Cultural importance of Neurolaena lobata (L.) Cass. from Nariño (Colombia) and neutralization of the biological activities of Bothrops asper venom by its ethanol extract

Abstract

Background: owing to the difficulties for accessing health centers and the limited availability of antivenoms in rural areas of Colombia, in many rural communities people rely on traditional medicine based on the use of plant extracts as a therapeutic resource for the snakebite envenoming. In the department of Nariño, the potential of these alexiteric plants is unknown. This work determined the cultural importance of Neurolaena lobata (L.) Cass., one of the plants most frequently used by the rural communities of Tumaco, municipality with high incidence of poisonings, and assessed the efficacy of an extract of this plant to inhibit toxic effects of the venom of the snake Bothrops asper.

Methods: semi-structured interviews were conducted with 14 randomly sampled individuals and the Cultural Importance index (CI) of the plant was calculated. Phytochemical tests were carried out and a battery of biological assays was applied to determine the neutralizing capacity of the extract on the lethal, coagulant, hemorrhagic, and myotoxic activities of the venom.

Results: the CI of this plant (0.0544) reflects its ethnobotanical value for the rural communities of Tumaco. The ethanolic extract from the leaves contains tannins, flavonoids, alkaloids, saponins, and sesquiterpene lactones. Neutralization assays revealed that the extract inhibited the coagulant activity of B. asper venom, but failed to inhibit the myotoxic, and lethal activities, and only partially reduced the hemorrhagic effect. Moreover, the extract showed toxicity when assessed for lethality and myotoxicity.

Conclusions: despite the cultural importance of the plant, our experimental findings do not support the claim that the crude extract of N. lobata inhibits the toxicity of the venom of B. asper of Colombia.

Keywords: Bothrops asper, Neurolaena lobata, alexiteric plants.