Role of hyaluronidase inhibitors in the neutralization of toxicity of Egyptian horned viper Cerastes cerastes venom

Hyperglycosylation impairs the inhibitory activity of rCdtPLI2, the first recombinant beta-phospholipase A2 inhibitor

Crotoxin, a phospholipase A2 (PLA2) complex and the major Crotalus venom component, is responsible for the main symptoms described in crotalic snakebite envenomings and a key target for PLA2 inhibitors (PLIs). PLIs comprise the alpha, beta and gamma families, and, due to a lack of reports on beta-PLIs, this study aimed to heterologously express CdtPLI2 from Crotalus durissus terrificus venom gland to improve the knowledge of the neglected beta-PLI family. Thereby, recombinant CdtPLI2 (rCdtPLI2) was produced in the eukaryotic Pichia pastoris system to keep some native post-translational modifications. rCdtPLI2 (~41 kDa) presents both N- and O-linked glycans. Alpha-mannosidase digested-rCdtPLI2 (1 mol) strongly inhibited (73%) CB-Cdc catalytic activity (5 moles), demonstrating that glycosylations performed by P. pastoris affect rCdtPLI2 action. Digested-rCdtPLI2 also inhibited PLA2s from diverse Brazilian snake venoms. Furthermore, rCdtPLI2 (1 mol) abolished the catalytic activity of Lmr-PLA2 (5 moles) and reduced the CTx-Cdc (5 moles) enzyme activity by 65%, suppressing basic and acidic snake venom PLA2s. Additionally, crotalic antivenom did not recognize rCdtPLI2, suggesting a lack of neutralization by antivenom antibodies. These findings demonstrate that studying snake venom components may reveal interesting novel molecules to be studied in the snakebite treatment and help to understand these underexplored inhibitors.

Phenolic Profile, Antioxidant, Anti-Enzymatic and Cytotoxic Activity of the Fruits and Roots of Eleutherococcus senticosus (Rupr. et Maxim.) Maxim

Eleutherococcus senticosus (Rupr. et Maxim.) Maxim. is well-known for its adaptogenic properties in traditional Eastern medicine. It has been categorized as an endangered species due to the over-exploitation of the roots. As a result, alternatives must be found, including the usage of renewable aerial parts such as fruits. The goal of this research was to determine the phenolic compounds and the enzymatic, antioxidant, and cytotoxic activities of the intractum gained from the E. senticosus fruits and the mixture of chloroform-methanol roots extract with naringenin (3:7:5). The obtained results showed, that the intractum contained 1.02 mg/g ext. of polyphenols, 0.30 mg/g ext. of flavonoids, and 0.19 mg/g ext. of phenolic acids. In turn, the mixture of chloroform-methanol roots extract with naringenin (3:7:5) contained 159.27 mg/g ext. of polyphenols, 137.47 mg/g ext. of flavonoids, and 79.99 mg/g ext. of phenolic acids. Regarding the anti-enzymatic assay, the IC50 values for tyrosinase and hyaluronidase were equal to 586.83 and 217.44 [μg/mL] for the intractum, and 162.56 and 44.80 [μg/mL] for the mixture, respectively. Both preparations have possessed significant antioxidant activity in the ABTS, DPPH, and ferrozine tests. No cytotoxic effect on the FaDu and HEP G2 cancer cell lines was observed. Our findings support the traditional use of fruits and roots. Moreover, the results indicate also that adaptogens are rather nontoxic for normal and cancer cells, which corresponds with some hypotheses on adaptogens activity.

Efficient identification of Acetylcholinesterase and Hyaluronidase inhibitors from Paeonia parnassica extracts through a HeteroCovariance Approach

ETHNOPHARMACOLOGICAL RELEVANCE

On the basis of the relevant reference in the poem Theriaca of the ancient Greek physician Nicander and its traditional use, Paeonia parnassica was selected for the evaluation of two extracts obtained from the roots and aerial parts to inhibit hydrolytic enzymes involved in snake envenomation. The secondary metabolites which contribute to these activities were detected through a novel HeteroCovariance NMR based approach. Afterwards these ingredients were isolated, identified and evaluated for their inhibitory potency.

AIM OF THE STUDY

The identification of acetylcholinesterase and hyaluronidase inhibitors from Paeonia parnassica extracts was used as a case study for the introduction of a recently developed methodology to evaluate ethnopharmacological data and exploit them for the discovery of bioactive natural compounds. This process is based on the fractionation of the selected extracts and the simultaneous phytochemical analysis and biological assessment of the resulting fractions, which permits the rapid detection of the specified secondary metabolites prior to any laborious and time-consuming purification.

MATERIALS AND METHODS

The roots and aerial parts of P. parnassica were extracted using methanol: water 50:50 and the two resulted extracts were fractionated by Centrifugal Partition Chromatography. The obtained fractions were evaluated in-vitro for their ability to inhibit acetylcholinesterase and hyaluronidase enzymes and their ¹H NMR spectra were recorded. The biological activity was statistically correlated with the spectral data through the HeteroCovariance Approach (HetCA). Finally the purification, identification and biological evaluation of targeted secondary metabolites were carried out.

RESULTS

The general chemical structures and some explicit secondary metabolites which contribute (e.g. gallotannins, gallic acid derivatives) or not (characteristic "cage-like" monoterpenes of the genus, glycosylated flavonoids) to the anti-acetylcholinesterase and anti-hyaluronidase activities were detected through HetCA. The consequent isolation and biological evaluation of targeted compounds were performed in order to validate the effectiveness and precision of the methodology. This procedure revealed the most active ingredients of both extracts obtained from roots and aerial parts against the above mentioned biological targets, as well as other compounds possessing moderate activity.

CONCLUSIONS

The results of this study contributed to the verification of the ancient text Theriaca regarding the use of Paeonia parnassica to treat the snake bite symptoms. Furthermore, the ingredients of the Paeonia parnassica extracts, which were responsible for their anti-cholinesterase and anti-hyaluronidase activities, were determined applying a HetCA methodology before their isolation. Therefore, the current work provides clear evidence that HetCA could consist an efficient tool for the exploitation of traditional medicine information in order to discover bioactive natural compounds and develop new pharmacotherapies which serve the needs of contemporary medicine.

Biochemical and molecular characterization of the hyaluronidase from Bothrops atrox Peruvian snake venom

Snake venoms are a rich source of enzymes such as metalloproteinases, serine proteinases phospholipases A2 and myotoxins, that have been well characterized structurally and functionally. However, hyaluronidases (E.C.3.2.1.35) have not been studied extensively. In this study, we describe the biochemical and molecular features of a hyaluronidase (Hyal-Ba) isolated from the venom of the Peruvian snake Bothrops atrox. Hyal-Ba was purified by a combination of ion-exchange and gel filtration chromatography. Purified Hyal-Ba is a 69-kDa (SDS-PAGE) monomeric glycoprotein with an N-terminal amino acid sequence sharing high identity with homologous snake venom hyaluronidases. Detected associated carbohydrates were hexoses (16.38%), hexosamines (2.7%) and sialic acid (0.69%). Hyal-Ba selectively hydrolyzed only hyaluronic acid (HA; specific activity = 437.5 U/mg) but it did not hydrolyze chondroitin sulfate or heparin. The optimal pH and temperature for maximum activity were 6.0 and 40 °C, respectively, and its Km was 0.31 μM. Its activity was inhibited by EDTA, iodoacetate, 2-mercaptoethanol, TLCK and dexamethasone. Na⁺ and K⁺ (0.2 M) positively affect hyaluronidase activity; while Mg²⁺, Br²⁺, Ba²⁺, Cu²⁺, Zn²⁺, and Cd²⁺ reduced catalytic activity. Hyal-Ba potentiates the hemorrhagic and hemolytic activity of whole venom, but decreased subplantar edema caused by an l-amino acid oxidase (LAAO). The Hyal-Ba cDNA sequence (2020 bp) encodes 449 amino acid residues, including the catalytic site residues (Glu135, Asp133, Tyr206, Tyr253 and Trp328) and three functional motifs for N-linked glycosylation, which are conserved with other snake hyaluronidases. Spatial modeling of Hyal-Ba displayed a TIM-Barrel (α/β) fold and an EGF-like domain in the C-terminal portion. The phylogenetic analysis of Hyal-Ba with other homologous Hyals showed the monophyly of viperids. Further, Hyal-Ba studies may extend our knowledge of B. atrox toxinology and provides insight to improve the neutralizing strategies of therapeutic antivenoms.

Rosemary leaves extract: Anti-snake action against Egyptian Cerastes cerastes venom

The morbidity caused by viper bites is very dangerous and the anti-venom therapy couldn't treat the local injures such as hemorrhage, edema, necrosis and inflammation of bitten tissues. Searching for safe and effective anti-venom compounds from natural sources is very important. This study was designed to explore the neutralizing ability of Rosmarinus officinalis L. leaves aqueous extract (RMAE) against Egyptian Cerastes cerastes (Cc) viper venom toxicity. The RMAE contained a considerable amount of phenolic and flavonoid contents with 3,300 and 800 mg/100 g dry weight, respectively. The RMAE showed a considerable variation of phenolic acids by using HPLC technique. Rosmarinic acid is the major component of the RMAE which recorded 400 mg/100 g dry weight and 64% of all the identified compounds. In vitro, the RMAE neutralized the enzymatic activities of proteases, l-amino acid oxidases, and phospholipases A2 of the Cc venom dose-dependently. In addition, the RMAE effectively neutralized the gelatinolytic, fibrinogenolytic, hemolytic and procoagulant activities of Cc venom. In vivo, the RMAE markedly reduced lethality, hemorrhage, edema, muscle and liver toxicities induced by Cc venom. In conclusion, the venom neutralizing property of the RMAE gives a new prospect for efficient treatment of the lethal viper bites.

LC-ESI-MS/MS profiling of phenolics in the leaves of Eleutherococcus senticosus cultivated in the West Europe and anti-hyaluronidase and anti-acetylcholinestarase activities

Neither secondary metabolites of the spring leaves nor the autumn leaves of Eleutherococcus senticosus species cultivated in Poland, or the bioactivity are known. The richest in polyphenols was the autumn leaves (171.1 mg/g DE), while in flavonoids the spring leaves (107.9 mg/g DE). Using LC-ESI-MS/MS, protocatechuic acid has been identified as the most abundant compound in the spring and autumn leaves (200 and 70 μg/g DE, respectively). Amongst flavonoids, naringenin 7-O-glucoside occurred in the largest amount (20 and 10 mg/g DE in the spring and autumn leaves, respectively). The autumn leaves inhibited Hyal the strongest (74.3%), comparing to the spring leaves (33%). A weak inhibition was found towards AChE (0.64 and 5.8% for the autumn and spring leaves, respectively). To our best knowledge, no information was available on the phytochemical composition and activity of the leaves of E. senticosus cultivated in Poland.

Viper venom hyaluronidase and its potential inhibitor analysis: a multipronged computational investigation

Viper venom hyaluronidase (VV-HYA) inhibitors have long been used as therapeutic agents for arresting the local and systemic effects caused during its envenomation. Henceforth, to understand its structural features and also to identify the best potential inhibitor against it the present computational study was undertaken. Structure-based homology modeling of VV-HYA followed by its docking and free energy-based ranking analysis of ligand, the MD simulations of the lead complex was also performed. The sequence analysis and homology modeling of VV-HYA revealed a distorted (β/α)₈ folding as in the case of hydrolases family of proteins. Molecular docking of the resultant 3D structure of VV-HYA with known inhibitors (compounds 1-25) revealed the importance of molecular recognition of hotspot residues (Tyr 75, Arg 288, and Trp 321) other than that of the active site residues. It also revealed that Trp 321 of VV-HYA is highly important for mediating π-π interactions with ligands. In addition, the molecular docking and comparative free energy binding analysis was investigated for the VV-HYA inhibitors (compounds 1-25). Both molecular docking and relative free energy binding analysis clearly confirmed the identification of sodium chromoglycate (compound 1) as the best potential inhibitor against VV-HYA. Molecular dynamics simulations additionally confirmed the stability of their binding interactions. Further, the information obtained from this work is believed to serve as an impetus for future rational designing of new novel VV-HYA inhibitors with improved activity and selectivity.

Honey shows potent inhibitory activity against the bovine testes hyaluronidase

The purpose of this study was to investigate the anti-hyaluronidase activities of honeys from different botanical origins honeys in order to determine their anti-inflammatory properties. The total phenolic contents, total flavonoids and total tannin levels of six types of honey, chestnut, oak, heather, pine, buckwheat and mixed blossom, were determined. Concentration-related inhibition values were tested turbidimetrically on bovine testis hyaluronidase (BTHase) as IC50 (mg/mL). All honeys exhibited various concentration-dependent degrees of inhibition against BTHase. Inhibition values varied significantly depending on honeys' levels of phenolic contents, flavonoid and tannin. The honeys with the highest anti-hyaluronidase activity were oak, chestnut and heather. In conclusion, polyphenol-rich honeys have high anti-hyaluronidase activity, and these honeys have high protective and complementary potential against hyaluronidase-induced anti-inflammatory failures.