Sodium Ascorbate

S.A. El-Mowafy, et al. Journal of applied microbiology, 2014, 117(5), 1388-1399.

Researches have shown that sodium ascorbate is a signal-modulator and virulence-inhibitor for P. aeruginosa.
The work first measured the MIC of ascorbate on the P aeruginosa strain PAO1, then all subsequent experiments used lower concentrations than that MIC to avoid any findings being affected by reduced cell viability.
Subinhibitory amounts of sodium ascorbate were tested on cell signalling via a reporter strain test. The results indicated that the signalling molecules C4-HSL and 3-oxo-C12-HSL were significantly downregulated at sub-MICs of sodium ascorbate (P < 0.01).
It also studied the effects of sub-MIC amounts of sodium ascorbate on virulence factors and found that ascorbate reduced activities of elastase, protease and hemolysin. Among the other things, pyocyanin activity dropped, biofilm production fell, and Pseudomonas motility also changed.
It used RT-PCR analysis to test the effect of ascorbate on expression of QS regulatory genes. The finding was that QS regulator genes lasI, lasR, rhlI, rhlR, pqsR and pqsA were reduced compared with untreated P aeruginosa PAO1, which supported the fact that ascorbate suppresses QS molecularly by modulating gene expression.

Türkün, Murat, et al. Journal of Adhesive Dentistry, 2009, 11(1).

This paper compared the effect of various levels (2.5%, 5%, and 10%) of sodium ascorbate hydrogel on composite shear bond strength following enamel bleaching with 10% carbamide peroxide gel. These findings point to sodium ascorbate in 10% hydrogel posing a therapeutic use in clinical use, rather than solution. But sodium ascorbate hydrogel applied in a concentration lower than 10% may not be as effective at reverse-acting damaged bond strength as the agent applied in a concentration of 10%.
· Materials and methods: Sixty flat buccal enamel surfaces from 30 bovine incisors were randomly assigned to six groups: control (control), bleached control, and four experimental groups receiving different amounts and formulations of sodium ascorbate after bleaching. They were fixed with Clearfil SE Bond, thermocycled, and then sheared-bonded.
· Test results: The 10% sodium ascorbate hydrogel group was far stronger bond than both the untreated control and bleached control group (p < 0.05). There were no differences in the other groups and the control, which did not receive treatment. Among the antioxidant-treated groups, only the 10% sodium ascorbate solution and 10% hydrogel groups had significantly stronger bond strengths than the bleached control group (p < 0.05). The 10% sodium ascorbate hydrogel group had the highest bond strengths of all antioxidant-treated groups (p < 0.05).