Cutibacterium acnes growth and biofilm formation is inhibited by flavonoids

Cutibacterium acnes is the cause of inflammatory acne and implanted devices associated infections. This study investigated flavonoids belonging to the 4 classes: flavanones (hesperidin, neohesperidin, naringenin, naringin, and eriodictyol), flavones (diosmetin, diosmin), isoflavone (genistein), and flavonols (kaempferol, galangin) as inhibitors of C. acnes growth in planktonic and biofilm form and assessed its potential to impact the integrity of cell membrane. Flavonoids could inhibit C. acnes growth, minimal inhibitory concentration (MIC) was in range 50-200 mg/L, with the lowest MIC (50 mg/L) for neohesperidin and eriodictyol. Minimal biofilm inhibitory concentrations were in range 25-200 mg/L, with the lowest values and highest antibiofilm potential recorded for eriodictyol, genistein, and kaempferol. Impact on cell membrane was significant in the presence of almost all examined flavonoids, as determined by crystal violet uptake assay. Flavonoids, especially eriodictyol, represent promising underexplored agents for combating infections and processes linked with the presence of C. acnes.