Snake venom induced local toxicities: plant secondary metabolites as an auxiliary therapy

Snakebite is a serious medical and socio-economic problem affecting the rural and agricultural laborers of tropical and sub-tropical region across the world leading to high morbidity and mortality. In most of the snakebite incidences, victims usually end up with permanent tissue damage and sequelae with high socioeconomic and psychological impacts. Although, mortality has been reduced markedly due to anti-venom regimen, it is associated with several limitations. Snake venom metalloprotease, hyaluronidase and myotoxic phospholipase A2 are the kingpins of tissue necrosis and extracellular matrix degradation. Thus, inhibition of these enzymes is considered to be the rate limiting step in the management of snakebite. Unfortunately, tissue necrosis and extracellular matrix degradation persists even after the administration of anti-venom. At present, inhibitors from snake serum and plasma, several synthetic compounds and their analogs have been demonstrated to possess anti-snake venom activities, but the use of plant metabolites for this purpose has an added advantage of traditional knowledge and will make the treatment cheaper and more accessible to the affected population. Therefore, the clinical and research forums are highly oriented towards plant metabolites and interestingly, certain phytochemicals are implicated as the antibody elicitors against venom toxicity that can be exploited in designing effective anti-venoms. Based on these facts, we have made an effort to enlist plant based secondary metabolites with antiophidian abilities and their mechanism of action against locally acting enzymes/toxins in particular. The review also describes their functional groups responsible for therapeutic beneficial and certainly oblige in designing potent inhibitors against venom toxins.