The PLA2 inhibitor from Crotalus durissus terrificus blood plasma (CNF) inhibits group III-PLA2 from honeybee venom

Crotalus neutralizing factor (CNF) is an endogenous glycoprotein from Crotalus durissus terrificus snake blood that inhibits secretory phospholipases A2 (sPLA2) from the Viperid but not from Elapid venoms (subgroups IA and IIA, respectively). In the present study, we demonstrated that CNF can inhibit group III-PLA2 from bee venom by forming a stable enzyme-inhibitor complex. This finding opens up new possibilities for the potential use of CNF and/or CNF-based derivatives in the therapeutics of bee stings.

Inhibition of enzymatic activities of Bothrops asper snake venom and docking analysis of compounds from plants used in Central America to treat snakebite envenoming

ETHNOPHARMACOLOGICAL RELEVANCE

Snakebite envenoming is a public health problem of high impact in Central America. Bothrops asper, known as barba amarilla, terciopelo, and equis, is the snake species responsible for most snakebites in Central America. In this region, there is a long-standing tradition on the use of plants in the management of snakebites, especially in indigenous communities. Ethnomedical use of Eryngium foetidum L., Neurolaena lobata (L.) Cass. and Pimenta dioica (L.) Merr. to treat snakebite envenoming has been reported in Belice, Guatemala, Nicaragua, and Costa Rica. Extracts of the leaves of these plants have shown anti-venom activities in in vitro assays in previous studies.

AIM OF THE STUDY

To assess the ability of organic fractions from these three plants to inhibit enzymatic activities associated with toxicity of the venom of B. asper, and to study, by docking analysis, the interaction of metalloproteinase and phospholipases A₂ (PLA₂) from B. asper venom with secondary metabolites previously described in these plants.

MATERIALS AND METHODS

Organic fractions were obtained from these three plant species and their ability to neutralize proteolytic, PLA₂ and in vitro coagulant activities of B. asper venom was assessed. A phytochemical analysis was carried out in these fractions. The interaction of secondary metabolites previously described in these plants with three toxins from B. asper venom (a metalloproteinase, a PLA₂ and a PLA₂ homologue) was investigated by docking analysis.

RESULTS

The inhibitory activity of plants was mainly concentrated in their polar fractions. Acetonic fraction from P. dioica was the most active against PLA₂ activity, while the acetonic fraction of E. foetidum completely inhibited the proteolytic activity of the venom. Coagulant activity was partially inhibited only by the acetone and ethyl acetate fractions of P. dioica. Phytochemical analysis of the most bioactive fractions identified flavonoids, saponins, essential oils, coumarins, alkaloids, tannins and sesquiterpene lactones. Docking analysis revealed high affinity interactions of several secondary metabolites of these plants with residues in the vicinity of the catalytic site of these enzymes and, in the case of PLA₂ homologue myotoxin II, in the hydrophobic channel.

CONCLUSIONS

Various fractions from these plants have inhibitory activity against enzymatic actions of B. asper venom which are directly associated with toxicological effects. Docking analysis showed structural evidence of the interaction of secondary metabolites with three toxins. These observations provide support to the potential of these plants to inhibit relevant toxic components of this snake venom.

Observation of Bothrops atrox Snake Envenoming Blister Formation from Five Patients: Pathophysiological Insights

In the Brazilian Amazon, Bothrops atrox snakebites are frequent, and patients develop tissue damage with blisters sometimes observed in the proximity of the wound. Antivenoms do not seem to impact blister formation, raising questions regarding the mechanisms underlying blister formation. Here, we launched a clinical and laboratory-based study including five patients who followed and were treated by the standard clinical protocols. Blister fluids were collected for proteomic analyses and molecular assessment of the presence of venom and antivenom. Although this was a small patient sample, there appeared to be a correlation between the time of blister appearance (shorter) and the amount of venom present in the serum (higher). Of particular interest was the biochemical identification of both venom and antivenom in all blister fluids. From the proteomic analysis of the blister fluids, all were observed to be a rich source of damage-associated molecular patterns (DAMPs), immunomodulators, and matrix metalloproteinase-9 (MMP-9), suggesting that the mechanisms by which blisters are formed includes the toxins very early in envenomation and continue even after antivenom treatment, due to the pro-inflammatory molecules generated by the toxins in the first moments after envenomings, indicating the need for local treatments with anti-inflammatory drugs plus toxin inhibitors to prevent the severity of the wounds.

Bleeding and Thrombosis: Insights into Pathophysiology of Bothrops Venom-Related Hemostasis Disorders

Toxins from Bothrops venoms targeting hemostasis are responsible for a broad range of clinical and biological syndromes including local and systemic bleeding, incoagulability, thrombotic microangiopathy and macrothrombosis. Beyond hemostais disorders, toxins are also involved in the pathogenesis of edema and in most complications such as hypovolemia, cardiovascular collapse, acute kidney injury, myonecrosis, compartmental syndrome and superinfection. These toxins can be classified as enzymatic proteins (snake venom metalloproteinases, snake venom serine proteases, phospholipases A₂ and L-amino acid oxidases) and non-enzymatic proteins (desintegrins and C-type lectin proteins). Bleeding is due to a multifocal toxicity targeting vessels, platelets and coagulation factors. Vessel damage due to the degradation of basement membrane and the subsequent disruption of endothelial cell integrity under hydrostatic pressure and tangential shear stress is primarily responsible for bleeding. Hemorrhage is promoted by thrombocytopenia, platelet hypoaggregation, consumption coagulopathy and fibrin(ogen)olysis. Onset of thrombotic microangiopathy is probably due to the switch of endothelium to a prothrombotic phenotype with overexpression of tissue factor and other pro-aggregating biomarkers in association with activation of platelets and coagulation. Thrombosis involving large-caliber vessels in B. lanceolatus envenomation remains a unique entity, which exact pathophysiology remains poorly understood.

Isohemigossypolone: Antiophidic properties of a naphthoquinone isolated from Pachira aquatica Aubl

We investigated the antiophidic properties of isohemigossypolone (ISO), a naphthoquinone isolated from the outer bark of the Pachira aquatic Aubl. The inhibition of phospholipase A₂, coagulant, fibrinogenolytic, hemorrhagic and myotoxic activities induced by Bothrops pauloensis venom (Pb) was investigated. For this, we use samples resulting from the incubation of Pb with ISO in different concentrations (1:1, 1:5 and 1:10 w/w), we also evaluated the condition of treatment using ISO after 15 min of venom inoculation. The activities of phospholipase A₂, coagulant, fibrinogenolytic, hemorrhagic and myotoxic induced by the B. pauloensis venom were significantly inhibited when the ISO was pre-incubated with the crude venom. For in vivo neutralization tests, the results were observed even when the ISO was applied after 15 min of inoculation of the venom or metalloprotease (BthMP). Also, to identify the inhibition mechanism, we performed in silico assays, across simulations of molecular coupling and molecular dynamics, it was possible to identify the modes of interaction between ISO and bothropic toxins BmooMPα-I, Jararacussin-I and BNSP-7. The present study shows that naphthoquinone isohemigossypolone isolated from the P. aquatica plant inhibited part of the local and systemic damage caused by venom proteins, demonstrating the pharmacological potential of this compound in neutralizing the harmful effects caused by snakebites.

Examination of the Efficacy and Cross-Reactivity of a Novel Polyclonal Antibody Targeting the Disintegrin Domain in SVMPs to Neutralize Snake Venom

Snake envenomation can result in hemorrhage, local necrosis, swelling, and if not treated properly can lead to adverse systemic effects such as coagulopathy, nephrotoxicity, neurotoxicity, and cardiotoxicity, which can result in death. As such, snake venom metalloproteinases (SVMPs) and disintegrins are two toxic components that contribute to hemorrhage and interfere with the hemostatic system. Administration of a commercial antivenom is the common antidote to treat snake envenomation, but the high-cost, lack of efficacy, side effects, and limited availability, necessitates the development of new strategies and approaches for therapeutic treatments. Herein, we describe the neutralization ability of anti-disintegrin polyclonal antibody on the activities of isolated disintegrins, P-II/P-III SVMPs, and crude venoms. Our results show disintegrin activity on platelet aggregation in whole blood and the migration of the SK-Mel-28 cells that can be neutralized with anti-disintegrin polyclonal antibody. We characterized a SVMP and found that anti-disintegrin was also able to inhibit its activity in an in vitro proteolytic assay. Moreover, we found that anti-disintegrin could neutralize the proteolytic and hemorrhagic activities from crude Crotalus atrox venom. Our results suggest that anti-disintegrin polyclonal antibodies have the potential for a targeted approach to neutralize SVMPs in the treatment of snakebite envenomations.

Repurposing Cancer Drugs Batimastat and Marimastat to Inhibit the Activity of a Group I Metalloprotease from the Venom of the Western Diamondback Rattlesnake, Crotalus atrox

Snakebite envenomation causes over 140,000 deaths every year, predominantly in developing countries. As a result, it is one of the most lethal neglected tropical diseases. It is associated with incredibly complex pathophysiology due to the vast number of unique toxins/proteins present in the venoms of diverse snake species found worldwide. Here, we report the purification and functional characteristics of a Group I (PI) metalloprotease (CAMP-2) from the venom of the western diamondback rattlesnake, Crotalus atrox. Its sensitivity to matrix metalloprotease inhibitors (batimastat and marimastat) was established using specific in vitro experiments and in silico molecular docking analysis. CAMP-2 shows high sequence homology to atroxase from the venom of Crotalus atrox and exhibits collagenolytic, fibrinogenolytic and mild haemolytic activities. It exerts a mild inhibitory effect on agonist-induced platelet aggregation in the absence of plasma proteins. Its collagenolytic activity is completely inhibited by batimastat and marimastat. Zinc chloride also inhibits the collagenolytic activity of CAMP-2 by around 75% at 50 μM, while it is partially potentiated by calcium chloride. Molecular docking studies have demonstrated that batimastat and marimastat are able to bind strongly to the active site residues of CAMP-2. This study demonstrates the impact of matrix metalloprotease inhibitors in the modulation of a purified, Group I metalloprotease activities in comparison to the whole venom. By improving our understanding of snake venom metalloproteases and their sensitivity to small molecule inhibitors, we can begin to develop novel and improved treatment strategies for snakebites.

What's eating you? dusky pigmy rattlesnake envenomation and management

The dusky pigmy rattlesnake (Sistrurus miliarius barbouri) is a pit viper (Crotalidae family) along with diamondback rattlesnakes, water moccasins, and copperheads. Although it is a small snake, it is responsible for envenomations requiring hospitalization. We present the case of a 54-year-old man who was bitten in the left index finger with onset of coagulopathy successfully treated with crotalidae polyvalent immune fab (CPIF) antivenom.

Expression of an scFv antibody fragment in Nicotiana benthamiana and in vitro assessment of its neutralizing potential against the snake venom metalloproteinase BaP1 from Bothrops asper

Human accidents with venomous snakes represent an overwhelming public health problem, mainly in rural populations of underdeveloped countries. Their high incidence and the severity of the accidents result in 81,000 to 138,000 deaths per year. The treatment is based on the administration of purified antibodies, produced by hyper immunization of animals to generate immunoglobulins (Igs), and then obtained by fractionating hyper immune plasma. The use of recombinant antibodies is an alternative to conventional treatment of snakebite envenoming, particularly the Fv fragment, named the single-chain variable fragment (scFv). We have produced recombinant single chain variable fragment scFv against the venom of the pit viper Bothrops asper at high levels expressed transiently and stably in transgenic plants and in vitro cultures that is reactive to BaP1 (a metalloproteinase from B. asper venom). The yield from stably transformed plants was significantly (p > 0.05) higher than the results in from transient expression. In addition, scFvBaP1 yields from systems derived from stable transformation were: transgenic callus 62 μg/g (±2); biomass from cell suspension cultures 83 μg/g (±0.2); culture medium from suspensions 71.75 mg/L (±6.18). The activity of scFvBaP1 was confirmed by binding and neutralization of the fibrin degradation induced by BnP1 toxins from B. neuwiedi and by Atroxlysin Ia from B. atrox venoms. In the present work, we demonstrated the potential use of plant cells to produce scFvBaP1 to be used in the future as a biotechnological alternative to horse immunization protocols to produce anti-venoms to be used in human therapy against snakebites.

Anti-ophidian activity of Bredemeyera floribunda Willd. (Polygalaceae) root extract on the local effects induced by Bothrops jararacussu venom

Bredemeyera floribunda roots are popularly used to treat snakebites in the semiarid region of Northeast Brazil, and previous studies indicate the anti-ophidian actions of triterpenoid saponins found in its roots. To assess B. floribunda root extract (BFRE) activity against the effects of Bothrops jararacussu venom (BjuV), antiphospholipasic, antiproteolytic, antihemorrhagic, antinecrotic, and anti-edematogenic activities were investigated in mice. Phytochemical analysis revealed the presence of saponins, flavonoids, and sugars, with rutin and saccharose being the major constituents of BFRE. Acute toxicity was determined and BFRE was nontoxic to mice. Phospholipase A2 and proteolytic activities induced by BjuV were inhibited in vitro by BFRE at all concentrations tested herein. BFRE (150 mg/kg) inhibited paw edema induced by BjuV (50 µg/animal), reducing total edema calculated by area under the curve, but carrageenan-induced paw edema was unchanged. Hemorrhagic and necrotizing actions of BjuV (50 µg/animal) were considerably decreased by BFRE treatment. Thus, BFRE blocked the toxic actions of B. jararacussu venom despite having no anti-inflammatory activity, which points to a direct inhibition of venom's toxins, as demonstrated in the in vitro assays. The larger amounts of rutin found in BFRE may play a role in this inhibition, since 3',4'-OH flavonoids are known inhibitors of phospholipases A2.

Potential Utilization of a Polysaccharide from the Marine Algae Gayralia oxysperma, as an Antivenom for Viperidae Snakebites

Worldwide, snakebites have serious implications for human health. The administration of antivenom is the official treatment used to reverse the toxic activities of envenomation. However, this therapy is not efficient to treat the local effects, leading to the amputation or deformity of affected limbs. As such, alternative treatments are needed. Here, we analyze the ability of a polysaccharide from the green marine alga Gayralia oxysperma (Go3) to inhibit the effects of venom from Bothrops jararaca and Lachesis muta. B. jararaca or L. muta venoms were incubated together with sulfated heterorhamnans from Go3, and the in vitro (coagulation, proteolytic, and hemolytic) and in vivo (hemorrhagic, myotoxic, edematogenic, and lethal) activities of venoms were assessed. Additionally, Go3 was injected before and after the injection of venoms, and the toxic activities were further tested. When incubated with the venoms, Go3 inhibited all activities, though results varied with different potencies. Moreover, Go3 neutralized hemorrhagic, myotoxic, and edematogenic activities when injected before or after injection with B. jararaca and L. muta venom. Go3 also blocked the coagulation of plasma in mice caused by the venoms in an ex vivo test. Therefore, Go3 has the potential to be used as antivenom for B. jararaca and L. muta bites, notably exhibiting higher efficacy on L. muta venom.

Inhibition of a Snake Venom Metalloproteinase by the Flavonoid Myricetin

Most of the snakebite envenomations in Central and South America are caused by species belonging to Bothrops genus. Their venom is composed mainly by zinc-dependent metalloproteinases, responsible of the hemorrhage characteristic of these envenomations. The aim of this study was to determine the inhibitory ability of ten flavonoids on the in-vitro proteolytic activity of Bothrops atrox venom and on the hemorrhagic, edema-forming and myonecrotic activities of Batx-I, the most abundant metalloproteinase isolated from this venom. Myricetin was the most active compound, exhibiting an IC 50 value of 150 μ M and 1021 μ M for the inhibition of proteolytic and hemorrhagic activity, respectively. Independent injection experiments, with a concentration of 1600 μ M of myricetin administered locally, immediately after toxin injection, demonstrated a reduction of 28 ± 6 % in the hemorrhagic lesion. Additionally, myricetin at concentrations 800, 1200 and 1600 μ M promoted a reduction in plasma creatine kinase activity induced by Batx-I of 21 ± 2 % , 60 ± 5 % and 63 ± 2 % , respectively. Molecular dynamics simulations coupled with the adaptive biasing method suggest that myricetin can bind to the metalloproteinase active site via formation of hydrogen bonds between the hydroxyl groups 3', 4' and 5' of the benzyl moiety and amino acid Glu143 of the metalloproteinase. The hydroxyl substitution pattern of myricetin appears to be essential for its inhibitory activity. Based on this evidence, myricetin constitutes a candidate for the development of inhibitors to reduce local tissue damage in snakebite envenomations.

Inactivation of Venom PLA₂ Alleviates Myonecrosis and Facilitates Muscle Regeneration in Envenomed Mice: A Time Course Observation

Snake venom is a complex cocktail of toxins which induces a series of clinical and pathophysiological manifestations in victims, including severe local tissue damage and systemic alterations. Deinagkistrodon acutus (D. acutus) ranks among the “big four” life-threatening venomous species in China, whose venom possesses strong myotoxicity and hematotoxicity that often lead to permanent disability or muscle atrophy. Varespladib, an inhibitor of mammalian phospholipase A₂ (PLA₂), has been recently reproposed as an effective antidote against snakebite envenomation. The present study aimed at evaluating the protective role of varespladib on muscle regeneration in envenomed mice. Mice were grouped and subjected to inoculation with D. acutus venom or a mixture of venom and varespladib or control vehicle in the gastrocnemius muscle. Local injuries including hemorrhage, myonecrosis, ulceration, and systemic damages including general dysfunction, visceral failure, and inflammatory responses were observed at 1, 3, 7, 14, and 21 days. The results indicated that most of the muscle myonecrosis and hemorrhage were alleviated by varespladib. Besides, the pretreated mice recovered rapidly with lesser atrophy and muscle fibrosis. In conclusion, the findings of the present study suggested that varespladib is an effective antidote that could neutralize D. acutus venom and allow for earlier and improved rehabilitation outcome.

Assessment of the anti-snakebite properties of extracts of Aniba fragrans Ducke (Lauraceae) used in folk medicine as complementary treatment in cases of envenomation by Bothrops atrox

ETHNOPHARMACOLOGICAL RELEVANCE

Extracts of leaves and bark of Aniba fragrans are used as tea (decoction) to treat snakebites in communities in the Brazilian Amazon. The aqueous extract of the leaves of A. fragrans has been proven to be effective against Bothrops venom, but only when pre-incubated with the venom. This study sought to assess the potential of different types of extract of this species to inhibit the biological activities of Bothrops atrox venom (BaV) when used the same way as in folk medicine. The main classes of secondary metabolites and the concentrations of phenolics in the extracts were also determined.

MATERIALS AND METHODS

Four types of extract of A. fragrans were prepared: aqueous extract of the leaf (AEL), aqueous extract of the bark (AEB), hydroalcoholic leaf extract (HLE) and extract of the residue from hydrodistillation of the leaf (ERHL). The phytochemical profiles of the aqueous extracts were determined using thin layer chromatography (TLC), and the concentrations of phenolics were measured by colorimetric assays. To investigate the potential of the extracts to inhibit the biological activities of BaV, in vitro tests for antiphospholipase and antifibrinolytic activities were performed. In vivo tests for antihemorrhagic and antidefibrinating activities were also carried out, as well as antimicrobial tests for activity against the main bacteria found in the oral cavity of snakes. Interaction between the extracts and the proteins in BaV was assessed by electrophoresis (SDS-PAGE) and Western blot (WB). The cytotoxicity of the extracts was assessed in a strain of MRC-5 human fibroblasts.

RESULTS

Terpenoids, flavonoids and condensed and hydrolysable tannins were detected in all the extracts. Metabolites such as coumarins, fatty acids and alkaloids were present in some extracts but not in others, indicating different phytochemical profiles. Phenolics content varied between extracts, and there were more tannins in AEB and HLE. In the in vitro tests, the extracts inhibited the phospholipase and fibrinolytic activities of BaV in the two ratios of venom to extract used. HLE exhibited effective antimicrobial action as it inhibited growth of 11 of the 15 bacteria investigated, including Morganella morganii, the main bacteria described in the oral cavity of snakes. The extracts failed to inhibit the defibrinating activity of BaV, and only the Bothrops antivenom had a significant effect (96.1%) on this activity. BaV-induced hemorrhage was completely inhibited by AEL and AEB when the pre-incubation (venom:extract) protocol was used. When administered orally, as in folk medicine, both AEB and AEL produced significant inhibition of hemorrhagic activity (maximum inhibition 46.5% and 39.2%, respectively). SDS-PAGE and WB of the extracts pre-incubated with BaV showed that the main proteins in the venom had been precipitated by the extracts. None of the four extracts showed cytotoxic effects in the tests carried out with a human fibroblast cell line.

CONCLUSION

In addition to being effective in reducing hemorrhage when administered orally, the extracts displayed a high antimicrobial potential against microorganisms involved in secondary infections at the site of the snakebite. Once the extracts have been tested in accordance with the appropriate regulations, this species could potentially be used to produce a phytomedicine for complementary treatment of the secondary infections due to bacteria that aggravate the local signs and symptoms after snakebite envenomation.

The effects of Cissampelos pareira extract on envenomation induced by Bothropsdiporus snake venom

ETHNOPHARMACOLOGICAL RELEVANCE

Ophidian accidents are a serious public health problem in Argentina; the Bothrops species is responsible for 97% of these accidents, and in particular, B. diporus is responsible for 80% of them. In the northeast of the country (Corrientes Provinces), Cissampelos pareira L. (Menispermaceae) is commonly used against the venom of B. diporus; its use is described in almost all ethnobotanical literature from countries where the plant grows.

AIM OF THE STUDY

In this study, the in vitro and in vivo antivenom activities of C. pareira extracts were evaluated against B. diporus venom, with a particular focus on the local effects associated with envenoming. The seasonal influence on the chemical composition of the active extracts was also studied, in order determine the associated range of variability and its influence on the antivenom activity.

MATERIALS AND METHODS

This research was conducted using aerial parts (leaves, flowers, tender stems) and roots of Cissampelos pareira collected from two different phytogeographic regions of Corrientes (Argentina); Paso de la Patria and Lomas de Vallejos. In addition, to perform a seasonal analysis and to evaluate the metabolic stability, material was collected at three different growth stages. In vivo and in vitro anti-snake venom activities were tested, and a bio-guided chromatographic separation was performed in order to determine the active chemicals involved. The fractions obtained were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and the chemical profile of the most active constituent was analyzed by ultra high-performance liquid chromatography coupled to quadrupole/high-resolution mass spectrometry (Q-Orbitrap). (UHPLC-MS).

RESULTS

The alcoholic extract was found to be the most active The bio-guided fractionation allowed selection one fraction to be analyzed by UHPLC-MS in order to identify the components responsible for the activities found; this identified five possible flavonoids.

CONCLUSIONS

Our studies of the activity of C. pareira against the venom of B. diporus have confirmed that this species possesses inhibitory effects in both in vitro and in vivo models. Moreover, the present data demonstrate that certain flavonoids may mitigate some of the venom-induced local tissue damage.

Rattling the border wall: Pathophysiological implications of functional and proteomic venom variation between Mexican and US subspecies of the desert rattlesnake Crotalus scutulatus

While some US populations of the Mohave rattlesnake (Crotalus scutulatus scutulatus) are infamous for being potently neurotoxic, the Mexican subspecies C. s. salvini (Huamantlan rattlesnake) has been largely unstudied beyond crude lethality testing upon mice. In this study we show that at least some populations of this snake are as potently neurotoxic as its northern cousin. Testing of the Mexican antivenom Antivipmyn showed a complete lack of neutralisation for the neurotoxic effects of C. s. salvini venom, while the neurotoxic effects of the US subspecies C. s. scutulatus were time-delayed but ultimately not eliminated. These results document unrecognised potent neurological effects of a Mexican snake and highlight the medical importance of this subspecies, a finding augmented by the ineffectiveness of the Antivipmyn antivenom. These results also influence our understanding of the venom evolution of Crotalus scutulatus, suggesting that neurotoxicity is the ancestral feature of this species, with the US populations which lack neurotoxicity being derived states.

Carbon monoxide releasing molecule-2 inhibition of snake venom thrombin-like activity: novel biochemical "brake"?

A complication of defibrinogenation therapy with snake venom enzymes such as ancrod is hypofibrinogenemia associated bleeding secondary to no human-derived inhibitor being available to inactivate or diminish the activity of such enzymes. Of interest, ancrod contains a critical histidine residue without which enzymatic activity is inhibited, and carbon monoxide has been demonstrated to inhibit biomolecular function by interacting with histidine moieties in ion channels. We tested the hypothesis that exposure of three different snake venoms containing serine proteases with thrombin-like activity (which included ancrod) to carbon monoxide derived from carbon monoxide releasing molecule-2 would diminish their effects on plasmatic coagulation as assessed by thrombelastography. In the case of the Malayan pit viper and Eastern diamondback rattlesnake venoms, carbon monoxide diminished the effects of thrombin-like activity. In contrast, timber rattlesnake venom demonstrated enhancement of "thrombin-generating" activity with simultaneous loss of thrombin-like activity in response to carbon monoxide exposure. These findings may serve as the rational basis for not just continuing to investigate the potential of snake venom enzymes as clinical defibrinogenating agents, but to also to assess the potential to stop such agents from becoming a catalytic "runaway train" by judicious application of a biochemical "brake" such as carbon monoxide.

The inhibitory potential of the condensed-tannin-rich fraction of Plathymenia reticulata Benth. (Fabaceae) against Bothrops atrox envenomation

ETHNOPHARMACOLOGICAL RELEVANCE

Ethnobotanical studies have shown that Plathymenia reticulata Benth. (Fabaceae) has been widely used in cases of snake envenomation, particularly in Northern Brazil. In light of this, the aim of this study was to evaluate the inhibitory potential of the condensed-tannin-rich fraction obtained from the bark of P. reticulata against the main biological activities induced by Bothrops atrox venom (BaV).

MATERIALS AND METHODS

The chemical composition of the aqueous extract of P. reticulata (AEPr) was first investigated by thin-layer chromatography (TLC) and the extract was then fractionated by column chromatography on Sephadex LH-20. This yielded five main fractions (Pr1, Pr2, Pr3, Pr4 and Pr5), which were analyzed by colorimetry to determine their concentrations of total phenolics, total tannins and condensed tannins and to assess their potential for blocking the phospholipase activity of BaV. The Pr5 fraction was defined as the fraction rich in condensed tannins (CTPr), and its inhibitory potential against the activities of the venom was evaluated. CTPr was evaluated in different in vivo and in vitro experimental protocols. The in vivo protocols consisted of (1) pre-incubation (venom:CTPr, w/w), (2) pre-treatment (orally administered) and (3) post-treatment (orally administered) to evaluate the effect on the hemorrhagic and edematogenic activities of BaV; in the in vitro protocol the effect on phospholipase and coagulant activity using pre-incubation in both tests was evaluated.

RESULTS

There was statistically significant inhibition (p<0.05) of hemorrhagic activity by CTPr when the pre-incubation protocol was used [55% (1:5, w/w) and 74% (1:10, w/w)] and when pre-treatment with doses of 50 and 100mg/kg was used (19% and 13%, respectively). However, for the concentrations tested, there was no statistically significant inhibition in the group subjected to post-treatment administered orally. CTPr blocked 100% of phospholipase activity and 63.3% (1:10, w/w) of coagulant activity when it was pre-incubated with BaV. There was a statistically significant reduction (p<0.05) in edema induced by BaV in the oral protocols. Maximum inhibition was 95% (pre-treatment).

CONCLUSION

Our findings indicate that CTPr could be a good source of natural inhibitors of the components of snake venom responsible for inducing local inflammation.

Structural Basis for the Inhibition of a Phospholipase A2-Like Toxin by Caffeic and Aristolochic Acids

One of the main challenges in toxicology today is to develop therapeutic alternatives for the treatment of snake venom injuries that are not efficiently neutralized by conventional serum therapy. Venom phospholipases A2 (PLA2s) and PLA2-like proteins play a fundamental role in skeletal muscle necrosis, which can result in permanent sequelae and disability. This leads to economic and social problems, especially in developing countries. In this work, we performed structural and functional studies with Piratoxin-I, a Lys49-PLA2 from Bothropspirajai venom, complexed with two compounds present in several plants used in folk medicine against snakebites. These ligands partially neutralized the myotoxic activity of PrTX-I towards binding on the two independent sites of interaction between Lys49-PLA2 and muscle membrane. Our results corroborate the previously proposed mechanism of action of PLA2s-like and provide insights for the design of structure-based inhibitors that could prevent the permanent injuries caused by these proteins in snakebite victims.

Single chain antibody fragment with serine protease inhibitory property capable of neutralizing toxicity of Trimeresurus mucrosquamatus venom

Trimeresurus mucrosquamatus (TM) is one of majorities of snake envenomation with necrotic and hemorrhagic toxin in Taiwan. In this study, chickens were used as an alternative animal model for immunization with TM venom. Using phage display technology to process four rounds of panning, selected single chain variable fragments (scFv) could specifically recognize TM venom proteins, which were later identified as a group of homogeneous venom serine protease. The specific scFv antibodies showed various inhibitory effects on sheep RBC lysis induced by TM venom using an indirect hemolytic assay in vitro. In addition, the survival times of mice were extended to certain degrees when treated with these scFv antibodies individually or in a combination. To elucidate the inhibitory mechanism, we used molecular modeling to build up the serine protease structure to simulate the possible interactions with scFv antibodies. The results suggested that the CDR-loop of the scFv antibodies (3S10 or 4S1) might bind at the 99-loop of venom serine protease so as to affect substrate access due to the partial collapse of the subsite S2 and the partial movement of the subsite S4. It is hoped these chicken-derived antibodies could be applied to develop diagnostic and therapeutic agents against snakebites.

Plants used to treat snakebites in Santarém, western Pará, Brazil: an assessment of their effectiveness in inhibiting hemorrhagic activity induced by Bothrops jararaca venom

ETHNOPHARMACOLOGICAL RELEVANCE

The poor distribution and limited availability of antivenoms in Brazil have led to greater use of plants to treat snakebites. Very often such plants are the only alternative available to riverside communities.

MATERIALS AND METHODS

Direct questionnaire-based interviews were conducted with members of the Cucurunã, São Pedro and Alter do Chão communities in Santarém, Pará, Brazil. For each of the 12 most frequently mentioned species aqueous extracts were prepared and the phytochemical profiles determined by thin layer chromatography. The concentrations of phenolic compounds (tannins and flavonoids) in the aqueous extracts were determined by colorimetric assays. To assess inhibition of the hemorrhagic activity of Bothrops jararaca venom, solutions containing the venom mixed with aqueous extracts in the ratios 1:12 and 1:48 were tested (w/w). SDS-PAGE and Western blot were used to assess the action of the extracts on Bothrops jararaca venom.

RESULTS

In all, 24 plants belonging to 19 families were mentioned in the survey as being used to treat snakebites. Leaves (84%), seeds (60.9%) and inner bark (53%) were cited as the most frequently used parts in folk remedies, which were usually prepared in the form of a decoction (62.5%), tincture (45%) or maceration (22.5%). Hemorrhage induced by Bothrops jararaca venom was completely inhibited by aqueous extracts of Bellucia dichotoma, Connarus favosus, Plathymenia reticulata and Philodendron megalophyllum, which had a high phenolic content and contained condensed and hydrolyzable tannins. The results of SDS-PAGE showed that some venom protein bands were not visible when the venom was preincubated with the extracts that had completely inhibited hemorrhagic activity of the venom. Western blot showed that the extracts did not have any enzymatic action on the proteins in the venom as it failed to detect low-molecular-weight bands, which are indicative of possible enzymatic cleavage.

CONCLUSIONS

Traditional use of plants to treat snakebites is a common practice in the western region of Pará, Brazil. Our findings show that some plant extracts were able to inhibit snake venom-induced hemorrhage in vitro. In vivo studies are being carried out to validate the traditional use of these species to treat snakebites.

PhTX-II a basic myotoxic phospholipase A₂ from Porthidium hyoprora snake venom, pharmacological characterization and amino acid sequence by mass spectrometry

A monomeric basic PLA₂ (PhTX-II) of 14149.08 Da molecular weight was purified to homogeneity from Porthidium hyoprora venom. Amino acid sequence by in tandem mass spectrometry revealed that PhTX-II belongs to Asp49 PLA₂ enzyme class and displays conserved domains as the catalytic network, Ca²⁺-binding loop and the hydrophobic channel of access to the catalytic site, reflected in the high catalytic activity displayed by the enzyme. Moreover, PhTX-II PLA₂ showed an allosteric behavior and its enzymatic activity was dependent on Ca²⁺. Examination of PhTX-II PLA₂ by CD spectroscopy indicated a high content of alpha-helical structures, similar to the known structure of secreted phospholipase IIA group suggesting a similar folding. PhTX-II PLA₂ causes neuromuscular blockade in avian neuromuscular preparations with a significant direct action on skeletal muscle function, as well as, induced local edema and myotoxicity, in mice. The treatment of PhTX-II by BPB resulted in complete loss of their catalytic activity that was accompanied by loss of their edematogenic effect. On the other hand, enzymatic activity of PhTX-II contributes to this neuromuscular blockade and local myotoxicity is dependent not only on enzymatic activity. These results show that PhTX-II is a myotoxic Asp49 PLA₂ that contributes with toxic actions caused by P. hyoprora venom.

Synergism between basic Asp49 and Lys49 phospholipase A2 myotoxins of viperid snake venom in vitro and in vivo

Two subtypes of phospholipases A₂ (PLA₂s) with the ability to induce myonecrosis, ‘Asp49’ and ‘Lys49’ myotoxins, often coexist in viperid snake venoms. Since the latter lack catalytic activity, two different mechanisms are involved in their myotoxicity. A synergism between Asp49 and Lys49 myotoxins from Bothrops asper was previously observed in vitro, enhancing Ca²⁺ entry and cell death when acting together upon C2C12 myotubes. These observations are extended for the first time in vivo, by demonstrating a clear enhancement of myonecrosis by the combined action of these two toxins in mice. In addition, novel aspects of their synergism were revealed using myotubes. Proportions of Asp49 myotoxin as low as 0.1% of the Lys49 myotoxin are sufficient to enhance cytotoxicity of the latter, but not the opposite. Sublytic amounts of Asp49 myotoxin also enhanced cytotoxicity of a synthetic peptide encompassing the toxic region of Lys49 myotoxin. Asp49 myotoxin rendered myotubes more susceptible to osmotic lysis, whereas Lys49 myotoxin did not. In contrast to myotoxic Asp49 PLA₂, an acidic non-toxic PLA₂ from the same venom did not markedly synergize with Lys49 myotoxin, revealing a functional difference between basic and acidic PLA₂ enzymes. It is suggested that Asp49 myotoxins synergize with Lys49 myotoxins by virtue of their PLA₂ activity. In addition to the membrane-destabilizing effect of this activity, Asp49 myotoxins may generate anionic patches of hydrolytic reaction products, facilitating electrostatic interactions with Lys49 myotoxins. These data provide new evidence for the evolutionary adaptive value of the two subtypes of PLA₂ myotoxins acting synergistically in viperid venoms.

Aqueous leaf extract of Jatropha gossypiifolia L. (Euphorbiaceae) inhibits enzymatic and biological actions of Bothrops jararaca snake venom

Snakebites are a serious public health problem due their high morbi-mortality. The main available specific treatment is the antivenom serum therapy, which has some disadvantages, such as poor neutralization of local effects, risk of immunological reactions, high cost and difficult access in some regions. In this context, the search for alternative therapies is relevant. Therefore, the aim of this study was to evaluate the antiophidic properties of Jatropha gossypiifolia, a medicinal plant used in folk medicine to treat snakebites. The aqueous leaf extract of the plant was prepared by decoction and phytochemical analysis revealed the presence of sugars, alkaloids, flavonoids, tannins, terpenes and/or steroids and proteins. The extract was able to inhibit enzymatic and biologic activities induced by Bothrops jararaca snake venom in vitro and in vivo. The blood incoagulability was efficiently inhibited by the extract by oral route. The hemorrhagic and edematogenic local effects were also inhibited, the former by up to 56% and the latter by 100%, in animals treated with extract by oral and intraperitoneal routes, respectively. The inhibition of myotoxic action of B. jararaca reached almost 100%. According to enzymatic tests performed, it is possible to suggest that the antiophidic activity may be due an inhibitory action upon snake venom metalloproteinases (SVMPs) and/or serine proteinases (SVSPs), including fibrinogenolytic enzymes, clotting factors activators and thrombin like enzymes (SVTLEs), as well upon catalytically inactive phospholipases A2 (Lys49 PLA2). Anti-inflammatory activity, at least partially, could also be related to the inhibition of local effects. Additionally, protein precipitating and antioxidant activities may also be important features contributing to the activity presented. In conclusion, the results demonstrate the potential antiophidic activity of J. gossypiifolia extract, including its significant action upon local effects, suggesting that it may be used as a new source of bioactive molecules against bothropic venom.

Counteraction of Bothrops snake venoms by Combretum leprosum root extract and arjunolic acid

ETHNOPHARMACOLOGICAL RELEVANCE

Serotherapy against snakebite is often unavailable in some regions over Brazil, where people make use of plants from folk medicine to deal with ophidic accidents. About 10% of Combretum species have some ethnopharmacological use, including treatment of snakebites.

MATERIALS AND METHODS

We evaluated the ability of the extract of Combretum leprosum and its component arjunolic acid to reduce some in vivo and in vitro effects of Bothrops jararacussu and Bothrops jararaca venoms. The protocols investigated include phospholipase, proteolytic, collagenase, hyaluronidase, procoagulant, hemorrhagic, edematogenic, myotoxic and lethal activities induced by these venoms in Swiss mice.

RESULTS

Oral pre-treatment with arjunolic acid reduced the Bothrops jararacussu lethality in up to 75%, while preincubation prevented the death of all the animals. Hemoconcentration effect of Bothrops jararacussu venom was confirmed two hours after i.p. injection, while preincubation with arjunolic acid preserved the hematocrit levels. Both Combretum leprosum extract and arjunolic acid abolished the myotoxic action of Bothrops jararacussu venom. Preincubation of Bothrops jararacussu venom with the extract or arjunolic acid prevented the increase of plasma creatine kinase activity in mice. The hemorrhagic activity of Bothrops jararaca crude venom was reduced down to about 90% and completely inhibited by preincubation with 10 mg/kg or 100 mg/kg Combretum leprosum extract, respectively, while the preincubation and the pretreatment with 30 mg/kg of arjunolic acid reduced the venom hemorrhagic activity down to about 12% and 58%, respectively. The preincubation of the venom with both extract and 30 mg/kg arjunolic acid significantly reduced the bleeding amount induced by Bothrops jararacussu venom. The extract of Combretum leprosum decreased the edema formation induced by Bothrops jararacussu venom both in preincubation and pretreatment, but not in posttreatment. Similarly, arjunolic acid preincubated with the venom abolished edema formation, while pre- and posttreatment have been partially effective. Some enzymatic activities of Bothrops jararacussu and Bothrops jararaca venoms, i.e. phospholipase A2, collagenase, proteolytic and hyaluronidase activities, were to some extent inhibited by the extract and arjunolic acid in a concentration-dependent manner.

CONCLUSIONS

Altogether, our results show that Combretum leprosum extract can inhibit different activities of two important Brazilian snake venoms, giving support for its popular use in folk medicine in the management of venomous snakebites.

Bothrops jararaca venom metalloproteinases are essential for coagulopathy and increase plasma tissue factor levels during envenomation

BACKGROUND/AIMS

Bleeding tendency, coagulopathy and platelet disorders are recurrent manifestations in snakebites occurring worldwide. We reasoned that by damaging tissues and/or activating cells at the site of the bite and systemically, snake venom toxins might release or decrypt tissue factor (TF), resulting in activation of blood coagulation and aggravation of the bleeding tendency. Thus, we addressed (a) whether TF and protein disulfide isomerase (PDI), an oxireductase involved in TF encryption/decryption, were altered in experimental snake envenomation; (b) the involvement and significance of snake venom metalloproteinases (SVMP) and serine proteinases (SVSP) to hemostatic disturbances.

METHODS/PRINCIPAL FINDINGS

Crude Bothrops jararaca venom (BjV) was preincubated with Na2-EDTA or AEBSF, which are inhibitors of SVMP and SVSP, respectively, and injected subcutaneously or intravenously into rats to analyze the contribution of local lesion to the development of hemostatic disturbances. Samples of blood, lung and skin were collected and analyzed at 3 and 6 h. Platelet counts were markedly diminished in rats, and neither Na2-EDTA nor AEBSF could effectively abrogate this fall. However, Na2-EDTA markedly reduced plasma fibrinogen consumption and hemorrhage at the site of BjV inoculation. Na2-EDTA also abolished the marked elevation in TF levels in plasma at 3 and 6 h, by both administration routes. Moreover, increased TF activity was also noticed in lung and skin tissue samples at 6 h. However, factor VII levels did not decrease over time. PDI expression in skin was normal at 3 h, and downregulated at 6 h in all groups treated with BjV.

CONCLUSIONS

SVMP induce coagulopathy, hemorrhage and increased TF levels in plasma, but neither SVMP nor SVSP are directly involved in thrombocytopenia. High levels of TF in plasma and TF decryption occur during snake envenomation, like true disseminated intravascular coagulation syndrome, and might be implicated in engendering bleeding manifestations in severely-envenomed patients.

An isoflavone from Dipteryx alata Vogel is active against the in vitro neuromuscular paralysis of Bothrops jararacussu snake venom and bothropstoxin I, and prevents venom-induced myonecrosis

Snakebite is a neglected disease and serious health problem in Brazil, with most bites being caused by snakes of the genus Bothrops. Although serum therapy is the primary treatment for systemic envenomation, it is generally ineffective in neutralizing the local effects of these venoms. In this work, we examined the ability of 7,8,3'-trihydroxy-4'-methoxyisoflavone (TM), an isoflavone from Dipteryx alata, to neutralize the neurotoxicity (in mouse phrenic nerve-diaphragm preparations) and myotoxicity (assessed by light microscopy) of Bothrops jararacussu snake venom in vitro. The toxicity of TM was assessed using the Salmonella microsome assay (Ames test). Incubation with TM alone (200 μg/mL) did not alter the muscle twitch tension whereas incubation with venom (40 μg/mL) caused irreversible paralysis. Preincubation of TM (200 μg/mL) with venom attenuated the venom-induced neuromuscular blockade by 84% ± 5% (mean ± SEM; n = 4). The neuromuscular blockade caused by bothropstoxin-I (BthTX-I), the major myotoxic PLA₂ of this venom, was also attenuated by TM. Histological analysis of diaphragm muscle incubated with TM showed that most fibers were preserved (only 9.2% ± 1.7% were damaged; n = 4) compared to venom alone (50.3% ± 5.4% of fibers damaged; n = 3), and preincubation of TM with venom significantly attenuated the venom-induced damage (only 17% ± 3.4% of fibers damaged; n = 3; p < 0.05 compared to venom alone). TM showed no mutagenicity in the Ames test using Salmonella strains TA98 and TA97a with (+S9) and without (−S9) metabolic activation. These findings indicate that TM is a potentially useful compound for antagonizing the neuromuscular effects (neurotoxicity and myotoxicity) of B. jararacussu venom.

Inhibitory effect of the plant Clusia fluminensis against biological activities of Bothrops jararaca snake venom

The ability of extracts of the plant Clusia fluminensis Planch & Triana (Clusiaceae Lindl.) to neutralize proteolysis, clotting, hemolysis, hemorrhagic and lethality activities of Bothrops jararaca snake venom was studied. Clusianone and lanosterol from the flower and fruit extracts, respectively, were also tested. The extracts of different organs of C. fluminensis inhibited proteolysis and hemolysis induced by B. jararaca venom, but with different potencies. Only the stems prevented blood clotting. Only the acetone extract of the fruit protected mice from hemorrhage while the acetone or methanol extracts prevented mice from death. Clusianone and lanosterol did not inhibit clotting or hemorrhage, but the former inhibited proteolysis and the latter hemolysis.

Solanidane and iminosolanidane alkaloids from Solanum campaniforme

From the leaves of Solanum campaniforme (Solanaceae), eight solanidane alkaloids were isolated, four of which contain a p-hydroxyphenylethylamine unit. Their structures were established as: 22β,23β-epoxy-solanida-1,4-dien-3-one; 22α,23α-epoxy-10-epi-solanida-1,4,9-trien-3-one; 22α,23α-epoxy-solanida-4-en-3-one; 22β,23β-epoxy-solanida-4-en-3-one; (E)-N-[8'(4-hydroxyphenyl)ethyl]-22α,23α-epoxy-solanida-1,4,9-trien-3-imine; (E)-N-[8'(4-hydroxyphenyl)ethyl]-22α,23α-epoxy-solanida-1,4-dien-3-imine; (Z)-N-[8'(4-hydroxyphenyl)ethyl]-22α,23α-epoxy-solanida-1,4,9-trien-3-imine and (Z)-N-[8'(4-hydroxyphenyl)ethyl]-22α,23α-epoxy-solanida-1,4-dien-3-imine. All structures were determined using spectroscopic techniques, such as 1D and 2D NMR, and HRESIMS. The cytotoxicity and the antiophidic activities of the alkaloids were evaluated. The alkaloids did not show any cytotoxicity, but inhibited the main toxic actions of Bothrops pauloensis venom.

Inhibition of venom serine proteinase and metalloproteinase activities by Renealmia alpinia (Zingiberaceae) extracts: comparison of wild and in vitro propagated plants

ETHNOPHARMACOLOGICAL RELEVANCE

The plant Renealmia alpinia has been used in folk medicine to treat snakebites in the northwest region of Colombia. In addition, it has been shown to neutralize edema-forming, hemorrhagic, lethal, and defibrin(ogen)ating activities of Bothrops asper venom. In this work, extracts of Renealmia alpinia obtained by micropropagation (in vitro) and from specimens collected in the wild were tested and compared in their capacity to inhibit enzymatic and toxic activities of a snake venom metalloproteinase isolated from Bothrops atrox (Batx-I) venom and a serine proteinase (Cdc SII) from Crotalus durissus cumanensis venom.

MATERIALS AND METHODS

We have investigated the inhibition capacity of Renealmia alpinia extracts on enzymatic and toxic actions of isolated toxins, a metalloproteinase and a serine proteinase. The protocols investigated included inhibition of proteolytic activity on azocasein, inhibition of proteolytic activity on fibrinogen, inhibition of pro-coagulant activity, inhibition of hemorrhagic activity and inhibition of edema-forming activity.

RESULTS

Colorimetric assays detected the presence of terpenoids, flavonoids, tannins and coumarins in Renealmia alpinia extracts. Renealmia alpinia extracts inhibited the enzymatic, hemorrhagic and fibrinogenolytic activities of Batx-I. Extracts also inhibited coagulant, defibrin(ogen)ating and edema-forming activities of Cdc SII. Results highlight that Renealmia alpinia in vitro extract displayed comparable inhibitory capacity on venom proteinases that Renealmia alpinia wild extract. No alteration was observed in the electrophoretic pattern of venom proteinases after incubation with Renealmia alpinia extracts, thus excluding proteolytic degradation or protein denaturation/precipitation as a mechanism of inhibition.

CONCLUSIONS

Our results showed that Renealmia alpinia wild and in vitro extracts contain compounds that neutralize metallo- and serine proteinases present in snake venoms. The mechanism of inhibition is not related to proteolytic degradation of the enzymes nor protein aggregation, but is likely to depend on molecular interactions of secondary metabolites in the plant with these venom proteinases.

Antiophidic activity of the extract of the Amazon plant Humirianthera ampla and constituents

ETHNOPHARMACOLOGICAL RELEVANCE

Although serotherapy against snakebite has been discovered more than one hundred years ago, antivenom is not available all over Brazil. The use of plants from folk medicine is common mainly in the Brazilian Amazon area. One of these plants is named Humirianthera ampla (HA).

MATERIALS AND METHODS

We have investigated HA extract and constituents' antiophidic activity in different experimental protocols against some Bothrops snake venoms (Bothrops jararacussu, Bothrops atrox and Bothrops jararaca). The protocols investigated include phospholipase, proteolytic, pro-coagulant, hemorrhagic, edematogenic and myotoxic activities induced by these venoms in Swiss mice.

RESULTS

All the venoms caused an increase in the rate of creatine kinase (CK) release from isolated muscles, indicating damage to the sarcolemma. The crude extract of HA decreased the myotoxic activity in a concentration-dependent fashion. The presence of HA 300 μg/mL decreased up to 96% of Bothrops jararacussu and 94% of Bothrops atrox myotoxicity after 90 min of exposure. In vivo myotoxicity of Bothrops atrox venom was decreased in 75% when the venom was preincubated with HA 500 mg/kg. Similar results were observed with lupeol against Bothrops jararacussu and Bothrops atrox venoms. The hemorrhagic activity was evaluated by intradermal injection of Bothrops atrox venom. Preincubation and oral pre- and posttreatment with HA decreased hemorrhage by 100%, 45% and 45%, respectively. Bothrops atrox venom also induced formation of edema, which was significantly inhibited by pre- and posttreatment with HA. All the venoms showed extensive pro-coagulating properties, and these activities were inhibited by up to 90% with HA, which presented concentration-dependent inhibition. Finally, proteolytic and phospholipase activities of the venoms were all inhibited by increasing concentrations of HA, lupeol and sitosterol. The inhibition of these activities might help explain the actions against in vivo myotoxicity and the in vivo effects observed, i.e., edema, myotoxicity, pro-coagulation and hemorrhage.

CONCLUSIONS

Altogether, our results give support for the popular use of HA extracts in cases of accidents with snakes, suggesting that it can be used as an adjunct in the management of venomous snakebites.

[The toxicity of venom of Bothrops (Rhinocerophris) alternatus in different areas of Cordoba State in Argentina]

Snake venoms can show biochemical and toxicological variability even in specimens from the same specie. The geographical localization of the snakes is one of the factors that can influence those variations. By these reasons the venom from specimens of Bothrops (Rhinocerophis) alternatus ("crucera", "yararágrande"), one of the snakes of highest medical importance in Argentina, from three different regions of Córdoba was studied. Lehtal potency, hemorrhagic, coagulant on plasma and thrombin like activities as well as the electrophoretic patterns of venom from snakes of Calamuchita, Traslasierras and the East of the province were determined. The venom from the snakes of the three regions showed the characteristic activities of the venom of the majority of Bothrops, causing hemorrhage, hemostatic disturbances acting on plasma or directly on fibrinogen with a "thrombin like activity". The different samples were very similar regarding their biochemical characteristics and toxic potencies at difference of previous observations on venoms from the same specie in different regions of other provinces fro Argentina. Bivalent antivenom, the one used by the Provincial Ministry of Health to treat the bothropic accidents, neutralized in all the cases the toxic activities of the venom in very similar range of neutralizing potency.

Green pit viper antivenom from Thailand and Agkistrodon halys antivenom from China compared in treating Cryptelytrops albolabris envenomation of mice

OBJECTIVE

To compare the relative efficacy of the green pit viper antivenom from Thailand and Agkistrodon halys antivenom from China. DESIGN. In-vivo experimental study.

SETTING

A wildlife conservation organisation, a university, a poison information centre, and a regional hospital in Hong Kong.

MAIN OUTCOME MEASURES

Pre- and post-antivenom lethal dose 50 (LD50) of the Cryptelytrops albolabris venom, median effective dose (ED50) of green pit viper antivenom and Agkistrodon halys antivenom against a lethal dose of the venom. SUBJECTS. Adult mice.

RESULTS

The intraperitoneal LD50 of the venom from locally caught Cryptelytrops albolabris was 0.14 microL. After post-exposure treatment with 10 microL of antivenom, it was elevated to 0.36 microL and 0.52 microL by the green pit viper antivenom and the Agkistrodon halys antivenom, respectively. The ED50 was 32.02 microL for green pit viper antivenom and 6.98 microL for Agkistrodon halys antivenom. Both green pit viper antivenom and Agkistrodon halys antivenom ameliorated the lethality of Cryptelytrops albolabris venom in mice.

CONCLUSION

The overall superior neutralisation capacity of Agkistrodon halys antivenom over green pit viper antivenom may be related to the geographic proximity of the venoms used for antivenom preparation. The results point towards the need for further comparison of the two antivenoms on protein or immunoglobulin weight basis, and with respect to non-lethal clinically significant toxicities.

"Too good to be true": the controversy over the use of permanganate of potash as an antidote to snake poison and the circulation of Brazilian physiology in the nineteenth century

This article examines an international controversy over the most visible scientific event of Brazilian physiology in the nineteenth century. In 1881, Brazilian scientist João Baptista Lacerda stated that he had found an efficient antidote to the poison of Brazilian snakes: permanganate of potash (nowadays, potassium permanganate). His findings were given great publicity in Brazil and traveled rapidly around the world. Scientists, especially in France, contradicted Lacerda's claims. They argued that permanganate of potash could not be a genuine antidote to snake bites since it could not neutralize snake venom when diffused in the body. Lacerda turned down such criticism, claiming that clinical observation provided solid evidence for the drug's local action, on the spot surrounding the bite. The controversy over the use of permanganate of potash as an antidote to snake bite illustrates different regimes of proof that could be mobilized in favor of a physiological discovery.

Contribution of cinnamic acid analogues in rosmarinic acid to inhibition of snake venom induced hemorrhage

In our previous paper, we reported that rosmarinic acid (1) of Argusia argentea could neutralize snake venom induced hemorrhagic action. Rosmarinic acid (1) consists of two phenylpropanoids: caffeic acid (2) and 3-(3,4-dihydroxyphenyl)lactic acid (3). In this study, we investigated the structural requirements necessary for inhibition of snake venom activity through the use of compounds, which are structurally related to rosmarinic acid (1). By examining anti-hemorrhagic activity of cinnamic acid analogs against Protobothrops flavoviridis (Habu) venom, it was revealed that the presence of the E-enoic acid moiety (-CH=CH-COOH) was critical. Furthermore, among the compound tested, it was concluded that rosmarinic acid (1) (IC(50) 0.15 μM) was the most potent inhibitor against the venom.

Metal ion binding to anticoagulation factor II from the venom of Agkistrodon acutus: stabilization of the structure and regulation of the binding affinity to activated coagulation factor X

Anticoagulation factor II (ACF II) isolated from the venom of Agkistrodon acutus is an activated coagulation factor X (FXa)-binding protein with both anticoagulant and hypotensive activities. The thermodynamics of the binding of alkaline earth metal ions to ACF II and their effects on the stability of ACF II and the binding of ACF II to FXa were investigated by isothermal titration calorimetry, fluorescence, differential scanning calorimetry, and surface plasmon resonance. The binding of ACF II to FXa does not have an absolute requirement for Ca(2+). Mg(2+), Sr(2+), and Ba(2+) can induce the binding of ACF II to FXa. The radii of the cations bound in ACF II crucially affect the binding affinity of ACF II for cations and the structural stability of ACF II against guanidine hydrochloride and thermal denaturation, whereas the radii of cations bound in FXa markedly affect the binding affinity between ACF II and FXa. The binding affinities of ACF II for cations and the capacities of metal-induced stabilization of ACF II follow the same trend: Ca(2+) > Sr(2+) > Ba(2+). The metal-induced binding affinities of ACF II for FXa follow the trend Mg(2+) > Ca(2+) > Sr(2+) > Ba(2+). Although Mg(2+) shows significantly low binding affinity with ACF II, Mg(2+) is the most effective to induce the binding of ACF II with FXa. Our observations suggest that in blood the bindings of Ca(2+) in two sites of ACF II increase the structural stability of ACF II, but these bindings are not essential for the binding of ACF II with FXa, and that the binding of Mg(2+) and Ca(2+) to FXa may be essential for the recognition between FXa and ACF II. Like Ca(2+), the abundant Mg(2+) in blood also plays an important role in the anticoagulation of ACF II.

Protective effects of Mucuna pruriens seed extract pretreatment against cardiovascular and respiratory depressant effects of Calloselasma rhodostoma (Malayan pit viper) venom in rats

The protective effects of Mucuna pruriens seed extract (MPE) against the cardio-respiratory depressant and neuromuscular paralytic effects induced by injection of Calloselasma rhodostoma (Malayan pit viper) venom in anaesthetized rats were investigated. While MPE pretreatment did not reverse the inhibitory effect of the venom on the gastrocnemius muscle excitability, it significantly attenuated the venom-induced cardio-respiratory depressant effects (p < 0.05). The protection effects may have an immunological mechanism, as indicated by the presence of several proteins in the venom that are immunoreactive against anti-MPE. However, we cannot rule out the possibility that the pretreatment may exert a direct, non-immunological protective action against the venom.

Isolation and biological characterization of Batx-I, a weak hemorrhagic and fibrinogenolytic PI metalloproteinase from Colombian Bothrops atrox venom

A hemorrhagic metalloproteinase, named Batx-I, was isolated from the venom of Bothrops atrox specimens (from Southeastern Colombian region) by a combination of CM-Sephadex C25 ion-exchange and Affi-gel Blue affinity chromatographies. This enzyme accounts for about 45% of venom proteins, and it has an ESI-MS isotope-averaged molecular mass of 23296.2 Da and a blocked N-terminus. Two internal fragments sequenced by mass spectrometric analysis showed similarity to other SVMPs from Bothrops venoms. To investigate the possible participation of Batx-I in the envenomation pathophysiology, proteolytic, fibrinogenolytic, hemorrhagic, and other biological activities were evaluated. The minimal hemorrhagic dose obtained was 17 microg/20 g body weight. The enzyme showed proteolytic activity on azocasein, comparable with activity of BaP1. This activity was inhibited by EDTA and 1, 10 o-phenanthroline but not by aprotinin, pepstatin A or PMSF. Fibrinogenolytic activity was analyzed by SDS-PAGE, revealing a preference for degrading the A alpha- and B beta-chains, although partial degradation of the gamma-chain was also detected. The protein lacks coagulant and defibrinating activity. The CK levels obtained, clearly reflects a myotoxic activity induced by Batx-I. The hemorrhagic and fibrinogenolytic activities exhibited by the isolated PI-SVMP may play a role in the hemorrhagic and blood-clotting disorders observed in patients bitten by B. atrox in Colombia.

The highly specific platelet glycoprotein (GP) VI agonist trowaglerix impaired collagen-induced platelet aggregation ex vivo through matrix metalloproteinase-dependent GPVI shedding

BACKGROUND

C-type lectin proteins (CLPs) have diverse targets including platelet GPIb, GPVI and integrin alpha(2)beta(1), and affect platelet function in a various way. In this study, we characterized a huge, heterodimeric venom protein, trowaglerix, which belongs to the CLP family.

METHODS

We purified a potent platelet-aggregation inducer, trowaglerix, from the crude venom of Tropidolaemus wagleri. Biotinylated trowaglerix was used for binding assays, and immunoblotting was used to investigate the signal transduction involved.

RESULTS

Two distinct subunits of trowaglerix with similar masses of around 16 kDa were eluted by high-performance liquid chromatography after reduction and alkylation. Trowaglerix induced platelet aggregation of washed human platelets and platelet-rich plasma (PRP) in a concentration-dependent manner. Biotinylated trowaglerix specifically bound to platelet membrane GPVI, but not to GPIb or alpha(2) integrin. Treatment with trowaglerix induced GPVI loss in human platelets in vitro and impaired the platelet aggregation of mouse PRP ex vivo in response to collagen but not in response to adenosine diphosphate (ADP). However, GM6001, a matrix metalloproteinase (MMP) inhibitor, inhibited trowaglerix-induced GPVI cleavage and restored the platelet responsiveness of PRP to collagen.

CONCLUSIONS

Trowaglerix activates platelets through specific binding to GPVI, leading to kinases-dependent exposure of functional alpha(IIb)beta(3) and platelet aggregation, and also induces MMP-dependent GPVI shedding from platelets.

Ethnobotanical survey of folk plants for the treatment of snakebites in Southern part of Tamilnadu, India

Ethnobotanical surveys were conducted in four different indigenous groups in Southern parts of Tamilnadu, India, using a questionnaire. The herbal practitioners in the study area were interviewed, and information on medicinal plants was collected from the traditional healers called "Vaidyars". This survey covers 72 medicinal plants belonging to 53 families that are used for the treatment of snakebite in a traditional way. Traditional approach was evaluated scientifically with some selected plant extracts (7.2 mg/kg bw) and partially purified fractions (2.4 mg/kg bw) were orally administered to mice experimentally envenomed with rattlesnake venom s.c. injection (2.5-15 microg/kg bw). Tested fractions (Aristolochia indica, Hemidesmus indicus, Gloriosa superba, Strychnos nux-vomica, Eclipta prostrata, and Andrographis paniculata) showed potent neutralizing effect against the venom. Compared to the extracts, administration of purified fractions was more effective in increasing the body weight. Control mice injected with the venom alone showed weight loss and severe toxicity at 15 microg/kg bw. The purified fractions (2.4 mg/kg bw) produced significant protection against venom induced changes in serum SOD and LPx levels. The isolated fractions effectively inhibited the toxic effect of snake venoms in vitro than in vivo. The above observations confirmed the protective activity of plants-Aristolochia indica, Hemidesmus indicus, Gloriosa superba, Strychnos nux-vomica, Eclipta prostrata, and Andrographis paniculata against the lethal action of snake venom and need further investigation.

Severe coagulopathy associated with white-lipped green pit viper bite

The authors report a case of Trimeresurus albolabris (white-lipped green pit viper) bite in a 6-year-old girl living in rural Yuen Long. Despite repeated use of Agkistrodon halys antivenin, the patient developed severe coagulopathy with defibrination syndrome on the fourth day of envenomation, which was also refractory to therapy with fresh frozen plasma. When treatment was switched to green pit viper antivenin, the coagulopathy resolved promptly. The case is illustrative of the potential lethality to children of snakebites in Hong Kong and suggests that the A halys antivenin may not be effective for the treatment of T albolabris bites.

Properties and cDNA cloning of antihemorrhagic factors in sera of Chinese and Japanese mamushi (Gloydius blomhoffi)

An antihemorrhagic protein has been isolated from the serum of Chinese mamushi (Gloydius blomhoffi brevicaudus) by using a combination of ethanol precipitation and a reverse-phase high-performance liquid chromatography (HPLC) on a C8 column. This protein-designated Chinese mamushi serum factor (cMSF)-suppressed mamushi venom-induced hemorrhage in a dose-dependent manner. It had no effect on trypsin, chymotrypsin, thermolysin, and papain but inhibited the proteinase activities of several snake venom metalloproteinases (SVMPs) including hemorrhagic enzymes isolated from the venoms of mamushi and habu (Trimeresurus flavoviridis). A similar protein (Japanese MSF, jMSF) with antihemorrhagic activity has also been purified from the sera of Japanese mamushi (G. blomhoffi). The N-terminal 70 and 51 residues of the intact cMSF and jMSF were directly analyzed; a similarity between the sequences of two MSFs to that of antihemorrhagic protein (HSF) from habu serum was noticed. To obtain the complete amino acid sequences of MSFs, cDNAs encoding these proteins were cloned from the liver mRNA of Chinese and Japanese vipers based on their N-terminal amino acid sequences. The mature forms of both MSFs consisted of 305 amino acids with a 19-residue signal sequence, and a unique 17-residue deletion was detected in their His-rich domains.

Evaluation of three Brazilian antivenom ability to antagonize myonecrosis and hemorrhage induced by Bothrops snake venoms in a mouse model

Despite preventing death after snakebites, there is little evidence that polyvalent antivenoms (PAVs) protect against myotoxicity and local damages. We evaluated antibothropic Brazilian PAVs from three manufacturers against the myotoxicity and hemorrhagic activity of Bothrops jararacussu and B. jararaca venoms, respectively, by using two protocols: preincubation of PAVs with venom, and i.v. pretreatment with PAVs, prior to the venom inoculation. In this investigation, we used doses of PAVs ranging from 0.4 to 4.0mL/mg of venom equivalent up to 10 times the amount recommended by the producers for the clinical practice in Brazil. In our preincubation protocol in vivo, PAVs antagonized myotoxicity of B. jararacussu venom by 40-95%, while our pretreatment protocol antagonized myotoxic activity by 0-60%. Preincubation of antivenoms with B. jararaca venom antagonized its hemorrhagic activity by 70-95%, while pretreatment antagonized hemorrhagic activity by 10-50%. Although all PAVs demonstrated partial antagonism against both venoms, the magnitude of these effects varied greatly among the manufactures. The results suggest that the current clinical doses of these PAVs may have negligible antimyotoxic effect.

Neutralization of snake venom phospholipase A2 toxins by aqueous extract of Casearia sylvestris (Flacourtiaceae) in mouse neuromuscular preparation

Aqueous extract of Casearia sylvestris (Flacourtiaceae) has been shown to inhibit enzymatic and biological properties of some Bothrops and Crotalus venoms and their purified phospholipase A(2) (PLA(2)) toxins. In this work we evaluated the influence of C. sylvestris aqueous extract upon neuromuscular blocking and muscle damaging activities of some PLA(2)s (crotoxin from C. durissus terrificus, bothropstoxin-I from B. jararacussu, piratoxin-I from B. pirajai and myotoxin-II from B. moojeni) in mouse phrenic-diaphragm preparations. Crotoxin (0.5 microM) and all other PLA(2) toxins (1.0 microM) induced irreversible and time-dependent blockade of twitches. Except for crotoxin, all PLA(2) toxins induced significant muscle damage indices, assessed by microscopic analysis. Preincubation of bothropstoxin-I, piratoxin-I or myotoxin-II with C. sylvestris extract (1:5 (w/w), 30 min, 37 degrees C) significantly prevented the neuromuscular blockade of preparations exposed to the mixtures for 90 min; the extent of protection ranged from 93% to 97%. The vegetal extract also neutralized the muscle damage (protection of 80-95%). Higher concentration of the C. sylvestris extract (1:10, w/w) was necessary to neutralize by 90% the neuromuscular blockade induced by crotoxin. These findings expanded the spectrum of C. sylvestris antivenom activities, evidencing that it may be a good source of potentially useful PLA(2) inhibitors.

Suramin counteracts the haemostatic disturbances produced by Bothrops jararaca snake venom

Snakebite accidents produced by Bothrops jararaca typically results in haemostatic changes including pro- and anticoagulant disturbs as well as interference with platelets. Suramin is a hexasulfonated naphthylurea derivative that was recently characterized as a thrombin inhibitor (Monteiro et al., 2004. Suramin interaction with human alpha-thrombin: inhibitory effects and binding studies. Int. J. Biochem. Cell Biol. 36(10), 2077-2085). Here, we evaluated the ability of suramin to counteract some of the haemostatic disturbs produced by B. jararaca venom. In vitro assays showed that suramin inhibited venom-induced hydrolysis of a number of synthetic substrates: S-2238, S-2266, S-2302 and S-2288, being this ability more prominent towards the thrombin substrate S-2238 (IC(50)=4.3 microM). It was also observed that suramin impaired the fibrinogen clotting induced by B. jararaca venom (IC(50)=124 microM). Accordingly, increasing concentrations of suramin progressively delayed venom-induced plasma clotting, with complete inhibition attained at concentrations above 1.0 mM. In addition, the platelet-aggregating properties of B. jararaca venom were inhibited by suramin in a dose-dependent fashion (IC(50)=127 microM). Suramin showed no effect in the in vivo hemorrhagic effect of venom in mouse skin. The in vivo effect of suramin was further tested using a previously established venous thrombosis model in rats induced by intravenous administration of B. jararaca venom combined with stasis. Venom doses of 100 microg/kg produced 100% of thrombus incidence (10.6+/-1.7 mg). On the other hand, previous administration of suramin partially inhibited thrombus formation. Thus, 12.5 or 25 mg/kg of suramin decreased thrombus weight by 24% and 40%, respectively. Remarkably, co-administration of 3 microL/kg of antibothropic serum (which has no effect on thrombus formation) and 12.5 mg/kg of suramin decreased thrombus weight by 75%, suggesting a synergic effect. Altogether, we demonstrate here that suramin inhibits in vitro and in vivo haemostatic changes caused by B. jararaca venom. At this point, this drug could be of potential interest for association with conventional antiserum therapy.

Enzymatic and immunochemical characterization of Bothrops insularis venom and its neutralization by polyspecific Bothrops antivenom

Herein we compared the biological activities of Bothrops insularis and Bothrops jararaca venoms as well as their neutralization by polyspecific Bothrops antivenom (PBA). On account of that, we investigated their antigenic cross-reactivity and the neutralization of lethal, myotoxic and defibrinating activities by polyspecific and species-specific antivenoms. Silver-stained SDS-PAGE gels evidenced many common bands particularly above 47 kDa between B. jararaca and B. insularis venoms. However, some protein bands between 46 and 28 kDa were observed exclusively in B. jararaca venom. Both venoms presented gelatinolytic, caseinolytic, fibrinogenolytic and phospholipase A(2) activities. No hyaluronidase activity was detected in both venoms by zymography. Polyspecific and species-specific antivenoms showed similar titers to B. jararaca and B. insularis venoms by ELISA, and recognized similar components by immunoblotting. The PBA was effective in neutralizing the lethal, myotoxic and defibrinating activities of both venoms as well as to abrogate microcirculatory disturbances induced by B. insularis venom. No statistically significant difference was observed for minimal hemorrhagic doses between both venoms. Antigenic cross-reactivity was evident between both venoms. Since toxic and enzymatic activities were similar, we speculate that B. insularis venoms can induce a local damage in humans comparable to that observed in other Bothrops venoms. Besides, the PBA was effective in neutralizing the toxic activities of B. insularis venom.

BJ-48, a novel thrombin-like enzyme from the Bothrops jararacussu venom with high selectivity for Arg over Lys in P1: Role of N-glycosylation in thermostability and active site accessibility

BJ-48, a serine protease from the venom of Bothrops jararacussu, was purified to homogeneity using affinity chromatography on p-aminobenzamidine-agarose followed by HPLC gel filtration. BJ-48 presented 52kDa by SDS-PAGE analysis and 48,036Da by electron spray mass spectrometry. The enzyme was shown to be highly glycosylated with 42% of N-linked carbohydrates composed of Fuc(1):GalN(4):GlcN(5):Gal(1):Man(2) and a high content of sialic acid residues (8-12%). BJ-48 had optimal esterase activity at pH 7.5 and displayed maximum catalytic rate at 50 degrees C. Its hydrolytic activity was strongly inhibited by aprotinin and dithiothreitol while N-tosyl-l-phenylalanine chloromethyl ketone, 6-aminocaproic acid, E-64 and soybean trypsin inhibitor (SBTI) were ineffective. The kinetics of BJ-48 with chromogenic substrates revealed an unprecedented selectivity (10(4)-fold) for Arg over Lys in P1. BJ-48 proved to be a thrombin-like enzyme (TLE) with a specific fibrinogen-clotting activity of 73.4NIH units/mg. The TLE rapidly digested human fibrinogen Bbeta chain, but the Aalpha chain was cleaved specifically to release fibrinopeptide A with k(cat)/K(m)=2.1 microM(-1)s(-1). The TLE showed no activity toward other thrombin substrates like protein C, protease-activated receptor-1 or inhibitors such as hirudin and antithrombin. A non-denaturing procedure using PNGase F and neuraminidase followed by hydrophobic interaction chromatography was employed to obtain active BJ-48 forms with variable carbohydrate content. Compared to the native enzyme, total or partially deglycosylated BJ-48 forms presented up to 2-fold reduction in their specific activities upon heating at 55/65 degrees C or treatment with SBTI. These results point out a role for BJ-48 glycosylation in thermostability and controlling the access of some canonical protein inhibitors to the active site.

Isolation, characterization and molecular cloning of AnMIP, a new alpha-type phospholipase A2 myotoxin inhibitor from the plasma of the snake Atropoides nummifer (Viperidae: Crotalinae)

A new phospholipase A(2) (PLA(2))-inhibitory protein was isolated from the plasma of Atropoides nummifer, a crotaline snake from Central America. This inhibitor was named AnMIP, given its ability to neutralize the activity of basic PLA(2) myotoxins of its own and related venoms. The cDNA of AnMIP was cloned and sequenced, showing that it belongs to the alpha group of phospholipase A(2) inhibitors (PLIs). AnMIP appears as a homotrimer in the native state, held together by non-covalent forces, with a subunit molecular mass of 22,247-22,301 and an isoelectric point of 4.1-4.7. This trimeric structure is the first observed in a PLIalpha from American crotaline snakes, previously reported only in Asian species. Sequencing, mass spectrometry, and analytical isoelectrofocusing indicated the existence of isoforms, as reported for other PLIalphas isolated from snake plasma. The inhibitory profile of AnMIP showed specificity towards group II PLA(2)s, either belonging to the catalytically-active (D49) or -inactive (K49) subtypes, exemplified in this study by Bothrops asper myotoxin I and A. nummifer myotoxin II, respectively. By phylogenetic analysis it was shown that AnMIP is closely related to CgMIP-II, previously isolated from the plasma of Cerrophidion godmani, showing 93% amino acid sequence identity.

[Biological and immunological characteristics of the poison of Bothrops cotiara (Serpentes: Viperidae)]

Bothrops cotiara is a venomous snake sporadically found in the province of Misiones in Argentina, South of Brazil and Paraguay. Data on the clinics of the envenomation produced by its bite and on its venom are scarce. There is no information on the neutralizing capacity of the antivenoms available. In this study, the lethal potency, hemorrhagic, necrotizing, coagulant and thrombin-like, defibrinogenating, indirect hemolytic and fibrinolytic activities of the venom of B. cotiara specimens from the province of Misiones were determined. The toxic activities were within the range of those described for the other Bothrops species from Argentina, and the electrophoretic and chromatographic studies showed similarities with those described for the other bothropic venoms. The immunochemical reactivity of six South American anti Viper antivenoms (ELISA) have a strong reactivity with all the antivenoms studied. The neutralizing capacity of three of these therapeutic antivenoms against the lethal potency and hemorrhagic, necrotizing, coagulant, thrombin-like and hemolytic activities showed a very close neutralizing capacity. Our data strongly suggest that the antivenoms for therapeutic use available in this area of South America are useful to neutralize the toxic and enzymatic activities of the venom of this uncommon specie of Bothrops.