Snakebites and ethnobotany in the northwest region of Colombia Part II: Neutralization of lethal and enzymatic effects of Bothrops atrox venom

Twelve of 74 ethanolic extracts of plants used by traditional healers for s nakebites in the northwest region of Colombia, were active against lethal e ffect of Bothrops atrox venom when they were i.p. injected into mice (18-20 g). After preincubation of sublethal doses of every extract (0.5-3.0 mg/mo use) with 1.5 i.p. lethal dose 50% (LD50) (99.3 mu g) of venom, seven of th em demonstrated 100% neutralizing capacity within 48 h. These were the stem barks of Brownea rosademonte (Caesalpiniaceae) and Tabebuia rosea (Bignoni aceae); rhizomes of Renealmia alpinia (Zingiber-aceae) and Heliconia curtis partha (Heliconiaceae); the whole plants of Pleopeltis percussa (Polypodiac eae) and Trichomanes elegans (Hymenophyllaceae): and the ripe fruits of Cit rus limon (Rutaceae). The other five extracts showing pal tial neutralizati on (45-80%; 10-30% survival rate in the control group receiving the venom a lone; P < 0.05) were: leaves, branches and stem of Costus Iasius (Costaceae ); the whole plant of Sida acuta (Malvaceae); rhizomes of Dracontium croati i (Araceae); leaves and branches of Bixa orellana (Bixaceae) and Struthanth us orbicularis (Loranthaccae). When the extracts were independently adminis tered per oral or i.p. route 60 min before an i.m. venom injection (204 mu g = 1.5 i.m. LD50), C. limon, T. elegans, B. orellana and T. rosea extracts had partial and significant. neutralizing capacity against B. atrox venom lethal effect. C. limon extract was also partially effective when it was ad ministered either i.v. 15 min before or i.p. 5 min after an i.m. venom inje ction. Three of the 12 extracts with anti-lethal effect (C. limon, D. croat ii and S. acuta) were devoid of antiphospholipase A(2) activity, when they were rested against one minimum indirect hemolytic dose of B. anos venom (2 mu g) in agarose-erythrocyte-egg yolk gels. (C) 2000 Elsevier Science Irel and Ltd. All rights reserved.