Oxyresveratrol promotes biofilm formation, cell attachment and aggregation of Streptococcus gordonii in the presence of sucrose

Abstract

ABSTRACT Streptococcus gordonii is a commensal colonizer of oral cavity that initiates the formation of dental plaque. Oxyresveratrol is a natural purification from plants with antibacterial effects on various oral bacteria including Streptococcus mutans. The aim of this study was to investigate the effects of oxyresveratrol on S. gordonii. The basic viability, biofilm formation and cell aggregation of S. gordonii treated with oxyresveratrol were investigated. Oxyresveratrol dose-dependently inhibited the growth of S. gordonii in the absence of sucrose. However, in the presence of sucrose, it promoted biofilm formation under MIC. Both the biofilm formation and extracellular polysaccharides synthesis reached the maximum level at ½ MIC (250 μg/mL) oxyresveratrol. The gene expressions of abpA, abpB, scaA, gtfG, hsa, cshA, cshB, ccpA, srtA and sspB were upregulated when treated with 62.5 and 125 μg/mL oxyresveratrol. A total eight of the ten genes were significantly upregulated at 250 μg/mL oxyresveratrol except abpB and sspB, which were downregulated at 250 μg/mL without significance. In conclusion, oxyresveratrol has dual-effects on S. gordonii. Considering its specific biofilm suppressive effect on S. mutans, it might be a candidate for bacterial interspecies modulator applied in caries prevention.