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

Development of a membrane-disruption assay using phospholipid vesicles as a proxy for the detection of cellular membrane degradation

Snakebite envenoming is a global health issue that affects millions of people worldwide, and that causes morbidity rates surpassing 450,000 individuals annually. Patients suffering from snakebite morbidities may experience permanent disabilities such as pain, blindness and amputations. The (local) tissue damage that causes these life-long morbidities is the result of cell- and tissue-damaging toxins present in the venoms. These compounds belong to a variety of toxin classes and may affect cells in various ways, for example, by affecting the cell membrane. In this study, we have developed a high-throughput in vitro assay that can be used to study membrane disruption caused by snake venoms using phospholipid vesicles from egg yolk as a substrate. Resuspended chicken egg yolk was used to form these vesicles, which were fluorescently stained to allow monitoring of the degradation of egg yolk vesicles on a plate reader. The assay proved to be suitable for studying phospholipid vesicle degradation of crude venoms and was also tested for its applicability for neutralisation studies of varespladib, which is a PLA2 inhibitor. We additionally made an effort to identify the responsible toxins using liquid chromatography, followed by post-column bioassaying and protein identification using high-throughput venomics. We successfully identified various toxins in the venoms of C. rhodostoma and N. mossambica, which are likely to be involved in the observed vesicle-degrading effect. This indicates that the assay can be used for screening the membrane degrading activity of both crude and fractionated venoms as well as for neutralisation studies.

The potential of Brazilian native plant species used in the therapy for snakebites: A literature review

Snakebite envenoming is a potentially fatal disease categorized as a neglected public health issue for not receiving the appropriate attention from national and international health authorities. The most affected people by this problem usually live in poor rural communities, where medical resources are often sparse and, in some instances, there is even a scarcity of serum therapy. The administration of the appropriate antivenom is the only specific treatment available, however it has limited efficacy against venom-induced local effects. In this scenario, various plant species are used as local first aid for the treatment of snakebite accidents in Brazil, and some of them can effectively inhibit lethality, neurotoxicity, hemorrhage, and venom enzymes activities. This review compiles a list of plants used in the treatment of snakebites in Brazil, focusing on the native Brazilian species registered in the databases Pubmed, Scielo, Scopus and Google Scholar. All these searches were limited to peer-reviewed journals written in English, with the exception of a few articles written in Portuguese. The most cited native plant species were Casearia sylvestris Sw., Eclipta prostrata (L.) L., Mikania glomerata Spreng., Schizolobium parahyba (Vell.) S.F.Blake and Dipteryx alata Vogel, all used to decrease the severity of toxic signs, inhibit proteolytic and hemorrhagic activities, thus increasing survival time and neutralizing myotoxicity effects. Different active compounds showing important activity against the snake venoms and their toxins include flavonoids, alkaloids and tannins. Although some limitations to the experimental studies with medicinal plants were observed, including lack of comparison with control drugs and unknown active extracts compounds, species with anti-venom characteristics are effective and considered as candidates for the development of adjuvants in the treatment of snake envenomation. Further studies on the chemistry and pharmacology of traditionally used plant species will help to understand the role that snakebite herbal remedies may display in local medical health systems. It might also contribute to the development of alternative or complementary treatments to reduce the number of severe disabilities and deaths.

Plant-Derived Toxin Inhibitors as Potential Candidates to Complement Antivenom Treatment in Snakebite Envenomations

Snakebite envenomations (SBEs) are a neglected medical condition of global importance that mainly affect the tropical and subtropical regions. Clinical manifestations include pain, edema, hemorrhage, tissue necrosis, and neurotoxic signs, and may evolve to functional loss of the affected limb, acute renal and/or respiratory failure, and even death. The standard treatment for snake envenomations is antivenom, which is produced from the hyperimmunization of animals with snake toxins. The inhibition of the effects of SBEs using natural or synthetic compounds has been suggested as a complementary treatment particularly before admission to hospital for antivenom treatment, since these alternative molecules are also able to inhibit toxins. Biodiversity-derived molecules, namely those extracted from medicinal plants, are promising sources of toxin inhibitors that can minimize the deleterious consequences of SBEs. In this review, we systematically synthesize the literature on plant metabolites that can be used as toxin-inhibiting agents, as well as present the potential mechanisms of action of molecules derived from natural sources. These findings aim to further our understanding of the potential of natural products and provide new lead compounds as auxiliary therapies for SBEs.

Four new cycloartane-type triterpenoids from the leaves of Combretum mellifluum Eichler: assessment of their antioxidant and antileishmanial activities

The beneficial pharmacological actions including antioxidant effects as an antileishmanial, antibacterial, antifungal, antidiabetic, anti-inflammatory, antitumor, antiviral, and analgesic of compounds isolated from Combretum mellifluum Eichler (Combretaceae) are well established. The aim of the present study was to determine the phytochemistry as well as assess the antioxidant and antileishmanial activities of the leaves from Combretum mellifluum Eichler (Combretaceae). Analysis of ethanolic extract resulted in isolation and identification of two epimeric mixtures of four previously unknown cycloartane-type triterpenoids, methyl quadrangularate M and methyl 24-epiquadrangularate M, and 2α,3β,24β-trihydroxy-cycloart-25-ene and 2α, 3β, 24α-trihydroxy-cycloart-25-ene, and eight known compounds. Their structures were using one-dimensional nuclear magnetic resonance (1D NMR), 2D NMR and high-resolution electrospray ionization mass spectroscopy (HRESIMS) analysis. Further, the extract and fractions were tested for antioxidant potential. The ethyl acetate and aqueous fractions demonstrated the highest antioxidant activity against 2,2-dipheny-1-picrylhydrazl (DPPH) free radicals, which correlated directly with total flavonoid content. All extracts and fractions from C. mellifluum Eichler were assessed for antileishmanial activity. The supernatant fraction exhibited highest potential, inhibiting the growth of Leishmania amazonensis with IC₅₀ value 31.29 μg/ml. Our findings provide information on the chemical composition of C. mellifluum and the potential beneficial therapeutic usefulness as an antioxidant agent in various diseases.

Ethnobotanical Documentation, Phytochemical Screening, and Cytotoxicity Evaluation of Medicinal Plants Used to Manage Snakebite Envenomation in Mwingi West Subcounty, Kenya

Snakebite envenomation (SBE) is a life-threatening global public health problem affecting over 2.7 million persons annually, with a bigger burden lying in the developing world. Despite the successful management of SBE by antivenom therapy in conventional medicine, it is of low efficacy due to the diverse venom composition across snake types, which limits its usefulness. As a result, inhabitants of the sub-Sahara region, where SBE incidence is high, utilise medicinal plants as an alternative remedy for SBE. However, most plants have not been ethnobotanically documented and validated empirically and hence this study is needed. An ethnobotanical survey to document medicinal plants used to manage SBE in Migwani ward, Mwingi West Subcounty, Kitui County, was conducted between January and February, 2021. Ethnobotanical data were collected from 45 purposefully sampled respondents from Migwani ward using semistructured questionnaires, field walks, and oral interviews. In this study, 14 medicinal plants which are used to manage SBE were documented. Four plants with the highest Relative Frequency of Citation (RFC) (Entada leptostachya Harms-stem bark (0.58), Senna singueana-roots (0.53), Securidaca longipendunculata-roots (0.36), and Strychnos henningsii-stem bark (0.46)) were selected and extracted using water, methanol, and dichloromethane according to the standard procedures. Qualitative phytochemical analysis of the plant extracts and their cytotoxic effects on brine shrimp nauplii (brine shrimp lethality assay) was conducted according to the standard techniques. Qualitative phytochemical screening revealed the presence of anti-SBE-associated phytochemicals, such as alkaloids, saponins, tannins, phenols, and flavonoids, in the aqueous and methanolic extracts of the studied plant extracts. However, the tested phytochemicals were not detected in dichloromethane extracts of all the studied extracts. The anti-SBE effects of the documented plants could be attributable to these associated bioactive phytocompounds, which are synthesized by the studied plants and transfered to humans when consumed. Furthermore, the aqueous and methanolic extracts of Entada leptostachya and Senna singueana had high LC₅₀ of >1000 µg/ml and were considered noncytotoxic. However, Securidaca longipendunculata had an LC₅₀ of <1000 µg/ml and was considered slightly cytotoxic. Further empirical investigations to characterise the bioactive phytochemicals and their safety should be done.

Doxycycline treatment reestablishes renal function of Wistar rats in experimental envenomation with Bothrops jararacussu venom

Acute kidney injury is one of the main complications of ophidian accidents and the leading cause of death in patients who survive the initial damage effects of venom. The hypothesis proposed in this investigation is that the pharmacological repositioning of doxycycline (doxy) attenuates renal injury provoked by Bothrops jararacussu (Bj) venom. Male Wistar rats were subjected or not (control) to experimental envenomation with Bj venom (3.5 mg/kg, im). Doxy (3 mg/kg, ip) was administered 2 h after envenoming. Envenomation with Bj venom promoted tissue damage in the renal cortex (moderate degree, score 3) in 24 h associated with decreased glomerular and tubular function, which promoted proteinuria and polyuria. Doxy treatment prevented the increase in urinary volume in 3 times, the increase in plasma creatinine in 33%, the increase in blood urea-nitrogen accumulation in 65%, the increase in urinary Na⁺ excretion in 2 times, marked proteinuria and kidney cortex injury induced by Bj envenomation. Bj venom promoted increase in protein content (66%) and reduction of 45% (Na⁺+K⁺)-ATPase activity in the renal cortex. The enzyme was detected mainly in the luminal membrane. Doxy treatment was effective in preventing the mentioned alterations, maintaining (Na⁺+K⁺)-ATPase in the basolateral membranes.

Phytochemical composition, antisnake venom and antibacterial activities of ethanolic extract of Aegiphila integrifolia (Jacq) Moldenke leaves

Snakebites are considered a major neglected tropical disease, resulting in around 100,000 deaths per year. The recommended treatment by the WHO is serotherapy, which has limited effectiveness against the toxins involved in local tissue damage. In some countries, patients use plants from folk medicines as antivenoms. Aegiphila species are common plants from the Brazilian Amazon and are used to treat snakebites. In this study, leaves from Aegiphila integrifolia (Jacq) Moldenke were collected from Roraima state, Brazil and its ethanolic extract was evaluated through in vitro and in vivo experiments to verify their antiophidic activity against Bothrops atrox crude venom. The isolated compounds from A. integrifolia were analyzed and the chemical structures were elucidated on the basis of infrared, ultraviolet, mass, ¹H and ¹³C NMR spectrometry data. Among the described compounds, lupeol (7), betulinic acid (1), β-sitosterol (6), stigmasterol (5), mannitol (4), and the flavonoids, pectolinarigenin (2) and hispidulin (3), were identified. The ethanolic extract and flavonoids (2 and 3) partially inhibited the proteolytic, phospholipase A2 and hyaluronidase activities of B. atrox venom, and the skin hemorrhage induced by this venom in mice. Antimicrobial activity against different bacteria was evaluated and the extract partially inhibited bacterial growth. Thus, taken together, A. integrifolia ethanolic extract has promising use as an antiophidic and antimicrobial.

Bacterial expression of a snake venom metalloproteinase inhibitory protein from the North American opossum (D.virginiana)

A variety of opossum species are resistant to snake venoms due to the presence of antihemorrhagic and antimyotoxic acidic serum glycoproteins that inhibit several toxic venom components. Two virtually identical antihemorrhagic proteins isolated from either the North American opossum (D. virginiana) or the South American big-eared opossum (D. aurita), termed oprin or DM43 respectively, inhibit specific snake venom metalloproteinases (SVMPs). A better understanding of the structure of these proteins may provide useful insight to determine their mechanism of action and for the development of therapeutics against the global health concern of snake-bite envenomation. The aim of this work is to produce a recombinant snake venom metalloproteinase inhibitor (SVMPI) similar to the above opossum proteins in Escherichia coli and determine if this bacterially produced protein inhibits the proteolytic properties of Western Diamondback rattlesnake (C. atrox) venom. The resulting heterologous SVMPI was produced with either a 6-Histidine or maltose binding protein (MBP) affinity tag on either the C-terminus or N-terminus of the protein, respectively. The presence of the solubility enhancing MBP affinity tag resulted in significantly more soluble protein expression. The inhibitory activity was measured using two complementary assays and the MBP labeled SVMPI showed 7-fold less activity as compared to the 6-Histidine labeled SVMPI. Thus, the bacterially derived SVMPI with an unlabeled N-terminus showed high inhibitory activity (IC₅₀ = 4.5 μM). The use of a solubility enhancing MBP fusion protein construct appears to be a productive way to express sufficient quantities of this mammalian protein in E. coli for further study.

Snakebite epidemiology and health-seeking behavior in Akonolinga health district, Cameroon: Cross-sectional study

Background

Snakebite envenoming causes 81,000–138,000 annual human deaths and pain, terror, or disability in 4.5–5.4 million victims. Accurate community-based epidemiological data is scarce. Our objective was to assess snakebite incidence, mortality, and health-seeking behavior, in an affected health district of Cameroon.

Methods

We conducted a cross-sectional multicluster household survey in Akonolinga health district, Centre Region, Cameroon, from October to December 2016. Using probability-proportional-to-size, 20 villages were randomly selected, then, all inhabited households were systematically selected. Annual incidence and adjusted odds-ratio for predictors were estimated.

Findings

Among the 9,924 participants, 66 suffered a snakebite during the past year: the resulting incidence is 665 (95%CI: 519–841) per 100,000 inhabitants per year. Victims were aged 5-75y (median: 34y), 53% were male and 57% farmer-cultivators. Two children died (case-fatality rate: 3%); 39 (59%) presented severity signs, including 2 (3%) neurotoxic syndromes, 20 (30%) systemic digestive syndromes, and 17 (26%) severe cytotoxic syndromes. Non-severe cases included 20 (30%) mild cytotoxic syndromes and 7 (11%) dry bites. Only two victims (3%) received antivenom. 59 (89%) used family traditional practices, 25 (38%) traditional healers, and 31 (47%) consulted health facilities. Median delays to these three care-options were 5, 45, and 60 minutes, respectively. Traditional treatments included incisions (n = 57; 86%), tourniquets (n = 51; 77%) and black-stones (n = 44; 67%). The two last procedures were also used in health facilities (n = 18). Consulting traditional healers was associated with severity (adjusted-OR: 19.6 (2.5–156), p = 0.005) and complications (aOR: 17.3, 2.4–123, p = 0.004). Long-term disabilities were subjective psychological trauma (n = 47; 71%), finger amputation (n = 1; 2%), ankylosis (n = 1; 2%) and chronic pain (n = 1; 2%).

Conclusions

We observed alarming levels of snakebite incidence, mortality, antivenom scarcity, and use of traditional medicine. It could represent several thousands of victims at national level. We suggested conducting a country-wide study, and improving antivenom supply, first-aid training, for traditional healers and health professionals.

On a global scale, snakebite envenoming causes more than 100,000 human deaths annually, as well as pain, terror, or serious disabilities in about 5 million victims, as reported by the World Health Organization. However, accurate data from community-based surveys are lacking, especially in Sub-Saharan Africa. Our aim was to assess the burden of snakebite in Akonolinga health district in Centre Region, Cameroon. We conducted a cross-sectional household survey in 20 randomly selected villages. Our study shows that about 6.6 victims per 1,000 inhabitants are bitten by a snake yearly, and that 3% of those victims die. The two victims who died in our survey were children who did not receive antivenom. Among all victims, 59% presented with severe symptoms, but only 3% received antivenom, and the majority used some traditional treatment. Consulting traditional healers was associated with clinical severity and medical complications. In summary, we found three main problems: a high burden in terms of incidence, severity and death; a lack of access to antivenoms; and the common use of potentially harmful traditional practices (causing delay and complications). This could represent tens of thousands of victims on a national level. We suggest conducting a country-wide representative study.

Potential use of extract of the plant Schwartiza brasiliensis (choisy) bedell ex gir.-Cañas against the toxic effects of the venom of Bothrops jararaca or B. jararacussu

Envenomation by snakes is a worldwide health public issue, and antivenoms are less efficient in neutralizing local toxic effects. Thus, more efficient therapies to treat patients deserve attention, and plants have been extensively tested. So, the aim of this work was to evaluate the effect of the aqueous fraction of the plant Schwartzia brasiliensis to inhibit some toxic activities of Bothrops jararaca or B. jararacussu venom. S. brasiliensis inhibited coagulant, hemolytic, proteolytic, hemorrhagic, edematogenic, and lethal activities of both venoms, regardless if plant was mixed together with venoms or injected after them as well as the route of administration (intravenous, oral or subcutaneous) of the plant. The S. brasiliensis extract showed no toxicity to mice or red blood cells. Thus, S. brasiliensis may be useful as an alternative treatment for snakebite envenomation and aid antivenom therapy to neutralize relevant toxic activities in patients bitten by Bothrops species.

Plants and Phytocompounds Active Against Bothrops Venoms

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Snakebite envenomation is an important health problem in tropical countries, with severe human and social consequences. In Latin America, the Bothrops species constitute the main threat to humans, and the envenomation caused by these species quickly develops into severe local tissue damage, including swelling, hemorrhaging, myonecrosis, skin ulceration, and pain. The systemic effects of envenomation are usually neutralized by antivenom serum therapy, despite its intrinsic risks. However, neutralization of local tissue damage remains a challenge. To improve actual therapy, two major alternatives are proposed: the rational design of new specific antibodies for most of the tissue damaging/ poor immunogenic toxins, or the search for new synthetic or natural compounds which are able to inhibit these toxins and complement the serum therapy. Natural compounds isolated from plants, mainly from those used in folk medicine to treat snakebite, are a good choice for finding new lead compounds to improve snakebite treatment and minimize its consequences for the victims. In this article, we reviewed the most promising plants and phytocompounds active against bothropic venoms.

Lapachol and synthetic derivatives: in vitro and in vivo activities against Bothrops snake venoms

Background

It is known that local tissue injuries incurred by snakebites are quickly instilled causing extensive, irreversible, tissue destruction that may include loss of limb function or even amputation. Such injuries are not completely neutralized by the available antivenins, which in general are focused on halting systemic effects. Therefore it is prudent to investigate the potential antiophidic effects of natural and synthetic compounds, perhaps combining them with serum therapy, to potentially attenuate or eliminate the adverse local and systemic effects of snake venom. This study assessed a group of quinones that are widely distributed in nature and constitute an important class of natural products that exhibit a range of biological activities. Of these quinones, lapachol is one of the most important compounds, having been first isolated in 1882 from the bark of Tabebuia avellanedae.

Methodology/Principal findings

It was investigated the ability of lapachol and some new potential active analogues based on the 2-hydroxi-naphthoquinone scaffold to antagonize important activities of Bothrops venoms (Bothrops atrox and Bothrops jararaca) under different experimental protocols in vitro and in vivo. The bioassays used to test the compounds were: procoagulant, phospholipase A₂, collagenase and proteolytic activities in vitro, venom-induced hemorrhage, edematogenic, and myotoxic effects in mice. Proteolytic and collagenase activities of Bothrops atrox venom were shown to be inhibited by lapachol and its analogues 3a, 3b, 3c, 3e. The inhibition of these enzymatic activities might help to explain the effects of the analogue 3a in vivo, which decreased skin hemorrhage induced by Bothrops venom. Lapachol and the synthetic analogues 3a and 3b did not inhibit the myotoxic activity induced by Bothrops atrox venom. The negative protective effect of these compounds against the myotoxicity can be partially explained by their lack of ability to effectively inhibit phospholipase A₂ venom activity. Bothrops atrox venom also induced edema, which was significantly reduced by the analogue 3a.

Conclusions

This research using a natural quinone and some related synthetic quinone compounds has shown that they exhibit antivenom activity; especially the compound 3a. The data from 3a showed a decrease in inflammatory venom effects, presumably those that are metalloproteinase-derived. Its ability to counteract such snake venom activities contributes to the search for improving the management of venomous snakebites.

A Review on Venom Enzymes Neutralizing Ability of Secondary Metabolites from Medicinal Plants

OBJECTIVES

Medicinal plants are vital sources of bioactive compounds that are useful for the treatment of patients with snake bites or are indirectly applicable for boosting the effects of conventional serum therapy. These plants are being used traditionally by local healers and tribes for the treatment of patients with snake bites and therefore can be used as an alternative against snake envenomation. Scientifically, using the secondary metabolites of plants to neutralize venom enzymes has an extra benefit of being based on traditional knowledge; also, the use of such metabolites for the treatment of patients with snake bites is cheaper and the treatment can be started sooner.

METHODS

All the available information on various secondary metabolites exhibiting venom neutralizing ability were collected via electronic search (using Google books, Pubmed, SciFinder, Scirus, Google Scholar, and Web of Science) and articles of peer-reviewed journals.

RESULTS

Recent interest in different plant has focused on isolating and identifying of different phytoconstituents that exhibit Phospholipase A2 activity and other venom enzyme neutralizing ability. In this support convincing evidence in experimental animal models are available.

CONCLUSION

Secondary metabolites are naturally present, have no side effect, are stable for a long time, can be easily stored, and can neutralize a wide range of snake enzymes, such as phospholipase A2, hyaluronidase, protease, L-amino acid oxidase, 5'nucleotidase, etc. The current review presents a compilation of important plant secondary metabolites that are effective against snake venom due to enzyme neutralization.

Medicinal Plants for the Treatment of Local Tissue Damage Induced by Snake Venoms: An Overview from Traditional Use to Pharmacological Evidence

Snakebites are a serious problem in public health due to their high morbimortality. Most of snake venoms produce intense local tissue damage, which could lead to temporary or permanent disability in victims. The available specific treatment is the antivenom serum therapy, whose effectiveness is reduced against these effects. Thus, the search for complementary alternatives for snakebite treatment is relevant. There are several reports of the popular use of medicinal plants against snakebites worldwide. In recent years, many studies have been published giving pharmacological evidence of benefits of several vegetal species against local effects induced by a broad range of snake venoms, including inhibitory potential against hyaluronidase, phospholipase, proteolytic, hemorrhagic, myotoxic, and edematogenic activities. In this context, this review aimed to provide an updated overview of medicinal plants used popularly as antiophidic agents and discuss the main species with pharmacological studies supporting the uses, with emphasis on plants inhibiting local effects of snake envenomation. The present review provides an updated scenario and insights into future research aiming at validation of medicinal plants as antiophidic agents and strengthens the potentiality of ethnopharmacology as a tool for design of potent inhibitors and/or development of herbal medicines against venom toxins, especially local tissue damage.

Isolation and characterization of bioactive compounds of Clematis gouriana Roxb. ex DC against snake venom phospholipase A2 (PLA2) computational and in vitro insights

Bioactive compounds were isolated from Clematis gouriana Roxb. ex DC. The compounds were separated, characterized, the structures elucidated and submitted to the PubChem Database. The PubChem Ids SID 249494134 and SID 249494135 were tested against phospholipases A₂ (PLA₂) of Naja naja (Indian cobra) venom for PLA₂ activity. Both the compounds showed promising inhibitory activity; computational data also substantiated the results. The two compounds underwent density functional theory calculation to observe the chemical stability and electrostatic potential profile. Molecular interactions between the compounds and PLA₂ were observed at the binding pocket of the PLA₂ protein. Further, this protein-ligand complexes were simulated for a timescale of 100 ns of molecular dynamics simulation. Experimental and computational results showed significant PLA₂ inhibition activity.

Setúbal S, Pontes AS, Nery NM, de Castro OB, Fernandes CFC, Honda ER, Zanchi FB, Calderon LA, Stábeli RG, Soares AM, Silva-Jardim I, Facundo VA, Zuliani JP. The effect of 3β, 6β, 16β-trihydroxylup-20(29)-ene lupane compound isolated from Combretum leprosum Mart. on peripheral blood mononuclear cells

BACKGROUND

The Combretum leprosum Mart. plant, popularly known as mofumbo, is used in folk medicine for inflammation, pain and treatment of wounds. From this species, it is possible to isolate three triterpenes: (3β, 6β, 16β-trihydroxylup-20(29)-ene) called lupane, arjunolic acid and molic acid. In this study, through preclinical tests, the effect of lupane was evaluated on the cytotoxicity and on the ability to activate cellular function by the production of TNF-α, an inflammatory cytokine, and IL-10, an immuno regulatory cytokine was assessed. The effect of lupane on the enzymes topoisomerase I and II was also evaluated.

METHODS

For this reason, peripheral blood mononuclear cells (PBMCs) were obtained and cytotoxicity was assessed by the MTT method at three different times (1, 15 and 24 h), and different concentrations of lupane (0.3, 0.7, 1.5, 6, 3 and 12 μg/mL). The cell function was assessed by the production of TNF-α and IL-10 by PBMCs quantified by specific enzyme immunoassay (ELISA). The activity of topoisomerases was assayed by in vitro biological assays and in silico molecular docking.

RESULTS

The results obtained showed that lupane at concentrations below 1.5 μg/mL was not toxic to the cells. Moreover, lupane was not able to activate cellular functions and did not alter the production of IL-10 and TNF-α. Furthermore, the data showed that lupane has neither interfered in the action of topoisomerase I nor in the action of topoisomerase II.

CONCLUSION

Based on preclinical results obtained in this study, we highlight that the compound studied (lupane) has moderate cytotoxicity, does not induce the production of TNF-α and IL-10, and does not act on human topoisomerases. Based on the results of this study and taking into consideration the reports about the anti-inflammatory and leishmanicidal activity of 3β, 6β, 16β-trihydroxylup-20(29)-ene, we suggest that this compound may serve as a biotechnological tool for the treatment of leishmaniasis in the future.

Effect of the triterpene 3β, 6β, 16β-trihydroxylup-20(29)-ene isolated from the leaves of Combretum leprosum Mart. on cutaneous wounds in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Combretum leprosum Mart. is a native species of the Caatinga, an important biome in the Brazilian semi-arid region. This species is commonly used in Brazil as a healing agent, as well as for the treatment of skin diseases.

AIM OF THE STUDY

This study investigated the healing potential of the ethanolic extract (EECL) and the bioactive triterpene 3β, 6β, 16β-trihydroxylup-20 (29)-ene (CLF-1) isolated from the leaves of C. leprosum.

MATERIALS AND METHODS

Skin wounds (1cm(2)) were created in the dorsal zone of mice with a scalpel blade number 15. The treatment consisted in a daily topical application of 100 μl of 150 mM NaCl, EECL and CLF-1 (at 10 μg/100 μl) for 12 days. The lesions were then macro and microscopically evaluated.

RESULTS

On postoperative day (POD) 2, the lesions treated with EECL and CLF-1 showed a moderate presence of vessels of the granulation tissue progressing in the dermis. The same effect was not observed in the control group. The treatment with EECL and CLF-1 stimulated angiogenesis, resulting in a rapid deposition of extracellular matrix (ECM). Moreover, the animals treated with EECL and CLF-1 showed smaller lesions on POD 7, primarily due to the contraction in the reticular dermis induced by organization of myofibroblasts, which was not observed in the group treated with NaCl. In addition, the lesions treated with EECL and CLF-1 showed ECM restructuration and presence of epithelium coating, which was not observed in the group treated with NaCl, in which the lesions showed no epithelial lining, suggesting delayed healing.

CONCLUSION

CLF-1 isolated from the leaves of C. leprosum may be considered to be an important molecule for the treatment of skin lesions. However, further investigations are necessary to establish its role in chronic lesions and to elucidate the mechanism of action involved in the cutaneous healing process. To the best of our knowledge, this is the first report describing the pro-healing activity of the ethanolic extract and the triterpene 3β, 6β, 16β-trihydroxylup-20(29)-ene isolated from leaves of C. leprosum.

Occurrence of sulfated fucose branches in fucosylated chondroitin sulfate are essential for the polysaccharide effect preventing muscle damage induced by toxins and crude venom from Bothrops jararacussu snake

Snake envenoming is an important public health problem around the world, particularly in tropics. Beyond deaths, morbidity induced by snake venoms, such as myotoxicity, is of pivotal consequence to population. Bothrops jararacussu is the main venomous snake in southeast region of Brazil, and particularly presents strong myotoxic effect. The only available therapy, antibothropic antivenom, poorly affects venom-induced myotoxicity. The aim of this study is to assess the ability of fucosylated chondroitin sulfate (fucCS), a glycosaminoglycan with anticoagulant and antithrombotic properties, and its derivatives to inhibit toxic activities of B. jararacussu crude venom and its isolated toxins, named bothropstoxins (BthTX-I and BthTX-II). The in vitro myotoxic activities induced by crude venom, by BthTX-I alone and by toxins together were abolished by fucCS. Carboxyl reduction (fucCS-CR) kept this ability whereas defucosilation (defucCS) abrogates myoprotection. We observed the same pattern in the response of these polysaccharides in antagonizing the increase in plasma creatine kinase (CK) levels, the reduction of skeletal muscle CK content and the rise of myeloperoxidase (MPO) activity induced by crude venom and isolated toxins. FucCS inhibited edematogenic activity and partially prevented the reduction of total leukocytes in blood when pre-incubated with crude venom. Furthermore, the venom procoagulant effect was completely antagonized by increasing concentrations of fucCS, although this polyanion could stop neither the tail bleeding nor the skin hemorrhage induced by Bothrops jararaca venom. The B. jararacussu phospholipase, hyaluronidase, proteolytic and collagenase activities were inhibited in vitro. The results suggest that fucCS could be able to interact with both toxins, and it is able to inhibit BthTX-II phospholipase activity. Light microscopy of extensor digitorum longus muscle (EDL) muscle showed myoprotection by fucCS, once necrotic areas, edema and inflammatory cells were all decreased as compared to venom injection alone. Altogether, data show that fucCS was able to inhibit myotoxicity and inflammation induced by B. jararacussu venom and its phospholipase toxins, BthTX-I and BthTX-II. Thus, fucosylated chondroitin sulfate is a new polyanion with potential to be used as an adjuvant in the treatment of snakebites in the future.