram baseadas em dados de RMN de ¹H e 13C. RMN, uni e bidimensional e comparação com dados da literatura.

This work describes the chemical study of two medicinal plants of the Amazon Philodendron scabrum K. Krause (Araceae) and Vatairea guianensis Aubl. (Fabaceae). Essential oils composition from stems of Philodendron scabrum K. Krause (Araceae) and fruits of Vatairea guianensis Aubl. (Fabaceae), respectively were analyzed in GC-FID and GC-MS. The major constituents from stems of P. scarabum were caryophyllene oxide (22.42%), α-copaene (16.08%) and β-bisabolene (12.01%) and from fruits of V. guianensis were (9Z)-octadecenoic acid (24.95%) and docosahexenoic acid (24.17%). β-sitosterol and alkylresorcinol 1-hexadecanoyl-2,6-dihydroxybenzene were isolated from ethanolic extracts from stems of P. scabrum and from ethanolic extracts from fruits of V. guianensis, the athraquinones chrysophanol and physcion were isolated. The structure of isolated compounds we determinate wered based on data from ¹H and 13C NMR, including two dimensional analyses and comparison with literature data.

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.

A quimioterapia é o único procedimento farmacológico validado para a terapêutica da leishmaniose e da malária, consideradas doenças negligenciadas para o desenvolvimento de fármacos pelas indústrias farmacêuticas. Com a não renovação medicamentosa, o surgimento de resistência, os efeitos colaterais e o longo período de tratamento indicam a necessidade do desenvolvimento de novos e mais eficientes fármacos. A Floresta Amazônica é a região com a maior biodiversidade do planeta, com uma riqueza de animais e plantas produtoras de moléculas com atividades biológicas relevantes para o desenvolvimento e exploração biotecnológica. Algumas destas moléculas, obtidas de extratos vegetais e de venenos de anuros, apresentam atividade leishmanicida e plasmodicida, o que demonstra o potencial desta biodiversidade para a investigação de novas drogas. A moderna abordagem na pesquisa de novos fármacos envolve a associação de química combinatória, high-throughput screening, bioinformática, interação molecular, cristalografia e o estudo dinâmico de toxicidade sistêmica e celular, que atualmente no Brasil, estão distribuídas em poucos grupos acadêmicos sem a devida associação industrial. Esta deficiência, agregada ao excesso de regulamentação para o acesso ao material biológico, sobretudo, proveniente de unidades de conservação, populações tradicionais e nações indígenas, é um importante entrave para o desenvolvimento deste tipo de pesquisa. A associação de grupos de pesquisa do Brasil, estimulados por políticas governamentais de financiamento acadêmico e industrial, são essenciais para a superação destas dificuldades, de forma que nos próximos anos possam surgir novos produtos para terapia de doenças negligenciadas oriundas da biodiversidade amazônica.

Chemotherapy is the only validated therapy for the treatment for the neglected diseases leishmaniasis and malaria. However, the emergence of drug resistance, collateral effects and long-term treatment encourage the development of new and more efficient drugs. The Amazon tropical forest includes the richest areas of biodiversity in the world, including a great number of microbes, plant and animal species that produce a source of interesting biologically active molecules. Several of these molecules, obtained from plant extracts and frog venom have leishmanicidal and plasmodicidal activity, highlighting the potential of this biodiversity for the development of new drugs. In research, modern approaches in new drug development are carried out using combinatorial chemistry, high-throughput screening, bioinformatics, molecular interaction, crystallography and dynamic studies of cellular and systemic toxicity. In Brazil, these techniques are mainly present in only a few academic groups with no efficient connection to industry. The problem associated with over-regulation for accessing the biological material in restricted areas, local populations and indigenous areas places major barriers in the path of research and development of new drugs. Thus, the association of academic research groups in Brazil, encouraged and supported by government and industry, is essential to overcome these major barriers related to the development of new products for treatment of neglected diseases from Amazonian biodiversity in future years.

Metalloproteinases are abundant enzymes in crotaline and viperine snake venoms. They are relevant in the pathophysiology of envenomation, being responsible for local and systemic hemorrhage frequently observed in the victims. Snake venom metalloproteinases (SVMP) are zinc-dependent enzymes of varying molecular weights having multidomain organization. Some SVMP comprise only the proteinase domain, whereas others also contain a disintegrin-like domain, cysteine-rich, and lectin domains. They have strong structural similarities with both mammalian matrix metalloproteinases (MMP) and members of ADAMs (a disintegrin and metalloproteinase) group. Besides hemorrhage, snake venom metalloproteinase induce local myonecrosis, skin damage, and inflammatory reaction in experimental models. Local inflammation is an important characteristic of snakebite envenomations inflicted by viperine and crotaline snake species. Thus, in the recent years there is a growing effort to understand the mechanisms responsible for SVMP-induced inflammatory reaction and the structural determinants of this effect. This short review focuses the inflammatory effects evoked by SVMP.