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Epigallocatechin-3-gallate (EGCG), a polyphenol derived from Green Tea, is one of the sources of natural bioactive compounds which are currently being developed as medicinal ingredients. Besides other biological activities, this natural compound exhibits anti-cariogenic effects. However, EGCG has low physical-chemical stability and poor bioavailability. Thus, the purpose of this study was to develop and characterize lipid-chitosan hybrid nanoparticle with EGCG and to evaluate its in vitro activity against cariogenic planktonic microorganisms. Lipid-chitosan hybrid nanoparticle (LCHNP-EGCG) were prepared by emulsion and sonication method in one step and characterized according to diameter, polydispersity index (PdI), zeta potential (ZP), encapsulation efficiency (EE), mucoadhesion capacity and morphology. Strains of Streptococcus mutans, Streptococcus sobrinus and Lactobacillus casei were treated with LCHNP-EGCG, and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were evaluated. LCHNP-EGCG exhibited a size of 217.3 ± 5.1 nm with a low polydispersity index (0.17) and positive zeta potential indicating the presence of chitosan on the lipid nanoparticle surface (+33.7 mV). The LCHNP-EGCG showed a spherical morphology, high stability and a mucoadhesive property due to the presence of chitosan coating. In addition, the EGCG encapsulation efficiency was 96%. A reduction of almost 15-fold in the MIC and MBC against the strains was observed when EGCG was encapsulated in LCHNP, indicating the potential of EGCG encapsulation in lipid-polymer hybrid nanoparticles. Taking the results together, the LCHNP-EGCG could be an interesting system to use in dental care due to their nanometric size, mucoadhesive properties high antibacterial activity against relevant planktonic microorganisms. [ABSTRACT FROM AUTHOR]

Although epigallocatechin-3-gallate (EGCG) from green tea has been successfully used in the prevention and treatment of several infectious and immunoinflammatory diseases because of its proven anti-inflammatory, antioxidant, antimicrobial, and antiresorptive role, its use as an intracanal dressing has not been proposed. The aim of this study was to develop a formulation based on EGCG for endodontic use by assessing its physicochemical and biological properties. Initially, physicochemical characterization of EGCG was performed by ultraviolet-visible and fluorescence spectroscopy to evaluate if the properties were maintained in acidic pH and time (1–6, 24, and 27 hours). After that, biological studies evaluated the developed formulation of EGCG at different concentrations (1.25, 5, 10, and 20 mg/mL). The tissue compatibility with subcutaneous tissue of mice was evaluated by plasma leakage after 24 hours and the examination of macroscopic and microscopic features at 7, 21, and 63 days after the insertion of polyethylene tubes containing the formulations. The repair of experimentally induced periapical lesions in dog's teeth by radiographic and histopathologic analysis was also evaluated. The scores were statistically analyzed by the chi-square and Fisher exact test. Analysis of variance followed by the Tukey posttest were used for the quantitative analysis. The significance level was 5%. The physicochemical characterization performed under ultraviolet-visible spectrophotometry showed that the EGCG properties remained unaltered in acid pH and function of time, keeping its wavelength to 274 nm. Macroscopic parameters evaluated at 7, 21, and 63 days showed that all concentrations presented no epithelial ulceration or presence of mild superficial tissue necrosis, edema, or vascularization with no significant difference in the control group. During all periods of microscopic examination, all groups presented the absence of abscess foci and edema and the presence of fibrous capsule and neovascularization. The presence of reparative tissue with a gentle presence of neutrophilic inflammatory cells was also observed for all groups, except for the calcium hydroxide paste group, which presented a more pronounced inflammation and tissue necrosis at days 7 and 21 (P <.001). At day 63, all groups presented an absence of inflammatory infiltrate and necrosis. The evaluation of dog teeth showed that treatment with the EGCG formulation provided a reduction of the periapical radiolucent area and allowed the repair of apical and periapical tissues (P >.05). The developed formulation based on EGCG from green tea presented physicochemical stability and tissue compatibility and provided the repair of periapical lesions when used as an intracanal dressing. [ABSTRACT FROM AUTHOR]

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• Dental caries is still one of the most prevalent diseases in children worldwide. • The effect of green tea and its extract, EGCG, as mouthwashes in children at high caries risk and prevalence was studied. • Rinsing with EGCG solution effectively reduces the levels of mutans streptococci and lactobacilli in the oral cavity of children. • Both EGCG and green tea could be used as alternatives to chlorhexidine-based mouthwashes. • The reduction of mutans streptococci was higher than lactobacilli. This study was conducted to evaluate and compare the antimicrobial efficacy of green tea and its extract epigallocatechin-3-gallate (EGCG) as a mouthwash in children. The study group included 47 children aged 5-12 years at high caries risk and prevalence. Children selected were asked to rinse with one of the substances (EGCG, green tea, chlorhexidine and distilled water) for one min. A non-stimulated salivary sample (2 mL) was collected at baseline and after rinsing. The concentration of cariogenic microorganisms (mutans streptococci and lactobacilli) was determined before and after rinsing based on the count of colony-forming units (CFU). CFU were counted with the aid of a stereomicroscope through the perfunctory identification of the morphological characteristics of CFU. The microbial reduction percentage was then calculated. The analysis of the effectiveness of the treatments showed that there was a significant reduction in relation to the values obtained before and after the mouthwash, both for mutans streptococci (pCHX = 0.001; pEGCG = 0.001; pGreen Tea = 0.005; pDistilled Water = 0.018) and lactobacilli (pCHX = 0.001; pEGCG = 0.002; pGreen Tea = 0.008; pDistilled Water = 0.033). The percentage of microbial reduction of both cariogenic microorganisms caused by the EGCG solution was higher than green tea and distilled water, but less than CHX. The percentage of microbial reduction by the EGCG solution for mutans streptococci was 79.9%, green tea 68.3%, distilled water 50.6% and CHX 95.5%. For lactobacilli, the percentage reduction of all solutions was relatively lower when compared to mutans streptococci. For the EGCG solution it was 72.09%, followed by green tea 59.17% and distilled water 41.96%, but less than CHX 86.02%. Rinsing with EGCG solution reduced the levels of mutans streptococci and lactobacilli in the oral cavity of children. Although EGCG had better antimicrobial activity than green tea, this study supports the effectiveness of both as an antibacterial mouthwash option. Both EGCG and green tea could be used as alternatives to chlorhexidine-based mouthwashes. [ABSTRACT FROM AUTHOR]