Inhibition of streptococcal biofilm formation by Aronia by extracellular RNA degradation

BACKGROUND: The accumulation of oral bacterial biofilms is one of the primary etiological factors for oral diseases. Aronia melanocarpa extracts display general health benefits, including antimicrobial activities. This study evaluates the inhibitory effect of Aronia juice on oral streptococcal biofilm formation. RESULTS: Exposure to 1/10-diluted Aronia juice for 1 min significantly decreased in vitro streptococcal biofilm formation (P < 0.001). No remarkable difference was noted in streptococcal growth by Aronia under the same conditions. Interestingly, 1 week of oral rinse with diluted Aronia juice led to significantly fewer salivary streptococcal colony-forming units (CFUs) relative to oral rinsing with tap water (P < 0.05). Furthermore, Aronia exerted an extracellular RNA-degrading effect, and RNase inhibitor alleviated Aronia-dependent streptococcal biofilm inhibition. CONCLUSION: Aronia might inhibit initial biofilm formation by decomposing extracellular RNA, which plays an important role in bacterial biofilm formation. Our data suggest that oral rinsing with Aronia juice will aid in treating oral biofilm-dependent diseases easily and efficiently.