RESUMO
Aim: In-Vitro and In-Vivo safety and anti-asthmatic activity of stem bark extracts of Prunus africana and Warburgia ugandensis against induced asthma in BALB/c mice. Methodology: Cytotoxicity on Vero E6 cells were investigated using MTT assay. Acute toxicity was determined by administering single oral gavages of extracts to five groups of BALB/c at 500, 889.56, 1581.64, 2812.15 and 5000mg/kg body weight doses. Efficacy against induced asthma was determined by assaying heart blood serum for ovalbumin specific immunoglobulin E (IgE) antibodies and quantification of eosinophil proportion in Bronchoalveolar lavage fluid (BALF). Eight sensitized groups were used, 2 were controls, 3 were treated with P. africana extract and 3 with W. ugandensis; each treatment group received one dose concentration of 125, 250 or 500mg/kg body weight of either plant extracts. Results: P. africana CC50 was 104.08μg/ml while W. ugandensis had CC50 > 250 μg/ml. In acute toxicity, mortality and signs of toxicity were recorded within 24 hours and the mice monitored for 14 days. There was 20%, 60% and 100% mortality within 24 hours for mice that received P. africana extracts at 1581.64, 2812.15 and 5000mg/kg body weight respectively. Lethal dose (LD50) for P. africana was 2201.207mg/kg body weight. W. ugandensis extracts had no mortality recorded and the LD50 was >5000mg/kg body weight. Treatment with P. africana extracts at 500mg/kg body weight reduced the IgE and BALF Eosinophil to 0.100±0.0001 and 2.80±0.20 respectively which were significantly different from positive controls P<0.05. W. ugandensis extracts at the same concentration reduced the IgE and BALF eosinophils to 0.134±0.00016 and 3.80±0.20 respectively and were significantly different from positive controls P<0.05. Conclusion: The results attested that P. africana and W. ugandensis stem bark extracts have anti-asthmatic property though there is need for further validation of anti-asthmatic chemical compounds to augment the findings.