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Open Access Research article

Antimicrobial activity against oral pathogens and immunomodulatory effects and toxicity of geopropolis produced by the stingless bee Melipona fasciculata Smith

Silvana A Liberio12, Antônio Luís A Pereira2, Richard P Dutra14, Aramys S Reis1, Maria José AM Araújo1, Nadia S Mattar1, Lucilene A Silva1, Maria Nilce S Ribeiro4, Flávia Raquel F Nascimento13, Rosane NM Guerra13 and Valério Monteiro-Neto35*

Author Affiliations

1 Laboratório de Imunofisiologia, Universidade Federal do Maranhão, Av. dos Portugueses, SN, CEP: 65.080-040, São Luís, Maranhão, Brazil

2 Departamento de Odontologia, Universidade Federal do Maranhão, Av. dos Portugueses, SN, CEP: 65.080-040, São Luís, Maranhão, Brazil

3 Laboratório de Microbiologia, Universidade Federal do Maranhão, Av. dos Portugueses, SN, CEP: 65.080-040, São Luís, Maranhão, Brazil

4 Laboratório de Farmacognosia, Universidade Federal do Maranhão, São Luís, Av. dos Portugueses, SN, CEP: 65.080-040, Maranhão, Brazil

5 Laboratório de Microbiologia, Centro Universitário do Maranhão, Rua Josué Montello No. 1, CEP: 65.075-120, São Luís, Maranhão, Brazil

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BMC Complementary and Alternative Medicine 2011, 11:108  doi:10.1186/1472-6882-11-108

Published: 4 November 2011

Abstract

Background

Native bees of the tribe Meliponini produce a distinct kind of propolis called geopropolis. Although many pharmacological activities of propolis have already been demonstrated, little is known about geopropolis, particularly regarding its antimicrobial activity against oral pathogens. The present study aimed at investigating the antimicrobial activity of M. fasciculata geopropolis against oral pathogens, its effects on S. mutans biofilms, and the chemical contents of the extracts. A gel prepared with a geopropolis extract was also analyzed for its activity on S. mutans and its immunotoxicological potential.

Methods

Antimicrobial activities of three hydroalcoholic extracts (HAEs) of geopropolis, and hexane and chloroform fractions of one extract, were evaluated using the agar diffusion method and the broth dilution technique. Ethanol (70%, v/v) and chlorhexidine (0.12%, w/w) were used as negative and positive controls, respectively. Total phenol and flavonoid concentrations were assayed by spectrophotometry. Immunotoxicity was evaluated in mice by topical application in the oral cavity followed by quantification of biochemical and immunological parameters, and macro-microscopic analysis of animal organs.

Results

Two extracts, HAE-2 and HAE-3, showed inhibition zones ranging from 9 to 13 mm in diameter for S. mutans and C. albicans, but presented no activity against L. acidophilus. The MBCs for HAE-2 and HAE-3 against S. mutans were 6.25 mg/mL and 12.5 mg/mL, respectively. HAE-2 was fractionated, and its chloroform fraction had an MBC of 14.57 mg/mL. HAE-2 also exhibited bactericidal effects on S. mutans biofilms after 3 h of treatment. Significant differences (p < 0.05) in total phenol and flavonoid concentrations were observed among the samples. Signs toxic effects were not observed after application of the geopropolis-based gel, but an increase in the production of IL-4 and IL-10, anti-inflammatory cytokines, was detected.

Conclusions

In summary, geopropolis produced by M. fasciculata can exert antimicrobial action against S. mutans and C. albicans, with significant inhibitory activity against S. mutans biofilms. The extract with the highest flavonoid concentration, HAE-2, presented the highest antimicrobial activity. In addition, a geopropolis-based gel is not toxic in an animal model and displays anti-inflammatory effect.