Anti-venom potential of Pakistani medicinal plants: inhibition of anticoagulation activity of Naja naja karachiensis toxin

Phospholipase A (PLA) is ubiquitous in nature and the most noxious component of Naja naja karachiensis venom. The present work was designed to study the role of PLA as anticoagulant in an egg yolk assay and to assess the potential of the extracts of 29 medicinal plants of Pakistan to counter this action. Coagulation assays with venom were performed in vitro with hen's egg yolk mixture. Subsequently this effect was endeavoured to neutralize with plants extract and compared with standard antisera. Venom at concentration of 5 μg clotted within 125 sec compared to venom-free egg yolk (control) mixture which clotted in 100 sec. Citrullus colocynthis, Rubia cordifolia and Stenolobium stans (11% extracts) were found to stop anticoagulant action as recorded with reference standard antidote. On the other hand, Albizia lebbeck, Brassica nigra, Matthiloa incana, Nerium indicum and Rhazya stricta (17% extracts) were declared completely abortive. Moreover, Allium cepa, Allium sativum, Althaea officinalis, Bauhinia variegate, Calotropis procera (flowers), Calotropis procera (exudates), Cedrus deodara, Citrus limon, Cuminum cyminum, Enicostemma hyssopifolium, Fogonia cretica, Leucas capitata, Momordica charantia, Ocimum sanctum, Pinus roxburghii, Pistacia integerrima, Psoralea corylifolia, Sapindus mukorossi, Terminalia arjuna, Trichodesma indicum and Zingiber officinalis (72% extracts) showed restoration against anticoagulation behaviour, i.e. anticoagulation decreased from 92% to 20%. However, further research is inevitable for isolation and structure elucidation of bioactive constituent(s) from active plants extract.