Abstract

Sapindus saponins extracted from Sapindus mukorossi Gaertn. have been reported to exert antibacterial activity against Cutibacterium acnes ( C. acnes ). However, there are no reports about their potentials against its biofilm, which is a major contributor to the antibiotic resistance of C. acnes . This study aimed to investigate the synergistic antibiofilm activity and action of the combination of Sapindoside A and B (S AB ) against C. acnes . S AB with sub-MICs significantly inhibited the early-formed and mature biofilm of C. acnes and decreased the adhesion and cell surface hydrophobicity ( p < 0.05). Also, S AB greatly reduced the production of exopolysaccharide and lipase ( p < 0.05), and the binding mode of S AB and lipase was predicted by molecular docking, via hydrogen bonds and hydrophobic interactions. Biofilm observed with electron microscopies further confirmed the high antibiofilm activity of S AB against C. acnes . Furthermore, a significant down-regulation of biofilm biosynthesis-associated genes was observed. The combination index explained the synergistic effects of S AB leading to the above results, and the contribution of S A was greater than that of S B . The current results showed that S AB had synergistic antibiofilm activity against C. acnes , and the Sapindoside A played a major role, indicating that S AB could be a natural antiacne additive against C. acnes biofilm-associated infections.