Antimicrobial activities of seasonally collected bee products: honey, propolis, royal jelly, venom, and mellitin.

Ethanolic extracts of seasonally collected natural bee products (honey, propolis, royal jelly (RJ), and bee venom (BV)) were tested for their potential as antimicrobial agents against antibiotic-resistant bacteria and fungi. These extracts exhibited various inhibitory effects on antibiotic-resistant bacteria (Streptococcus pneumoniae, Staphylococcus aureus, MRSA, Salmonella typhimurium, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus vulgaris, and Haemophilus influenzae) and fungi (Aspergillus brasiliensis and Candida albicans), with the exception of S. pneumonia, which was not inhibited by honey and RJ extracts, and P. aeruginosa, which was not inhibited by RJ extracts. Interestingly, extracts of BV and its major content, melittin (MEL), displayed a wide spectrum of antimicrobial activity against all tested bacteria and fungi. This is the first study to show that propolis extract has bactericidal activity against S. pneumoniae and that BV extract and MEL have antibacterial activity against P. vulgaris, H. influenzae, and H. influenzae type b. Extracts of bee products collected in the spring generally exhibited the most significant antibacterial and antifungal activities. Based on total phenolic content (TPC) and total flavonoid content (TFC), it was found that spring samples of propolis, RJ, and honey, in that order, were the richest. Also, LC-MS-MS analysis of MEL content in BV demonstrated that it was the highest in spring sample. In terms of MIC and MBC values, Gram-positive bacteria were the most susceptible to bee products. First and foremost, the antimicrobial activity of bee products was ranked in descending order based on MIC values: BV, MEL, propolis, RJ, and honey.