Snake Venoms in Drug Discovery: Valuable Therapeutic Tools for Life Saving

Abstract

Animal venoms are used as defense mechanisms or to immobilize and digest prey. In fact, venoms are complex mixtures of enzymatic and non-enzymatic components with specific pathophysiological functions. Peptide toxins isolated from animal venoms target mainly ion channels, membrane receptors and components of the hemostatic system with high selectivity and affinity. The present review shows an up-to-date survey on the pharmacology of snake-venom bioactive components and evaluates their therapeutic perspectives against a wide range of pathophysiological conditions. Snake venoms have also been used as medical tools for thousands of years especially in tradition Chinese medicine. Consequently, snake venoms can be considered as mini-drug libraries in which each drug is pharmacologically active. However, less than 0.01% of these toxins have been identified and characterized. For instance, Captopril^® (Enalapril), Integrilin^® (Eptifibatide) and Aggrastat^® (Tirofiban) are drugs based on snake venoms, which have been approved by the FDA. In addition to these approved drugs, many other snake venom components are now involved in preclinical or clinical trials for a variety of therapeutic applications. These examples show that snake venoms can be a valuable source of new principle components in drug discovery.

Keywords: Snake venoms; drug discovery; pharmacology; therapeutic applications; toxins.

Figure 1

A schematic representation of snake venoms, aiming to assess the significance of snake venoms as a resource of novel drugs. Snake Venom Metalloproteinase (SVMP), Phospholipase A2 (PLA2), Cysteine-rich secretory protein (CRISP), Vascular Endothelial Growth Factor (VEGF), C-type lectin-like toxin (CTL), Serine proteinase (SVSP), L-amino acid oxidase (LAAO), Bradykinin Potentiating Peptide (BPP).

Figure 2

Phylogeny of snake species.

Figure 3

Snake venom composition.

Figure 4

Amino acid sequences of snake venom non-enzymatic proteins and peptides. Sequence alignment of two proteins for each non-enzymatic family [82,86,87,88,89,90,91,92,93,94,95,96]. All cysteine residues are shaded in grey. The peptide lengths and percentages of sequence identities are given on the right.