Cleansing effect of acidic L-arginine on human oral biofilm

Abstract

BackgroundDental plaque formed on tooth surfaces is a complex ecosystem composed of diverse oral bacteria and salivary components. Accumulation of dental plaque is a risk factor for dental caries and periodontal diseases. L-arginine has been reported to decrease the risk for dental caries by elevating plaque pH through the activity of arginine deiminase in oral bacteria. Here we evaluated the potential of L-arginine to remove established oral biofilms.MethodsBiofilms were formed using human saliva mixed with Brain Heart Infusion broth supplemented with 1 % sucrose in multi-well plates or on plastic discs. After washing the biofilms with saline, citrate (10 mM, pH3.5), or L-arginine (0.5 M, pH3.5), the retained biofilms were analyzed by crystal violet staining, scanning electron microscopy, and Illumina-based 16S rDNA sequencing.ResultsWashing with acidic L-arginine detached oral biofilms more efficiently than saline and significantly reduced biofilm mass retained in multi-well plates or on plastic discs. Illumina-based microbiota analysis showed that citrate (pH3.5) preferentially washed out Streptococcus from mature oral biofilm, whereas acidic L-arginine prepared with 10 mM citrate buffer (pH3.5) non-specifically removed microbial components of the oral biofilm.ConclusionsAcidic L-arginine prepared with citrate buffer (pH3.5) effectively destabilized and removed mature oral biofilms. The acidic L-arginine solution described here could be used as an additive that enhances the efficacy of mouth rinses used in oral hygiene.Electronic supplementary materialThe online version of this article (doi:10.1186/s12903-016-0194-z) contains supplementary material, which is available to authorized users.

Potential benefits of arginine formulation in oral health care products

“…Clinical investigations containing Arg dentifrices or mouth rinses showed a protective effect against development of dental caries in young subjects. In addition, Arg and fluoride synergistically suppressed Streptococcus mutans growth and biofilm formation . A dentifrice containing 1.5% Arg, a calcium compound, and fluoride (parts per million; ppm) has been developed and authenticated for use.…”

“…In addition, it has been reported to reduce the pathogenicity of herpes simplex and influenza viruses, probably due to compromised function of proteins in the envelope. 31 The functions of Arg has revealed that it is in involved in the regulation of immune cells in cancer, inflammation, infections, etc. 26,[32][33][34][35][36][37][38][39][40] Arg is synthesized from glutamine, glutamate, and proline via the intestinal-renal axis in humans and other mammals (such as pigs, sheep, and rats).…”

“…In addition, Arg and fluoride synergistically suppressed Streptococcus mutans growth and biofilm formation. 31 A dentifrice containing 1.5% Arg, a calcium compound, and fluoride (parts per million; ppm) has been developed and authenticated for use. Its mode of action is based on the ADS pathway of nonpathogenic arginolytic bacteria.…”

“…As Arg increases the solubility of proteins and suppresses their aggregation by changing the surface tension, it has been used for solubilization of exogenously expressed proteins or antibodies for pharmaceutical use. In addition, it has been reported to reduce the pathogenicity of herpes simplex and influenza viruses, probably due to compromised function of proteins in the envelope . The functions of Arg has revealed that it is in involved in the regulation of immune cells in cancer, inflammation, infections, etc …”

ArcR modulates biofilm formation in the dental plaque colonizer Streptococcus gordonii

“…However, at high concentrations (≥50 m m ), arginine can disrupt coaggregation between S. gordonii and F. nucleatum by inhibiting the F. nucleatum adhesin RadD . High concentrations of arginine also disrupt multispecies oral microbial biofilms or S. gordonii monospecies biofilms …”