In vitro antibacterial activity of methanol, ethanol, and ethyl acetate extracts of raw and processed honey was tested against Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis, Bacillus cereus, Enterococcus faecalis, and Micrococcus luteus) and Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhi). Both types of honey showed antibacterial activity against tested organisms with the zone of inhibition (ZOI) ranging from 6.94 to 37.94？mm, while E. coli, S. typhi, and P. aeruginosa showed that sensibility towards all the extracts with ZOI ranges between 13.09 to 37.94？mm. The methanol extract showed more potent activity than other organic extracts. Gram-negative bacteria were found to be more susceptible as compared to Gram-positive bacteria except E. faecalis. The broth microdilution assay gave minimum inhibitory concentrations (MIC) value of 625？μg/mL, while the minimum bactericidal concentration (MBC) ranges between 625？μg/mL 2500？μg/mL. The study showed that honey has antibacterial activity (bacteriostatic and bactericidal effect), similar to antibiotics, against test organisms and provides alternative therapy against certain bacteria. 1. Introduction Natural products and their derivatives (including antibiotics) represent more than 50% of all drugs in clinical use in the world. According to World Health Organization estimates, about 80 percent of people living in developing countries rely on harvested wild plants for some part of their primary health care . There are several reports on the antimicrobial activity of different herbal extracts in different regions of the world [2, 3]. Due to the side effects and the resistance that pathogenic microorganisms have developed against antibiotics, recently much attention has been paid to extracts and biologically active compounds isolated from natural species used in herbal medicine. The antibacterial activity of honey was first recognized in 1892, by Dustmann . Honey has been used as a medicine in many cultures for a long time. However, it has a limited use in medicine due to lack of scientific support . It has been rediscovered by the medical profession and it is gaining acceptance as an antibacterial treatment of topical infections resulting from burns and wounds . It is well established that honey inhibits a broad spectrum of bacterial species. More recently, honey has been reported to have an inhibitory effect to around 60 species of bacteria including aerobes and anaerobes, Gram positives, and Gram negatives . There are many reports of
M. Gulluce, M. Sokmen, D. Daferera et al., “In vitro antibacterial, antifungal, and antioxidant activities of the essential oil and methanol extracts of herbal parts and callus cultures of Satureja hortensis L,” Journal of Agricultural and Food Chemistry, vol. 51, no. 14, pp. 3958–3965, 2003.
N. Abuharfeil, R. Al-Oran, and M. Abo-Shehada, “The effect of bee honey on the proliferative activity of human B- and T-lymphocytes and the activity of phagocytes,” Food and Agricultural Immunology, vol. 11, no. 2, pp. 169–177, 1999.
A. Hannan, M. Barkaat, S. Saleem, M. Usman, and W. A. Gilani, Manuka honey and its antimicrobial potential against multi drug resistant strains of Typhoidal salmonellae, Ph.D. thesis, Department of Microbiology, University of Health Science, Lahore, Pakistan, 2004.
T. Patton, J. Barrett, J. Brennan, and N. Moran, “Use of a spectrophotometric bioassay for determination of microbial sensitivity to manuka honey,” Journal of Microbiological Methods, vol. 64, no. 1, pp. 84–95, 2006.
N. S. Al-Waili and K. Y. Saloom, “Effects of topical honey on post-operative wound infections due to gram positive and gram negative bacteria following caesarean sections and hysterectomies,” European Journal of Medical Research, vol. 4, no. 3, pp. 126–130, 1999.
S. S. Radwan, A. A. El-Essawy, and M. M. Sarhan, “Experimental evidence for the occurrence in honey of specific substances active against microorganisms,” Zentralblatt fur Mikrobiologie, vol. 139, no. 4, pp. 249–255, 1984.
L. Boukraa, H. Benbarek, and A. Moussa, “Synergistic action of starch and honey against Candida albicans in correlation with diastase number,” Brazilian Journal of Microbiology, vol. 39, no. 1, pp. 40–43, 2008.
V. Mullai and T. Menon, “Bactericidal activity of different types of honey against clinical and environmental isolates of Pseudomonas aeruginosa,” Journal of Alternative and Complementary Medicine, vol. 13, no. 4, pp. 439–441, 2007.
A. E. Heuvelink, F. L. A. M. Van Den Biggelaar, J. T. M. Zwartkruis-Nahuis et al., “Occurrence of verocytotoxin-producing Escherichia coli O157 on Dutch dairy farms,” Journal of Clinical Microbiology, vol. 36, no. 12, pp. 3480–3487, 1998.
C. Basualdo, V. Sgroy, M. S. Finola, and J. M. Marioli, “Comparison of the antibacterial activity of honey from different provenance against bacteria usually isolated from skin wounds,” Veterinary Microbiology, vol. 124, no. 3-4, pp. 375–381, 2007.