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-1β 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-1β 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.
Department of Biosciences and Oral Diagnosis, Laboratory of Microbiology and Immunology, Institute of Science and Technology, Univ Estadual Paulista/UNESP, Av, Engenheiro Francisco José Longo, 777-Jardim São Dimas, São José dos Campos, SP, Brazil. jroliveira16@hotmail.com
Jonatas Rafael
JR
de Oliveira
Vinicius Carlos
VC
de Castro
Polyana
P
das Graças Figueiredo Vilela
Samira Esteves Afonso
SE
Camargo
Cláudio Antonio Talge
CA
Carvalho
Antonio Olavo Cardoso
AO
Jorge
Luciane Dias
LD
de Oliveira
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D001938:Brazil; D002176:Candida albicans / Q000187:drug effects*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D008264:Macrophages / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D010936:Plant Extracts / Q000494:pharmacology*; D010946:Plants, Medicinal / Q000737:chemistry*; D009057:Stomatognathic Diseases / Q000378:metabolism / Q000382:microbiology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D000900:Anti-Bacterial Agents; D010936:Plant Extracts; D014409:Tumor Necrosis Factor-alpha