Brazilian red propolis in combination with ß-lactams exerts an efficient antibacterial action over methicillin-resistant Staphylococcus aureus (MRSA) strains.

AIMS: The antibacterial activity of red propolis extract (RPE) and brown propolis extracts (BPE) and the synergistic effect of RPE with cefoxitin (CEFO), imipenem (IMI), and ertapenem (ERTA) was evaluated in vitro against methicillin-resistant Staphylococcus aureus (MRSA) strains. METHODS AND RESULTS: MRSA ATCC 33591, community-associated (CA-MRSA) USA300, and four clinical isolates were used. A broth microdilution assay was performed to obtain inhibitory and bactericidal concentrations of BPE, RPE, CEFO, IMI, and ERTA. RPE in combination with CEFO, IMI, and ERTA was evaluated on the formation or eradication of biofilm. The bacterial relative membrane conductivity of the strains was assessed after RPE and combinations exposition. Surface/binding computational analyzes between RPE compounds and penicillin binding protein 2a (PBP2a) were performed. BPE samples had no activity against MRSA (MICs 3.2-5 g l-1; MBCs 10-15 g l-1), so the subsequent assays were carried out only with RPE and antimicrobials. RPE exerted a bacteriostatic action (MICs 0.0156-0.125 g l-1; MBCs 0.5-2 g l-1) but the combinations with IMI and ERTA showed the highest inhibition, as observed in the time-kill curve. However, the FICI index showed synergism (≥0.5) only to RPE + IMI. This combination was the most effective in inhibiting the biofilm and showed the highest values of membrane conductivity. Computational predictions indicated that RPE constituents may interact with PBP2a. CONCLUSION: RPE and RPE + IMI exerted an antibacterial and antibiofilm activity on MRSA strains probably due to membrane/wall damage and interactions with PBP2a.

Brazilian red propolis exerts a cytotoxic action against prostate cancer cells and upregulates human monocyte functions.

Different propolis samples can be obtained in Brazil, such as green, brown and red. Studies related to Brazilian red propolis (BRP) have increased in the last few years, so the aim of this study was to investigate its effects on the prostate cell lines LNCaP and PC-3 and on human monocytes. BRP chemical composition was analyzed by HPLC-DAD, the viability of monocyte and cancer cell by MTT assay. Cytokine production (TNF-α, IL-1ß, IL-6, IL-10) by monocytes was quantitated by ELISA, the expression of cell markers (TLR-2, TLR-4, HLA-DR, CD80) and reactive oxygen species by flow cytometry. The candidacidal activity and the effects of supernatant of treated monocytes on tumor cells were assessed. BRP affected LNCaP viability after 48 and 72 h, while PC-3 cells were more resistant over time. BRP upregulated CD80 and HLA-DR expression, and stimulated TNF-α, IL-6 and IL-10 production. BRP enhanced the fungicidal activity of monocytes, displayed an antioxidant action and the supernatant of BRP-treated monocytes diminished LNCaP viability. In the search for new immunomodulatory and antitumoral agents, BRP exerted a selective cytotoxic activity on prostate cancer cells and an immunomodulatory action, suggesting its potential for clinical trials with oncological patients and for the discovery of new immunomodulatory and antitumor drugs.

Brazilian green propolis: A novel tool to improve the cytotoxic and immunomodulatory action of docetaxel on MCF-7 breast cancer cells and on women monocyte.

Docetaxel (DTX) is used against breast cancer despite its side effects such as toxicity and immunosuppression. Here we investigated the cytotoxic and immunomodulatory effects of the ethanol solution extract of propolis (EEP) in combination with DTX on MCF-7 breast cancer cells and on women's monocyte. The cytotoxic potential of EEP + DTX was assessed by MTT assay and the type of tumor cell death was evaluated by flow cytometry. The effects of EEP + DTX on the migration and invasion of MCF-7 cells were analyzed. Cytokine production by monocytes was assessed by ELISA and the expression of cell surface markers was evaluated by flow cytometry. We also assessed the fungicidal activity of monocytes against Candida albicans and the generation of reactive oxygen species (ROS). Finally, the impact of the supernatants of treated monocytes in the viability, migration, and invasiveness of tumor cells was assessed. EEP enhanced the cytotoxicity of DTX alone against MCF-7 cells by inducing necrosis and inhibiting their migratory ability. EEP + DTX exerted no cytotoxic effects on monocytes and stimulated HLA-DR expression, TNF-α, and IL-6 production, exerted an immunorestorative action in the fungicidal activity, and reduced the oxidative stress. Our findings have practical implications and reveal new insights for complementary medicine.

Effects of Propolis and Phenolic Acids on Triple-Negative Breast Cancer Cell Lines: Potential Involvement of Epigenetic Mechanisms.

Triple-negative breast cancer is an aggressive disease frequently associated with resistance to chemotherapy. Evidence supports that small molecules showing DNA methyltransferase inhibitory activity (DNMTi) are important to sensitize cancer cells to cytotoxic agents, in part, by reverting the acquired epigenetic changes associated with the resistance to therapy. The present study aimed to evaluate if chemical compounds derived from propolis could act as epigenetic drugs (epi-drugs). We selected three phenolic acids (caffeic, dihydrocinnamic, and p-coumaric) commonly detected in propolis and the (-)-epigallocatechin-3-gallate (EGCG) from green tea, which is a well-known DNA demethylating agent, for further analysis. The treatment with p-coumaric acid and EGCG significantly reduced the cell viability of four triple-negative breast cancer cell lines (BT-20, BT-549, MDA-MB-231, and MDA-MB-436). Computational predictions by molecular docking indicated that both chemicals could interact with the MTAse domain of the human DNMT1 and directly compete with its intrinsic inhibitor S-Adenosyl-l-homocysteine (SAH). Although the ethanolic extract of propolis (EEP) did not change the global DNA methylation content, by using MS-PCR (Methylation-Specific Polymerase Chain Reaction) we demonstrated that EEP and EGCG were able to partly demethylate the promoter region of RASSF1A in BT-549 cells. Also, in vitro treatment with EEP altered the RASSF1 protein expression levels. Our data indicated that some chemical compound present in the EEP has DNMTi activity and can revert the epigenetic silencing of the tumor suppressor RASSF1A. These findings suggest that propolis are a promising source for epi-drugs discovery.

The chemical composition and events related to the cytotoxic effects of propolis on osteosarcoma cells: A comparative assessment of Colombian samples.

Osteosarcoma (OSA) is a type of bone cancer showing an aggressive biological behavior with metastatic progression. Because propolis potential for the development of new antitumoral drugs has been indicated, we evaluated the chemical composition of Colombian propolis samples and the mechanisms involved in their cytotoxic effects on OSA cells. The chemical composition was analyzed by GC-MS and the DPPH free radical scavenging activity was measured. Cluster and principal components analysis were used to establish an association with their inhibitory concentration 50% (IC50 ). Cell viability was analyzed by MTT assay; apoptosis was determined by flow cytometry; mitochondrial membrane permeability and reactive oxygen species were evaluated by rhodamine 123 and DCFH-DA. Transwell assay was used to evaluate the invasiveness of propolis-treated cells. Samples were grouped: Cluster 1 contained diterpenes and benzophenones and showed the highest antiradical activity; Cluster 2 was characterized by triterpenes, fatty acid, and diterpenes. Usm contained diterpenes and triterpenes different of the other samples and Sil contained triterpenes and flavonoids. Apoptosis, mitochondrial membrane alteration, and suppression of cell invasion were the main mechanisms involved in the inhibition of OSA cells in vitro, suggesting the potential of Colombian propolis to discover new antitumor drugs.

Brazilian propolis promotes immunomodulation on human cells from American Tegumentar Leishmaniasis patients and healthy donors infected with L. braziliensis.

American Tegumentar Leishmaniasis (ATL) is an infectious disease caused by Leishmania parasites with ineffective treatment. The properties of propolis have been studied in different experimental studies, however, few works have investigated the effects of propolis on human-derived peripheral blood mononuclear cells (PBMC) in leishmaniasis models. Thus, we investigate the immunomodulatory effects of propolis treatment on PBMC from ATL patients and on PBMC from healthy donors infected with Leishmania braziliensis. Our data demonstrate that propolis pretreatment shows immunomodulatory effects on both healthy donors and ATL patients adherent cells, increasing IL-4 and IL-17 and decreasing IL-10, in either the presence or absence of the L. braziliensis infection, demonstrating that propolis contributes with the decrease of the inflammation and could also contribute with parasite control.

Citral and eugenol modulate DNA damage and pro-inflammatory mediator genes in murine peritoneal macrophages.

Citral and eugenol have been broadly studied because of their anti-inflammatory, antioxidant and antiparasitic potentials. In this study, the effects of citral (25, 50 and 100 µg/mL) and eugenol (0.31, 0.62, 1.24 and 2.48 µg/mL) on the expression (RT-PCR) of the pro-inflammatory mediator genes NF-κB1, COX-2 and TNF-α were evaluated in mouse peritoneal macrophages with or without activation by a bacterial lipopolysaccharide (LPS). Additionally, the genotoxic potentials of two compounds and their capacities to modulate the DNA damage induced by doxorubicin (DXR) were investigated using the comet assay. The data revealed that neither citral nor eugenol changed COX-2, NF-κB1 or TNF-α expression in resting macrophages. However, in LPS-activated cells, citral induced the hypoexpression of COX-2 (100 µg/mL) and TNF-α (50 and 100 µg/mL). Hypoexpression of TNF-α was also detected after cellular exposure to eugenol at the highest concentration (2.48 µg/mL). Both compounds exhibited genotoxic potential (citral at 50 and 100 µg/mL and eugenol at all concentrations) but also showed chemopreventive effects, in various treatment protocols. Both citral and eugenol might modulate inflammatory processes and DXR-induced DNA damage, but the use of these compounds must be viewed with caution because they are also able to induce primary DNA lesions.

Propolis: Antineoplastic Activity, Constituents, and Mechanisms of Action.

Propolis is a beehive product with great pharmacological potential, including antineoplastic activity. OBJECTIVES: The aim of this study is to provide an actual understanding of the existent scientific information regarding the antiproliferative effect of propolis, proposed mechanisms of action, and challenges to meet. METHODS: An assessment of the scientific literature was attained using the PubMed and SciFinder platforms. Research papers, clinical trials, and reviews published between the years 2000 - 2021, were considered. The words "anticancer", "antitumor", "antiproliferative" and "propolis" were used in the search criteria. CONCLUSION: A summary of several antiproliferative activities of different types of propolis is exposed. The potential health benefits of propolis are discussed. The variable plant origin of propolis partially accounts for its anti-cancer activities. Even when some mechanisms of action of propolis have been proposed, much of the genesis of how this effect is produced is yet to be answered, including several molecular mechanisms in different biological systems.

Propolis anti-inflammatory effects on MAGE-1 and retinoic acid-treated dendritic cells and on Th1 and T regulatory cells.

Background: Propolis exhibits huge potential in the pharmaceutical industry. In the present study, its effects were investigated on dendritic cells (DCs) stimulated with a tumor antigen (MAGE-1) and retinoic acid (RA) and on T lymphocytes to observe a possible differential activation of T lymphocytes, driving preferentially to Th1 or Treg cells. Methods: Cell viability, lymphocyte proliferation, gene expression (T-bet and FoxP3), and cytokine production by DCs (TNF-α, IL-10, IL-6 and IL-1ß) and lymphocytes (IFN-γ and TGF-ß) were analyzed. Results: MAGE-1 and RA alone or in combination with propolis inhibited TNF-α production and induced a higher lymphoproliferation compared to control, while MAGE-1 + propolis induced IL-6 production. Propolis in combination with RA induced FoxP3 expression. MAGE-1 induced IFN-γ production while propolis inhibited it, returning to basal levels. RA inhibited TGF-ß production, what was counteracted by propolis. Conclusion: Propolis affected immunological parameters inhibiting pro-inflammatory cytokines and favoring the regulatory profile, opening perspectives for the control of inflammatory conditions.

Propolis consumption by asymptomatic HIV-individuals: Better redox state? A prospective, randomized, double-blind, placebo-controlled trial.

Propolis is a natural product has many biological properties of clinical interest, such as anti-inflammatory and antioxidant. Considering that people living with HIV/aids (PLWHA) on effective combined antiretroviral therapy (cART) present early aging due to an intense immune activation, inflammation, and redox imbalance, propolis consumption could offer a benefit to such patients. This double-blind longitudinal study evaluated whether Brazilian green propolis pills intake (500 mg/day for three months) would decrease the oxidative stress of virological suppressed HIV-individuals. To compare each group (propolis, n = 20 versus placebo, n = 20) in both moments (M0, before and M1, after the intervention), the following markers were assessed: plasma malondialdehyde (MDA), carbonylation, total oxide nitric, total antioxidant capacity (TAP), superoxide dismutase, catalase, and NFkB and NRF2 gene expression. Data were analyzed using Poisson, Gamma distribution and ANOVA followed by Tukey-Kramer. The groups were homogeneous regarding age, gender, time of diagnosis/ treatment, cART scheme, CD4+ T cell count, and no changes were observed in the diet food, or patients' lifestyles. A decreased MDA concentration was seen in the propolis group (M0 = 0.24 ± 0.13, M1 = 0.20 ± 0.10 protein nmol/mg; p = 0.005) as well as a slight but non-significant increase of TAP (M0 = 49.07 ± 13.26, M1 = 52.27 ± 14.86%; p = 0.06). One may conclude that propolis promoted a lower lipid peroxidation and improved the antioxidant system, suggesting that its use may be beneficial to PLWHA in an attempt to contain the intense inflammatory and oxidant activity.

Propolis antiviral and immunomodulatory activity: a review and perspectives for COVID-19 treatment.

OBJECTIVES: Viral outbreaks are a frequent concern for humans. A great variety of drugs has been used to treat viral diseases, which are not always safe and effective and may induce adverse effects, indicating the need for new antiviral drugs extracted from natural sources. Propolis is a bee-made product exhibiting many biological properties. An overview of viruses, antiviral immunity, propolis safety and its immunomodulatory and antiviral action is reported, as well as perspectives for coronavirus disease 2019 (COVID-19) treatment. PubMed platform was used for data collection, searching for the keywords "propolis", "virus", "antiviral", "antimicrobial" and "coronavirus". KEY FINDINGS: Propolis is safe and exerts antiviral and immunomodulatory activity; however, clinical trials should investigate its effects on individuals with viral diseases, in combination or not with antiviral drugs or vaccines. SUMMARY: Regarding COVID-19, the effects of propolis should be investigated directly on the virus in vitro or on infected individuals alone or in combination with antiviral drugs, due to its immunomodulatory and anti-inflammatory action. Propolis administration simultaneously with vaccines should be analyzed, due to its adjuvant properties, to enhance the individuals' immune response. The search for therapeutic targets may be useful to find out how propolis can help to control COVID-19.

Propolis from southeastern Brazil produced by Apis mellifera affects innate immunity by modulating cell marker expression, cytokine production and intracellular pathways in human monocytes.

OBJECTIVES: Propolis is a bee-made product used for centuries due to its diverse biological properties, including its immunomodulatory action. This work aimed at investigating whether propolis may affect monocyte functions challenged with retinoic acid (RA), B subunit of Escherichia coli heat-labile enterotoxin (EtxB), human melanoma-associated antigen-1 (MAGE-1) and lipopolysaccharide (LPS). METHODS: Monocytes from healthy donors were treated with the stimuli separately or in the presence of propolis. Cell viability was evaluated by MTT assay, cell marker expression was assessed by flow cytometry, cytokine production by ELISA, gene expression by RT-qPCR. KEY FINDINGS: Propolis alone maintained TLR-2, TLR-4, HLA-DR, CD40 and CD80 expression in the monocytes; however, its combination with either MAGE-1 or LPS decreased CD40 expression triggered by the stimuli. Propolis maintained RA action on cell marker expression. Propolis inhibited TNF-α (with either EtxB or MAGE-1) and IL-6 (with either RA or MAGE-1), and increased IL-10 (with MAGE-1) production. Propolis downmodulated LC3 expression induced by LPS. It also induced a lower NF-kB expression than control cells and its combination with RA induced a higher expression than the stimulus alone. CONCLUSIONS: Propolis potentially affected innate immunity by downmodulating the monocytes pro-inflammatory activity.

Apoptosis-related gene expression induced by Colombian propolis samples in canine osteosarcoma cell line.

BACKGROUND AND AIM: Osteosarcoma (OSA) is the most common bone tumor in canines and humans. This study aimed to assess the cytotoxic and apoptotic effects of Colombian propolis samples on a canine OSA cell line (OSCA-8) by evaluating the expression of BCL-2, BAX, CASPASE 9, CASPASE 8, and TNFR1 genes involved in the apoptosis pathway. MATERIALS AND METHODS: After treating the cells with five Colombian propolis samples (Usm, Met, Fus, Sil, and Caj), we evaluated cell viability and lactate dehydrogenase (LDH) release. Early and late apoptosis was determined by flow cytometry using annexin V/propidium iodide. Furthermore, the effects of three selected samples on gene expression were analyzed by real-time polymerase chain reaction. RESULTS: The Colombian propolis samples reduced OSCA-8 cell viability and increased LDH release. All samples induced apoptosis significantly and upregulated BCL-2 and CASPASE 8 expression. Usm and Sil increased BAX expression, Met and Sil induced CASPASE 9 expression, and Usm increased TNFR1. CONCLUSION: Colombian propolis samples exhibited cytotoxic and apoptotic effects on canine OSA cells, and CASPASE 8 upregulation indicated apoptosis induction by the extrinsic pathway.

Propolis increases Foxp3 expression and lymphocyte proliferation in HIV-infected people: A randomized, double blind, parallel-group and placebo-controlled study.

HIV infection and the prolonged use of antiretroviral therapy (ART) contribute to persistent inflammation and immune deregulation in people living with HIV/AIDS (PLWHA). Propolis is a bee product with plenty of biological properties, including immunomodulatory and anti-inflammatory action. This work aimed to evaluate possible changes in the immune/inflammatory response in PLWHA under ART after propolis intake. Asymptomatic PLWHA were double-blindly randomized into parallel groups receiving propolis (500 mg/day, n = 20) for 3 months or placebo (n = 20). Plasma cytokines (TNF-α, IL-2, IL-4, IL-6, IL-10 and IL17) were evaluated by cytometric bead array; cytokine production by PBMC (IFN-γ, IL-5, IL-17, IL-10, IL-1ß, IL-18, and IL-33) was assessed by ELISA; gene expression (T-bet, GATA-3, RORγt and Foxp3) was determined by RT-qPCR, and cell proliferation was analysed by flow cytometry using CFSE staining. The average of gender, age, CD4+/CD8+ T cell count, time of diagnosis and treatment were similar in both groups. No differences were observed in cytokine levels nor in inflammasome activation. However, Pearson's correlation showed that IL-10 was directly correlated to CD4+ T cell count and inversely to IFN-γ after treatment with propolis. Foxp3 expression and lymphocyte proliferation increased in the propolis group. Data suggested that daily propolis consumption may improve the immune response and decrease the inflammatory status in asymptomatic PLWHA under ART.

Polymerase chain reaction detection of enterotoxins genes in coagulase-negative staphylococci isolated from Brazilian Minas cheese.

For a long time, Staphylococcus aureus has been always thought to be the only pathogenic species among Staphylococcus, while coagulase-negative staphylococci (CNS) were classified as contaminant agents. However, molecular techniques have shown that these microorganisms also possess enterotoxin-encoding genes. The aim of this study was to analyze the frequency of genes for staphylococcal enterotoxins SEA, SEB, SEC, and SED in CNS strains isolated from Minas soft cheese and to assess the in vitro production of toxins. CNS were found in 65 (72.2%) samples of cheese: 23 were Staphylococcus saprophyticus, 16 Staphylococcus warneri, 10 Staphylococcus epidermidis, 9 Staphylococcus xylosus, 3 Staphylococcus haemolyticus, 2 Staphylococcus schleiferi subsp. schleiferi, and 1 each Staphylococcus capitis subsp. urealyticus and Staphylococcus caprae. Seventeen (26.2%) CNS strains had genes for enterotoxins, and sea was more frequently found (18.5%), followed by sec in three and seb in two strains, whereas the sed gene was not found. S. saprophyticus showed enterotoxin genes in 6 of 23 isolates, but only sea was observed. On the other hand, five strains of S. warneri showed the sea, seb, or sec gene. In spite of the presence of these enterotoxin genes, these strains did not produce enterotoxins in vitro. It is essential to understand the real role of CNS in food, and based on the presence of enterotoxin genes, CNS should not be ignored in epidemiological investigations of foodborne outbreaks.

In vitro cytotoxic effect of Brazilian green propolis on human laryngeal epidermoid carcinoma (HEp-2) cells.

Propolis is a sticky dark-colored material showing a very complex chemical composition that honeybees collect from plants. It has been used in folk medicine since ancient times, due to several biological properties, such as antimicrobial, anti-inflammatory, antioxidant and immunomodulatory activities, among others. Its antitumor action in vivo and in vitro has also been reported, using propolis extracts or its isolated compounds. The goal of this work was to evaluate propolis's cytotoxic action in vitro on human laryngeal epidermoid carcinoma (Hep-2) cells. These cells were incubated with different concentrations of this bee product for different time periods, and morphology and the number of viable HEp-2 cells analyzed. Data showed that propolis exhibited a cytotoxic effect in vitro against HEp-2 cells, in a dose- and time-dependent way. Propolis solvent had no effects on morphology and number of viable cells, proving that the cytotoxic effects were exclusively due to propolis components. Since humans have been using propolis for a long time, further assays will provide a better comprehension of propolis's antitumor action.

Beyond the Biological Effect of a Chemically Characterized Poplar Propolis: Antibacterial and Antiviral Activity and Comparison with Flurbiprofen in Cytokines Release by LPS-Stimulated Human Mononuclear Cells.

Bee propolis, especially Euro-Asian poplar propolis, is among the most well-known natural products traditionally used to treat pharyngitis and minor wounds. The aim of this research was to investigate the pharmacological properties responsible for poplar propolis effectiveness using, for the first time, different in vitro approaches applied to a chemically characterized sample. The anti-inflammatory activity was compared with flurbiprofen by determining pro-inflammatory cytokines released by lipopolysaccharide-stimulated human peripheral blood mononuclear cells (PBMC). The antibacterial activity against Gram+ and Gram- bacteria was assessed, as well as antiviral effects on H1N1 influenza a virus. Poplar propolis (5 and 25 µg/mL) exerted a concentration-dependent anti-inflammatory activity. In this range of concentrations, propolis effect was not inferior to flurbiprofen on cytokines released by lipopolysaccharide (LPS)-stimulated human PBMC. Poplar propolis was found to upregulate IL-6 and IL-1ß in non-stimulated PBMC. S. aureus, S. pyogenes, and S. pneumoniae were the most susceptible bacterial strains with inhibitory concentrations ranging from 156 to 625 µg/mL. A direct anti-influenza activity was not clearly seen. Effective anti-inflammatory concentrations of propolis were significantly lower than the antibacterial and antiviral ones and results suggested that the anti-inflammatory activity was the most important feature of poplar propolis linked to its rationale use in medicine.

A new chemotherapeutic approach using doxorubicin simultaneously with geopropolis favoring monocyte functions.

AIMS: Chemotherapy has been widely used to treat cancer although it may affect non-target cells involved in the immune response. This work aimed at elucidating whether the chemotherapeutic agent doxorubicin in combination with geopropolis produced by Melipona fasciculata Smith could affect nontumor immune cells, evaluating their immunomodulatory effects on human monocytes. MAIN METHODS: Cell viability, expression of cell markers (HLA-DR, TLR-2, TLR-4, C80 and CD40), cytokine production (TNF-α, IL-1ß, IL-6 and IL-10), intracellular pathways (NF-κB and autophagy), the microbicidal activity of monocytes and hydrogen peroxide (H2O2) production were analyzed. KEY FINDINGS: Data showed that doxorubicin + geopropolis diminished IL-6 secretion, stimulated TNF-α and IL-10 production, TLR-4 and CD80 expression, NF-κB and autophagy pathway, as well as the bactericidal activity. SIGNIFICANCE: Our findings revealed a new chemotherapeutic approach using doxorubicin simultaneously with geopropolis without affecting human monocytes viability and exerting immunomodulatory effects, favoring cell functions. While doxorubicin altered some immunological parameters, the addition of geopropolis compensated some changes.

Positive effects of antitumor drugs in combination with propolis on canine osteosarcoma cells (spOS-2) and mesenchymal stem cells.

The combination of lower concentrations of antitumor drugs (carboplatin - CARB, doxorubicin - DOX, and methotrexate - MET) with propolis was investigated against canine osteosarcoma (spOS-2) and mesenchymal stem cells (MSC) in vitro. The mechanism of action in the combinations was analyzed. spOS-2 cells were incubated up to 72 h with propolis (50 µg/ml) alone or in combination with CARB (10-400 µmol/l), DOX (0.5-2 µmol/l) or MET (50-200 µmol/l). Cell viability was assessed by MTT assay, apoptosis/necrosis by flow cytometry, and MSC was incubated with the optimum combination. Propolis alone exerted no cytotoxic action against spOS-2 cells, whereas CARB (400, 200 and 100 µmol/l) exhibited the highest cytotoxic effects comparing to DOX and MET. The combination of propolis with the lowest concentrations of CARB led to better results comparing to CARB alone, which was not observed using DOX and MET. Apoptosis was involved in the action of propolis + CARB in spOS-2 cells. MSC were not affected by CARB/propolis, indicating that the cytotoxic action of the combination was specific to tumor cells but not to normal ones. Propolis improved the action of CARB against spOS-2 cells using lower concentrations of this drug, without affecting MSC. These findings are relevant and indicate a possible application of propolis in OSA treatment.

Microbiological control and antibacterial action of a propolis-containing mouthwash and control of dental plaque in humans.

Propolis is a bee product with several biological properties. This study aimed at investigating a propolis-containing mouthwash, its organoleptic properties, microbial contamination and its antibacterial action in vitro. This mouthwash was assessed in vivo to control dental plaque in humans. The presence of microorganisms was analyzed and the minimum inhibitory concentration against Streptococcus mutans was determined. A comparative study was done in vivo using propolis, chlorhexidine, and propolis plus chlorhexidine in lower concentrations for 14 days. Dental plaque was analyzed by the Patient Hygiene Performance (PHP) index. The odontological product was yellow, cloudy, free of microbial contamination, and exerted an inhibitory action in vitro. Individuals who used a propolis-containing mouthwash for 14 consecutive days in combination or not to chlorhexidine showed a similar PHP index to chlorhexidine alone. The product exerted an antibacterial action in vitro and in vivo, exhibiting a positive action in the control of dental plaque.