Figure 2.

Antibacterial activity of hop extract against P. acnes strains determined in the agar diffusion test. Diameter of the zone of inhibition [mm] is indicated. A commercially available acne-gel with clindamycin served as positive control. Another commercial acne-gel with retinol and a Boswellia serrata extract (Bs) was additionally tested (A). The antibacterial activity of hop extract against S. aureus strains was determined in the agar diffusion test. The diameter of the inhibition zone [mm] is indicated. The acne-gel with clindamycin served as positive control. The acne-gel with retinol and a Boswellia serrata extract (Bs) was a comparative product (B). Data are expressed as means ± SD of two independent experiments (ns, not significant, p ≤ 0.05 (*)).