Mouthwash containing a biosurfactant and chitosan: An eco-sustainable option for the control of cariogenic microorganisms

The aim of the present study was to determine the antimicrobial action and toxicity of mouthwashes formulated with a biosurfactant, chitosan of a microbial origin and peppermint (Mentha piperita) essential oil (POE). Chitosan was extracted from the biomass of a fungus from the order Mucorales grown in yam bean broth. Three biosurfactants produced by Pseudomonas aeruginosa UCP 0992 (PB), Bacillus cereus UCP 1615 (BB) and Candida bombicola URM 3718 (CB) were tested. Six mouthwashes were prepared, the active ingredients of which were the biosurfactant, chitosan and POE. The minimum inhibitory concentration (MIC) was determined for the test substances separately, in combinations and in the mouthwash formulas. The toxicity of the mouthwashes was tested using MTT (3-(4,5-dimethylthiazole-2-il)-2,5-diphenyltetrazolium bromide) for the L929 (mouse fibroblast) and RAW 264.7 (mouse macrophage) cell lines. All substances tested had a MIC for cariogenic microorganisms. The combinations of the CB and PB biosurfactants with chitosan demonstrated an additive effect on the majority of microorganisms tested. The toxicity of the mouthwashes was significantly lower than that of the commercial mouthwash. The present findings demonstrate that mouthwashes containing natural products constitute a safe, effective, natural alternative to commercially available mouthwashes for the control of oral microorganisms. •Mouthwashes were prepared with biosurfactant, chitosan and essential oil.•Chitosan was extracted from Mucorales and three biosurfactants were tested.•All substances tested had a MIC for cariogenic microorganisms.•Toxicity of natural mouthwashes was significantly lower than a commercial one.•The natural mouthwashes are a safe, effective, alternative to the market.