Abstract:
Adhatoda schimperiana is a plant believed to have several therapeutic effects including anti-asthmatic properties. The objective of this study was to investigate the bronchodialatory, anti-inflammatory effects and toxicity of the hydromethanolic extract of leaves of this plant. METHODS: The isolated guinea-pig trachea pre-contracted with histamine and acetylcholine was used to study the relaxation of hydromethanolic extract of leaves Adhatoda shimperiana. Salbutamol and atropine were used as standards. The effect of the hydromethanol extract of leaves of Adhatoda schimperiana on carageenin-induced acute inflammation was evaluated by the rat hind paw edema method. Oral and interaperitoneal acute toxicity studies of the extract were performed on mice. RESULTS: The hydromethanolic extract of Adhatoda schimperiana inhibited contractions of guinea pig tracheal chains induced by acetylcholine and histamine with an EC50 of 4.66 mg/ml and 5.92 mg/ml, respectively. Salbutamol and atropine also showed similar concentration dependent relaxation of the tracheal chains pre-contracted with both acetylcholine and histamine. The inhibitory activity of atropine was lower than the extract and salbutamol. The extract exhibited a moderate degree of antiinflammatory activity. The LD50 of the extract for oral acute toxicity study was found to be 1286.76 mg/kg with 95 % confidence limit of 1161.9 – 1418.0. The plant extract therefore presents a relatively low acute toxicity. CONCLUSION: The results of this study show anti-inflammatory activity and a relatively potent relaxant (bronchodialatory) effect of Adhatoda schimperiana on the tracheal chain of the guinea pig. These activities justify the traditional use of this plant in the treatment of bronchoconstrictive diseases. More detailed studies are required to investigate the mechanism of action, the toxicity and the therapeutic utility of Adhatoda schimperiana for further development towards a proper drug.
