The effects of Tamarindus indica seed extract as anti-snake venom against Dabola russeli, Naja kaouthia and Ophiophagus hannah in mice

Abstract

Globally, snakebite cases are estimated to be around 5 million annually affecting mainly the residents of poorer counties like Africa and Asia, and in 2009 WHO has categorised it as a ‘neglected tropical disease’. Currently the standard treatment for snake envenomation is the use of anti-snake venom (ASV) therapy. However this is expensive and not readily available in smaller hospitals in the developing world. Herbal medicine has been and is still in use in some cultures for the treatment of snakebite and one such plant is Tamarindus indica. This plant is found in many countries where snake envenomation is also prevalent. This study was conducted to evaluate the potential of using T. indica seed extract (TSE) to inhibit the effects of snake venom of three snakes; namely Naja kaouthia, Ophiophagus hannah and Daboia russelli. The testa of tamarind seed was used and it underwent ethanolic soxhlet extraction to obtain TSE. The inhibition of the activity of the following enzymes i.e phospholipase A2 (PLA2), proteinase and phosphomonoesterase (PME) in vitro by the three snake venoms with TSE was studied. SDS-PAGE experiment was conducted to observe the effects of TSE on venom proteins. In vivo acute subcutaneous (SC) toxicity of TSE in ICR mice was conducted. Study on the inhibition of lethality was conducted on each of the three snake venoms when SC TSE was injected into mice. Venom concentration and site were fixed but TSE concentration, time and site of injection were manipulated. Findings from venom enzymatic inhibition studies showed that, TSE was able to significantly reduce (p<0.05) all three venom enzymatic activities i.e PLA2, proteinase and PME. SDS-PAGE experiment showed that venom protein bands were disrupted when venom reacted with TSE. No signs of toxicity were observed over a period of 4 weeks when mice were exposed to SC TSE 60 mg/20 g body weight except for skin ulcers. Histological examination on liver, both kidneys and skin at the site of SC injection showed no changes compared to the control group injected with SC distilled water. TSE was able to increase the survival rate of ICR mice when exposed to each of the three snake venoms regardless of the site of injecting SC TSE. Mice injected with N. kaouthia or D. russelli venom, had increased 24 hour survival rate when SC TSE was given at 15 minutes; and of mice injected with O. hannah venom the 24 hour survival rate increased with higher TSE concentration when given sooner. In conclusion, SC TSE was safe to be injected up to 60mg/20 g and has the potential to delay the effects of venom from N. kaouthia, O. hannah and D. russelli.