Concentrations Of Propolis Research Articles

Evaluation of Antibacterial Potential of Carbonated Hydroxyapatite Combined with Propolis on Porphyromonas gingivalis

Carbonated hydroxyapatite is ideal as a bone graft material because it has similar organic matters to the bone, excellent osteoconductive properties, and good biodegradation in the body. Hydroxyapatite contains the risk of being contaminated by bacteria called Porphyromonas gingivalis (P. gingivalis) in the oral cavity because it has no vascularization, therefore, facilitating adhesion of bacteria, and when applied in the oral cavity, it may cause an infection that then inhibits healing. Thus, it is necessary to use a material that has an antibacterial effect with low potential of causing resistance to treat the postsurgical infection properly. Propolis has antibacterial, antiviral, antifungal, antitumor, and immunomodulatory activities. Propolis contains a large number of flavonoids and phenols. The phenol compound in propolis is usually called caffeic acid phenethyl ester (CAPE), and it has a good antibacterial property. The study aims to evaluate the antibacterial effect of carbonated hydroxyapatite when immersed with different propolis concentrations of 2.5%, 5%, 7.5%, and 10% for 24 h and to measure the zone of inhibition against P. gingivalis. The Kruskal–Wallis test resulted in p = 0.00 (p < 0.05), indicating that there were significant differences among the test groups. The data processing was followed by Mann–Whitney U-test, and the results showed a significant difference in the group of carbonated hydroxyapatite-10 % propolis compared with the other groups. Inhibition zone of carbonated hydroxyapatite that immersed with propolis 10% showed the largest mean of diameters zone of inhibition.

Antioxidant, antiradical and antipyretic effects of olive oil extract of propolis

This study was carried out to determine the antioxidant, antiradical and antipyretic effects and the total phenolic content of poplar-type olive oil extract of propolis (OOEP). As a result of the analysis of olive oil extract of propolis with HPLC, it was determined that the main phenolic compounds were caffeic acid phenethyl ester (CAPE), dimethoxycinnamic acid, caffeic acid, ferulic acid, p-coumaric acid, and vanillin. Propolis was extracted with cold-pressed virgin olive oil at different concentrations (control, 10, 20, 30 and 40%). The total phenolic content of these extracts was determined by Folin Ciocalteu, antioxidant activity by phosphomolybdenum, and antiradical activity by DPPH methods. It was determined that as the propolis concentration increased, total phenolic content, antioxidant, and antiradical activity also increased. The olive oil extract of propolis showed antipyretic effect in Wistar albino rats in which hyperthermia was induced by yeast. As a result, it is suggested that olive oil extract of propolis has antioxidant, antiradical and antipyretic effects; and it may be a healthier alternative to alcoholic extracts.

Effect of Propolis Coating on Oil Uptake and Quality Properties of Fried Potato (Solanum tuberosum) Strips

The use of edible coatings is a suitable method to reduce oil uptake in fried foods. In this research, the effects of propolis gum on the physicochemical properties of fried potato strip were evaluated.
 The propolis coating was performed at three concentrations 1%, 1.5%, 2% w/v. Potato strips were dipped in the coating solutions followed by air drying. Viscosity of coating was measured in two shear rate 0.048 and 62.11 1/s. The treatments were fried in canola oil and analyzed for fat uptake and moisture retention.
 One-way analysis of variance (ANOVA) was used and mean comparison was performed by Duncan’s new multiple range test.
 The results showed that by increasing in shear rate, viscosity of coating was decreased. By increasing in propolis concentration, the coating pick up, moisture content, frying yield, were increased while oil uptake were decreased.
 According to the results, 2% concentration propolis gum reduced oil absorption in fried potato strips. Due to their facility to use, propolis gum suggested for coating and usage in industrial potato fries production.

Comparison of Rosin and Propolis Antimicrobials in Cellulose Acetate Fibers Against Staphylococcus aureus

The quantitative difference in the antibacterial response was measured for pine rosin and propolis against Staphylococcus aureus ATCC 12598. The activity was studied for fibrous networks that form entirely bio-based cellulose-acetate (CA) materials. The analysis considers the effects of bacterial input, additive dosage, solvent type, variation in preparation, as well as the effect of storage time. Based on the results, the electrospun network structure is dependent on the solvent and the concentration of rosin and propolis. Both rosin and propolis improved the cellulose acetate solution processability, yet they formed beads at high concentrations. Rosin and propolis created strong antibacterial properties when these material systems were immersed in the liquid for 24 h at room temperature. The response remained visible for a minimum of two months. The electrospun networks of water and DMAc solvent systems with 1 to 5 wt% rosin content were clearly more efficient (i.e., decrease of 4 to 6 logs in colony forming units per mL) than the propolis networks, even after two months. This efficiency is likely due to the high content of abietic acids present in the rosin, which is based on the Fourier transform infrared spectra. The results of the additional analysis and cell cultivation with dermal fibroblast cells indicated an impairing effect on skin tissue by the rosin at a 1 wt% concentration compared to the pure CA fibers.

The effect of the addition of propolis to resin-modified glass ionomer cement bracket adhesive materials on the growth inhibition zone of Streptococcus mutans

Background: Orthodontic treatments progress alongside the development of adhesive materials. The present study aimed to determine the antibacterial properties of propolis, a natural product, in a mixture of resin-modified glass ionomer cement by observing the growth inhibition zone of Streptococcus mutans. Methods: This was an in vitro study conducted on 45 samples of adhesive material, which were divided into control group (resin-modified glass ionomer cement bracket adhesive material), two groups of propolis concentrations (15%, and 25%) and duration (0, 15, and 30 days). The antibacterial effect of each sample was evaluated against S. mutans using an agar plate diffusion test. Measurement of the diameter of the growth inhibition zone of S. mutans was carried out. The data obtained were analyzed statisticallyThe significance value of the Kruskal Wallis and Mann-Whitney test was set at p <0.05, while the significance value of the normality and homogeneity test was set at p> 0.05). Datas in this study that were not normally distributed (p = 0.012) but homogeneous (p = 0.110) were analyzed by the Kruskal-Wallis test (p = 0.003) and then the Mann-Whitney test was performed to determine differences in significance between groups. Results: There was a relationship between concentration and duration of propolis to the growth inhibition zone of S. mutans (p=0.003). The addition of 25% propolis concentration inhibited the growth of S. mutans more than the addition of 15% and without propolis (control group). The addition of propolis to resin-modified glass ionomer cement for 15 days was more effective in inhibiting the growth of S. mutans. Conclusion: The addition of propolis to adhesive materials provides an inhibitory effect on the growth of S. mutans, which may be effective in the world of preventive dentistry.

The effect of Propolis on inhibition of Aspergillus parasiticus growth, aflatoxin production and expression of aflatoxin biosynthesis pathway genes.

Aflatoxins are one of the most important mycotoxins, which have been classified as Group I carcinogenic compounds by the International Agency for Research on Cancer. This investigation aimed to examine the effect of Propolis on inhibition of the Aspergillus parasiticus growth, aflatoxin production and expression of aflatoxin biosynthesis pathway genes. A standard strain of Aspergillus parasiticus (ATCC 15517) was used to perform antifungal susceptibility test, using a microdilution method in accordance with the CLSI M38-A2 guidelines. The aflatoxin concentrations in the control and treated media were determined by HPLC. Also, the quantitative changes in the level of nor-1, ver-1 and omtA genes expression in aflatoxin biosynthetic pathway were analyzed using Real-Time PCR method. The results showed that the minimum inhibitory concentrations (MIC) of propolis was 100 µg/ml. The results showed that total levels of aflatoxin decreased from 386.1 ppm to 3.01 ppm at 50 µg/ml of propolis. In addition, quantitative real-time PCR analysis showed that the level of nor-1, ver-1 and omtA genes expression was significantly decreased after treatment with propolis extract. The findings reveal that propolis extract, have a significant inhibitory effect on important genes for aflatoxin biosynthesis pathway in aflatoxin production.

Phytochemical Characterisation and Antibacterial Activity of Propolis on Cariogenic Microrganisms

Background: Dental caries is also known as tooth decay is as a result of the softening of hard dental tissues from factors of multiple origins, with dental plaque bacteria being one of the most important factors. Due to the resistance of microorganisms to common antibiotics, modern medical sciences had been looking for new approaches in the treatment and prevention of oral diseases. &#x0D; Objective: This study aimed to phytochemically characterise, evaluate the antibacterial activity of propolis on bacteria responsible for dental caries.&#x0D; Methodology: This was an experimental study that took place in the Laboratory of Chemistry and Microbiology (Clinque Universities des Montagne (CUM)) of Bangangté between January to April 2018.&#x0D; Chemical screening of the aqueous and hydroethanolic extracts revealed the presence of secondary metabolites namely alkaloids, flavonoids, tannins, coumarins, saponins and terpenes, those being more abundant in the aqueous extract. The content of flavonoids was high. Macro-dilution was used to determine the minimum inhibitory concentrations (MIC) of propolis and Müller Hinton agar was used for obtaining the minimum bactericidal concentrations (MBC) and determination of inhibition diameters of the bacteria.&#x0D; Results: The flavonoid content in the aqueous extract was estimated at 222.85 mg/ml and 18.77 mg/ml for the hydroalcoholic extracts. S mutans and Lactobacillus spp. were isolated from samples collected from caries affected teeth. The aqueous extract of propolis generally generates greater inhibition diameters than that of the hydroalcoholic extract on both lactobacillus and Streptococcus mutans, The MBC of the aqueous extract on S. mutans and Lactobacillus spp. was 50 mg/ml and the MIC was 25 mg/ml. The hydroalcoholic extract did not have MBC on both S. mutans and Lactobacillus spp. However, the MIC of this extract on both bacteria was 50 mg/ml. These antibacterial properties were not statically significant as that of gentamicin.&#x0D; Conclusion: The evaluation of the antibacterial activity of our various extracts by determination of the MIC and MBC revealed that propolis was endowed with inhibitory properties vis-à-vis the growth of most bacterial strains tested: Streptococcus mutans and Lactobacillus spp. all 2 being gram-positive bacteria.

Chemical composition and antibacterial activity of Algerian propolis against fish pathogenic bacteria

Five different varieties of propolis from four sites from Sétif region (East of Algeria) (Babor, Setif; Ain-Abbassa and El-Hamma), and one site from the center of Algeria (Tizi-Ouzou) were chemically analysed by gas chromatography-mass spectrometry. One hundred and two compounds were identified including aromatic acids, linear hydrocarbons and their acids, terpenes and alcaloïdes. Furthermore, the in vitro bacteriostatic and bactericidal activities of the aqueous extracts were evaluated against one Gram positive (Bacillus subtilis, used as probiotics in aquaculture) and two Gram negative (Vibrio anguillarum and Vibrio harveyi, pathogenic for fish) bacteria. The obtained results showed that all aqueous extracts of propolis inhibit the growth of B. Subtilis while the growth inhibition of fish pathogens was achieved when using higher propolis concentrations. These antibacterial properties would warrant further studies on the clinical applications of propolis in aquaculture field.&#x0D; Keywords: Bactericidal activity; Chemical characterization; Propolis; Vibrio.

Honey and Propolis have Antifungal Property against Select Dermatophytes and Candida albicans

Objective. To determine the antifungal properties of honey from two different floral sources (sunflower and coconut) and Philippine propolis against selected dermatophytes and Candida albicans.&#x0D; Methods. The minimum inhibitory concentration (MIC) of honey and propolis against Trichophyton rubrum, T. mentagrophytes, Microsporum gypseum, Epidermophyton floccosum and Candida albicans was determined using the broth macrodilution method (NCCLS M38-P). Disk diffusion method was used to determine the zones of inhibition. Clotrimazole served as comparator drug.&#x0D; Results. Sunflower and coconut honey inhibited all test fungi, with coconut honey yielding lower MICs. However, propolis performed better than both sunflower and coconut honey. T. mentagrophytes was most sensitive to the test agents. Zones of inhibition were not produced by sunflower honey for Trichophyton mentagrophytes, Microsporum gypseum, and Epidermophyton floccosum; by coconut honey for Microsporum gypseum, and by propolis for Epidermophyton floccosum. No zone of inhibition was exhibited by honey and propolis for Candida albicans.&#x0D; Conclusion. Honey and aqueous propolis extract exhibit antifungal properties against Trichophyton rubrum, T. mentagrophytes, Microsporum gypseum, Epidermophyton floccosum and Candida albicans. Although honey and propolis have inhibitory activities against these organisms, clotrimazole is still relatively superior based on the zone of inhibition produced by the test drugs.

In Vivo Biocompatibility, Mechanical, and Antibacterial Properties of Cements Modified with Propolis in Different Concentrations.

Objectives The focus of this triple-blind randomized study was to evaluate the mechanical properties, antibacterial effect, and in vivo biocompatibility of glass ionomer cements (GICs) modified with ethanolic extracts of propolis (EEP). Materials and Methods For biocompatibility tests, 135 male Wistar rats were used and divided into nine groups: Group C (control, polyethylene), Groups M, M10, M25, M50 (Meron; conventional, and modified with 10%, 25%, 50% EEP, respectively), Groups KC, KC10, KC25, KC50 (Ketac Cem; conventional, and modified with 10%, 25%, 50% EEP, respectively). The tissues were analyzed under an optical microscope for different cellular events in different time intervals. Shear bond strength test (SBST) on cementation of metal matrices ( n = 10, per group), adhesive remnant index (ARI) in bovine incisors ( n = 10, per group), and antibacterial properties by the agar diffusion test ( n = 15, per group) were analyzed. Statistical Analysis Data were analyzed by Kruskal–Wallis test followed by Dunn, and one-way analysis of variance test followed by Tukey’s test ( p < 0.5). Results Morphological evaluation demonstrated intense inflammatory infiltrate in Groups M10 and KC10 in the time intervals of 7 ( p = 0.001) and 15 ( p = 0.006) days. Multinucleated giant cells were shown to be more present in Group M1, with statistical difference from Control and KC50 Groups in the time interval of 7 days ( p = 0.033). The SBST showed no statistical significance among the groups ( p > 0.05). Antibacterial property showed a statistically significant difference between Meron and Meron 50%-EEP Groups, and between Ketac and Ketac 50%-EPP Groups ( p = 0.001). Conclusions The intensity of histological changes resulting from the cements was shown to be inversely proportional to the concentration of propolis added; Ketac 50%-EPP was the concentration that had the most favorable biocompatibility results. Addition of EEP to GIC did not negatively change the SBST and ARI. Antibacterial property demonstrated a concentration-dependent effect.

Metal Content of Nutritional and Toxic Value in Different Types of Brazilian Propolis.

Brazilian raw propolis samples (brown, green, red, and yellow) were investigated to evaluate the content of three elements of nutritional value (Cu, K, and Se) and three toxic metals (As, Cd, and Pb). The propolis samples (n = 19) were obtained from different regions of Brazil and analysed by atomic absorption spectrometry after microwave-assisted digestion. A descriptive analysis of the variables was carried out, and nonparametric tests (Kruskal–Wallis or Mann–Whitney) were performed to verify the differences in metal contents. The elemental concentrations of the Brazilian propolis were in the following ranges: As < 0.048–8.47 μg·g−1, Pb < 0.006–0.72 μg·g−1, Cu 0.57–11.60 μg·g−1, Se < 0.041–0.54 μg·g−1, and K 0.23–7.94 mg·g−1; Cd was below LOD (0.008 μg·g−1) in all samples, except one. Seven samples exceeded the limits defined for As or Pb by the Brazilian regulation.

Comparison of Antiviral Effect of Olive Leaf Extract and Propolis with Acyclovir on Herpes Simplex Virus Type 1

While acyclovir, a nucleoside analogue, is widely used for herpes simplex virus type 1 (HSV-1), emergence of drug-resistant viruses due to frequent usage of this class of medicines, and their toxic side effects require exploring novel active molecules. Despite the studies on developing synthetic molecules in medical sciences and pharmacology, herbs as a natural source of biologically-active compounds remain popular. In this in vitro study, olive leaf extract (OLE) and propolis alone or in combination with acyclovir were investigated for their antiviral efficacy in HSV-1.Toxic doses of OLE, propolis, and dimethyl sulfoxide, propolis diluent, for Hep-2 (ATCC, CCL-23) cells were determined by conventional cell culture. Using "endpoint" method, the viral dose infecting half of the cell culture (TCID50) was calculated, and viral quantity was determined with Spearman-Karber method. Antiviral effects of OLE and propolis on HSV-1 were investigated by conventional cell culture and real-time cell analysis (RTCA). Combinations of the two extracts with one another and with acyclovir were evaluated by RTCA. Active substances prepared at three different dilutions were added to tubes with HSV-1 of logTCID50: 11.5 in descending order starting from the highest non-toxic concentration, and they were left at room temperature for two different durations (one hour and three hours). The aliquots taken from the tubes were cultured in plates containing Hep-2 cells and evaluated after 72 hours. Combinations of extracts and acyclovir at concentrations at least four times lower than the lowest concentration showing antiviral efficacy against HSV-1 were cultured with Hep-2 cells in the e-plates of the xCELLigence RTCA device, measurements were obtained at 30 minute intervals, and data were recorded in real time. In the test with two different durations and at different concentrations of OLE and propolis, antiviral efficacy was observed both with one-hour and three-hour incubation at a concentration of 10 μg/ ml for propolis and 1.2 mg/ml for OLE with RTCA. The duration and concentration of the greatest decrease in viral quantity were in the first one hour and 10 μg/ml for propolis, and in the first one hour and 1.2 mg/ ml for OLE. Combination of propolis and OLE with acyclovir caused no cytopathic effects, and the combination of extracts led to delayed cytopathic effect. According to these results, propolis and OLE, alone and in combinations with acyclovir, have antiviral efficacy against HSV-1. These agents may reduce the dose and side effects of acyclovir in case of co-administration since they exert their effects through a different mechanism than acyclovir,possibly through direct virucidal activity, inhibition of virus internalization or viral inhibition in early stages of replication (inhibition of adsorption/binding of viral particles to the cell). These extracts that do not require conversion to active form have the potential to reduce infectivity in oral lesions, prevent spread, and be used in the topical treatment of acyclovir-resistant HSV infections, particularly in immunocompromised patients. However, in vivo studies should be conducted to determine their medicinal properties and potential toxicities. These results should be supported by further comprehensive studies and the efficacy against other viruses should also be investigated.

Characteristic assay of incorporation of carbonated hydroxyapatite–propolis as an alternative for alveolar bone loss therapy on periodontitis: An in vitro study

Aim: To examine the characteristics of carbonated hydroxyapatite (CHA) incorporated with propolis in the concentrations of 5%, 7.5%, and 10%. Materials and Methods: In this in vitro study, the CHA bone graft (GamaCHA) material was immersed in the propolis solution with the concentrations of 5%, 7.5%, and 10% by serial dilution method for 24h at room temperature. Absorbance readings of loading and release assay were carried out using UV-Vis spectrophotometers at 289nm. Antibacterial testing was done by calculating the inhibition zone of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. The microtetrazolium (MTT) assay was used for viability test of fibroblast NIH 3T3 cell culture by measuring the optical density in the enzyme-linked immunosorbent assay (ELISA) reader. The data of the study were analyzed with one-way analysis of variance (ANOVA) (loading, release, antibacterial P. gingivalis, and viability test) and Kruskal–Wallis (antibacterial A. actinomycetemcomitans). Results: The results showed that CHA incorporated with 10% propolis had the highest loading percentage, the largest diameter of bacterial inhibition zone, and the highest fibroblast viability (P < 0.05). However, the difference in the concentrations of propolis incorporated with CHA did not affect the percentage of propolis release (P > 0.05). Conclusion: CHA incorporated with 10% propolis solution showed highest loading percentage, antibacterial activity, and viability.

The effect of the addition of propolis to resin modified glass ionomer cement bracket adhesive materials on the growth inhibition zone of Streptococcus mutans

Background: Orthodontic treatments progress alongside the development of adhesive materials. The aim of the present study was to determine the antibacterial properties of propolis, a natural product, in a mixture of resin modified glass ionomer cement by observing the growth inhibition zone of Streptococcus mutans. Methods: This was an in vitro study conducted on 45 samples of adhesive material, which were divided into three groups of propolis concentrations (0%, 15%, and 25%) and duration (0, 15, and 30 days). The antibacterial effect of each sample was evaluated against S. mutans using an agar plate diffusion test. Measurement of the diameter of the growth inhibition zone of S. mutans were carried out. The data obtained were analyzed statistically by Kruskal Wallis test. Results: There was a relationship between concentration and duration of propolis to the growth inhibition zone of S. mutans (p<0.05). The addition of 25% propolis concentration inhibited the growth of S. mutans more than the addition of 15% and 0% propolis concentration. The addition of 0%, 15%, and 25% propolis concentration to resin modified glass ionomer cement for 15 days was more effective in inhibiting the growth of S. mutans. Conclusion: The addition of propolis to adhesive materials provides an inhibitory effect on the growth of S. mutans, which may be effective in the world of preventive dentistry.

Development of propolis nanoparticles for the treatment of bovine mastitis: in vitro studies on antimicrobial and cytotoxic activities

This study describes the development of propolis nanoparticles (PNP) to treat bovine mastitis. Three PNP prepared with varying concentrations of propolis (5% and 7%, w/v) and the surfactants [poloxamer (1%, 3%, and 4%, w/v) and soy lecithin (0.25%, 0.7%, and 1%, w/v)]. PNP were characterized according to their size, polydispersity, zeta potential, pH, morphology, and physical stability. PNP were evaluated for their in vitro antimicrobial and cytotoxic effects. PNP obtained were spherical with a monodisperse distribution (polydispersity index &lt; 0.2) and an average particle size between 181 and 201 nm. Stability studies showed that PNP were stable over 150 d. The encapsulation efficiency of total phenolic content varied between 73% and 91%. The chromatographic profile of phenolic compounds from PNP showed selective encapsulation efficiency according to the polarity of compounds. All PNP showed antimicrobial activity against Staphylococcus aureus with a minimum inhibitory concentration ranging from 156 to 310 μg mL−1. The IC50(the concentration responsible for reduction of cellular viability by half) for epithelial cells of bovine mammary gland (MAC-T, mammary alveolar cell-T) varied from 122.2 to 268.4 μg mL−1. Results showed that PNP represent a promising nanocarrier for high concentrations of propolis extract in a stable aqueous medium, while, at the same time, presenting antimicrobial activity accompanied by moderate cytotoxicity to the MAC-T cells.

Study of antimicrobial and physicochemical properties of LDPE/propolis extruded films

In this study, blended films of low-density polyethylene (LDPE) and different concentrations of propolis (5, 10, 15, and 20% w/w) were prepared by the extrusion method, and their antimicrobial and mechanical properties were investigated. Antimicrobial effects of the LDPE/propolis blended films were studied against Staphylococcus aureus, Escherichia coli, Aspergillus niger, and Saccharomyces cerevisiae strains. The results indicated the inhibitory effects of these films against A. niger and S. cerevisiae, especially at propolis concentrations ≥ 15% w/w. The mechanical properties of the films such as tensile strength and elongation at break decreased with the addition of propolis, with the change in tensile strength being statistically significantly with respect to the control film (0% propolis). Incorporation of propolis into the LDPE films caused increased water vapor permeability and oxygen transmission rate (OTR) values compared with the control film. However, significant changes were only observed in the OTR values of the blended films containing 15 and 20% w/w propolis. Fourier transform infrared spectra, as well as thermal analysis data from thermal gravimetric analysis and differential scanning calorimetry, revealed that the addition of propolis (5–20% w/w) to the LDPE polymer matrix did not cause significant changes in chemical structure and certain mechanical properties. Field emission scanning electron microscopy images revealed that the morphological structures of the LDPE/propolis films were swollen and had island-like forms in comparison with the control, and this property progressed with rising propolis concentrations. These observations demonstrated the lack of strong interactions between LDPE and propolis.

Chrysin enhances anticancer drug-induced toxicity mediated by the reduction of claudin-1 and 11 expression in a spheroid culture model of lung squamous cell carcinoma cells

The aberrant expression of claudins (CLDNs), which are tight junctional proteins, is seen in various solid tumors, but the regulatory mechanisms and their pathophysiological role are not well understood. Both CLDN1 and CLDN11 were highly expressed in human lung squamous cell carcinoma (SCC). Chrysin, found in high concentration in honey and propolis, decreased CLDN1 and CLDN11 expression in RERF-LC-AI cells derived from human lung SCC. The phosphorylation level of Akt was decreased by chrysin, but those of ERK1/2 and c-Jun were not. LY-294002, an inhibitor of phosphatidylinositol 3-kinase, inhibited the phosphorylation of Akt and decreased the expression levels of CLDN1 and CLDN11. The association between phosphoinositide-dependent kinase 1 (PDK1) and Akt was inhibited by chrysin, but the phosphorylation of PDK1 was not. Immunoprecipitation and quartz-crystal microbalance assays revealed that biotinylated-chrysin binds directly to Akt. The knockdown of CLDN1 and CLDN11 using small interfering RNAs increased the transepithelial flux of doxorubicin (DXR), an anthracycline anticancer drug. Similarly, both chrysin and LY-294002 increased DXR flux. Neither CLDN1 knockdown, CLDN11 knockdown, nor chrysin changed the anticancer drug-induced cytotoxicity in a two-dimensional culture model, whereas they enhanced cytotoxicity in a spheroid culture model. Taken together, chrysin may bind to Akt and inhibit its phosphorylation, resulting in the elevation of anticancer drug-induced toxicity mediated by reductions in CLDN1 and CLDN11 expression in RERF-LC-AI cells. We suggest that chrysin may be useful as an adjuvant chemotherapy in lung SCC.

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-1β 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.

Seasonal variation of propolis from southern Brazil:

Previous studies have reported on the phytotherapeutic potential of propolis from southern Brazil (Urupema, Santa Catarina State), in particular, its efficacy in the treatment of bovine mastitis. The present study evaluates the effect of seasonal variation on the chemical composition of propolis from southern Brazil and its resultant antimicrobial and cytotoxic activities in the context of treating bovine mastitis. Antimicrobial activity against Staphylococcus aureus was assessed, along with the cytotoxicity and induction of apoptosis in MAC-T bovine mammary epithelial cells. With the exception of spring propolis, the flavonoid quercetin was the main compound present in all samples. The minimum inhibitory concentration (MIC) of propolis against S. aureus from mastitic milk was 140 μg/mL for samples collected during the spring, autumn, and winter seasons, but 280 μg/mL for samples collected in summer. For MAC-T cells, the spring propolis extract was more toxic with an IC50 of 120 μg/mL. However, for 120 μg/mL of spring propolis extract, only 0.77% of necrotic and 37% of apoptotic MAC-T cells were found, respectively. Nonetheless, the induction of cell deaththrough apoptosis by propolis extract suggests less severe damage to bovine mammary glands. Moreover, only negligible seasonal variation was found in the chemical composition of propolis from southern Brazil, and no biological activities were determined to be harmful. Therefore, this propolis shows promise as an alternative to commercial antimicrobials in the control of bovine mastitis, offering support for organic milk production.

Propolis as a potential alternative for the control of Dekkera bruxellensis in bioethanol fermentation

Dekkera bruxellensis is one of the most important contaminant yeasts of alcoholic fermentation. The use of propolis, which can selectively target contaminating yeasts without affecting the starter one, Saccharomyces cerevisiae, could be a useful nonconventional strategy for controlling the growth of contaminant yeasts. The objective of this research was to evaluate four samples of propolis produced by Apis mellifera honeybees from different regions of Argentina as antimicrobial agents against the growth of D. bruxellensis and S. cerevisiae. Hydroalcoholic extracts of propolis were prepared with ethanol:water (70:30 v/v), and the specific absorbance and final concentration of the samples were evaluated. A qualitative in vitro assay in solid medium was performed with different propolis concentrations, and the evaluation of yeast growth was based on a qualitative scale. A quantitative in vitro assay in liquid medium was also performed to assess the yeast cell number, using two different propolis concentrations. The cell number of D. bruxellensis decreased 1.52 and 1.85 log cycles with the two propolis extracts utilised at a concentration of 4.5 mg mL-1 while the cell number of S. cerevisiae decreased 0.48 and 0.76 log cycles with the same samples of propolis. The results from both assays demonstrated the selectivity of propolis use on the yeast species, leading to a higher inhibition of D. bruxellensis growth. This indicates a good potential for using propolis at the concentration of 4.5 mg mL-1, as a nonconventional strategy to control the growth of D. bruxellensis without significantly affecting S. cerevisiae, the yeast starter of ethanol fermentation.