Anti venom activity of medicinal plants from south America

Abstract

The use of plants to subdue or reverse the effects of snakebite has long been recognized. Plant extracts were widely used as therapy for snakebite by South American traditional healers, and especially in tropical regions where plant resources are diverse and plentiful. Several medicinal plants are also believed to have been used as a source ofsnakebite antidote. Reference to the use of plants as part of early indigenous ethnomedical practices appears in traditional drug recipesrecovered from chronicles of Spanish explorers and includesevidence that methods were passed on orally through generations. The most frequently encountered poisonous snake genera found in regions of South America include: Bothrops (jarara/ lanceheads), Crotalus(casabel/rattlesnakes), Lachesis(surucucú/bushmasters) and Micrurus (coral). Coralsnakes have very powerful venombut confrontation with thesesnakesisinfrequent because of their quiet and secretive character. A bibliographic revision helped usidentify more than one hundred seventy plants with anti-venom activity in South America. Most are identified using their common names, sometimes making it difficult to determinetheformal taxonomic name. Furthermore, the absence of availablereferences or other documentation to verify oreven designate a properscientific name continuesto pose a problem. There have been numerous attempts to study and characterize the anti-venom activity in native plants. We show that modern methods that provide unequivocal identification of active compounds together with in vitro and in vivo assays have enabled both evaluation and validation of ancestral knowledge. Among the pharmacologically active secondary metabolites isolated from plants, flavonoids are most frequently cited inhibiting phospholipases, lipoxygenases and metalloproteases.