Antiprotozoal Effect of Snake Venoms and Their Fractions: A Systematic Review

Abstract

Background: Protozoal infection is a lingering public health issue of great concern, despite efforts to produce drugs and vaccines against it. Recent breakthrough research has discovered alternative antiprotozoal agents encompassing the use of snake venoms and their components to cure these infections. This study collated the existing literature to examine the antiprotozoal effect of snake venoms and their fractions. Methods: We conducted a systematic review following the PRISMA guidelines. The PubMed and Embase databases were searched from their inception until 13 October 2021. Articles were screened at the title, abstract and full-text phases. Some additional studies were obtained through the manual search process. Results: We identified 331 studies via the electronic database and manual searches, of which 55 reporting the antiprotozoal effect of snake venoms and their components were included in the review. Around 38% of studies examined the effect of whole crude venoms, and a similar percentage evaluated the effect of a proportion of enzymatic phospholipase A2 (PLA2). In particular, this review reports around 36 PLA2 activities and 29 snake crude venom activities. We also report the notable phenomenon of synergism with PLA2 isoforms of Bothrops asper. Importantly, limited attention has been given so far to the antiprotozoal efficacies of metalloproteinase, serine protease and three-finger toxins, although these venom components have been identified as significant components of the dominant venom families. Conclusion: This study highlights the impact of snake venoms and their fractions on controlling protozoal infections and suggests the need to examine further the effectiveness of other venom components, such as metalloproteinase, serine protease and three-finger toxins. Future research questions in this field must be redirected toward synergism in snake venom components, based on pharmacological usage and in the context of toxicology. Ascertaining the effects of snake venoms and their components on other protozoal species that have not yet been studied is imperative.

Bactericidal Effects of Snake Venom Phospholipases A2: A Systematic Review and Analysis of Minimum Inhibitory Concentration

“…Overall, our systematic search identified 24 articles on the bactericidal effect of svPLA 2 s. The majority of the studies (80%) found through the search were on the PLA 2 s of snakes from the Viperidae family, whereas 20% were on the PLA 2 s from snakes of the Elapidae family. There are considerable variations in the composition of snake venoms recorded even from closely related species and within species [6]. Evidence of intra-genus or intra-specific variation in venom compositions has been documented in pit vipers and adders [36].…”

“…Snake venom PLA 2 s (svPLA 2 s) are enzymatic proteins with low molecular weights. They catalyze the hydrolysis of the 3-sn-phosphoglyceride-dependent calcium 2-acyl ester bond, yielding lysophospholipids and fatty acid products [6]. Snake venom PLA 2 s have similar toxicological profiles, including cytotoxicity, myotoxicity, oedema, inflammation, neurotoxicity, hypotension, anticoagulant activity, hemolysis, hyperalgesia, and microbicidal activity [5].…”

“…Studies on crude snake venoms and/or their fractions often result in potential therapeutic molecules against bacteria and other parasites [6]. Snake venoms are composed of a spectrum of protein-based constituents.…”

“…Snake venoms are composed of a spectrum of protein-based constituents. These components could be categorized into four broad groups [6], namely: (1) The dominant group, which consists of the three-finger toxins (3FTx), phospholipases A2 (PLA 2 ), snake venom metalloproteases (SVMP), and snake venom serine proteases (SVSP), (2) The second group consists of a small number of proteins, which includes Kunitz peptides (KUN), cysteine-rich secretory proteins (CRiSP), L-amino acid oxidases (LAAO), C-type lectins (CTL), disintegrins (DIS), and natriuretic peptides (NP), (3) The third group contains the rarely observed snake venom proteins, including venom nerve growth factor (VNGF), vascular endothelial growth factor (VEGF), acetylcholinesterases, hyaluronidases, 5 -nucleotidases, phosphodiesterases (PDE), and snake venom metalloprotease inhibitors, and (4) finally, the fourth group includes cobra venom factors (CVF), galactose-binding proteins, aminopeptidases, and waprins.…”

The Potassium Channel Blocker β-Bungarotoxin from the Krait Bungarus multicinctus Venom Manifests Antiprotozoal Activity

“…In addition, there are effects of snake venoms on microorganisms. Thus, the venoms can exhibit antiviral (reviewed in [ 6 ]), antibacterial (reviewed in [ 7 ]), and antiprotozoal activities (reviewed in [ 3 , 8 ]). By the present time, snake venom peptides and proteins with such activities have been identified.…”