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

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.

Efeito do tratamento com própolis de Scaptotrigona aff. postica sobre o desenvolvimento do tumor de Ehrlich em camundongos / Effect of propolis of Scaptotrigona aff. postica on the development of the tumor of Ehrlich in mice

Neste trabalho foi investigado o efeito do extrato hidroalcoólico de própolis (EHP) de Scaptotrigona aff. postica sobre o desenvolvimento do tumor de Ehrlich na forma sólida, sobre a celularidade dos órgãos linfóides dos animais portadores de tumor, bem como, sobre a produção de óxido nítrico (NO) pelos macrófagos destes animais. Camundongos Swiss foram divididos em quatro grupos: controle, EHP 0,5; EHP 5 e EHP 50, os quais foram tratados por via intraperitoneal com dose única de solução salina (NaCl 0,9 por cento); 0,5; 5 ou 50 mg de EHP/kg de animal, respectivamente. Depois de 48 h do tratamento, os animais foram inoculados com 10(5) células do tumor de Ehrlich nas patas. Os resultados mostraram que o tratamento com EHP nas doses de 5 e 50 mg/kg inibiu de forma significativa o desenvolvimento do tumor a partir do 6º dia pós-inóculo quando comparado ao controle e ao EHP 0,5. Além disso, houve aumento significativo da celularidade do baço e da medula óssea nos grupos EHP 0,5 e EHP 5 em relação ao controle. A produção de NO estimulada com concanavalina A (ConA) apresentou uma significante diminuição nos grupos tratados com EHP em relação ao controle. Pode-se concluir que o tratamento com EHP apresentou efeito antitumoral quando administrado nas doses de 5 e 50 mg/kg, o que pode estar relacionado com a sua composição química e com a inibição da produção de NO.

It was investigated the effect of hydroalcoholic extract (HEP) of propolis from Scaptotrigona aff. postica on the solid Ehrlich tumor, on the tumor-bearing mice lymphoid organs and on the nitric oxide (NO) production. Swiss mice were divided in 4 groups: control, HEP 0.5; HEP 5 and HEP 50 that was treated by intraperitoneal route with a single dose of saline solution (NaCl 0.9 percent) or 0.5 or 5 or 50 mg of HEP/kg body weight, respectively. After 48 h of treatment, the animals were inoculated with 10(5) tumor cells in their footpad. The results showed that the treatment with HEP in the doses of 5 and 50 mg/kg inhibited the development of the tumor from the 6th day post inoculums when compared to the control and to the HEP 0.5 groups. Besides, there was an increase of spleen and bone marrow cell number in HEP 0.5 and HEP 5 as compared to the control. Concanavalin A (ConA)-stimulated NO production was decreased in all HEP-treated groups when compared to the control. In conclusion, the treatment with HEP had an anti-tumor effect what may be related to its chemical composition and to the inhibition of NO production.

The potential use of propolis as a cariostatic agent and its actions on mutans group streptococci.

Propolis is a resinous substance made by bees. It possesses many biological activities, and many studies have reported its potential application in the control of dental caries. However, variability in the chemical composition of propolis is a potential problem in its quality control, especially since propolis has already been incorporated into products for oral use. Therefore, a critical analysis of the available data on propolis is warranted. The present review discusses the in vitro and in vivo studies published in the period between 1978 and 2008 regarding the effects of propolis on Streptococcus mutans growth, bacterial adherence, glucosyltransferase activity, and caries indicators. Several investigations carried out with crude propolis extracts, isolated fractions, and purified compounds showed reductions in Streptococcus mutans counts and interference with their adhesion capacity and glucosyltransferase activity, which are considered major properties in the establishment of the cariogenic process. Data from in vivo studies have demonstrated reductions in Streptococcus mutans counts in saliva, the plaque index, and insoluble polysaccharide formation. These findings indicate that propolis and/or its compounds are promising cariostatic agents. However, the variation in the chemical composition of propolis due to its geographical distribution is a significant drawback to its routine clinical use. Thus, further studies are needed to establish the quality and safety control criteria for propolis in order for it to be used in accordance with its proposed activity.