Abstract

Phytochemical screening of the crude stem bark extracts of Mangifera indicarevealed the presence of alkaloids, phenols, tannins, saponins and cardiac glycosides. The antibacterial activity of the crude extracts were assayed using the agar well diffusion methods on clinical bacterial isolates of Escherichia coli,Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumonia andStreptococcus pneumonia obtained from patients previously diagnosed with respiratory tract infections. At a concentration of 50 mg/ml, the crude extracts inhibited the growth of all the respiratory tract pathogens, though with varying degrees of susceptibility depending on the bacterium and the extracting solvent. The MIC values ranged from 12.5 - 200 mg/ml, while the MBC values ranged from 50 - 400 mg/ml and this is very important for people who depend on the plant for their health care needs. The presence of the bioactive compounds has been linked to the antimicrobial activity of the extracts. The activity of the crude drug was more under acidic conditions and at elevated temperatures. The results obtained in this study support the use of the plant in herbal medicine. The stem bark of the M. indica tree can be used as a source of broad spectrum oral antibiotic to fight respiratory tract pathogens.

Key words: Phytochemical screening, Mangifera indica, bioactive, herbal medicine, respiratory tract, pathogens.