One more new species of Chaerilobuthus Lourenço & beigel, 2011 (Scorpiones: Chaerilobuthidae) from Early Cretaceous Burmite

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  One more new species of Chaerilobuthus Lourenço & beigel, 2011 (Scorpiones: Chaerilobuthidae) from Early Cretaceous Burmite Abstract . – The genus Chaerilobuthus is probably the most speciose group among those found in Burmite. In some recent publications most aspects concerning the family Chaerilobuthidae Lourenço & Beigel, 2011 and the genera composing it were precisely discussed; consequently, no further comments will be provided in this contribution. Only one more new species belonging to the genus Chaerilobuthus is described. Chaerilobuthus franzschmidti Lourenço sp . n ., represents the 16th species to be described for this genus confirming therefore the strong speciose characteristic of the group. The new species shows some marked morphological differences when compared to the previous known species, attesting the existence of a major variability within Chaerilobuthus . Lourenço W. R. & Velten J., 2026. – Une nouvelle espèce pour le genre Chaerilobuthus Lou...

In vitro inhibition of snake venom toxins by varespladib, marimastat, nafamostat and dimercaprol

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By Holger Krisp - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=17574465

In vitro inhibition of snake venom toxins by varespladib, marimastat, nafamostat and dimercaprol

Abstract

Snakebite envenoming causes more than 130,000 deaths and more than 400,000 disabilities per year and has been classified as a priority Neglected Tropical Disease by the World Health Organization (WHO). While antivenom therapy remains the mainstay of snakebite treatment, small molecule therapeutics (SMTs) have been proposed as potential adjuncts to antivenom, particularly as oral treatment in the prehospital setting. Several SMTs have demonstrated efficacy in preclinical models of snakebite envenoming, with varespladib, a secreted phospholipase A2 (sPLA2) inhibitor, being granted orphan drug status for its potential to treat snakebite. The present study investigated the potential of four SMTs (e.g., varespladib, marimastat, nafamostat and dimercaprol) to neutralise toxic components present in the venom of southern African snake species. In vitro experimentation found that varespladib potently inhibited snake venom phospholipase A2 (svPLA2) activity in Bitis arietans (IC50 = 0.221 μM) and B. gabonica (IC50 = 0.276 μM). Marimastat exhibited potent inhibition of snake venom metalloproteinase (svMP) in several snake species with IC50 values ranging from 0.0042–3.06 μM, while dimercaprol, a metal chelator, was a lower potency svMP inhibitor with IC50 values ranging from 5.01–79.8 μM. Nafamostat proved to be an inhibitor of snake venom serine protease (svSP) in B. arietans (IC50 = 3.72 μM), B. gabonica (IC50 = 3.80 μM) and Causus rhombeatus (IC50 = 0.261 μM). These data demonstrate that SMTs are effective inhibitors of the relevant enzymes in several snake species and support the proposal that SMTs could be developed for therapeutic intervention in snakebite envenoming.
Le Roux, A., Cloete, S. J., Petzer, J. P., & Petzer, A. (2025). In vitro inhibition of snake venom toxins by varespladib, marimastat, nafamostat and dimercaprol. Toxicon, 108626. https://doi.org/10.1016/j.toxicon.2025.108626