Effect of Sublethal Blue Light on Herbal Extract Activity Against Volatile Sulfide Compound Production by Fusobacterium nucleatum

Previously, we have shown that sublethal exposure of blue light caused increased cell membrane permeability in Fusobacterium nucleatum. The aim of the present study was to test the effect of this exposure on the activity of Lavender, Sage, Echinacea and Mastic gum extracts against volatile sulfide compound (VSC) production by Fusobacterium nucleatum. Bacterial suspensions were pre-exposed to blue light (400–500 nm) bellow minimal inhibitory dosage (sub-MID). Exposed and nonexposed samples were inoculated into test tubes containing growth medium, filtered saliva with or without herbal extracts. Following incubation, test tubes were tested for malodor production (odor judge scores), VSC levels (OralChroma), salivary protein degradation (SDS-PAGE) and bacterial cell membrane damage (fluorescence microscopy). Results showed that sub-MID blue light exposure significantly increased the ability of Lavender and Echinacea to reduce VSC production by Fusobacterium nucleatum by more than 30%. These results suggest that sublethal blue light exposure may be useful to increase the efficacy of antimalodor agents.