~ 6 ~ American Journal of Essential Oils and Natural Products 2020; 8(2): 06-11 ISSN: 2321-9114 AJEONP 2020; 8(2): 06-11 © 2020 AkiNik Publications Received: 03-01-2020 Accepted: 04-03-2020 Adebayo Gbolade Phytotherapy Research Group, Department of Pharmacognosy, College of Pharmacy, Igbinedion University Okada, Edo State, Nigeria. Oluwasegun Adedokun Phytotherapy Research Group, Department of Pharmacognosy, College of Pharmacy, Igbinedion University Okada, Edo State, Nigeria. Elizabeth Igbinomwanhia Phytotherapy Research Group, Department of Pharmacognosy, College of Pharmacy, Igbinedion University Okada, Edo State, Nigeria. Moshood Alli Phytotherapy Research Group, Department of Pharmacognosy, College of Pharmacy, Igbinedion University Okada, Edo State, Nigeria. Corresponding Author: Adebayo Gbolade Phytotherapy Research Group, Department of Pharmacognosy, College of Pharmacy, Igbinedion University Okada, Edo State, Nigeria. Lethality of Bryophyllum pinnatum (Lam.) Oken (Crassulaceae) Leaf Methanol Extract and Fractions against Naja nigricollis and Bitis arietans Venoms Adebayo Gbolade, Oluwasegun Adedokun, Elizabeth Igbinomwanhia and Moshood Alli Abstract Bryophyllum pinnatum (Lam.) Oken (Crassulaceae), a traditional anti-hypertensive, anti-inflammatory, anti-fever and anti-cancer remedy is also popular in Indian traditional herbal remedies for snake bite treatment. Studies evaluating the anti-venom activity of this plant are scarce. This study aims to evaluate the inhibitory effects of leaf methanol extract and solvent fractions of B. pinnatum against local effects induced by Bitis arietans and Naja nigricollis snake venoms. Inhibition of adenosine diphosphate- induced platelet aggregation, antioxidant, total phenol content and in vivo and in vitro effects on toxicity induced by the two venoms were evaluated. With Bitis arietans in vitro assay model, methanol extract, dichloromethane (DCM) and aqueous fractions gave concentration-dependent inhibition of platelet aggregation at 100 - 500 μg/ml which ranked as: methanol extract > aqueous fraction > DCM fraction at 500 μg/ml. The aqueous fraction with maximal inhibition of 31.5% appeared to be the most potent inhibitor of Naja nigricollis induced platelet aggregation. Concentration-dependent DPPH free radical scavenging activity which were comparatively less than the reference antioxidant, ascorbic acid was observed at tested concentrations of 20 - 100 μg/ml. There appears to be a correlation between the total phenolic contents of this plant and its radical scavenging activity with the polar aqueous fraction being the richest (31.3 mg gallic acid equivalent/g). Venom neutralization was remarkable in a dose-dependent manner at 24h and 48h (75% protection for DCM fraction, and 100% for aqueous fraction at 100 mg/kg) against Bitis arietans-LD99 envenomed mice. Order of antivenin potency is: DCM fraction > aqueous fraction = methanol extract on Naja nigricollis at 24h. Rats envenomed with LD50 of snake venoms displayed complete protection of Naja nigricollis-treated rats only with methanol extract and DCM fraction in 48h, and of Bitis arietans-envenomed animals with all tested doses of methanol extract at 24h and the aqueous fraction in 48h. In conclusion, the results indicate the potential antiophidic activity of B. pinnatum leaf particularly against local effects induced by Bitis arietans thereby justifying its folkloric usage. Keywords: Bryophyllum pinnatum, Naja nigricollis venom, Bitis arietans venom, platelet aggregation, antioxidant activity, phenolic content Introduction Snake bite is an occupational hazard in tropical and sub-tropical countries like Nigeria. The WHO reports that 174 snake bites per 100,000 population occur in Nigeria yearly and that the saw-scaled or carpet viper is responsible for 90% of bites [1] . Four families of venomous snakes found in Nigeria include Viperodae, Elapidae, Colubridae and Actraspididae, but three species, carpet viper (Echis ocellatus), black-necked spitting cobra (Naja nigricollis) and puff adder (Bitis arietans) belonging to the first two families are the most important snakes associated with envenoming in Nigeria [2, 3] . Snakebite envenomation is a worldwide problem, which is a major cause of mortality and morbidity in developing countries and still remains a neglected public health problem. In Nigeria, the Benue valley is predominant for most of these tragedies where prevalence of 497 per 100,000 persons per year and mortality rate of 12.2% are reported, with Echis ocellatus accounting for about 66% [2, 3] . Males and farmers were reported to be more vulnerable to snake bites especially in the rainy season in Gombe [4] and Benue communities [3] of Nigeria. Recently, studies of snake bites among hospitalized Nigerian children in Benin City in the South [5] and Sokoto in the North West [6] with low prevalence rates have been published. Taraba state in Nigeria has been reported to have one of the high annual incidence (40.4% bites per 100,000) in the country [7] .