The oral microbiome contains more than 700 species, most of which are located in dental plaque, the authors write. The species vary as a result of environmental stimuli, including diet or oral hygiene, which can easily change the natural balance between commensal and pathogenic species. Species of bacteria that erode tooth enamel include Streptococcus mutans and Streptococcus sobrinus, whereas periodontal diseases are associated with increased populations of Gram-negative species, including Porphyromonas gingivalis, Campylobacter spp., and Treponema denticola, which produce endotoxins that cause the inflammation and gum tissue damage that lead to gum disease. “If S. mutans plays an essential role as initiator on caries disease, P. gingivalis is typically found on chronic periodontitis and has been proposed as the “keystone” microbe in periodontitis initiation, whereas F. nucleatum[Fusobacterium nucleatum] S. mutans plays an essential role as initiator on caries disease,” the researchers write.
The ability to block bacterial adhesion was even more pronounced when the polyphenols were combined with the oral probiotic. “Results confirmed a complementary action of both caffeic acid and p-coumaric acid, and S. dentisani in the competence process against S. mutans adhesion,” the authors write.
Digestion of polyphenols starts in the mouth, and the team’s results indicated that polyphenol metabolites may play a role in some of the effects against the pathogens. “Our results confirmed for the first time the relevance of bacterial and cellular phenolic metabolism as well as a complementary metabolic action,” they note. “This metabolism included the degradation of precursors into phenolic metabolites as well as other enzymatic reactions.”
The authors suggest that the reported in vitro study represents a useful starting point for investigating the mechanisms of action of red wine polyphenols against oral disease. “Further steps should be addressed toward the use of mixed biofilms models which can mimic bacteria–bacteria interactions as well as some other conditioning factors that should be added to multifactorial assays,” they write. “Once molecular mechanisms of action become elucidated, in vivo studies of periodontal and cariogenic diseases are recommended, in order to evaluate the potential of polyphenols as preventive therapies in the management of cariogenic and periodontal diseases.”