Effect of a new variety of Apis mellifera propolis on mutans streptococci

The effects of a new variety of propolis, from Northeastern Brazil (BA), on growth of mutans streptococci, cell adherence, and water-insoluble glucan (WIG) synthesis were evaluated. Propolis from Southeastern (MG) and Souther n (RS) Brazil were also tested as an extension of our previous work. Ethano lic extracts of propolis (EEP) were prepared and analyzed by reversed-phase HPLC. For the antibacterial activity assays, minimum inhibitory concentrat ions (MIC) and minimum bactericidal concentrations (MBC) of EEPs against St reptococcus mutans, S. sobrinus, and S. cricetus were determined. Cell adhe rence of S. mutans and S. sobrinus to a glass surface was measured spectrop hotometrically at 550 nm. WIG synthesized from sucrose by glucosyltransfera se (Gtf) was extracted and quantified by the phenol-sulfuric method. The HP LC profile of the new variety of propolis was entirely different from South eastern and Southern propolis. Neither flavonoid aglycones nor p-coumaric a cid were detected in EEP BA. All EEPs demonstrated biological activities ag ainst mutans streptococci; EEP BA showed the highest potency in all in vitr o parameters evaluated in this study. The ranges of MIC values were 50 (EEP BA)-400 mu g/ml (MG), for S. mutans; and 25 (BA)-400 mu g/ml (MG), for S. sobrinus and S. cricetus. The bactericidal concentration of EEPs was four t o eight times the MIC values. The adherence of S. mutans and S. sobrinus ce lls and WIG synthesis were markedly inhibited by EEPs, demonstrating signif icant inhibition at all concentrations compared with the control (80% ethan ol) (p < 0.05). EEP BA showed 80% inhibition of cell adherence and WIG synt hesis at concentrations as low as 12.5 and 7.8 mu g/ml, respectively. The r esults show that the new variety of propolis was exceptionally effective in all in vitro parameters tested against mutans streptococci; biological eff ects of propolis are likely not to be due solely to flavonoids and (hydroxy )cinnamic acid derivatives.