Acute Toxicity and In-vivo Venom-Neutralizing Activity of the Aqueous Root Extract of E. divinorum against Bitis arietans Venom

Abstract

Background: Snakebite envenoming remains an important public health concern, particularly in rural settings where access to conventional antivenom may be limited. Medicinal plants such as Euclea divinorum are traditionally used for snakebite management, but their safety and venom-neutralising efficacy require controlled experimental evaluation. Aims: The study aims to assess the acute toxicity of Bitis arietans venom and the aqueous root extract of Euclea divinorum and to evaluate the extract's venom-neutralising activity in vivo in experimental mice. Study Design: A controlled laboratory animal study evaluating the acute toxicity (LD₅₀) and venom-neutralising efficacy (ED₅₀) of an aqueous root extract of E. divinorum against B. arietans venom. Place and Duration of Study: Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Nairobi, from January to May 2024. Methodology: To determine the median lethal dose (LD₅₀) of B. arietans venom, lyophilised venom was administered intraperitoneally to male mice weighing 18–30 g at doses of 2.74, 4.11, 6.16, 9.24, 13.86, and 20.79 mg/kg. Mortality was recorded over 24 hours, and probit analysis was used to determine the LD₅₀. To determine the LD₅₀ of E. divinorum, powdered root extract reconstituted in phosphate-buffered saline (PBS) was administered at doses of 10, 100, and 1000 mg/kg. Mortality was recorded over 24 hours, and the LD₅₀ was determined using Lorke’s method. The extract's neutralisation potential was evaluated by intraperitoneal administration of 2.5 × LD₅₀ venom combined with extract doses of 100, 200, and 300 mg/kg. The 24-hour mortality data were subjected to probit analysis to determine the median effective dose (ED₅₀). Results: The LD₅₀ values of B. arietans venom and the E. divinorum extract were 5.940 and 316 mg/kg, respectively. The ED₅₀ of the E. divinorum extract was 69.965 mg/kg. Conclusion: The aqueous root extract of E. divinorum demonstrated in vivo venom-neutralising activity against B. arietans venom in mice.