Figure 1. Impact of prebiotic compounds at 1% total concentration on the growth of S. epidermidis (blue) and P. acnes (red), measured by optical density (A620nm) at 30 hr

Of the extracts tested, a synergistic combination of black currant and pine was selected for further study in vivo because it showed the highest inhibition level of P. acnes and stimulated S. epidermidis (see Figure 1).3