Protective effect of Euphorbia hirta and its components against snake venom induced lethality

A comprehensive review on recent advances in the use of ethnomedicinal plants and their metabolites in snake bite treatment

Snakebites are a severe medical and social issue, particularly in tropical and subtropical countries with minimal medical facilities, where the most dangerous snakes are found. Worldwide, most rural areas use medicinal plants alone or in combination as antidotes for snakebite treatment. Local knowledge of medicinal plants for snakebite treatment plays a more critical role in primary healthcare services in rural areas. As a result of this review, it is revealed that 39% of herbs, 38% of shrubs, 18% of trees, 2% of climbers, 2% of bulbs, and 1% of ferns have snake antivenom potential, which is indicative of the presence of numerous phytochemicals such as alkaloids, coumarins, curcuminoids, flavonoids, steroids, triterpenoids, and cinnamic acid in particular plants. According to the availability of information, the data focus on the plants, their families, and their parts from various literature sources. In the future, the valuable plants reported here and their phytoconstituents may be potential sources for developing effective natural drugs for snake bite treatments. Therefore, this review is a comprehensive study of the snake antivenom potential of various medicinal plants and their bioactive compounds.

Three finger toxins of elapids: structure, function, clinical applications and its inhibitors

The WHO lists snakebite as a "neglected tropical disease". In tropical and subtropical areas, envenoming is an important public health issue. This review article describes the structure, function, chemical composition, natural inhibitors, and clinical applications of Elapids' Three Finger Toxins (3FTX) using scientific research data. The primary venomous substance belonging to Elapidae is 3FTX, that targets nAChR. Three parallel β-sheets combine to create 3FTX, which has four or five disulfide bonds. The three primary types of 3FTX are short-chain, long-chain, and nonconventional 3FTX. The functions of 3FTX depend on the specific toxin subtype and the target receptor or ion channel. The well-known effect of 3FTX is probably neurotoxicity because of the severe consequences of muscular paralysis and respiratory failure in snakebite victims. 3FTX have also been studied for their potential clinical applications. α-bungarotoxin has been used as a molecular probe to study the structure and function of nAChRs (Nicotinic Acetylcholine Receptors). Acid-sensing ion channel (ASIC) isoforms 1a and 1b are inhibited by Mambalgins, derived from Black mamba venom, which hinders their function and provide an analgesic effect. α- Cobra toxin is a neurotoxin purified from Chinese cobra (Naja atra) binds to nAChR at the neuronal junction and causes an analgesic effect for moderate to severe pain. Some of the plants and their compounds have been shown to inhibit the activity of 3FTX, and their mechanisms of action are discussed.

Phytochemical characterization and phospholipase A2 inhibitory effect of Vitex negundo L. root extracts

ETHNOPHARMACOLOGICAL RELEVANCE

Snake bites are a critical health issue in many parts of the world particularly in Asian countries lacking efficient health facilities in rural areas. Cobra is the most common snake type in Asia and is responsible for a large number of mortalities particularly in rural areas. Plants are usually considered the most effective and easy-to-approach treatment for snake bites in rural areas of various countries. Vitex negundo L. is an important medicinal plant traditionally used to treat snake bite envenomation in many countries of Asia.

AIM OF THE STUDY

From literature survey of plants traditionally used in the treatment of snake bites in Asian countries including India, Pakistan and Sri Lanka, roots of V. negundo were selected for the present study. Anti-snake venom potential of its roots was assessed through various in vitro assays targeting the phospholipase A2 enzyme.

MATERIALS AND METHODS

V. negundo roots were sequentially extracted in different organic solvents to get fractions and in methanol to get total extract. The extracts were evaluated for phospholipase A2 (PLA2) inhibitory potential through inhibition of venom-induced hemolysis, ADP-induced platelet aggregation, PLA2-induced fatty acid hydrolysis and anticoagulant effect of cobra venom. Antioxidant power was determined using DPPH and superoxide radical scavenging assays. GC-MS and HPLC analysis was performed for the total methanol extract.

RESULTS

Strong PLA2 inhibitory effect was observed for all the extracts. The ethyl acetate, acetone and methanol fractions significantly inhibited toxic effects of cobra venom under in vitro conditions. Radical scavenging potential of these fractions was also significantly high as compared to non-polar fractions in both DPPH and superoxide scavenging assays. Phytochemical analysis indicated high phenolic and flavonoid contents in these fractions. GC-MS and HPLC analysis of total methanol extract confirmed the presence of bis(2-ethylhexyl) phthalate, phenol, o-Guaiacol, palmitic acid-methyl ester, methyl stearate, quercetin and kaempferol in the plant.

CONCLUSION

The study concluded that the roots of V. negundo, particularly their polar extracts, have strong PLA2 inhibitory effect against cobra venom confirming their traditional use to manage snake bites. The roots of this plant can be further studied for isolation of plant-based antisera.

Unraveling snake venom phospholipase A2: an overview of its structure, pharmacology, and inhibitors

Snake bite is a neglected disease that affects millions of people worldwide. WHO reported approximately 5 million people are bitten by various species of snakes each year, resulting in nearly 1 million deaths and an additional three times cases of permanent disability. Snakes utilize the venom mainly for immobilization and digestion of their prey. Snake venom is a composition of proteins and enzymes which is responsible for its diverse pharmacological action. Snake venom phospholipase A2 (SvPLA2) is an enzyme that is present in every snake species in different quantities and is known to produce remarkable functional diversity and pharmacological action like inflammation, necrosis, myonecrosis, hemorrhage, etc. Arachidonic acid, a precursor to eicosanoids, such as prostaglandins and leukotrienes, is released when SvPLA2 catalyzes the hydrolysis of the sn-2 positions of membrane glycerophospholipids, which is responsible for its actions. Polyvalent antivenom produced from horses or lambs is the standard treatment for snake envenomation, although it has many drawbacks. Traditional medical practitioners treat snake bites using plants and other remedies as a sustainable alternative. More than 500 plant species from more than 100 families reported having venom-neutralizing abilities. Plant-derived secondary metabolites have the ability to reduce the venom's adverse consequences. Numerous studies have documented the ability of plant chemicals to inhibit the enzymes found in snake venom. Research in recent years has shown that various small molecules, such as varespladib and methyl varespladib, effectively inhibit the PLA2 toxin. In the present article, we have overviewed the knowledge of snake venom phospholipase A2, its classification, and the mechanism involved in the pathophysiology of cytotoxicity, myonecrosis, anticoagulation, and inflammation clinical application and inhibitors of SvPLA2, along with the list of studies carried out to evaluate the potency of small molecules like varespladib and secondary metabolites from the traditional medicine for their anti-PLA2 effect.

Effect of gamma-irradiated honey bee venom on gene expression of inflammatory and anti-inflammatory cytokines in mice

In this study, the effect of gamma-irradiated honey bee venom (doses of 0, 2, 4, 6, and 8 kGy, volume of 0.1 ml and concentration of 0.2 mg/ml) was evaluated on the reduction of allergen compounds and the gene expression of inflammatory and anti-inflammatory cytokines in mice. Hence, edema activity induced by the bee venom irradiated at 4, 6, and 8 kGy was reduced, compared with the control group and that irradiated at 2 kGy. In contrast, the paw edema induced by the bee venom irradiated at 8 kGy increased, compared with 4 and 6 kGy. At all the time periods, there was a significant decrease in the gene expression of interferon gamma (IFN-γ), interleukin 6 (IL-6), and interleukin 10 (IL-10) in the bee venoms irradiated at 4, 6, and 8 kGy, compared with the control group and that irradiated at 2 kGy. In contrast, there was an increase in the gene expression of IFN-γ and IL-6 in the bee venom irradiated at 8 kGy, compared with those irradiated at 4 and 6 kGy. Therefore, gamma irradiation at 4 and 6 kGy reduced the gene expression of cytokines at each time period by decreasing the allergen compounds of honey bee venom.

A First Look at the Inhibitory Potential of Urospatha sagittifolia (Araceae) Ethanolic Extract for Bothrops atrox Snakebite Envenomation

Bothrops atrox snakebites are a relevant problem in the Amazon basin. In this biodiverse region, the ethnomedicinal approach plays an important role as an alternative to antivenom therapy. Urospatha sagittifolia (Araceae) is a plant used for this purpose; however, its neutralizing properties have not been scientifically accessed. To fill this gap, we investigated the ability of U. sagittifolia to modulate the catalytic activity of Bothrops atrox venom, and their toxic consequences, such as local damage and lethality. The venom profile of B. atrox was assessed by chromatography and electrophoresis. Inhibition of the three main enzymatic and medically important toxins from the venom was evaluated using synthetic substrates and quantified by chromogenic activity assays. Additionally, the neutralization of lethality, hemorrhage and edema were investigated by in vivo assays. The possible interactions between venom proteins and plant molecules were visualized by polyacrylamide gel electrophoresis. Finally, the phytochemical constituents present in the ethanolic extract were determined by qualitative and quantitative analyses. The ethanolic extract reduced the activity of the three main enzymes of venom target, achieving ranges from 19% to 81% of inhibition. Our in vivo venom neuralizations assays showed a significant inhibition of edema (38.72%) and hemorrhage (42.90%). Additionally, lethality was remarkably counteracted. The highest extract ratio evaluated had a 75% survival rate. Our data support the biomedical value of U. sagittifolia as a source of natural enzyme inhibitors able to neutralize catalytically active B. atrox venom toxins and their toxic effects.

Pharmacological Activities and Characterization of Phenolic and Flavonoid Compounds in Methanolic Extract of Euphorbia cuneata Vahl Aerial Parts

Euphorbia cuneata Vahl. (Euphorbiaceae) is a plant used in folk medicine for the treatment of pain and inflammation, although the biological basis for these effects has not been thoroughly investigated. The goal of this study was to investigate the pharmacological properties and characterization of phenolic and flavonoid compounds present in the aerial parts of E. cuneata. E. cuneata aerial parts were tested for antioxidant activity (DPPH), antibacterial activity, cell viability and cytotoxic effects, and anti-inflammatory activity. Phenolic and flavonoid contents (HPLC), and volatile constituents (GC-MS) were also characterized. The methanol extract had the highest antioxidant activity, while the ether extract had the lowest. The antioxidant activity of E. cuneata extract increased from (21.11%) at a concentration of 10 µg/mL to (95.53%) at a concentration of 1280 µg/mL. S. aureus was the most sensitive organism with the highest zone of inhibition and lowest MIC, with acetone extract; whereas C. tropicalis was the most resistant, with the lowest inhibition zone. MTT assay revealed that the methanol extract of E. cuneata had significant cytotoxic effects on the A549, Caco-2, and MDA-MB-231 cell lines, respectively. Lower concentrations of methanolic extract gave anti-inflammatory activity, and those effects were compared with indomethacin as a positive control. Pyrogallol was the most abundant phenolic acid, followed by caffeic, p-coumaric, ferulic, syringic, and gallic acids, respectively. The 7-hydroxyflavone and rutin flavonoids were also found in the extract. GC-mass analysis showed that aerial parts of E. cuneata were rich in methyl 12-hydroxy-9-octadecenoate. The volatile components were also composed of considerable amounts of hexadecanoic acid, methyl ester, (9E,12E)-octadeca-9,12-dienoyl chloride, and methyl octadeca-9,12-dienoate as well as a little amount of hexanal dimethyl acetal. It can be concluded that methanolic extract of E. cuneata could be used as an available source of natural bioactive constituents with consequent health benefits.

New Insights on Euphorbia dendroides L. (Euphorbiaceae): Polyphenol Profile and Biological Properties of Hydroalcoholic Extracts from Aerial Parts

Euphorbia dendroides L. is a rounded shrub commonly found in the Mediterranean area well-known, since ancient times, for its traditional use. The aim of the present study was to investigate the phytochemical profile as well as the antioxidant and anti-inflammatory properties of flower (FE), leaf (LE), fruit (FrE), and branch (BE) hydroalcoholic extracts. For this purpose, a preliminary phytochemical screening followed by RP-LC-DAD-ESI-MS analysis, as well as several in vitro cell-free colorimetric assays, were carried out. Moreover, the toxicity of the extracts was investigated by the brine shrimp lethality assay. All extracts showed a high content of polyphenols, in particular phenolic acids (chlorogenic acid 0.74-13.80 g/100 g) and flavonoids (rutin 0.05-2.76 g/100 g and isovitexin 8.02 in BE). All the extracts showed strong and concentration-dependent antioxidant and anti-inflammatory activity with, on average, the following order of potency: FE, LE, FrE, and BE. Interestingly, all the extracts investigated did not show any toxicity on Artemia salina. Moreover, the only LD50 found (BE, 8.82 mg/mL) is well above the concentration range, which has been shown the biological properties. Considering this, this study offers the first evidence of the possible use of the polyphenol extracts from the aerial parts of E. dendroides as promising antioxidant and anti-inflammatory agents.

Vanillic acid as phospholipase A2 and proteases inhibitor: In vitro and computational analyses

Enzymatic inhibition by natural compounds may represent a valuable adjuvant in snakebite serum therapy. The objective in this work was to evaluate possible in vitro interactions between vanillic acid and enzymes from Bothrops spp. and Crotalus durissus terrificus venoms, and also suggest a theory as how they interact based on molecular docking. Vanillic acid inhibited the phospholipase activity induced by Bothrops alternatus (∼25% inhibition); the caseinolytic activity induced by Bothrops atrox (∼30%), Bothrops jararacussu (∼44%), and C. d. terrificus (∼33%); the fibrinogenolysis induced by B. jararacussu, B. atrox, and C. d. terrificus (100%); the serine protease activity induced by Bothrops moojeni (∼45%) and Bothrops jararaca (∼66%); the hemolytic activity induced by B. moojeni (∼26%); the thrombolysis activity induced by B. atrox (∼30%) and B. jararacussu (∼20%); and the thrombotic activity induced by C. d. terrificus (∼8%). The compound was also capable of delaying the coagulation time in citrated plasma by 60, 35, and 75 Sec, when incubated with B. moojeni, B. atrox, and B. jararaca, respectively. The results obtained expand the possibilities for future pharmaceutical use of vanillic acid, considering the high homology degree among human and snake venom phospholipases A₂ and proteases (involved in chronic inflammatory diseases). Also, this compound can be used as adjuvant to improve currently available treatments for ophidism victims.

In vitro and in vivo inhibitory effects of Tabernaemontana alternifolia against Naja naja venom

Background

Tabernaemontana alternifolia root is traditionally used and practiced among few Indian tribes as an antidote for snakebites.

Objective

To combat and neutralize Naja naja venom using methanolic root extract of Tabernaemontana alternifolia and to explore its efficacy on venom biomarkers in search of newer herbal antidote or first-aid-point of care for therapeutics.

Materialization.

Pharmacological activities such as fibrinogenolytic, direct and indirect hemolytic activities for the neutralization of the venom were evaluated. Lethal toxicity annulation studies were performed using the murine model by pre-incubation and post-treatment protocols. Further, the neutralization of edema and myotoxicity were also evaluated.

Results

Electrophoretic analysis revealed that the complete neutralization of fibrinogen degradation was observed at 1:10 (w/w) (venom to extract). T. alternifolia exhibited an effective dose (ED₅₀) value of 87.20 µg/mL for venom-induced hemolysis. Venom at 2 µg concentration produced 11 mm of hemolytic radiance and was neutralized at 1:20 (w/w) venom to extract concentration. The survival time and the neurotoxic symptoms in mice were concluded to be delayed by both the methods of lethal toxicity inhibition using methanol extract. The edema ratio reduced the venom to extract ratio of 1:20 (w/w) from 173 ± 45% to 133.61% when subjected to 5 µg of venom concentration. The plant extract significantly neutralized the myotoxic activity.

Conclusion

T. alternifolia methanolic root extract could be a potent contributor in the effective treatment of N. naja venom-induced toxicity.

Metabolites from the citrus extracts inhibit the activity of selected proteins in Indian Cobra (Naja naja) venom

ETHNOPHARMACOLOGICAL RELEVANCE

Snakebite is a severe problem in many parts of the world, specifically in tropical and subtropical regions. A range of medicinal plant extracts are administered for treating snake bite. Of the many common plants, extracts of Citrus species have been documented to be used for treating snake bite and have been shown to decrease the snake venom toxicity.

AIM

The aim of the current work is to evaluate the utility of citrus peel extracts (Citrus aurantium L. and Citrus reticulate Blanco) in the management of Indian cobra envenomation.

MATERIALS AND METHODS

Peels of citrus species were evaluated for their phospholipase A₂, protease and haemolytic inhibition properties. The phytochemicals present in the extract were inferred using GC-MS. In-vivo studies, using mice model, were done to confirm the inhibitory effect of the extracts. Molecular docking was used to understand the possible binding modes of selected phytochemicals to snake venom phospholipase.

RESULTS

Citrus peel extracts are rich in polyphenols, flavonoids and tannins. The methanolic extract of Citrus aurantium L. and Citrus reticulate Blanco inhibits phospholipase (75%), protease (71%) and hemolysis (80%) activity of the venom. GC-MS analyses indicate the presence of β-sitosterol, n-hexadecanoic acid, eicosanoic acid, and flavone in both the extracts. In addition, C. reticulate extract contains α-tocopherol and squalene. Molecular docking revealed that α-tocopherol, spiro [androst-5-ene-17,1'-cyclobutan]-2'-one,3-hydroxy-(3β,17β)- and β-sitosterol acetate bind with moderate affinity to the catalytic site of phospholipase A2.

CONCLUSION

The present study provides new molecular insight and scientific evidence on the utility of the methanolic extracts of citrus peels to neutralize the venom toxins of Naja naja.

Combining in silico and in vitro approaches to identification of potent inhibitor against phospholipase A2 (PLA2)

Phospholipase A2 (PLA2) is the main constituent of snake venom. PLA2 enzymes catalyze the Ca2+ dependent hydrolysis of 2-acyl ester bonds of 3-sn-phospholipids, releasing fatty acids and lysophospholipids. Inside the body of the victim, PLA2 from snake venom induces either direct or indirect pathophysiological effects, including anticoagulant, inflammatory, neurotoxic, cardiotoxic, edematogenic, and myotoxic activities. Therefore, there is a need to find the potential inhibitors against PLA2 responsible for snakebite. In this study, we employed in silico and in vitro methods to identify the potential inhibitor against PLA2. Virtual screening and molecular docking studies were performed to find potent inhibitor against PLA2 using Traditional Chinese Medicine Database (TCM). Based on these studies, Scutellarin (TCM3290) was selected and calculated by density functional theory calculation at B3LYP/6-31G**++ level to explore the stereo-electronic features of the molecule. Further, molecular docking and DFT of Minocycline was carried out. Quantum polarized ligand docking was performed to optimize the geometry of the protein-ligand complexes. The protein-ligand complexes were subjected to molecular dynamics simulation and binding free energy calculations. The residence time of a protein-ligand complex is a critical parameter affecting natural influences in vitro. It is nonetheless a challenging errand to expect, regardless of the accessibility of incredible PC assets and a large variety of computing procedures. In this metadynamics situation, we used the conformational flooding technique to deal with rank inhibitors constructions. The systematic free energy perturbation (FEP) protocol and calculate the energy of both complexes. Finally, the selected compound of TCM3290 was studied in vitro analysis such as inhibition of PLA2 activity, hyaluronidase activity and fibrinogenolytic activity. The TCM3290 had a more binding affinity compare to Minocycline, and interacted with the key residues of TYR63 and GLY31. DFT represented the highest HOMO and LUMO energy of 0.15146 eV. MD simulation with 100 ns proved that an inhibitor binding mode is more stable inside the binding site of PLA2. In vitro analysis shows that TCM3290 significantly neutralized by PLA2. The above observations confirmed that Scutellarin (TCM3290) had a potent snake venom neutralizing capacity and could hypothetically be used for therapeutic drives of snakebite envenomation.

Edematic and coagulant effects caused by the venom of Bothrops rhombeatus neutralized by the ethanolic extract of Piper auritum

ETHNOPHARMACOLOGICAL RELEVANCE

In Colombia, the only authorized treatment to cure snakebite envenomation is with the use of antivenom. The antivenom neutralizes the systemic effects properly, but is not very effective at neutralizing local effects, thus several cases have lead to complications. On the other hand, rural communities turn to the use of plants that are easily accessible and available for basic health care. One of these plants is named Piper auritum (PA), which is traditionally highlighted in some indigenous communities of Antioquia and Chocó.

AIM OF THE STUDY

The main objective of this work was to characterize the venom's toxicity by determining the Minimum Edema Dose (MED), the Minimum Coagulant Dose-Plasma (MCD-P), the Minimum Hemorrhagic Dose (MHD) and to determine the neutralizing power of the Total Ethanolic Extract (TEE) from leaves of PA on the localized and systemic effects caused by the Bothrops rhombeatus venom.

MATERIALS AND METHODS

To begin, the minimum dose that causes edema-forming, coagulant and hemorrhagic activities was determined. The protocols investigated include coagulant and edematic activities caused by the venom of Bothrops rhombeatus which were neutralized by the TEE of PA.

RESULTS

The MCD-P was found to be 0.206 ± 0.026 μg, the MED is the same at 0.768 ± 0.065 μg, and the MHD is 3.553 ± 0.292 μg, which are different from the reports for Bothrops asper and Bothrops ayerbei. Next, a phytochemical screening was done to the TEE where mainly triterpenes, steroids, coumarins, saponins, and lignans were identified. Also present were 43,733 ± 2106 mg AG/g ES of phenols, which are secondary metabolites that are probably responsible for the neutralization of coagulant and edematic activities at rates of 2363.870 μL and 1787.708 μL of extract/mg of venom, respectively. As a comparative parameter, the National Institute Health's (NHI) effective dose of the antivenom was used as a comparative parameter. In addition, we determined the toxicity of the TEE of PA on to Artemia salina, being moderately toxic at 6 and 24 h, while the essential oil of PA at the same observation hours is in the extremely toxic range.

CONCLUSIONS

The results reflect that the extract of P. auritum has an anti-inflammatory effect similar to that of the NIH serum. It could be used as a complement of NIH antivenom, using them together so it contributes to effectively reduce inflammation and the socio-economic impact generated by the permanence of a patient victim of snakebite in health centers.

CLASSIFICATIONS

Immunological products and vaccines.

Perspective on the Therapeutics of Anti-Snake Venom

Snakebite envenomation is a life-threatening disease that was recently re-included as a neglected tropical disease (NTD), affecting millions of people in tropical and subtropical areas of the world. Improvement in the therapeutic approaches to envenomation is required to palliate the morbidity and mortality effects of this NTD. The specific therapeutic treatment for this NTD uses snake antivenom immunoglobulins. Unfortunately, access to these vital drugs is limited, principally due to their cost. Different ethnic groups in the affected regions have achieved notable success in treatment for centuries using natural sources, especially plants, to mitigate the effects of snake envenomation. The ethnopharmacological approach is essential to identify the potential metabolites or derivatives needed to treat this important NTD. Here, the authors describe specific therapeutic snakebite envenomation treatments and conduct a review on different strategies to identify the potential agents that can mitigate the effects of the venoms. The study also covers an increased number of literature reports on the ability of natural sources, particularly plants, to treat snakebites, along with their mechanisms, drawbacks and future perspectives.

Euphorbia-Derived Natural Products with Potential for Use in Health Maintenance

Euphorbia genus (Euphorbiaceae family), which is the third largest genus of angiosperm plants comprising ca. 2000 recognized species, is used all over the world in traditional medicine, especially in the traditional Chinese medicine. Members of this taxa are promptly recognizable by their specialized inflorescences and latex. In this review, an overview of Euphorbia-derived natural products such as essential oils, extracts, and pure compounds, active in a broad range of biological activities, and with potential usages in health maintenance, is described. The chemical composition of essential oils from Euphorbia species revealed the presence of more than 80 phytochemicals, mainly oxygenated sesquiterpenes and sesquiterpenes hydrocarbons, while Euphorbia extracts contain secondary metabolites such as sesquiterpenes, diterpenes, sterols, flavonoids, and other polyphenols. The extracts and secondary metabolites from Euphorbia plants may act as active principles of medicines for the treatment of many human ailments, mainly inflammation, cancer, and microbial infections. Besides, Euphorbia-derived products have great potential as a source of bioactive extracts and pure compounds, which can be used to promote longevity with more health.

Hemostatic and hepatoprotective bioactivity of Junci Medulla Carbonisata-derived Carbon Dots

AIM

To explore the hemostatic and hepatoprotective bioactivity of Junci Medulla Carbonisata-derived Carbon Dots (JMC-CDs).

MATERIALS & METHODS

The JMC-CDs were characterized using transmission electron microscopy, HPLC, Fourier transform IR, UV, fluorescence and x-ray photoelectron spectroscopy. The hemostatic effect of JMC-CDs was evaluated and confirmed by trauma hemorrhagic animal models and internal hemorrhage animal model induced by Deinagkistrodon acutus venom.

RESULTS

The JMC-CDs ranged in diameter from 1.0 to 8 nm and had a yield of 0.12%. Moreover, JMC-CDs not only possessed remarkable hemostatic efficacy but could also prevent hemorrhage-induced liver injury, as demonstrated by the reduced serum levels of biochemical indicators of liver damage such as aspartate aminotransferase, alanine amino transferase, alkaline phosphatase, total bilirubin and direct bilirubin.

CONCLUSION

The JMC-CDs may have great potentials in clinical practice.

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.

The detoxifying effects of structural elements of persimmon tannin on Chinese cobra phospholipase A 2 correlated with their structural disturbing effects well

The effects of persimmon tannin (PT) characteristic structural elements on Naja atra phospholipase A₂ (PLA₂)-induced lethality, myotoxicity, and hemolysis in mice models were determined. In addition, methods including surface plasmon resonance, dynamic light scattering, and Fourier transform infrared spectroscopy were explored to uncover the possible detoxifying mechanisms of PT on snake venom PLA₂. Our results revealed that PT characteristic elements (EGCG, ECG, A-type EGCG dimer, and A-type ECG dimer) could neutralize the lethality, myotoxicity, and hemolysis of PLA₂. Moreover, the detoxifying effects of the four structural elements correlated with their structural disturbing effects well. Our results proved that A-type EGCG dimer and A-type ECG dimer may be structural requirements for the detoxifying effects of PT. We propose that the high affinity of A-type EGCG dimer and A-type ECG dimer for PLA₂ and the considerable spatial structural disturbance of PLA₂ induced by the dimers may be responsible for their antilethality, antimyotoxicity, and antihemolysis on Chinese cobra PLA₂in vivo.

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.

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.

Quercetin-3-O-rhamnoside from Euphorbia hirta protects against snake Venom induced toxicity

BACKGROUND

The plant Euphorbia hirta is widely used against snake envenomations in rural areas and it was proved to be effective in animal models. Therefore, the scientific validation of its phytoconstituents for their antiophidian activity is aimed in the present study.

METHODS

E. hirta extract was subjected to bioactivity guided fractionation and the fractions that inhibited different enzyme activities of Naja naja venom in vitro was structurally characterized using UV, FT-IR, LC-MS and NMR spectroscopy. Edema, hemorrhage and lethality inhibition activity of the compound were studied in mice model. In addition, molecular docking and molecular dynamic simulations were also performed in silico.

RESULTS

The bioactive fraction was identified as Quercetin-3-O-α-rhamnoside (QR, 448.38 Da). In vitro experiments indicated that protease, phospholipase-A(2), hemolytic activity and hemorrhage inducing activity of the venom were inhibited completely at a ratio of 1:20 (venom: QR) w/w. At the same concentration, the edema ratio was drastically reduced from 187% to 107%. Significant inhibition (93%) of hyaluronidase activity was also observed at a slightly higher concentration of QR (1:50). Further, in in vivo analysis, QR significantly prolonged the survival time of mice injected with snake venom.

CONCLUSION

For the first time Quercetin-3-O-α-rhamnoside, isolated from E. hirta, has been shown to exhibit anti-snake venom activity against Naja naja venom induced toxicity.

GENERAL SIGNIFICANCE

Exploring such multifunctional lead molecules with anti-venom activity would help in developing complementary medicine for snakebite treatments especially in rural areas where anti-snake venom is not readily available.

Ethnobotanical survey of medicinal plants used in the Maseru district of Lesotho

ETHNOPHARMACOLOGICAL RELEVANCE

Ethnobotanical knowledge in Lesotho is passed on orally from one generation to another. As a result it has not been well documented. Existing publications have relied on previous literature and are limited either in terms of scope or coverage. Furthermore, some of them are out of print. Therefore, there are gaps in the documentation of medicinal plants used in Lesotho.

AIM OF THE STUDY

The purpose of the current study is to investigate common ailments in Lesotho's traditional medicine and document plants that are used in treating such ailments.

MATERIALS AND METHODS

Interviews were conducted in five urban and four rural areas of the capital town of Maseru, by means of questionnaires to elicit information on medicinal plant use to cure common ailments. The informants were 20 males and seven females comprising 15 traditional healers, 11 herbalists and one pharmacist.

RESULTS

Reproductive ailments were found to be the most commonly treated, followed by respiratory, degenerative and digestive problems. A list of the 80 plants used for treating the common ailments is given. A total of 44 families is represented, with Asteraceae, Fabaceae, Asphodelaceae and Poaceae families having the highest number of species used for medicinal purposes. The most frequently mentioned medicinal plants in interviews include; Elephantorrhiza elephantina, Pentanisia prunelloides, Hypoxis hermerocallidea, Eriocephalus sp., Salvia runcinata, Scabiosa columbaria, Dicoma anomala, Morella serrata, Xysmalobium undulatum, and Leobordea lanceolata. Due to the high demand of medicinal plants, some species such as L. lanceolata, Tephrosia capensis, E. elephantina, D. anomala and P. prunelloides were reported as over-harvested. In some cases animal products are added to the medicinal plants to enhance their curative abilities.

CONCLUSIONS

A total of 80 plants were recorded in the study as treating 38 common ailments in the Maseru district of Lesotho. Records of eight medicinal plants and 146 new medicinal uses of 34 plants that were not recorded elsewhere in literature are reported in the current study for the first time. The new records of medicinal plants used in traditional healing practices in Lesotho clearly show the need to document these practices, and the wealth of new knowledge gained with the current study reinforces the importance of extending the study to other parts of Lesotho.