Effect of a novel synbiotic on Streptococcus mutans

• Published in: Scientific reports Vol. 10; no. 1; p. 7951
• Main Authors: Bijle, Mohammed Nadeem, Neelakantan, Prasanna, Ekambaram, Manikandan, Lo, Edward C. M., Yiu, Cynthia Kar Yung
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 14-05-2020; Nature Publishing Group
• Subjects: 631/326; 631/61; Acid production; Arginine; Arginine - pharmacology; Biofilms; Biomass; Dental caries; Humanities and Social Sciences; Hydrogen-Ion Concentration; Lactic acid; Lactic Acid - biosynthesis; Lacticaseibacillus rhamnosus - physiology; multidisciplinary; Nitric oxide; pH effects; Probiotics - pharmacology; Science; Science (multidisciplinary); Streptococcus; Streptococcus infections; Streptococcus mutans - drug effects; Streptococcus mutans - growth & development; Streptococcus mutans - metabolism; Synbiotics
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-020-64956-8

We examined the effect of L-arginine - (i) on the growth of
L. rhamnosus
GG (LrG) and (ii) combined LrG synbiotic on the growth of cariogenic
S. mutans
. Viability of LrG was assessed using MTT/XTT assays, confocal imaging with ADS activity measurement. The effect of L-arginine (0.5%/1%/2%) (2×/24 h) with LrG on
S. mutans
was evaluated by measuring the colony forming units, biofilm biomass, real-time qPCR and confocal imaging. The pH of the spent media was measured immediately and 24 h post-treatment with assessment of lactic acid. The LrG viability was highest with 2% L-arginine (p < 0.001). Confocal imaging showed that 2% L-arginine increased biofilm thickness of LrG. The 2% L-arginine and LrG synbiotic significantly inhibited the growth of
S. mutans
(p < 0.001) reducing the viable counts (p = 0.002) and biofilm biomass (p < 0.001). The pH of spent media was the highest when treated with 2% L-arginine and LrG synbiotic (p < 0.001) with no difference between post-treatment and 24 h post-treatment (p > 0.05). Conversely, the 2% L-arginine and LrG synbiotic showed the lowest lactic acid production (p < 0.001). This study demonstrated that L-arginine enhanced the growth of LrG. The 2% L-arginine and LrG synbiotic synergistically inhibits the growth of
S. mutans
with significant potential to develop as an anti-caries regimen.