Figure 3

Effect of potential antimicrobial compounds of honey on formation as well as on a 42 h-old existing single-species biofilms of four Porphyromonas gingivalis strains. Methylglyoxal being the potential antimicrobial compound of Manuka honey and hydrogen peroxide as the potential antimicrobial compound of local German honey were added in three concentrations at the beginning of formation or on an already 42-h old biofilm. Colony forming units were determined each 6 h and 24 h after addition of the compounds (CFU counts within biofilm; *p < 0.05; **p < 0.01 each compared to controls at the respective time).