Ethanolic Extract Of Propolis Research Articles

Evaluation of the Potential of Brazilian Red Propolis Extracts: An Analysis of the Chemical Composition and Biological Properties

The optimized extraction process of natural matrices such as propolis that results in extracts with significant compounds has been one of the main needs of the industry. The aim of this work was to analyze the content of the active components of Brazilian red propolis extracts previously treated with ultrasound, as well as to evaluate in vitro their performance regarding antioxidant capacity and against bacteria and tumor cells. The results of the chromatographic analysis showed the influence of ultrasound treatment for higher yields of formononetin and kaempferol. However, just a higher content of these two components was not enough to interfere with higher concentrations of phenolic compounds and flavonoids among the extracts. The ten extracts obtained showed activity against two bacterial strains, and eight of them showed >70% cytotoxicity against five neoplastic cell lines. These results demonstrated the influence of ultrasound technology as a pretreatment in obtaining the ethanolic extracts of propolis, increasing the possibility of the applicability of Brazilian red propolis in different areas.

Biosynthesis of gold nanoparticles using ethanolic propolis extract for methylene blue and Rhodamine-B removal

• The green synthesis of gold nanoparticles (AuNPs) was done by propolis extract. • Photocatalytic degradation was performed using AuNPs under UV light. • AuNPs showed significant efficiency for methylene blue and Rhodamine B. The study proposed that gold nanoparticles (AuNPs) that were biosynthesized using propolis extract can degrade methylene blue (MB) and Rhodamine-B. First, the AuNPs were characterized using color change, electron microscopy, vis-UV spectroscopy, and Fourier-transform infrared (FTIR) analysis; then, the photocatalytic activity was measured under U.V. in various concentrations. The results showed a color change from yellowish to violet, indicating the reduction of Au 3+ to Au 0 . In addition, transmission electron microscopy (TEM) showed that the polydispersed shapes were in the nanoscale. Moreover, the biosynthesized AuNPs have high removal efficiency for MB and Rhodamine-B under U.V. irradiations. The implications of these findings proposed a new and sustainable method for the biosynthesis of AuNPs using the ethanolic propolis extract with the promising potential for removing contaminants in water.

Incorporation of Thymus vulgaris essential oil and ethanolic extract of propolis improved the antibacterial, barrier and mechanical properties of corn starch-based films

The present study illustrates the influence of Thymus vulgaris essential oils (TEOs), ethanolic extract of propolis (EEP), and their combination on corn starch-based films as antimicrobial packaging materials using the casting method. The FTIR results exhibited no structural change in the composite films after incorporating TEOs and EEP. However, the color properties of composite films were significantly affected by the addition of TEOs and EEP. The addition of TEOs and EEP increased the elongation at break from 5.8 to 13.5 % when TEOs and EEP added together, but tensile strength and modulus of the composite films decreased. The water solubility (SW) of composite films was significantly reduced when TEOs were added in the range of 17.31 % to 16.12 %. Also, the swelling ratio (SR) of all composite films was lower compared to the control film. The incorporation of EEP and TEOs did not change the water vapor permeability (WVP) of composite films significantly. However, the addition of EEP and TEOs in corn-starch films exhibited a synergic effect against Escherichia coli and Listeria monocytogenes. The developed antimicrobial composite films can be utilized in food packaging applications.

Quantitative Phytochemical Analysis of Ethanol Extract Kelulut Bee Propolis (Trigona laeviceps)

Kelulut bees are widely bred in Kalimantan. These bees do not have a stinger and easily adapt to new environments. Another characteristic of the kelulut bee is that it produces more propolis than honey. Kelulut Bee propolis contains tannins, alkaloids, flavonoids, and phenolics bioactive compounds with the potential to heal drugs. Following the concept of 'Back to Nature', namely increasing public interest in using natural ingredients to be used as medicine. Therefore, a test is needed to strengthen the utilization of this potential and quantitative phytochemical analysis is needed to determine the levels of each compound in kelulut bee propolis. The purpose of this research was to analyze the results of the quantitative phytochemical of ethanol extract of kelulut bee propolis (Trigona laeviceps). The research used non- experimental research with quantitative laboratory examination to analyze sample content. The results showed he quantitative phytochemical analysis of ethanol extract of kelulut bee propolis (Trigona laeviceps) showed a content of tannin compound 1.85 mg/ml, alkaloid 154.31 mg/ml, flavonoid 56.83 mg/ml and phenolic 120.37 mg/ml. Ethanol extract of bee propolis (Trigona laeviceps) showed a tannin compound content of 1.85 mg/ml, alkaloids 154.31 mg/ml, flavonoids 56.83 mg/ml and phenolic 120.37 mg/ml. Alkaloid had the highest concentration of 154.31 mg/ml, while tannin had the lowest concentration of 1.85 mg/ml.

The Cytotoxicity and Anticancer Effects of Propolis against the Oral Squamous Cell Carcinoma: In Vitro Study

Background and aim: A wide range of therapeutic properties, including anti-cancer properties, are attributed to propolis, a resinous product obtained from several plants that possess a variety of medicinal properties. A study on honeybee-produced propolis showed that in mice, it showed a significant reduction in the progression of squamous cell carcinoma in the head and neck, but in humans, its role in HNSCC remains unclear.
 Method and materials: Propolis was sampled from two types of Iranian. Extraction was done using ethanolic extracts of propolis. The cll viability was evaluated by MTT assay. Cancer cell lines were assessed for gene expression, such as mmp-2, mmp-9, bax, and bcl-2.
 Results: Increased sample concentrations reduced cell viability but did not cause significant cytotoxicity. A RT-PCR indicated that the Khalkhal sample produced more effects among the two samples, and the level of bax mRNA gene expression in the Khalkhal sample was increased. With an increasing concentration of Khalkhal samples, the expression increased. Increasing Khalkhal sample concentration also reduced mRNA levels of bcl-2, mmp-2, and mmp-9.
 Conclusion: Khalkhal’s propolis can be considered a suitable sample for the study of antiapoptotic and proapoptotic gene expression. Additionally, it can be used as a potential candidate for inhibiting the proliferation and spread of oral cancer cells.

Simulated gastrointestinal digestion/Caco-2 cell transport: Effects on biological activities and toxicity of a Brazilian propolis

The objective was to assess the effect of gastrointestinal digestion/Caco-2 cell transport on biological activities and toxicity of the ethanolic extract of organic propolis from southern Brazil (EEOP1). As principal results, the EEOP1 deactivated the ROO•, HOCl and O2•- reactive oxygen species, attenuated NF-κB transcription factor activation, and decreased the release of TNF-α and IL-6 in macrophages after Caco-2 cell transport, while CXCL2/MIP-2 release was reduced after gastrointestinal digestion. Furthermore, the phytochemical profile monitored by HPLC-ESI-QTOF-MS changed, especially for lignans, lignan-precursors and phenolic acids. Conversely, the antimicrobial activity was observed only in the non-digested EEOP1. The EEOP1 lethal dose to kill 50 % of the Galleria mellonella larvae was 1.1 g/kg, and its digested fraction had no toxic effect. Hence, there is indication that some phytochemicals present in the EEOP1 are resistant to the gastrointestinal tract and maintain their biological activities, as expected for a functional food ingredient.

Impact of Propolis on Escherichia coli and Bacillus subtilis Based on Total DNA, RNA and Protein Levels.

<b>Background and Objectives:</b> Propolis is a natural product derived from plant resins and collected by honeybees to protect the colony against different pathogens. The antimicrobial properties of an ethanolic extract of propolis (EEP) were investigated in this study. <b>Materials and Methods:</b> In the Egyptian Governorate of Giza, F1 carniolan honeybee (<i>Apis mellifera carnica</i> P.) colonies collected propolis in the autumn, spring and summer of 2019-2020. We investigated the antibacterial activity of EEP against Gram-positive <i>B. subtilis</i> and Gram-negative <i>E. coli</i>. Propolis was evaluated and its effects on the amounts of total DNA, RNA and protein in <i>Bacillus subtilis</i> and <i>Escherichia coli</i> were investigated. <b>Results:</b> Propolis inhibited the growth of <i>B. subtilis</i>. At 5% concentration, the inhibition zones were 8.66, 10.66 and 8.52 mm for autumn, spring and summer propolis, respectively, at 10% concentration, they were 19.66, 21.33 and 18.0 mm, respectively. Propolis also inhibited the growth of <i>E. coli</i> at a 5% concentration. The inhibition zones were 3.660, 4.00 and 4.33 mm for autumn, spring and summer propolis, respectively and at 10% concentration, they were 7.65, 8.33 and 7.33 mm, respectively. The inhibition zones were the largest (10.66 and 21.33 mm) for <i>B. subtilis</i> at 5 and 10% propolis, respectively, whereas slightly low inhibition zones (4.0 and 8.33 mm) were observed for <i>E. coli</i> (5 and 10% propolis, respectively) in spring. In <i>E. coli</i> and <i>B. subtilis</i>, propolis inhibited the replication of DNA-dependent RNA polymerase. <b>Conclusion:</b> The study showed that total DNA, RNA and protein levels in <i>B. subtilis</i> were reduced by 40, 15.52 and 52.6%, respectively, whereas those in <i>E. coli</i> were reduced by 12, 15 and 8%, respectively. Furthermore, propolis activity was less effective against Gram-negative bacteria than Gram-positive bacteria.

Indonesian Propolis Inhibit Proinflammatory Cytokines, Apoptosis and Oxidative Stress in Anthrax Animal Model

BACKGROUND: Anthrax is a zoonotic disease caused by Bacillus anthracis, whose endospores stimulate the release of pro-inflammatory cytokines and promote oxidative stress. Propolis, a natural resource that can be found in Indonesia, has been proven to have anti-apoptotic and antioxidant role which might be a potential adjuvant therapy for anthrax treatment. Hence in this study we aimed to investigate effect of propolis as an anti-inflammatory, anti-apoptotic, and antioxidant in anthrax rats model by examining the level of tumor necrosis factor (TNF)-α, caspase-3, and malondialdehyde (MDA), respectively.METHODS: This was an experimental post-test only study with 40 male rats weighed 180-200 g that were induced by anthrax spores injected subcutaneously. The rats were divided into one control positive group and four intervention groups that were administered with 200 mg/kgBW propolis extract for 7 to 14 days. The levels of serum TNF-α, caspase-3, and MDA were measured using enzyme-linked immunosorbent assay (ELISA) and analyzed with bivariate analysis.RESULTS: TNF-α, caspase-3, and MDA level were found lower in anthrax rats model given ethanol extract of propolis than the control group. The lowest concentration of TNF-α value was found in group administered with propolis extract 200 mg/kgBW for 7 days before the anthrax induction (6.136±0.205 pg/mL). The results were similar to the MDA serum and caspase-3 which were the lowest when the propolis was administered 7 days earlier (1.893±0.188 nmol/mL and 2.040±0.067 ng/mL). There was significant difference in the TNF-α, caspase-3, and MDA serum levels (p≤0.001) compared to control group.CONCLUSION: Propolis has anti-apoptotic and antioxidant effects which can be used as complementary therapy in anthrax infection.KEYWORDS: propolis, anthrax, anti-apoptotic, antioxidants

Antifungal activity of Propolis, Fluconazole and Chlorhexidine against Oral Candida albicans – A Comparative in-vitro Study

Objectives: To assess the in-vitro antifungal action of propolis in contrast with the standard medications, fluconazole and chlorhexidine against Oral Candida albicans. Materials and Methods: MIC (Minimum inhibitory concentration) as well as MFC (Minimum fungicidal concentration) were attained from propolis, fluconazole and chlorhexidine against oral Candida albicans and GC-MS Analysis were completed. The analysis of variance (ANOVA) and Repeated measures ANOVA tests were used for comparison of quantitative data. Results: The mean zone of inhibition showed an increasing trend with increase in concentration of all the extracts. At all concentrations mean zone of inhibition was identified to be significantly highest with chlorhexidine. The mean zone of inhibition at 25mcg/ml concentration was found to be most noteworthy for chlorhexidine followed by ethanolic and methanolic extracts of Propolis. Conclusions: Propolis has an antifungal activity against Candida albicans. The mean zone of inhibition showed an increasing trend with increase in concentration. Candida albicans remained resistant to all propolis extracts at low concentration of 5 mcg/ml.

Effects of Adding Ethanol Extract of Propolis on the Fermentation Quality, Aerobic Stability, Fatty Acid Profile, and In Vitro Digestibility of Alfalfa Silages

This study was planned to determine the effects of ethanol extract of propolis on the fermentation quality, fatty acid profile, aerobic stability, and in vitro digestibility of alfalfa silages. The ethanol extract of propolis was added to alfalfa at levels of 1000 mg/kg (PROP1), 2000 mg/kg (PROP2), and 3000 mg/kg (PROP3); propolis was not added to the control (CON) group. After the propolis was added, the pH value of the alfalfa silage declined, and the crude protein content was effectively preserved (p < 0.05). Adding propolis to alfalfa silages caused crude fiber, neutral detergent fiber, and acid detergent fiber (p < 0.05) to decrease. The ethanol extract of propolis significantly improved the lactic acid content and reduced the NH3-N content (p < 0.05). Propolis significantly improved the unsaturated fatty acid content (p < 0.05) and reduced the saturated fatty acid content (p < 0.05). In addition, propolis significantly improved the relative feed value, the digestibility of the organic matter, and the in vitro metabolic energy content (p < 0.05). These results show that the ethanol extract of propolis improves the silage quality of last cutting alfalfa silages, and has potential as an antimicrobial silage additive.

Cytotoxicity of Peruvian propolis and Psidium guajava on human gingival fibroblasts, PBMCs and HeLa cells

It is indisputable that every day it is demonstrated that natural products present diverse therapeutic benefits, which has boosted their incorporation within various products for clinical use. However, this must be accompanied by knowledge of their effect on cell lines to ensure their use is safe. The objective of this study was to evaluate the cytotoxic effect of two ethanolic extracts based on Peruvian natural products, on three human cell lines. Cervical cancer cell lines (HeLa), human gingival fibroblasts (HGF-1 - ATCC CRL-2014) (HGF-1) and peripheral blood mononuclear cells (PBMCs) were cultured and subsequently treated with preparations of ethanolic extracts of propolis (EEP) and Psidium guajava (EEG) from a concentration of 50 mg/mL to 0.024 mg/mL, by the 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazole bromide reduction assay. At a concentration of 0.24 mg/mL EEG, viability of 99.7±1.24%, 99.8±2.2% and 99.7±2.7% was observed in HeLa, HGF-1 and PBMCs, respectively; >90% cell viability values were observed with EPP at 0.024 mg/mL, with HGF-1 showing the highest viability (96.9±1.15%). A dose-dependent effect was observed for both extracts with a decrease in cell viability as concentrations increased (up to 50 mg/mL). EEP and EEG extracts at low concentrations do not show cytotoxicity in human cell lines, these findings are an advance in the preclinical evaluation on their safety and open a continuity to further studies for their potential applications in dentistry and medicine.

A comparative study on the effect of propolis and dentine bonding agent in treating dentine hypersensitivity.

To find out if there is a difference in the efficacy of propolis and seventh-generation dentine bonding agent in reducing dentine hypersensitivity. The randomised, single-blind study was conducted at the Department of Periodontology, Dow International Dental College, Dow University of Health Sciences, Karachi, from December 2018 to November 2019, and comprised patients with complaint of dentine hypersensitivity who were divided in group A which received 30% ethanolic extract of propolis, and group B which received dentine bonding agent. Recordings of dentine hypersensitivity were obtained at baseline, before and after the application of experimental agents, and on days 7, 15 and 30. The response was measured using the Schiff Cold Air Sensitivity Scale. Data was analysed using SPSS 20. Of the 52 patients, 19 (36.5%) were males and 33 (63.5%) were females. The overall mean age was 29.9 ± 6.5 years. Majority of the subjects were students i.e. 16 (30.8%) and housewives i.e. 11 (21.2%), while drivers, teachers, businessmen etc. constituted of 25 (48%) subjects. Significant reduction of dentine hypersensitivity was observed in both groups (p<0.05). Intergroup comparison showed non-significant differences (p>0.05). Propolis and dentine bonding agent had significant effect in reducing dentine hypersensitivity. The difference between the two was not significant.

Evaluation of Toothpaste Preparations Containing Propolis Ethanol Extract

ABSTRACT&#x0D; The Trigona bee is a native Asian bee that does not have a stinger and produces propolis. Propolis is useful as an antioxidant, antimicrobial, anti-inflammatory, and antiviral. This study aims to evaluate the preparation of toothpaste which is added from propolis ethanol extract. Extraction was carried out by maceration method using 96% ethanol. Toothpaste obtained was made in four formulas based on differences in concentration, evaluation of preparation, organoleptic, homogeneity, pH test, viscosity test, foam height test and preference were carried out. Data were analyzed descriptively. The preparation of propolis ethanol extract toothpaste with various concentrations of propolis extract showed organoleptic test results in the form of a light brown color, soft texture, distinctive smell of propolis, fresh taste typical of propolis, and homogeneous, preference test of four formulas, 50% chose ordinary from 5 options. Based on each evaluation test of the paste from the preparation of propolis ethanol extract that has been made, all of them meet the criteria and requirements for physical evaluation according to SNI toothpaste No. 12-352-1995.

Purification of Artepillin C (ARC) with Anticancer Activities from Supercritical CO2-Ethanol Extracts of Brazilian Green Propolis by Using Adsorption Column Chromatography

Phenolic compounds with varying phenolic structures are present in both terrestrial and marine organisms. Artepillin C (ARC) is a prenylated phenolic compound produced specifically in Brazilian green propolis. Earlier studies have demonstrated the potential of ARC as a dietary supplement for cancer prevention due to its ability to suppress tumor growth and metastasis. Here we report the development of an effective adsorption chromatography combined with supercritical CO2 extraction for the massive purification of ARC. A mixture of supercritical CO2 and ethanol extract of Brazilian green propolis was passed through a stainless chromatographic column packed with protruding metals at 4,000 psi and 50 °C to remove wax from the column’s base. ARC mixed with flavonoids collected from the top of the column was applied to another stainless column filled with silica gel under similar working conditions. After flavonoids were removed, strongly adsorbed ARC at the top portion of the column was collected by ethanol elution. The purity of ARC isolated using this method was between 90% and 95%, as indicated by HPLC chromatograms. Purified ARC strongly inhibited cancer cell division based on its cytotoxic effects on HCT116 human colon cancer cells, resulting in a significantly increased distribution of cells in the S phase. ARC also blocks the motility of HCT116 cells, indicating its ability to suppress tumor metastasis. The developed chromatographic purification protocol can be used to isolate prenylated phenolic compounds from marine organisms.

Fecal metabolomics reveals the positive effect of ethanol extract of propolis on T2DM mice

A large number of studies have shown that propolis has positive effects in the treatment of type 2 diabetes mellitus (T2DM). However, there are have only been a few reports that are based on an ultra-high performance liquid chromatography-quadrupole-time-of-flight-mass spectrometry (UPLC-Q-TOF-MS) analysis of the fecal metabolomics of ethanol extract of propolis (EEP) in the treatment of T2DM. The present investigation was designed to screen potential biomarkers of T2DM by the metabonomic method and to explain the possible anti-diabetes mechanism of EEP according to the changes in the biomarkers. The results showed that EEP improved the body weight (BW) of T2DM mice, lowered blood sugar levels, and significantly restored blood biochemical indicators related to T2DM, such as fasting insulin (FINS), homeostasis model assessment of insulin resistance (HOMA-IR), aspartate transaminase (AST), and alanine aminotransferase (ALT). Liver pathology showed that EEP reversed liver damage caused by T2DM. Metabolomics data identified 27 potential biomarkers in fecal samples. EEP effectively regulated the dysfunction in the metabolic pathways of glycerophospholipids, sphingolipids, riboflavins, and sterol lipids caused by T2DM. In summary, our research results revealed positive effects of EEP in the treatment of T2DM and provided potential candidate markers for further research and in the clinical treatment of T2DM.

Effects of Propolis on Serum Biochemical Parameters in Azaserine Treated Rats

Azaserine (o-diazoacetyl-L-serine) is an antimetabolite obtained from streptomycetes cultures and is used experimentally to produce atypical acinar cell focus (AACF) in rat exocrine pancreas. Propolis is a resinous hive product with antioxidant, anticarcinogenic, antimicrobial and anti-inflammatory effects that bees collect from the plants around them. In this study, we aimed performed to investigate the effect of ethanol extract of propolis (EEP) on serum biochemical changes in azaserin induced pancreatic cancer in Wistar rats. For this purpose, male Wistar albino rats were randomly divided into 4 groups, 10 in each group. AzCt and AzProp group 2-week-old male rats were given azaserine (30 mg/kg bw) intraperitoneally (ip). Propolis (EEP) (oral 80 mg/lt) was added to the drinking water of Prop and AzProp group rats. For the first time in this study, the effects of propolis on rats with neoplastic structures formed by azaserine were investigated in terms of biochemical parameters (AST, ALP, ALT, BILD, BILT, CHOL, LDH, TRIG, UREA, TAS, TOS and OSI). According to this; AzProp group values were compared to AzCt group, respectively, AST, UREA, TOS and OSI, there is a statistically significant difference in terms of values. As a result, it was seen that the oxidative stress caused by azaserine-induced neoplastic structures decreased with the use of propolis and that propolis had a positive effect on the measured biochemical parameters.

Bioactive Compounds, Antioxidant and Antimicrobial Activity of Propolis Extracts during In Vitro Digestion

The objective of this research was to determine the content of total phenols, total flavonoids, and the antioxidant and antimicrobial activity of the ethanolic extracts of propolis obtained by two methodologies during in vitro digestion. Ethanolic extracts of propolis were obtained by ultrasound and maceration and the yield and content of the bioactive compounds, as well as their antimicrobial and antioxidant activity, were evaluated. Yields higher than those reported in other investigations (71.6%) were obtained. The highest content of phenols and flavonoids in the ethanolic extracts was 34,406.6 mg GAE/100 g in propolis from San Pedro, obtained by maceration (SP M), and 19,523.2 mg QE/100 g in propolis from Teotitlán, obtained by ultrasound (TU), respectively, being higher than what is established in Mexican regulations. The antioxidant and antimicrobial activity of the extracts was not affected by the method of obtaining. At the end of the in vitro digestion there was an 80% loss of the phenolic content and a 90% loss of the flavonoid content. Therefore, antioxidant activity was affected. On the other hand, ultrasound improves the obtaining of bioactive compounds. In vitro digestion decreases the content of bioactive compounds; therefore, their functional properties are affected. Thus, it is important to consider technologies that allow extracts to be protected from in vitro digestion conditions.

Q-TOF LC-MS compounds evaluation of propolis extract derived from Malaysian stingless bees, Tetrigona apicalis, and their bioactivities in breast cancer cell, MCF7

Propolis is known to exhibit various phytochemical compounds that aid in several biological activities. The current study investigates the phytochemical compounds of ethanolic extract of propolis of Tetrigona apicalis (EEP) using Q-TOF LC-MS, its antioxidant properties using DPPH and ABTS+ radical scavenging assays, total phenolic (TPC) and flavonoid content (TFC), using Folin-Ciocalteu and Aluminium Chloride method, respectively, as well as proapoptotic effects, based on the selected IC50 of the cytotoxic study conducted for EEP using annexin V-FITC assay. Terpene and polyphenol were among of 17 identified compounds. The EC50 of EEP for DPPH and ABTS+ was 1.78 mg/mL and 1.68 mg/mL, while the EEP exhibited TPC and TFC values of 31.99 mgGAE/g and 66.4 mgQCE/g, respectively in which the parameters were strongly correlated. The IC50 of EEP effectively induces apoptosis in MCF7 cells. In conclusion, EEP possessed important phytochemical compounds that work excellently as antioxidants and anticancer agents.

Evaluation of Stabilized Chlorine Dioxide in Terms of Antimicrobial Activity and Dentin Bond Strength

Antimicrobial agents are recommended for disinfection of the cavity following mechanical dental caries removal prior to application of restorative material. There is limited information about stabilized Chlorine Dioxide (ClO2) as a cavity disinfectant. The objective of this study is to determine the antimicrobial activity and effect on dentin bond strength of ClO2 compared to chlorhexidine digluconate (CHX), sodium hypochlorite (NaOCl) and Ethanolic Propolis Extract (EPE). Antimicrobial activities of agents against oral pathogens (Staphylococcus aureus, Enterococcus faecalis, Streptococcus mutans, Lactobacillus acidophilus, Lactobacillus casei, Candida albicans, and Saccharomyces cerevisiae) and analyses of EPE were examined. Seventyfive mandibular third molars were sectioned, prepared and divided into five subgroups (n=15/group). Cavity disinfectants (2% CHX, 2.5% NaOCl, 30% EPE, 0.3% ClO2) were applied to etched dentin prior to adhesive and composite build-up. Shear bond strength (SBS) was evaluated with a universal testing machine at a crosshead speed of 0.5 mm/min. The SBS data were analyzed with One-way Analysis of Variance (ANOVA) and Tukey's post-hoc test (p <0.05). The failure modes were evaluated with a stereomicroscope. It was determined that the compared disinfectants were showed different inhibition zone values against oral pathogens. ClO2 exhibited the highest antimicrobial activity, followed by CHX, NaOCI and EPE, respectively. No statistically significant difference was observed in the SBS values between the disinfectant treated groups and control group. The failure modes were predominantly mixed. The use of 0.3% stabilized ClO2 as a cavity disinfectant agent exhibited high antimicrobial activity against oral pathogens and no adverse effects on SBS to etched dentin.

Antibacterial activity of Chinese propolis and its synergy with β-lactams against methicillin-resistant Staphylococcus aureus.

Propolis has exhibited effective antibacterial activities in preventing the growth of multiple pathogenic bacteria. However, the antibacterial activity of Chinese propolis against methicillin-resistant Staphylococcus aureus (MRSA) is almost unknown. The present study aimed to explore the antibacterial activity and action mechanism of Chinese propolis ethanol extract (CPEE) against MRSA. Thirteen compounds of CPEE were identified using HPLC-DAD/Q-TOF-MS, and none of them showed better anti-MRSA activity than CPEE. The diameter of inhibition zone (DIZ) of CPEE was 20.1mm. The minimal inhibitory concentration (MIC) of CPEE was 32mg/L, while the minimal bactericidal concentration (MBC) against MRSA was 64mg/L. Moreover, CPEE showed significant synergistic effects with β-lactam antibiotics (ampicillin and oxacillin). Nucleic acid and protein leakage assays showed that CPEE can stimulate the release of intracellular macromolecules by damaging the cell membrane integrity of MRSA. Live/dead-staining and SDS-PAGE assays further confirmed that CPEE could inhibit bacterial activities by disrupting the membrane. The reduction in PBP2a expression and β-lactamase activity, as shown by western blot and β-lactamase detection assays, suggested that CPEE was able to reverse the drug resistance of MRSA. These results demonstrated the anti-MRSA activity of CPEE was mainly due to changing the cell membrane and reversing resistance, which indicates that CPEE could be an attractive candidate for use in future food and medical applications.