Pharmacological Evaluation of Analgesic and Antivenom Potential from the Leaves of Folk Medicinal Plant Lobelia nicotianaefolia

Lobelia nicotianaefolia is a medicinal plant found in the Western ghat region of Karnataka (India), with a common name [Heddumbe]. The leaves are used in traditional health care system to treat various ailments including pain and snake bites but despite this there are no proper reports supporting it.  In the present study to understand its medicinal benefits, the leaf extracts were assessed for phytochemical contents and various pharmaceutical properties. The chloroform, ethanol and aqueous fractions of leaves were screened for phytochemicals and tested for acute toxicity by determining LD 50 values in mice. Antimicrobial potency was assessed using pathogenic bacterial and fungal species. The central and peripheral analgesic activity was evaluated by hot plate and acetic acid induced writhing method respectively. Venom neutralizing ability was performed in Swiss albino mice against Russell’s viper whole venom and its PLA2 fractions. The results inferred that LD 50 values for chloroform and ethanolic leaf fractions are 0.5 g/kg and 1 g/kg respectively, whereas aqueous extract was not toxic even at 4 g/kg in mice. Among the three extracts, ethanol fraction have showed a significant anti-microbial, analgesic and anti-venom properties whereas the activity was moderate in chloroform fraction and less in aqueous fraction. Taken together this study validates the strong pharmacological properties of Lobelia nicotianaefolia, which was traditionally used to treat pain and snake bite.