Estudos dos efeitos de antiacidos na farmacocinetica e reatividade do fluoreto com o esmalte dental apos aplicação topica de fluor em gel

Orientador: Jaime Aparecido CuryTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: Aplicação tópica de flúor em gel é um procedimento clinico rotineiro em Odontologia. Relatos de introxicação aguda devido a ingestão do gel são comuns. Assim, o objetivo deste trabalho foi verificar a capacidade de antiácido em reduzir a absorção do fluoreto (F ) sem interferir na reatividade com o esmalte. Aplicação tópica de gel a 10 voluntários adultos foi feita (2,2mgF /kg; Fluoride de gel " Kerr, 1,17.). Cada voluntário recebeu duas aplicaçSes tópicas com intervalos de 7 dias" precedidas da mastigação de dois comprimidos de hidróxido de alumínio - grupo tratado, ou de placebo - grupo controle. Foram feitas análises de F e eletrólitos no sangue e de F na urina. A concentração de F no esmalte dental foi determinada antes, logo após e 07 dias após as aplicaçSes tópicas. Os voluntários foram questionados quanto a sintomatologia clinica. A análise de F no sangue mostrou uma reduçSío de 577. da área sob curva de concentração - tempo sanguíneo no grupo tratado, sendo que a diferença de quantidade de F excretado na urina foi de 60'/.. N3o houve diferença de F formado e retido no esmalte dental quando são comparados os grupos controle e tratado. Efeitos colaterais só foram relatados no grupo controle. Concluímos que o hidróxido de alumínio diminui a absorção de F quando da aplicação tópica de gel sem interferir com sua reatividade com o esmalte dental, o que sugere seu uso para maior segurança durante este procedimento clinicoAbstract: Professional application of fluoride gel is a routine procedure in dentistry. Reports of acute fluoride tonicity due to gel in take are common. Thus, the purpose of this paper was to verify the capacity of antiacid in reducing the fluoride-F absorption without interfering with the enamel reactivity. Ten healthy adult volunteers were submitted to professional application of fluoride gel (2,2 mg/kg; Fluoride gel , Kerr, 1,17.). To each volunteer was made 2 professional application with a 7 day interval. Before the professional application they were asked to mastigate 2 aluminium hidroxide tablets-treated group or placebo tablets-control group. Fluoride and electrolytes contents were analysed in the blood. Urinalysis of F contents were also made. Fluoride concentration in the enamel was determinated before, just after and 7 days after the professional application. Volunteers were questioned about clinical signs and symptoms. Blood fluoride analysis showed a 57"/. decrease in the area under the concentration-blood time curve in the experimental group, the difference of fluoride excreted in the urine being 607.. There were no differences in the F enamel uptake and retention between the 2 groups. Side effects were seen only in the control group. We concluded that aluminium hidroxide decreases F absorption during professional application and doesn't interfere with the F reactivity in the enamel, thus its use is recommended to increase the safety during professional application of fluoride gelDoutoradoFarmacologiaDoutor em Ciência

Malva sylvestris inhibits inflammatory response in oral human cells. An in vitro infection model

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORThe aim of this study was to investigate the in vitro anti-inflammatory activity of Malva sylvestris extract (MSE) and fractions in a co-culture model of cells infected by Aggregatibacter actinomycetemcomitans. In addition, we evaluated the phytochemical content in the extract and fractions of M. sylvestris and demonstrated that polyphenols were the most frequent group in all samples studied. An in vitro dual-chamber model to mimic the periodontal structure was developed using a monolayer of epithelial keratinocytes (OBA-9) and a subepithelial layer of fibroblasts (HGF-1). The invasive periodontopathogen A. actinomycetemcomitans (D7S-1) was applied to migrate through the cell layers and induce the synthesis of immune factors and cytokines in the host cells. In an attempt to analyze the antimicrobial properties of MSE and fractions, a susceptibility test was carried out. The extract (MIC 175 mu g/mL, MBC 500 mu g/mL) and chloroform fraction (MIC 150 mu g/mL, MBC 250 mu g/mL) were found to have inhibitory activity. The extract and all fractions were assessed using a cytotoxicity test and results showed that concentrations under 100 mu g/mL did not significantly reduce cell viability compared to the control group (p > 0.05, viability > 90%). In order to analyze the inflammatory response, transcriptional factors and cytokines were quantified in the supernatant released from the cells. The chloroform fraction was the most effective in reducing the bacterial colonization (p 0.05, viability > 90%). In order to analyze the inflammatory response, transcriptional factors and cytokines were quantified in the supernatant released from the cells. The chloroform fraction was the most effective in reducing the bacterial colonization (p < 0.05) and controlling inflammatory mediators, and promoted the down-regulation of genes including IL-1beta, IL-6, IL-10, CD14, PTGS, MMP-1 and FOS as well as the reduction of the IL-1beta, IL-6, IL-8 and GM-CSF protein levels (p < 0.05). Malva sylvestris and its chloroform fraction minimized the A. actinomycetemcomitans infection and inflammation processes in oral human cells by a putative pathway that involves important cytokines and receptors. Therefore, this natural product may be considered as a successful dual anti-inflammatory-antimicrobial candidate1010FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORFAPESP [FAPESP - 2011/23980-5]CAPES [CAPES - 2317/2014-01]2011/23980-5; 2317/2014-01sem informaçã

Antibacterial activity of essential oils and their isolated constituents against cariogenic bacteria: a systematic review

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORDental caries remains the most prevalent and costly oral infectious disease worldwide. Several methods have been employed to prevent this biofilm-dependent disease, including the use of essential oils (EOs). In this systematic review, we discuss the antibacterial activity of EOs and their isolated constituents in view of a potential applicability in novel dental formulations. Seven databases were systematically searched for clinical trials, in situ, in vivo and in vitro studies addressing the topic published up to date. Most of the knowledge in the literature is based on in vitro studies assessing the effects of EOs on caries-related streptococci (mainly Streptococcus mutans) and lactobacilli, and on a limited number of clinical trials. The most promising species with antibacterial potential against cariogenic bacteria are: Achillea ligustica, Baccharis dracunculifolia, Croton cajucara, Cryptomeria japonica, Coriandrum sativum, Eugenia caryophyllata, Lippia sidoides, Ocimum americanum, and Rosmarinus officinalis. In some cases, the major phytochemical compounds determine the biological properties of EOs. Menthol and eugenol were considered outstanding compounds demonstrating an antibacterial potential. Only L. sidoides mouthwash (1%) has shown clinical antimicrobial effects against oral pathogens thus far. This review suggests avenues for further non-clinical and clinical studies with the most promising EOs and their isolated constituents bioprospected worldwide.Dental caries remains the most prevalent and costly oral infectious disease worldwide. Several methods have been employed to prevent this biofilm-dependent disease, including the use of essential oils (EOs). In this systematic review, we discuss the antibacterial activity of EOs and their isolated constituents in view of a potential applicability in novel dental formulations. Seven databases were systematically searched for clinical trials, in situ, in vivo and in vitro studies addressing the topic published up to date. Most of the knowledge in the literature is based on in vitro studies assessing the effects of EOs on caries-related streptococci (mainly Streptococcus mutans) and lactobacilli, and on a limited number of clinical trials. The most promising species with antibacterial potential against cariogenic bacteria are: Achillea ligustica, Baccharis dracunculifolia, Croton cajucara, Cryptomeria japonica, Coriandrum sativum, Eugenia caryophyllata, Lippia sidoides, Ocimum americanum, and Rosmarinus officinalis. In some cases, the major phytochemical compounds determine the biological properties of EOs. Menthol and eugenol were considered outstanding compounds demonstrating an antibacterial potential. Only L. sidoides mouthwash (1%) has shown clinical antimicrobial effects against oral pathogens thus far. This review suggests avenues for further non-clinical and clinical studies with the most promising EOs and their isolated constituents bioprospected worldwide20473297358FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIOR2008/55492-7; 2011/14757-0; 2011/15984-0; 2013/25080-7308644/2011-523038005263/2012-9

Antifungal potential of sideroxylon obtusifolium and syzygium cumini and their mode of action against Candida albicans

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORContext The emergence of resistant pathogens and toxicity of antifungals have encouraged an active search for novel candidates to manage Candida biofilms. Objective In this study, the little known species Sideroxylon obtusifolium T.D. Penn (Sapotacea) and Syzygium cumini (L.) Skeels (Myrtaceae), from the Caatinga biome in Brazil were chemically characterized and explored for their antifungal potential against C. albicans. Materials and methods We determined the effects of hydroalcoholic extracts/fractions upon fungal growth (minimum inhibitory and fungicidal concentrations, MIC/MFC), biofilm morphology (scanning electron microscopy) and viability (confocal laser scanning microscopy), proposed their mode of action (sorbitol and ergosterol assays), and finally investigated their effects against macrophage and keratinocyte cells in a cell-based assay. Data were analysed using one-way analysis of variance with Tukey-Kramer post-test (alpha = 0.05). Results The n-butanol (Nb) fraction from S. obtusifolium and S. cumini extract (Sc) showed flavonoids (39.11 +/- 6.62mg/g) and saponins (820.35 +/- 225.38mg/g), respectively, in their chemical composition and demonstrated antifungal activity, with MICs of 62.5 and 125 mu g/mL, respectively. Nb and Sc may complex with ergosterol as there was a 4-16-fold increase in MICs in the presence of exogenous ergosterol, leading to disrupted permeability of cell membrane. Deleterious effects were observed on morphology and viability of treated biofilms from concentrations as low as their MICs and higher. Sc was not toxic to macrophages and keratinocytes at these concentrations (p> 0.05), unlike Nb. Conclusions Nb and Sc demonstrated considerable antifungal activity and should be further investigated as potential alternative candidates to treat Candida biofilms.The emergence of resistant pathogens and toxicity of antifungals have encouraged an active search for novel candidates to manage Candida biofilms. In this study, the little known species Sideroxylon obtusifolium T.D. Penn (Sapotacea) and Syzygium cumini (L.) Skeels (Myrtaceae), from the Caatinga biome in Brazil were chemically characterized and explored for their antifungal potential against C. albicans. We determined the effects of hydroalcoholic extracts/fractions upon fungal growth (minimum inhibitory and fungicidal concentrations, MIC/MFC), biofilm morphology (scanning electron microscopy) and viability (confocal laser scanning microscopy), proposed their mode of action (sorbitol and ergosterol assays), and finally investigated their effects against macrophage and keratinocyte cells in a cell-based assay. Data were analysed using one-way analysis of variance with Tukey-Kramer post-test (alpha = 0.05). The n-butanol (Nb) fraction from S. obtusifolium and S. cumini extract (Sc) showed flavonoids (39.11 +/- 6.62mg/g) and saponins (820.35 +/- 225.38mg/g), respectively, in their chemical composition and demonstrated antifungal activity, with MICs of 62.5 and 125 mu g/mL, respectively. Nb and Sc may complex with ergosterol as there was a 4-16-fold increase in MICs in the presence of exogenous ergosterol, leading to disrupted permeability of cell membrane. Deleterious effects were observed on morphology and viability of treated biofilms from concentrations as low as their MICs and higher. Sc was not toxic to macrophages and keratinocytes at these concentrations (p> 0.05), unlike Nb. Nb and Sc demonstrated considerable antifungal activity and should be further investigated as potential alternative candidates to treat Candida biofilms541023122319FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIOR2013/25080-7; 2014/01723-9; 2011/23635-6308644/2011-5; 150682/2014-0552561/2011-

Anti-inflammatory, anti-osteoclastogenic and antioxidant effects of Malva sylvestris extract and fractions: in vitro and in vivo studies

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOGiven their medical importance, natural products represent a tremendous source of drug discovery. The aim of this study was to investigate Malva sylvestris L. extract and fractions and their pharmacological activities followed by chemical identification. The aqueous fraction (AF) was identified as the bioactive fraction in the in vitro and in vivo assays. The AF controlled the neutrophil migration to the peritoneal cavity by 66%, inhibited the antiedematogenic activity by 58.8%, and controlled IL-1 beta cytokine expression by 54%. The in vitro viability tests showed a concentration-dependent effect, where the MSE and fractions at concentrations under 10 mu g/ mL were non-toxic to cells. Transcriptional factors of carbonic anhydrase II (CAII), cathepsin K (Ctsk) and tartrate-resistant acid phosphatase (TRAP) were analyzed by qPCR in RAW 264.7 cell lines. The gene expression analysis showed that the AF was the only treatment that could downregulate all the study genes: CAII, Ctsk and TRAP (p<0.05). TRAP staining was used to evaluate osteoclast formation. AF treatments reduced the number of osteoclastogenesis 2.6-fold compared to the vehicle control group. Matrix metalloproteinase 9 (MMP-9) activity decreased 75% with the AF treatment. Moreover, the bioactive fraction had the ability to regulate the oxidation pathway in the ABTS (2,2-Azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) assay with an activity equivalent to 1.30 mu mol Trolox/g and DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals 1.01 g/L. Positive ion ESI-mass spectrometry for molecular ions at m/z 611 and 633 confirmed rutin as the major compound in the AF. The AF of M. sylvestris presented anti-inflammatory, controlled osteoclastogenic mechanisms and antioxidant abilities in different in vitro and in vivo methods. In addition, we suggest that given its multi-target activity the bioactive fraction may be a good candidate in the therapy of chronic inflammatory diseases.Given their medical importance, natural products represent a tremendous source of drug discovery. The aim of this study was to investigate Malva sylvestris L. extract and fractions and their pharmacological activities followed by chemical identification. The aqueous fraction (AF) was identified as the bioactive fraction in the in vitro and in vivo assays. The AF controlled the neutrophil migration to the peritoneal cavity by 66%, inhibited the antiedematogenic activity by 58.8%, and controlled IL-1 beta cytokine expression by 54%. The in vitro viability tests showed a concentration-dependent effect, where the MSE and fractions at concentrations under 10 mu g/ mL were non-toxic to cells. Transcriptional factors of carbonic anhydrase II (CAII), cathepsin K (Ctsk) and tartrate-resistant acid phosphatase (TRAP) were analyzed by qPCR in RAW 264.7 cell lines. The gene expression analysis showed that the AF was the only treatment that could downregulate all the study genes: CAII, Ctsk and TRAP (p<0.05). TRAP staining was used to evaluate osteoclast formation. AF treatments reduced the number of osteoclastogenesis 2.6-fold compared to the vehicle control group. Matrix metalloproteinase 9 (MMP-9) activity decreased 75% with the AF treatment. Moreover, the bioactive fraction had the ability to regulate the oxidation pathway in the ABTS (2,2-Azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) assay with an activity equivalent to 1.30 mu mol Trolox/g and DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals 1.01 g/L. Positive ion ESI-mass spectrometry for molecular ions at m/z 611 and 633 confirmed rutin as the major compound in the AF. The AF of M. sylvestris presented anti-inflammatory, controlled osteoclastogenic mechanisms and antioxidant abilities in different in vitro and in vivo methods. In addition, we suggest that given its multi-target activity the bioactive fraction may be a good candidate in the therapy of chronic inflammatory diseases119FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO2011/23980-

Phenolic composition, antibacterial and antioxidant activities of brazilian red propolis

Propolis is a resinous hive product collected by honeybees from various plant sources. It has a complex chemical composition, constituted by various phenolic compounds. Extracts of increasing polarity (n-hexane, chloroform, and ethanol) were obtained from a sample of red propolis from the state of Alagoas. Assays were carried out for determination of contents of phenolics, along with antibacterial and antioxidant activities. The EEP, fractions and sub-fractions showed strong biological activities and were related with phenolic the content compounds contents. The sub-fractions were more bioactive than the EEP and fractions, demonstrating that the antioxidant and antibacterial activities are not a result of synergistic effect between the various chemical compounds in propolis.FAPES

Apolar bioactive fraction of melipona scutellaris geopropolis on streptococcus mutans biofilm

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOThe aim of this study was to evaluate the influence of the bioactive nonpolar fraction of geopropolis on Streptococcus mutans biofilm. The ethanolic extract of Melipona scutellaris geopropolis was subjected to a liquid-liquid partition, thus obtaining the bioactive hexane fraction (HF) possessing antimicrobial activity. The effects of HF on S. mutans UA159 biofilms generated on saliva-coated hydroxyapatite discs were analyzed by inhibition of formation, killing assay, and glycolytic pH-drop assays. Furthermore, biofilms treated with vehicle control and HF were analyzed by scanning electron microscopy (SEM). HF at 250  μ g/mL and 400  μ g/mL caused 38% and 53% reduction in the biomass of biofilm, respectively, when compared to vehicle control (P 0.05). In conclusion, the bioactive HF of geopropolis was promising to control the S. mutans biofilm formation, without affecting the microbial population but interfering with its structure by reducing the biochemical content of biofilm matrix.The aim of this study was to evaluate the influence of the bioactive nonpolar fraction of geopropolis on Streptococcus mutans biofilm. The ethanolic extract of Melipona scutellaris geopropolis was subjected to a liquid-liquid partition, thus obtaining the bioactive hexane fraction (HF) possessing antimicrobial activity. The effects of HF on S. mutans UA159 biofilms generated on saliva-coated hydroxyapatite discs were analyzed by inhibition of formation, killing assay, and glycolytic pH-drop assays. Furthermore, biofilms treated with vehicle control and HF were analyzed by scanning electron microscopy (SEM). HF at 250 μg/mL and 400 μg/mL caused 38% and 53% reduction in the biomass of biofilm, respectively, when compared to vehicle control (P  0.05). In conclusion, the bioactive HF of geopropolis was promising to control the S. mutans biofilm formation, without affecting the microbial population but interfering with its structure by reducing the biochemical content of biofilm matrix2013FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO2009/12354-6; 2010/20214-7; 2013/10879-

The correlation between the phenolic composition and biological activities of two varieties of Brazilian propolis (G6 and G12)

Biological assays that have been performed on different types of Brazilian propolis have shown that type 6 propolis (G6) has a strong antimicrobial activity and a low flavonoid content. This study aimed to evaluate the correlation between the phenolic composition and the biological activities displayed by propol is G6 from the state of Bahia and green propol is, also known as type 12 (G12). The values of the flavonoids and the total phenolics in propol is G6 were different than those in propolis G12. Although the G12 variety presented greater antioxidant activity, propolis G6 proved to have greater antimicrobial and cytotoxic activities. The results showed that the phenolic compounds may not be the only compounds responsible for the biological activity. More detailed studies of the chemical composition and an assessment or the biological activity are required to establish the quality of propolis.Ensaios biológicos realizados com diferentes tipos de própolis brasileira têm mostrado que a própolis \ud do tipo 6 (G6) tem forte atividade antimicrobiana e menor teor de flavonóides. Este trabalho teve \ud como objetivo avaliar a correlação entre a composição fenólica e atividades biológicas apresentadas \ud pela própolis G6, do Estado da Bahia, e a própolis verde, do tipo 12 (G12). Os teores de flavonóides e \ud fenólicos totais na própolis G6 foram diferentes dos teores da própolis G12. Apesar da G12 apresentar \ud maior atividade antioxidante, a própolis G6 apresenta maior atividade antimicrobiana e citotóxica. \ud Os resultados mostraram que os compostos fenólicos não são os únicos compostos responsáveis pela \ud atividade biológica da própolis. Estudos mais específicos da composição química, em adição à avaliação \ud das atividades biológicas, são requeridos para determinar a qualidade da própolis

Própolis do sudeste e nordeste do Brasil: influência da sazonalidade na atividade antibacteriana e composição fenólica

The composition and biological activities of propolis, a resinous hive product collected by honeybees from various plant sources, depends on various factors such as season and vegetation of the area. The aim of this study was to evaluate the influence of the seasonal effect on the ethanolic extracts of Brazilian propolis (EEP) type 6 and type 12, collected during 6 months in terms of antibacterial activity and phenolic composition. The antimicrobial properties were evaluated by MIC and MBC on S. mutans Ingbritt 1600 and the profile of chemical composition by UV-visible spectrophotometry, HPLC-RF and GC-MS. The results demonstrated that the season in which propolis is collected influences its chemical composition, resulting in modifications in its antibacterial activity

Propolis from southeastern and northeastern of Brazil: the influence of seasonality in antibacterial activity and phenolic composition

The composition and biological activities of propolis, a resinous hive product collected by honeybees from various plant sources, depends on various factors such as season and vegetation of the area. The aim of this study was to evaluate the influence of the seasonal effect on the ethanolic extracts of Brazilian propolis (EEP) type 6 and type 12, collected during 6 months in terms of antibacterial activity and phenolic composition. The antimicrobial properties were evaluated by MIC and MBC on S. mutans Ingbritt 1600 and the profile of chemical composition by UV-visible spectrophotometry, HPLC-RF and GC-MS. The results demonstrated that the season in which propolis is collected influences its chemical composition, resulting in modifications in its antibacterial activity.The composition and biological activities of propolis, a resinous hive product collected by honeybees from various plant sources, depends on various factors such as season and vegetation of the area. The aim of this study was to evaluate the influence of the seasonal effect on the ethanolic extracts of Brazilian propolis (EEP) type 6 and type 12, collected during 6 months in terms of antibacterial activity and phenolic composition. The antimicrobial properties were evaluated by MIC and MBC on S. mutans Ingbritt 1600 and the profile of chemical composition by UV-visible spectrophotometry, HPLC-RF and GC-MS. The results demonstrated that the season in which propolis is collected influences its chemical composition, resulting in modifications in its antibacterial activity.3071512151