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

Evaluation of Saxifraga stolonifera phenolic extracts as a potential antivenom against Deinagkistrodon acutus venom: In vitro and in vivo studies

ETHNOPHARMACOLOGICAL RELEVANCE

In the snake-infested mountainous regions of China, Saxifraga stolonifera [L.] Meeb is widely utilized as an immediate remedy for venomous snake bites. However, the scientific understanding of S. stolonifera's efficacy in snakebite treatment remains limited and requires further investigation.

AIM OF THE STUDY

The aim of this study was to assess the inhibitory effects of Saxifraga stolonifera phenolic extracts (SSPE) on Deinagkistrodon acutus venom (DAV) and explore the potential of S. stolonifera as a valuable candidate for antivenom development.

MATERIALS AND METHODS

We employed our previously optimized extraction conditions to obtain SSPE. In vitro experiments utilizing diverse models were conducted to assess the inhibitory effects of the extracted phenolic compounds on DAV, specifically targeting phospholipase A2 (PLA2), proteolytic, fibrinolytic, and hyaluronidase enzymes. Furthermore, in vivo investigations were conducted to evaluate the inhibitory potential of the extracted compounds against DAV-induced hemorrhagic and edematogenic activity. To elucidate the chemical composition of the phenolic extracts, Ultra Performance Liquid Chromatography-mass spectrometry (UPLC-MS) analysis was performed.

RESULTS

Our in vitro inhibition study showed that S. stolonifera was able to inhibit the activities of PLA2 enzyme, proteolytic enzyme, hyaluronidase and fibrinogenolytic. The median effective dose (ED50) values of SSPE for inhibiting PLA2 enzyme, proteolytic enzyme and hyaluronidase activities were 0.115 mg/mL, 0.026 mg/mL and 0.238 mg/mL, respectively. The DAV-induced hemorrhagic and edematogenic effects of the SSPE were also successfully inhibited in vivo, and the high SSPE concentration was able to completely inhibit the hemorrhage and edema. It is noteworthy that the mice suffered no harm from the high SSPE concentration. The composition analysis showed that the phenolic substances contained in SSPE are gallic acid, protocatechuic acid, chlorogenic acid, rutin, kaempferol-3-O-ɑ-L-rhamnoside, kaempferol-3-O-β-D-glucopyranoside, quercetin and kaempferol.

CONCLUSIONS

This study provides scientific validation of the inhibitory efficacy of S. stolonifera as an emergency treatment for venomous snake bites, offering a theoretical foundation for future drug development strategies targeting snakebite.

The bioprospecting potential of Clusia fluminensis Planch. & Triana: a scoping review

Many biological activities are described for the Clusiaceae family. Clusia fluminensis, a species from Brazilian flora, is mainly employed for ornamental purposes. This review aimed to depict the current knowledge of C. fluminensis from a bioprospecting standpoint. "Clusia fluminensis" search term was applied in Scopus, Web of Science, PubMed and Bireme databases according to PRISMA-ScR statement. Selected papers on Phytochemistry or Bioactivity followed hand searching procedures. Bioactivity preclinical studies considered in vitro or in vivo biological systems, treated with plant extracts or isolated compounds. The outcomes were compared with standard or no treatment control groups. Critical appraisal of individual trials considered completeness in the research fields. Our results showed that 81% of the selected papers presented high level of completeness, 69% revealed phytochemical parameters and 31% biological applications of plant extracts and isolated compounds. Polyisoprenylated benzophenones, terpenoids, sterols and phenolic compounds were identified. Antiviral, insecticidal and snake antivenom activities were reported. In conclusion, the phytochemical data reinforce the reported activities. Potential applications in personal care, nutritional supplementation and pharmaceutical, food, chemical or textile industries were also identified. Toxicological and phytochemical complementary studies may be required.

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.

The Bioflavonoids Rutin and Rutin Succinate Neutralize the Toxins of B. jararaca Venom and Inhibit its Lethality

The venom of the Brazilian pit viper Bothrops jararaca (BjV) is a complex mixture of molecules, and snake venom metalloproteinases (SVMP) and serine proteinases (SVSP) are the most abundant protein families found therein. Toxins present in BjV trigger most of the deleterious disturbances in hemostasis observed in snakebites, i.e., thrombocytopenia, hypofibrinogenemia and bleedings. The treatment of patients bitten by snakes still poses challenges and the bioflavonoid rutin has already been shown to improve hemostasis in an experimental model of snakebite envenomation. However, rutin is poorly soluble in water; in this study, it was succinylated to generate its water-soluble form, rutin succinate (RS), which was analyzed comparatively regarding the chemical structure and characteristic features of rutin. Biological activities of rutin and RS were compared on hemostatic parameters, and against toxic activities of crude BjV in vitro. In vivo, C57BL/6 mice were injected i.p. with either BjV alone or pre-incubated with rutin, RS or 1,10-phenanthroline (o-phe, an SVMP inhibitor), and the survival rates and hemostatic parameters were analyzed 48 h after envenomation. RS showed the characteristic activities described for rutin - i.e., antioxidant and inhibitor of protein disulfide isomerase - but also prolonged the clotting time of fibrinogen and plasma in vitro. Differently from rutin, RS inhibited typical proteolytic activities of SVMP, as well as the coagulant activity of BjV. Importantly, both rutin and RS completely abrogated the lethal activity of BjV, in the same degree as o-phe. BjV induced hemorrhages, falls in RBC counts, thrombocytopenia and hypofibrinogenemia in mice. Rutin and RS also improved the recovery of platelet counts and fibrinogen levels, and the development of hemorrhages was totally blocked in mice injected with BjV incubated with RS. In conclusion, RS has anticoagulant properties and is a novel SVMP inhibitor. Rutin and RS showed different mechanisms of action on hemostasis. Only RS inhibited directly BjV biological activities, even though both flavonoids neutralized B. jararaca toxicity in vivo. Our results showed clearly that rutin and RS show a great potential to be used as therapeutic compounds for snakebite envenomation.