Anti-asthmatic activity of hydro alcoholic extract of Indigofera tinctoria L. leaves in guinea pig

This work aimed to evaluate the anti-asthmatic activity of the hydro alcoholic extract of Indigofera tinctoria L. leaves in guinea pig. It was administered orally at doses 75, 150 and 300 mg/kg. The animals were exposed to histamine 0.5 % aerosol and latent period of dyspnoea onset of animal was recorded. Its mechanism of action was investigated in vitro using isolated trachea. Results of these tests indicate that the extract increases the latent period of dyspnoea onset from 38±1.4 sec in control group to 47.5 ± 2.04, 77.5 ± 2.20 and 138 ± 3.14 sec in animals treated with the extract at doses 75, 150 and 300 mg/kg respectively (p<0.05). It completely relaxes the isolated trachea contracted with histamine at 10-5 M with EC50 equal to 0.036 mg/ml. Pre incubating the organ in bath containing the extract at 0.04, 0.05 and 0.06 mg/ml increases histamine EC50 from 4.6 10-8 M to 6.12 10-7, 6.8 10-6 and 10.21 10-5 M and reduces its maximal effect from 100 % to 90, 82 and 52 % respectively. These results indicate that the extract possesses bronchodilation activity which justifies the traditional use of Indigofera tinctoria as anti-asthmatic.