An integrative description of Euscorpius diagorasi sp. n. from Rhodes, Greece (Scorpiones: Euscorpiidae)

Posted by
  An integrative description of Euscorpius diagorasi sp. n. from Rhodes, Greece (Scorpiones: Euscorpiidae) Abstract The genus  Euscorpius  Thorell, 1876 comprises a diverse and taxonomically challenging group of scorpions in the Mediterranean, with Greece representing one of its principal centers of diversity. In this study, we provide an integrative description of  Euscorpius diagorasi   sp. n. , a new species from Rhodes Island, Greece. The new species is described on the basis of adult male and female morphology and mitochondrial COI sequence data. It is a small oligotrichous species characterized by a total length of approximately 21–25 mm, pale yellow to light brown coloration with darker reddish-brown pedipalps, pectinal tooth count of 8 in the male and 7 in the females, Pv = 7–8, Pe-et = 5–6, and a distinct mitochondrial lineage. Phylogenetic analyses based on COI recovered the Rhodian specimens as a strongly supported monophyletic lineage, sister to...

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

Posted by

 

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