Herbal antidote to snake venom
doi:10.1038/nindia.2015.141 Published online 26 October 2015
Researchers have isolated some triterpenoid compounds from the bark of a medicinal plant, which could inhibit tissue damage and bleeding induced by the venom of the saw-scaled viper1. These compounds are promising for developing new antivenoms.
Poisonous snakes such as the saw-scaled viper (Echis carinatus) can inject lethal doses of toxic enzymes when they bite. These enzymes destroy tissues, rupture blood vessels and induce stress on immune cells. Previous studies had shown that existing antivenoms fail to fully protect against long-term tissue damage at bite sites, which can necessitate limb amputation.
To find an effective therapy against viper venom, the researchers isolated lupeol, a triterpene, from the bark of the medicinal plant Crataeva nurvala and used it to prepare eight derivatives, including lupeol acetate and alkylated compounds. They then tested the efficacies of lupeol and these derivatives to inhibit venom-induced tissue damage and bleeding in mice.
The scientists discovered that three of the alkylated compounds significantly reduced venom-induced bleeding, whereas the other derivatives failed to inhibit bleeding. They found that the three alkylated compounds protected mouse tissue by inhibiting the activities of snake venom enzymes that damage skin and rupture blood vessels.
The alkylated compounds also protected specific mice immune cells and their cell-surface receptors against massive oxidative stresses produced by the venom, allowing tissue repair and wound healing to occur.
1. Katkar, G. D. et al. Lupeol derivative mitigates Echis carinatus venom-induced tissue destruction by neutralizing venom toxins and protecting collagen and angiogenic receptors on inflammatory cells. Biochim. Biophys. Acta Gen. Sub. 1850, 2393–2409 (2015)