INDIVIDUAL AND COMBINED ANTIMICROBIAL ACTIVITIES OF CRUDE EXTRACTS FROM HONEY, GARLIC AND GINGER AGAINST SELECTED HUMAN PATHOGENS

Abstract

Concerns about disease causing bacteria are now ever increasing. The common and immediate action to these disease causing microbes is the use of antibiotics. However, due to the challenges of drug-resistance in bacteria and the problems of affordability of the drugs, the search for new compounds from plant and animal sources that act against the pathogens has become crucial in many countries. The aim of this study was to investigate the possibility of using honey, garlic and ginger as source of antimicrobial sources to alleviate different ailments. Crude extracts of honey, garlic and ginger were obtained using distilled water, methanol (98%), and ethanol (97%) as extraction solvents. The antimicrobial activities of these crude extracts and their combinations were evaluated using disc diffusion method against Shigella boydii, Staphylococcus auerus, Salmonella Tyhimurium, Pseudomonas aeruginosa and Klebsiella pneumoniae. The MIC of crude extracts with the highest zone of inhibition was determined using the broth dilution method. The negative tubes from the MIC experiments were then sub-cultured into fresh MHA for MBC determination. The antimicrobial activities were performed at concentration of 10 mg/disc against the test pathogens. The results revealed that aqueous and alcoholic extracts of garlic had inhibitory activities against all tested pathogens except P. aeruginosa. Among the crude extracts, ethanolic crude extract of garlic showed the widest zone of inhibition (14 mm) against Salmonella Typhimurium despite the fact that it was resistant to the standard antibiotics used in this study. The MIC of the crude extracts was in the range of 3.90–15.625 mg/ml and the MBC was in the range of 15.625–62.5 mg/ml. In conclusion, the present study indicated that all extracts, except the aqueous extract of ginger showed varying inhibitory activities against the test pathogens at different concentrations and when using different extraction solvents. Further in vivo investigations and phytochemical screening are needed for the future implementation of these medicinal remedies.