Safety of Prunus africana and Warburgia ugandensis in asthma treatment

AbstractThe aim of the study was to determine the possible cytotoxicity of the aqueous stem bark extracts of Prunus africana and Warburgia ugandensis to Vero E6 cells and acute toxicity in BALB/c mice. Despite being some of the most popular medicinal plants used in Africa, little is known about the safety. In-vitro cytotoxicity tests on Vero E6 cells were investigated using MTT assay to assess the safety of the two plant extracts. Vero E6 cells on growing to confluence were incubated with different drug concentrations for 48h for the drug to take effect. Viability of the cells was measured by a scanning multiwell spectrophotometer, color intensity being equivalent to viable cells which reduce MTT to soluble formazan crystals. This was done by determining the CC50 of the extracts, CC50 being the concentration of the dose of the compound/extract that kills 50% of the cells. In acute toxicity a total of 55 mice were used. Mice were divided into eleven groups of 5 mice, one group served as negative control and ten groups received oral gavage doses at 500, 889.56, 1581.6, 2812.15 or 5000mg/kg body weight once. Mortality and other signs of toxicity were recorded within 24h and the weights of the surviving mice taken for 14days thereafter. P. africana had CC50 of 104.08μg/ml while W. ugandensis had CC50>250μg/ml and both were classified as not cytotoxic. There was no mortality observed in groups of mice that received P. africana extracts at 500 and 889.56mg/kg body weight. There was 20%, 60% and 100% mortality observed within 24h 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 in all dose levels and the LD50 was >5000mg/kg body weight. The weights of mice that survived the entire 14days in all groups increased and were not significantly different from that of controls p>0.05. From the in vitro and in vivo studies, the two extracts were safe to use. Though with their customary value among many Kenyan communities in management of asthma among other ailments there is a need for further validation of any anti-asthmatic properties and responsible chemical compounds to augment the findings