[On the antimicrobial activity of propolis and propolis constituents (author's transl)].

After a survey of the literature on the antimicrobial activity of the bee product propolis, the authors discuss their own findings as compared to the chemotherapeutical agents streptomycin, oxytetracycline, chloramphenicol, nystatin, griseofulvin and sulphamerazine. According to the results obtained by testing 25 isolated constituents on Bacillus subtilis, Staphylococcus aureus, Candida albicans and Trichophyton mentagrophytes, the antimicrobial properties of this mixture of natural substances are mainly attributable to the flavonoids pinocembrin, galangin, pinobanksin, pinobanksin-3-acetate as well as to the p-coumaric acid benzyl ester and a caffeic acid ester mixture. None of the isolated substances was as potent as the antibiotics tested for the purpose of comparison. The relatively good antimycetic activity of the 5,7-dihydroxyflavanone pinocembrin seems noteworthy. Finally, possible mechanisms of the antimicrobial action of the flavonoids are discussed.