An evidence based efficacy and safety assessment of the ethnobiologicals against poisonous and non-poisonous bites used by the tribals of three westernmost districts of West Bengal, India: Anti-phospholipase A2 and genotoxic effects.

Abstract

To explore the ethnobiological wisdom of the tribals of three western districts of West Bengal, India against poisonous and non-poisonous bites and stings, a quantitative approach was adopted. These age-old yet unexplored knowledge can be utilized in finding lead-molecules against poisonous and non-poisonous animal-bites. Further, an evidence-based approach is needed to assess the venom-neutralization ability of plants by experimental studies. During 2008-2009 and 2012-2017, 11 ethnomedicinal surveys were carried out to explore the use of medicinal flora and fauna via conducting open semi-structured interviews with 47 traditional healers (THs) or informants. The retrieved dataset was statistically evaluated using seven quantitative-indexes: use-value (UV), informants'-consensus-factor (ICF), fidelity-level (FL), relative-importance (RI), cultural importance-index (CI), index of agreement on remedies (IAR) and cultural agreement-index (CAI). Anti-phospholipaseA2 (PLA2) properties of selected plant extracts were also examined. In addition, the cytotoxicity and genotoxicity of the water extract of the plants showing high FL as well as significant PLA2 inhibitory potential were investigated using Allium cepa root tip assay. A total of 41 traditional-formulations (TFs) containing 40 plant species (of 39 genera from 28 families) and 3 animal species were prescribed by the THs. Fabaceae exhibited most number of medicinal plants. Piper nigrum (1.78) and Apis cerana indica and Crossopriza lyoni (both 0.21) exhibited the highest UV among the plants and the animals respectively. Stinging of centipede and dog/cat/hyena bite displayed highest ICF (1.00 each). Among the plants, the maximum RI (0.91) and CI (4.98) values were observed for Aristolochia indica. IAR (1.00) was recorded maximum for Achyranthes aspera, Gloriosa superba, Lycopodium cernuum, Smilax zeylanica and Streblus asper. Maximum CAI value was noted for Piper nigrum (5.5096). Among the animals, Apis cerana indica (0.31) and Crossopriza lyoni (1.52) displayed the highest RI and CI values respectively. Crossopriza lyoni (0.99) and Apis cerana indica (1.3871) exhibited maximum IAR and CAI values respectively. Plants showing higher FL exhibited higher anti-PLA2 activity via selective inhibition of human-group PLA2. In addition, Allium cepa root tip assay has indicated the safety and/or toxicity of the plant parts prescribed by the THs. Root water extracts of Aristolochia indica and Gloriosa superba exhibited significant genotoxicity and cytotoxicity. Three western districts of West Bengal is the natural abode for many tribal and non-tribal communities. A noteworthy correlation was established between the plants used against poisonous-bites and their anti-PLA2 activity. A few plant parts used by the THs also exhibited high toxicity. Such alternative medical practices serve as the only option in these underprivileged and backward areas during medical-exigencies.