Control of microorganisms of oral health interest with Arctium lappa L. (burdock) extract non-cytotoxic to cell culture of macrophages (RAW 264.7).

OBJECTIVES: To evaluate the antimicrobial activity of Arctium lappa L. extract on Staphylococcus aureus, S. epidermidis, Streptococcus mutans, Candida albicans, C. tropicalis and C. glabrata. In addition, the cytotoxicity of this extract was analyzed on macrophages (RAW 264.7). DESIGN: By broth microdilution method, different concentrations of the extract (250-0.4 mg/mL) were used in order to determine the minimum microbicidal concentration (MMC) in planktonic cultures and the most effective concentration was used on biofilms on discs made of acrylic resin. The cytotoxicity A. lappa L. extract MMC was evaluated on RAW 264.7 by MTT assay and the quantification of IL-1ß and TNF-α by ELISA. RESULTS: The most effective concentration was 250 mg/mL and also promoted significant reduction (log10) in the biofilms of S. aureus (0.438 ± 0.269), S. epidermidis (0.377 ± 0.298), S. mutans (0.244 ± 0.161) and C. albicans (0.746 ± 0.209). Cell viability was similar to 100%. The production of IL-1ß was similar to the control group (p>0.05) and there was inhibition of TNF-α (p<0.01). CONCLUSIONS: A. lappa L. extract was microbicidal for all the evaluated strains in planktonic cultures, microbiostatic for biofilms and not cytotoxic to the macrophages.

Cytotoxicity of Brazilian plant extracts against oral microorganisms of interest to dentistry.

BACKGROUND: With the emergence of strains resistant to conventional antibiotics, it is important to carry studies using alternative methods to control these microorganisms causing important infections, such as the use of products of plant origin that has demonstrated effective antimicrobial activity besides biocompatibility. Therefore, this study aimed to evaluate the antimicrobial activity of plant extracts of Equisetum arvense L., Glycyrrhiza glabra L., Punica granatum L. and Stryphnodendron barbatimam Mart. against Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus mutans, Candida albicans, Candida tropicalis, and Candida glabrata, and to analyze the cytotoxicity of these extracts in cultured murine macrophages (RAW 264.7). METHODS: Antimicrobial activity of plant extracts was evaluated by microdilution method based on Clinical and Laboratory Standards Institute (CLSI), M7-A6 and M27-A2 standards. The cytotoxicity of concentrations that eliminated the microorganisms was evaluated by MTT colorimetric method and by quantification of proinflammatory cytokines (IL-1ß and TNF-α) using ELISA. RESULTS: In determining the minimum microbicidal concentration, E. arvense L., P. granatum L., and S. barbatimam Mart. extracts at a concentration of 50 mg/mL and G. glabra L. extract at a concentration of 100 mg/mL, were effective against all microorganisms tested. Regarding cell viability, values were 48% for E. arvense L., 76% for P. granatum L, 86% for S. barbatimam Mart. and 79% for G. glabra L. at the same concentrations. About cytokine production after stimulation with the most effective concentrations of the extracts, there was a significant increase of IL-1ß in macrophage cultures treated with S. barbatimam Mart. (3.98 pg/mL) and P. granatum L. (7.72 pg/mL) compared to control (2.20 pg/mL) and a significant decrease of TNF-α was observed in cultures treated with G. glabra L. (4.92 pg/mL), S. barbatimam Mart. (0.85 pg/mL), E. arvense L. (0.83 pg/mL), and P. granatum L. (0.00 pg/mL) when compared to control (41.96 pg/mL). CONCLUSIONS: All plant extracts were effective against the microorganisms tested. The G. glabra L. extract exhibited least cytotoxicity and the E. arvense L. extract was the most cytotoxic.