The inhibitory effect of a fermented papaya preparation on growth, hydrophobicity, and acid production of Streptococcus mutans, Streptococcus mitis, and Lactobacillus acidophilus: its implications in oral health improvement of diabetics
Fermented papaya preparation (FPP) is a “natural health product.” The high incidence of dental caries, gingivitis, periodontitis, and oral microbial infection cases among patients with diabetes mellitus continues to prevail. The potential role of FPP against common oral microbiota (Streptococcus mutans, Streptococcus mitis, and Lactobacillus acidophilus) isolated from the human oral cavity was investigated using in vitro simulation models of dental plaque and caries. FPP showed an inhibitory effect against the growth (at 0.05 mg/mL: S. mutans: −6.9%; S. mitis: −4.47%, P < 0.05), acid production (at 0.05 mg/mL: S. mutans: +6.38%; L. acidophilus: +2.25%), and hydrophobicity (at 50 mg/mL: S. mutans: 1.01%, P < 0.01; S. mitis: 7.66%, P < 0.05) of tested microbiota.
The results of this study suggest that low doses of FPP may be a suitable complement to good oral hygiene practice for the effective prevention of dental caries, plaque, and gingivitis. The functional application of FPP as a constituent of a balanced diet and active lifestyle can make a positive contribution to the oral health status and well-being of patients with diabetes.
Epidemiological surveys have brought to light the high prevalence of dental caries, gingivitis, periodontitis, and oral microbial infection cases among patients with diabetes mellitus. In an attempt to explain this trend, multiple pathophysiological mechanisms have been suggested, including deficient nutritional intake, alterations in host response to oral microflora, compromised neutrophil function, and decreased phagocytosis and leukotaxis. Bacteria-triggered secretion of serum pro-inflammatory cytokines in the mouth may induce hyperglycemia and ultimately cause insulin resistance and contribute to the indirect destruction of pancreatic beta cells. A realistic management plan that includes regular oral hygiene practice and basic dental treatment is therefore fundamental for managing diabetes and its associated oral complications. Nowadays, active constituents extracted from plants are often included in the preparation of toothpaste, mouth rinses, dental floss, and chewing gum to ensure a stronger antimicrobial activity.
Ongoing studies focusing on the anticariogenic properties of polyphenols isolated from green tea, red chicory, cranberry juice, and shiitake mushrooms look promising. However, despite the numerous studies conducted on such functional foods, only a handful of plants can be clinically used to control dental plaque, caries formation, and mouth infections due to their effectiveness, stability, taste, and economic feasibility. Interestingly, dietary agents often lack bactericidal activity after commercial production, but retain their ability to manipulate oral microbiota by exhibiting other important properties such as antiadhesion, antibiofilm, and anti-inflammatory. Fermented papaya preparation (FPP: also known as Immun’Age®; Osato Research Institute, Gifu, Japan) is one such functional food. Clinical data now support the use of FPP as a dietary supplement in the management of type 2 diabetes mellitus by virtue of its ability to effectively reduce fasting blood glucose levels, low-density lipoprotein/high-density lipoprotein ratio, and inflammatory biomarkers such as C-reactive protein and uric acid. In this context, FPP may prove to be a valuable asset in reducing the risk of developing oral pathologies such as dental caries and gingivitis.
Collard and Roy reported a reduction in inflammation of the gums in FPP-supplemented rats with gingivitis. Despite postulations of the involvement of β-d-glucans (the major structural constituent of yeast cell walls) and complex amino acid and carbohydrates, the mechanisms behind the immunomodulatory role of FPP are still to be clarified. The current lack of comparative data of FPP in this particular domain of oral health has prompted us to carry out a preliminary assessment of the antimicrobial activities of FPP. Further studies are warranted to provide a comprehensive insight into the molecular inhibitory mechanisms demonstrated by FPP in this study. Indeed, oral health in communities affected by diabetes continues to impact health expenditures on dental services.
Prior to conducting each assay, American Type Culture Collection (ATCC) strains of Streptococcus mutans (25175), Streptococcus mitis (6249), and Lactobacillus acidophilus (4356) were grown for 24 h to reach stationary phase in sterile brain heart infusion (BHI: for Streptococcus strains) or MRS broth (for L. acidophilus) at 37°C. Standardization of bacterial suspension was made using sterile 0.85% sodium chloride with comparison against McFarland standards.