Biochemical and toxicological study of venom of Sri Lankan cobra

Abstract

Analysis of the Composition of Venom of Sri Lankan Cobra (Naja naja naja), and the study of the contribution of each component to the cumulative toxicity of Cobra Venom. Design, Setting and Methods: Interventional experimental study carried out in the Snake Venom Research Lab and Herpetarium of the Dept of Clinical Medicine, Animal House, Dept. of Biochemistry and Molecular Biology of the Faculty of Medicine, and the Dept of Zoology, Faculty of Science, University of Colombo. Several steps were used in the analysis. 1. Protein concentration of Cobra venom was determined. 2. Sodium Dodecyl Sulphate Poly-Acrylamide Gel Electrophoresis (SDS PAGE) was carried out to identify the basic protein content. 3. The venom was subjected to Gel Filtration on Superdex 75 HR 10/30-chromatography column coupled to an Ultra-Violet Absorption monitor to fractionate and identify the various proteins. The proteins of venom were subjected to toxicity studies to identify the contribution of individual components to the net toxicity exhibited in Cobra venom using in vitro and animal studies. Results: Venom bad a protein content of 36mg/ml. Initially from our toxicity studies of crude cobra venom it was found that the venom contains Phospholipase A2, necrotic and neuromuscular toxicities but had no protease or coagulant activities. SDS PAGE analysis showed the presence of five major components of venom. Out of the 6 purified fractions/proteins by Gel filtration, it was found that necrotic activity is present in various degrees in three fractions 4, 5, and 6 with the highest necrotic activity in fraction 6. Neuromuscular blocking action was detected in two fractions, 4th and 5th, the highest neuromuscular blocking action being in the fifth. Phospholipase A2 activity was present in 4th and 5th, highest being in the fifth. Fractions 1 to 6 had molecular weights 193 461, 99798,43777.19203,9973,2257 Dalton (D) respectively. Conclusion: The neuromuscular receptor blocking protein which has Phospholipase A2 activity and the protein that causes necrotizing activity have been identified for Sri-Lankan Cobra.