Antimicrobial activity of propolis samples from two different regions of Anatolia

Chemical Characterization and Biological Properties Assessment of Euphorbia resinifera and Euphorbia officinarum Moroccan Propolis

Although the plants of the genus Euphorbia are largely exploited by therapists in Morocco, the composition and antibacterial activities of propolis from these plants are still unknown. To address this gap, this study aimed to characterize the pollen type, the volatile compounds, and the phenolic and mineral profiles of three Euphorbia propolis samples collected in Morocco and evaluate their antimicrobial activities. The minimum inhibitory concentration of the propolis samples was determined by the microdilution method, and the anti-adherence activity was evaluated by the crystal violet assay. The examination of anti-quorum-sensing proprieties was performed using the biosensor Chromobacterium violaceum CV026. Pollen analysis revealed that Euphorbia resinifera pollen dominated in the P1 sample (58%), while E. officinarum pollen dominated in the P2 and P3 samples (44%). The volatile compounds were primarily composed of monoterpene hydrocarbons, constituting 35% in P1 and 31% in P2, with α-pinene being the major component in both cases, at 16% in P1 and 15% in P2. Calcium (Ca) was the predominant mineral element in both E. resinifera (P1) and E. officinarum (P2 and P3) propolis samples. Higher levels of phenols, flavonoids and dihydroflavonoids were detected in the E. officinarum P2 sample. The minimum inhibitory concentration (MIC) value ranged from 50 to 450 µL/mL against Gram-positive and Gram-negative bacteria. Euphorbia propolis displayed the ability to inhibit quorum sensing in the biosensor C. violaceum CV026 and disrupted bacterial biofilm formation, including that of resistant bacterial pathogens. In summary, the current study evidences the potential use of E. officinarum propolis (P2 and P3) to combat important features of resistant pathogenic bacteria, such as quorum sensing and biofilm formation.

Examination of Raw Samples and Ethanol Extracts of Gerês Propolis Collected in Different Years

Propolis, a natural resin created by bees, has garnered significant attention from both the scientific community and industry due to an impressive range of bioactivities. Nonetheless, the intrinsic variability in its chemical composition and bioactive profiles has been hindering propolis' full potential use. We previously showed that ethanol extracts (EEs) of a Portuguese propolis sample (Gerês) collected over four consecutive years displayed similar chemical and biological profiles, a constancy never documented before. However, the characteristics of the unprocessed samples of Gerês propolis were never described. Hence, the central objective of this study is to assess the quality parameters of unprocessed propolis samples collected from Gerês (G), over a four-year period (2019-2022), alongside the analysis of the chemical composition and bioactivities of the EEs prepared with the same raw samples. The ash, wax, balsam and water contents of the unprocessed samples-G19 to G22-showed minor fluctuations, likely attributed to uncontrollable natural events impacting the propolis source and collection process. On the other hand, the antimicrobial and antioxidant activities of all the four ethanol extracts (G19.EE-G22.EE) consistently align with prior studies. Furthermore, the Gerês propolis extracts showed remarkable uniformity in chemical composition parameters too, particularly concerning total polyphenol, flavonoid and ortho-diphenol contents. In summary, our research reinforces the beneficial properties of propolis and show that extracts' bioactivities remain within the reference ranges for Gerês propolis, despite minor differences in unprocessed samples, suggesting a consistent action over time. Thus, this work could be instrumental towards the establishment of standard parameters for propolis applications, offering valuable insights to this field of propolis research.

Synthesis of hydrophilic glyceryl monocaffeate with economical catalyst cation-exchange resin Amberlyst-35

BACKGROUND

Caffeic acid (CA) has anti-oxidation and anti-inflammatory. However, the poor hydrophilicity of CA limits its biological activities. In this work, hydrophilic glyceryl monocaffeate (GMC) was synthesized by esterification using different caffeoyl donors (deep eutectic solvent and solid CA). Cation-exchange resins were used as the catalysts. The effects of reaction conditions were also investigated.

RESULTS

The mass transfer limitation of esterification was eliminated using deep eutectic solvent. Compared with the previous catalysts (immobilized lipase Novozym 435), an economic cation-exchange resin, Amberlyst-35 (A-35), showed good catalytic performance for GMC preparation. The activation energies of GMC synthesis and CA conversion were 43.71 kJ mol^-1 and 43.07 kJ mol^-1 , respectively. The optimal reaction conditions were a temperature reaction of 90 °C, catalyst load of 7%, glycerol/CA molar ratio of 5:1 (mol mol^-1 ), and reaction time of 24 h, which resulted in a maximum GMC yield and CA conversion of 69.75 ± 1.03% and 82.23 ± 2.02%, respectively.

CONCLUSION

The results of the work showed a promising alternative for the synthesis of GMC. © 2023 Society of Chemical Industry.

Phenolic Constituents, Antioxidant and Antimicrobial Activity and Clustering Analysis of Propolis Samples Based on PCA from Different Regions of Anatolia

This study aimed to evaluate the biochemical composition and biological activity of propolis samples from different regions of Türkiye to characterize and classify 24 Anatolian propolis samples according to their geographical origin. Chemometric techniques, namely, principal component analysis (PCA) and a hierarchical clustering algorithm (HCA), were applied for the first time to all data, including antioxidant capacity, individual phenolic constituents, and the antimicrobial activity of propolis to reveal the possible clustering of Anatolian propolis samples according to their geographical origin. As a result, the total phenolic content (TPC) of the propolis samples varied from 16.73 to 125.83 mg gallic acid equivalent per gram (GAE/g) sample, while the number of total flavonoids varied from 57.98 to 327.38 mg quercetin equivalent per gram (QE/g) sample. The identified constituents of propolis were phenolic/aromatic acids (chlorogenic acid, caffeic acid, p-coumaric acid, ferulic acid, and trans-cinnamic acid), phenolic aldehyde (vanillin), and flavonoids (pinocembrin, kaempferol, pinobanksin, and apigenin). This study has shown that the application of the PCA chemometric method to the biochemical composition and biological activity of propolis allows for the successful clustering of Anatolian propolis samples from different regions of Türkiye, except for samples from the Black Sea region.

Developing a computational toolbased on an artificial neural network for predicting and optimizing propolis oil, an important natural product for drug discovery

Propolis is a promising natural product that has been extensively researched and studied for its potential health and medical benefits. The lack of requisite high oil-containing propolis and existing variation in the quality and quantity of essential oil within agro-climatic regions pose a problem in the commercialization of essential oil. As a result, the current study was carried out to optimize and estimate the essential oil yield of propolis. The essential oil data of 62 propolis samples from ten agro-climatic areas of Odisha, as well as an investigation of their soil and environmental parameters, were used to construct an artificial neural network (ANN) based prediction model. The influential predictors were determined using Garson's algorithm. To understand how the variables interact and to determine the optimum value of each variable for the greatest response, the response surface curves were plotted. The results revealed that the most suited model was multilayer-feed-forward neural networks with an R2 value of 0.93. According to the model, altitude was found to have a very strong influence on response, followed by phosphorous & maximum average temperature. This research shows that using an ANN-based prediction model with a response surface methodology technique to estimate oil yield at a new site and maximize propolis oil yield at a specific site by adjusting variable parameters is a viable commercial option. To our knowledge, this is the first report on the development of a model to optimize and estimate the essential oil yield of propolis.

Propolis: chemical diversity and challenges in quality control

Propolis is a resinous natural product produced by honeybees using beeswax and plant exudates. The chemical composition of propolis is highly complex, and varies with region and season. This inherent chemical variability presents several challenges to its standardisation and quality control. The present review was aimed at highlighting marker compounds for different types of propolis, produced by the species Apis mellifera, from different geographical origins and that display different biological activities, and to discuss strategies for quality control. Over 800 compounds have been reported in the different propolises such as temperate, tropical, birch, Mediterranean, and Pacific propolis; these mainly include alcohols, acids and their esters, benzofuranes, benzopyranes, chalcones, flavonoids and their esters, glycosides (flavonoid and diterpene), glycerol and its esters, lignans, phenylpropanoids, steroids, terpenes and terpenoids. Among these, flavonoids (> 140), terpenes and terpenoids (> 160) were major components. A broad range of biological activities, such as anti-oxidant, antimicrobial, anti-inflammatory, immunomodulatory, and anticancer activities, have been ascribed to propolis constituents, as well as the potential of these compounds to be biomarkers. Several analytical techniques, including non-separation and separation methods have been described in the literature for the quality control assessment of propolis. Mass spectrometry coupled with separation methods, followed by chemometric analysis of the data, was found to be a valuable tool for the profiling and classification of propolis samples, including (bio)marker identification. Due to the rampant chemotypic variability, a multiple-marker assessment strategy considering geographical and biological activity marker(s) with chemometric analysis may be a promising approach for propolis quality assessment.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11101-022-09816-1.

The Effect of Chitosan Type on Biological and Physicochemical Properties of Films with Propolis Extract

The aim of the research was to determine the influence of chitosan type and propolis extract concentration on biological and physicochemical properties of chitosan-propolis films in terms of their applicability in food packaging. The films were prepared using three types of chitosan: from crab shells, medium and high molecular weight and propolis concentration in the range of 0.75-5.0%. The prepared polysaccharide films were tested for antimicrobial properties, oxygen transmission rate (OTR) and water vapor transmission rate (WVTR). Moreover, sorption tests and structural analysis were carried out. Microbiological tests indicated the best antimicrobial activity for the film consisting of high molecular weight chitosan and 5.0% propolis extract. Both the type of chitosan and propolis concentration affected transmission parameters-OTR and WVTR. The best barrier properties were recorded for the film composed of high molecular weight chitosan and 5.0% propolis extract. The results of sorption experiments showed a slight influence of chitosan type and a significant effect of propolis extract concentration on equilibrium moisture content of tested films. Moreover, propolis extract concentration affected monolayer water capacity (Mm) estimated using the Guggenheim, Anderson and de Boer (GAB) sorption model. The obtained results indicate that chitosan films with an addition of propolis extract are promising materials for food packaging applications, including food containing probiotic microorganisms.

Baccharis dracunculifolia and Dalbergia ecastophyllum, Main Plant Sources for Bioactive Properties in Green and Red Brazilian Propolis

Nowadays, propolis is used as a highly valuable product in alternative medicine for improving health or treating a large spectrum of pathologies, an ingredient in pharmaceutical products, and also as a food additive. Different vegetal materials are collected by honeybees and mixed with wax and other own substances in order to obtain the final product, called propolis. It is known as the bee product with the widest chemical composition due to the raw material collected by the bees. Different types are known worldwide: green Brazilian propolis (having Baccharis dracunculifolia as the major plant source), red Brazilian propolis (from Dalbergia ecastophyllum), European propolis (Populus nigra L.), Russian propolis (Betula verrucosa Ehrh), Cuban and Venezuelan red propolis (Clusia spp.), etc. An impressive number of scientific papers already demonstrate the pharmacological potential of different types of propolis, the most important activities being the antimicrobial, anti-inflammatory, antitumor, immunomodulatory, and antioxidant activities. However, the bioactive compounds responsible for each activity have not been fully elucidated. This review aims to collect important data about the chemical composition and bioactive properties of the vegetal sources and to compare with the chemical composition of respective propolis types, in order to determine the connection between the floral source and the propolis properties.

Synthesis of Lipophilic Caffeoyl Alkyl Ester Using a Novel Natural Deep Eutectic Solvent

In this work, a novel method for lipophilic caffeoyl alkyl ester production was developed using a natural deep eutectic solvent (DES) consisting of choline chloride and caffeic acid (CA) as the caffeoyl donor. Cation-exchange resins were used as the catalyst to catalyze the esterification of fatty alcohols with the DES. Effects of the caffeoyl donor and reaction variables were investigated. Reaction thermodynamics were also analyzed. The results showed that the lipophilic caffeoyl alkyl ester production can be enhanced using the DES as the caffeoyl donor, and cation-exchange resin A-35 showed the best catalytic activity for the reaction. Under the optimized conditions (85 °C, stearyl alcohol/CA 8:1 (mol/mol), A-35 load 5% and 24 h), the maximum octodecyl caffeate (OC) yield (90.69 ± 2.71%) and CA conversion (95.17 ± 2.76%) were obtained with the DES as the caffeoyl donor, which were much higher than those obtained with solid CA as the caffeoyl donor (OC yield 40.97 ± 2.37% and CA conversion 44.26 ± 1.69%). The activation energy of CA conversion (67.57 kJ/mol) with the DES was lower than that with solid CA (90.19 kJ/mol). In addition, the mass transfer limitation can be decreased with the DES. Compared with solid CA as the caffeoyl donor, a fast reaction rate and low mass transfer limitation were obtained using the DES as the caffeoyl donor.

Application of an Inter-Species Extrapolation Method for the Prediction of Drug Interactions between Propolis and Duloxetine in Humans

Duloxetine (DLX) is a potent drug investigated for the treatment of depression and urinary incontinence. DLX is extensively metabolized in the liver by two P450 isozymes, CYP2D6 and CYP1A2. Propolis (PPL) is one of the popular functional foods known to have effects on activities of CYPs, including CYP1A2. Due to the high probability of using DLX and PPL simultaneously, the present study was designed to investigate the potent effect of PPL on pharmacokinetics (PKs) of DLX after co-administration in humans. A PK study was first conducted in 18 rats (n = 6/group), in which the plasma concentration of DLX and its major metabolite 4-hydroxy duloxetine (4-HD) with or without administration of PPL was recorded. Population PKs and potential effects of PPL were then analyzed using NONMEM software. Lastly, these results were extrapolated from rats to humans using the allometric scaling and the liver blood flow method. PPL (15,000 mg/day) exerts a statistically significant increase in DLX exposures at steady state, with a 20.2% and 24.6% increase in DLX C m a x , s s and the same 28.0% increase in DLX A U C s s when DLX (40 or 60 mg) was administered once or twice daily, respectively. In conclusion, safety issues are required to be attended to when individuals simultaneously use DLX and PPL at high doses, and the possibility of interactions between DLX and PPL might be noted.

Antimicrobial Efficacy of Triphala and Propolis-modified Glass Ionomer Cement: An In Vitro Study

Background

The antimicrobial activity of restorative materials has a major role in preventing recurrent caries.

Aim

To assess the antimicrobial activity of triphala and propolis-modified glass ionomer cement (GIC) against Streptococcus mutans and Lactobacillus.

Materials and methods

The samples were prepared using cylindrical molds (6 mm in diameter and 2 mm in thickness). A total of 30 samples were prepared containing 10 samples in each group. Group I, 10 samples of glass ionomer with aqueous extract of triphala were prepared; group II, 10 samples of glass ionomer with 50% of ethanolic extract of propolis (EEP); and group III as control consisting of 10 samples of glass ionomer. The samples were placed in to agar plates containing inoculum of S. mutans and Lactobacillus and incubated at 37°C for 48 hours and using a digital caliper, zones of inhibition formed around specimens were measured.

Results

Data obtained were analyzed using nonparametric Kruskal-Wallis test followed by pairwise comparison was done using Dunn-Bonferroni test. Group I and group II showed highest antimicrobial efficacy against S. mutans and Lactobacillus with no statistical significant difference, i.e., (p value > 0.05) but in both groups I and II, there was a statistical significant difference when comparing with group III i.e., (p < 0.05).

Conclusion

Thus, triphala and propolis-modified GIC provided higher antibacterial effect with increased level of inhibition against the S. mutans and Lactobacillus; hence, it can be used as a choice of restorative material to treat dental caries. Further studies are required to determine the physical and mechanical characteristics of the material.

How to cite this article

Paulraj J, Nagar P. Antimicrobial Efficacy of Triphala and Propolis-modified Glass Ionomer Cement: An In Vitro Study. Int J Clin Pediatr Dent 2020;13(5):457-462.

Chemical composition and antimicrobial activity of two extract of propolis against isolates of Staphylococcus spp. and multiresistant bacterials

ABSTRACT: There is a growing need to discover and develop alternative therapies for the treatment of mastitis caused by Staphylococcus spp. and multidrug-resistant bacterial infections. This study examined the chemical composition and antimicrobial potential of two propolis extracts (EPA and EPB) against seventy-seven isolates of Staphylococcus spp. obtained from subclinical bovine mastitis; three clinical strains of MRSA and two from clinical strains of S. aureus ATCC, identified as S. aureus ATCC 6538 and S. aureus ATCC 25923. The total phenolic content was determined by the Folin-Ciocalteau method, the total flavonoid content by the Dowd method and the phenolic profile was quantified by HPLC-DAD. The MBC values of the extracts were evaluated by broth microdilution method. The amount of total phenolic and flavonoid compounds was higher in EPA than EPB. Both extracts revealed the presence of caffeic, coumaric, cinnamic, ferulic and 3,4-dihydroxybenzoic acids, with higher concentrations of coumaric and cinnamic acids. Staphylococcus spp. isolates were susceptible to EPA (90.9%), EPB (83.1%) and oxacillin (80.5%). The oxacillin susceptible isolates were also susceptible to EPA (70.1%) and EPB (80.6%), whereas those oxacillin-resistant strains were also susceptible to EPA (40.0%) and to EPB (26.7%). MBC ranged from 34.3 to 68.7μm/mL for EPA and from 68.7 to 137.5μg/mL for EPB. Both extracts inhibited significantly (100%) the clinical strains of MRSA, S. aureus ATCC 6538 and S. aureus ATCC 25923 at the concentration of 68.7μg/mL. It is concluded that both extracts of propolis, whose main constituents are coumaric and cinnamic acids, have high antimicrobial activity against the microorganisms studied, and EPA also against oxacillin-resistant strains. These findings reinforce its potential use for the treatment of bovine mastitis.

Synthesis, Antibacterial Evaluation, and QSAR of Caffeic Acid Derivatives

The present study evaluates the antibacterial effects of a set of 16 synthesized caffeic acid ester derivatives against strains of Staphylococcus aureus and Escherichia coli, as well as discusses their structure-activity relationship (SAR). The antibacterial assays were performed using microdilution techniques in 96-well microplates to determine minimal inhibitory concentration (MIC). The results revealed that five of the compounds present strong to optimum antibacterial effect. Of the sixteen ester derivatives evaluated, the products with alkyl side chains, as propyl caffeate (3), butyl caffeate (6), and pentyl caffeate (7), presented the best antibacterial activity with MIC values of around 0.20 μM against Escherichia coli and only butyl caffeate (6) showing the same MIC against Staphylococcus aureus. For products with aryl substituents, the best MIC results against the tested strain of Escherichia coli were 0.23 µM for (di-(4-chlorobenzyl)) caffeate (13) and 0.29 µM for diphenylmethyl caffeate (10) and all were less active against the Staphylococcus aureus strain. Preliminary quantitative structure-activity relationship (QSAR) analyses confirmed that certain structural characteristics, such as a median linear carbon chain and the presence of electron withdrawal substituents at the para position of the aromatic ring, help potentiate antibacterial activity.

Characterization of the xanthine oxidase inhibitory activity of alk(en)yl phenols and related compounds

The inhibitory activity of xanthine oxidase (XO) is a combination of uric acid formation inhibition and superoxide anion (O₂^-) generation suppression. The inhibition of uric acid formation by XO is useful for the screening of natural compounds that prevent gout, while the suppression of O₂^- generation is useful for treating oxidative stress. Many edible plants contain abundant phenolic compounds and alk(en)yl phenols, and some of these compounds display XO inhibitory activity. This review focuses on XO inhibitory activity since this activity is used to characterize natural products. Recently, it was demonstrated that the inhibitory activity could be characterized using assays for XO inhibition, the suppression of O₂^- generation, DPPH radical scavenging and O₂^- radical scavenging. The inhibitory activity was divided three reaction types. The first is XO inhibition, the second O₂^- generation suppression by modification of enzyme molecules and the third two forms of O₂- scavenging. It was demonstrated that these three activities are related to both the hydroxy group arrangement in the phenol portion and the alk(en)yl chains. This characterization is useful for pursuing XO inhibitors and antioxidants in natural compounds.

Composition and functional properties of propolis (bee glue): A review

Propolis is a natural substance collected by honey bees from various plants such as, poplar, palm, pine, conifer secretions, gums, resins, mucilage and leaf buds. It is collected and brought very painstakingly by honey bees to be used for sealing cracks and crevices occurring in their hives. Originally, it as an antiseptic meant for preventing bee-hive from microbial infections along with preventing decomposition of intruders. Additionally, propolis has been used in folk medicine for centuries. The biological characteristics of propolis depend upon its chemical composition, plant sources, geographical zone and seasons. More than 300 compounds have been identified in propolis such as, phenolic compounds, aromatic acids, essential oils, waxes and amino acids. Many scientific articles are published every year in different international journals, and several groups of researchers have focused their attention on the chemical compounds and biological activity of propolis.

Mexican Propolis: A Source of Antioxidants and Anti-Inflammatory Compounds, and Isolation of a Novel Chalcone and ε-Caprolactone Derivative

The propolis produced by bees are used in alternative medicine for treating inflammation, and infections, presumably due to its antioxidant properties. In this context, five propolis from México were investigated to determine their inhibitory lipid peroxidation properties. The ethyl acetate extract from a red propolis from Chiapas State (4-EAEP) was the most potent (IC₅₀ = 1.42 ± 0.07 μg/mL) in the TBARS assay, and selected for further studies. This extract afforded two new compounds, epoxypinocembrin chalcone (6), and an ε-caprolactone derivative (10), as well as pinostrobin (1), izalpinin (2), cinnamic acid (3), pinocembrin (4), kaempherol (5), 3,3-dimethylallyl caffeate in mixture with isopent-3-enyl caffeate (7a + 7b), 3,4-dimethoxycinnamic acid (8), rhamnetin (9) and caffeic acid (11). The HPLC profile, anti-mycobacterial, and antioxidant properties of this extract was also determined. Most of the isolated compounds were also tested by inhibition of reactive oxygen species (ROS) in challenged mouse bone marrow-derived mast cells (BMMCs), and DPPH. Their anti-inflammatory activity was evaluated by TPA, and MPO (myeloperoxidase) activity by ear edema test in mice. The most potent compounds were 7a + 7b in the TBARS assay (IC₅₀ = 0.49 ± 0.06 μM), and 2 which restored the ROS baseline (3.5 μM). Our results indicate that 4-EAEP has anti-oxidant, and anti-inflammatory properties due to its active compounds, suggesting it has anti-allergy and anti-asthma potential.

Protective Effect of Propolis in Proteinuria, Crystaluria, Nephrotoxicity and Hepatotoxicity Induced by Ethylene Glycol Ingestion

BACKGROUND AND AIMS

Propolis is a natural honeybee product with wide biological activities and potential therapeutic properties. The aim of the study is to evaluate the protective effect of propolis extract on nephrotoxicity and hepatotoxicity induced by ethylene glycol in rats.

METHODS

Five groups of rats were used. Group 1 received drinking water, group 2 received 0.75% ethylene-glycol in drinking water, group 3 received 0.75% ethylene-glycol in drinking water along with cystone 500 mg/kg/body weight (bw) daily, group 4 received 0.75% ethylene-glycol in drinking water along with propolis extract at a dose of 100 mg/kg/bw daily, and group 5 received 0.75% ethylene-glycol in drinking water along with propolis extract at a dose of 250 mg/kg/bw daily. The treatment continued for a total of 30 d. Urinalyses for pH, crystals, protein, creatinine, uric acid and electrolytes, and renal and liver function tests were performed.

RESULTS

Ethylene-glycol increased urinary pH, urinary volume, and urinary calcium, phosphorus, uric acid and protein excretion. It decreased creatinine clearance and magnesium and caused crystaluria. Treatment with propolis extract or cystone normalized the level of magnesium, creatinine, sodium, potassium and chloride. Propolis is more potent than cystone. Propolis extract alleviates urinary protein excretion and ameliorates the deterioration of liver and kidney function caused by ethylene glycol.

CONCLUSIONS

Propolis extract has a potential protective effect against ethylene glycol induced hepatotoxicity and nephrotoxicity and has a potential to treat and prevent urinary calculus, crystaluria and proteinuria.

Chemical Composition and Antimicrobial Activities of Iranian Propolis

Background

With considering the importance of natural products for their remedial and therapeutic value, this research was aimed to analyze the chemical compositions and antimicrobial activity of four propolis samples from different areas of Iran (Chenaran, Taleghan, Morad Beyg, and Kalaleh) with various climates and flora.

Methods

Ethanolic (70% EtOH) and dichlromethane (DCM) extracts of Iranian propolis were analyzed by gas chromatography-mass spectrometry (GC-MS) methods, and antimicrobial activity was evaluated against Candida albicans, Escherichia coli, and Staphylococcus aureus using disk diffusion antimicrobial method.

Results

The results of GC-MS analysis showed the presence of fatty acids, flavonoids, terpenes, aromatic-aliphatic acids, and their related esters. The total flavonoids in DCM extract of Chenaran, Taleghan, Morad Beyg, and Kalaleh propolis were pinocembrin and pinostrobin chalcone. The common phenolic and terpene compounds detected in all four tested EtOH extracts were P-cumaric acid and dimethyl -1,3,5,6-tetramethyl-[1,3-(13C2)] bicycloce [5.5.0] dodeca-1,3,5,6,8,10-hexaene-9,10-dicarboxylate, respectively. The highest inhibitory diameter zone of the Iranian propolis against C. albicans, E. coli, and S. aureus was for DCM extract of Kalaleh propolis (13.33 mm), Morad Beyg propolis (12 mm), and Kalaleh (11.67 mm), respectively.

Conclusion

Iranian propolis showed antimicrobial activities against C. albicans, E. coli, and S. aurous, perhaps due to the presence of flavonoids, phenolic acids, and terpenes as active components that can be used alone or in combination with the selected antibiotics to synergize antibiotic effect, as well as to prevent microbial resistance to available antimicrobial drugs.

Comparative studies on polyphenolic profile and antimicrobial activity of propolis samples selected from distinctive geographical areas of Hungary

The present paper reports about a comparative survey on the chemical composition, antioxidant activity and in vitro antimicrobial activity of selected propolis samples collected in Hungary. The total levels of polyphenolic compounds including flavonoids in ethanolic extracts of propolis were assessed. The major constituents of ethanolic extracts of propolis were analysed by gas chromatography/mass spectrometry analysis. Total phenolic content was determined spectrophotometrically using a Folin-Ciocalteu reagent. Free radical scavenging activities were evaluated by means of 2,2-diphenyl-1-picrylhydrazyl assay. In vitro inhibitory activity was investigated against eight different bacterial strains by agar well diffusion assay. An extensive comparison was carried out regarding general parameters and specific polyphenolic components. The experimental data led to the observation that there is considerable variability in terms of the quality and the biological value of the distinctive propolis samples. These findings confirm the hypothesis of the study; versatile experimental results are required for proper, well-reasoned, balanced and standardised industrial applications. The major flavonoid components were found to be chrysin and pinocembrin; however, versatile minor components were also detected. The total polyphenol content of ethanolic extracts of propolis ranged between 104.6 mg/g and 286.9 mg/g (gallic acid equivalent). The radical scavenging activity of ethanolic extracts of propolis varied between 101.7 mg/g and 286.9 mg/g (ascorbic acid equivalent). As the quality of propolis depends on the season, vegetation and the area of collection, marked differences were found among the different products examined in terms of both composition and general characteristics. The studied samples exhibited significant differences in term of antimicrobial activities.

Cooperative Reinforcement of Ionic Liquid and Reactive Solvent on Enzymatic Synthesis of Caffeic Acid Phenethyl Ester as an In Vitro Inhibitor of Plant Pathogenic Bacteria

It is widely believed that lipases in ionic liquids (ILs) possess higher enzyme activity, stability and selectivity; however, reaction equilibrium is always limited by product inhibition, and the product is difficult to separate from non-volatile ILs using distillation. To solve this problem, using trialkylphosphine oxide (TOPO) as a complexing agent, a novel biphase of reactive solvent and IL was firstly reported for caffeic acid phenethyl ester (CAPE) production from methyl caffeate (MC) and 2-phenylethanol (PE) catalyzed by lipase via transesterification. The effects of the reaction parameters and their action mechanism were investigated, and the inhibition of CAPE against bacterial wilt pathogen Ralstonia solanacearum was firstly measured. The MC conversion of 98.83% ± 0.76% and CAPE yield of 96.29% ± 0.07% were obtained by response surface methodology in the 25 g/L TOPO-cyclohexane/[Bmim][Tf₂N] (1:1, v/v); the complex stoichiometry calculation and FTIR spectrum confirmed that the reversible hydrogen-bond complexation between TOPO and caffeates significantly enhances the cooperative effect of two phases on the lipase-catalyzed reaction. The temperature was reduced by 14 °C; the MC concentration increased by 3.33-fold; the ratio of catalyst to donor decreased by 4.5-fold; and Km decreased 1.08-fold. The EC₅₀ of CAPE against R. solanacearum was 0.17–0.75 mg/mL, suggesting that CAPE is a potential in vitro inhibitor of plant pathogenic bacteria.

Chemical Composition and Antimicrobial Activity of Populus nigra Shoot Resin

The chemical composition of Populus nigra shoot resin has been investigated by chromatographic and spectroscopic methods. The analyses resulted in identification of 19 known compounds. The resin exhibited low activity against selected microorganisms.

Effect of bee venom or proplis on molecular and parasitological aspects of Schistosoma mansoni infected mice

The present study was performed to elucidate the efficacy of Apis mellifera L bee venom (BV) or proplis (200 mg/kg orally for three consecutive days) on Schistosoma mansoni infected mice. The results recorded reduction in the total worm burden, numbers of immature eggs and the ova count in hepatic tissue in BV (sting or injection) or proplis treated groups as compared to the infected group. Histological examination illustrated a significant increase (P ≤ 0.05) in the diameter of hepatic granuloma in BV treated groups (272.78 and 266.9, respectively) and a significant decrease in proplis treated mice (229.35) compared with the infected group (260.67). Electrophoretic pattern of RNA showed a decrease in mean of maximal optical density in liver and intestine of S. mansoni infected mice treated with bee venom (sting or injection) as compared with infected group. Flow cytometry analyses of RNA or apoptotic percentage of worms recovered from BV sting (19 and 49 % respectively); BV injected (20.5 and 51.17 %, respectively) and proplis (35 and 23.93 %, respectively) groups were compared with S. mansoni infected group (37.87 and 39.21 %, respectively). It can be concluded that administration of bee venom or proplis are effective in case of S. mansoni infection. Although bee venom cause increase of granuloma diameter and this might be due to venom concentration and further studies are required to avoid such harmful effect.

Mexican propolis flavonoids affect photosynthesis and seedling growth

As a continuous effort to find new natural products with potential herbicide activity, flavonoids acacetin (1), chrysin (2) and 4',7-dimethylnarangenin (3) were isolated from a propolis sample collected in the rural area of Mexico City and their effects on the photosynthesis light reactions and on the growth of Lolium perenne, Echinochloa crus-galli and Physalis ixocarpa seedlings were investigated. Acacetin (1) acted as an uncoupler by enhancing the electron transport under basal and phosphorylating conditions and the Mg(2+)-ATPase. Chrysin (2) at low concentrations behaved as an uncoupler and at concentrations up to 100 μM its behavior was as a Hill reaction inhibitor. Finally, 4',7-dimethylnarangenin (3) in a concentration-dependent manner behaved as a Hill reaction inhibitor. Flavonoids 2 and 3 inhibited the uncoupled photosystem II reaction measured from water to 2,5-dichloro-1,4-benzoquinone (DCBQ), and they did not inhibit the uncoupled partial reactions measured from water to sodium silicomolybdate (SiMo) and from diphenylcarbazide (DPC) to diclorophenol indophenol (DCPIP). These results indicated that chrysin and 4',7-dimethylnarangenin inhibited the acceptor side of PS II. The results were corroborated with fluorescence of chlorophyll a measurements. Flavonoids also showed activity on the growth of seedlings of Lolium perenne and Echinochloa crus-galli.

Application of intelligent modeling to predict the population dynamics of Pseudomonas aeruginosa in Frankfurter sausage containing Satureja bachtiarica extracts

Stepwise regression, Genetic Algorithm-Artificial Neural Network (GA-ANN) and Co-Active Neuro Fuzzy Inference System (CANFIS) were used to predict the effect of Satureja extracts (water and ethanol) on the population dynamics of Pseudomonas aeruginosa in a complex food system (Frankfurter sausage). The stepwise regression, GA-ANN and CANFIS were fed with four inputs: concentration (at five levels 0, 2000, 4000, 6000 and 8000 ppm), type of extract (water and ethanol), temperature (at three levels 5, 15 and 25°С) and time (1-20 days). The results showed that the stepwise regression was good for modeling the population dynamics of P. aeruginosa (R(2) = 0.92). It was found that ANN with one hidden layer comprising 14 neurons gave the best fitting with the experimental data, so that made it possible to predict with a high determination coefficient (R(2) = 0.98). Also, an excellent agreement between CANFIS predictions and experimental data was observed (R(2) = 0.96). In this research, GA-ANN was the best approach to simulate the population dynamics of P. aeruginosa. Furthermore, Satureja bachtiarica ethanol extract was able to reduce P. aeruginosa population, showing stronger effect at 5 °C and the concentration of 8000 ppm.

Effects of an ethanol extract of Brazilian green propolis on human cytochrome P450 enzyme activities in vitro

Supplement-drug interaction on CYP enzyme activity is occasionally found to cause clinically adverse events, and no report on interactions of propolis is available either in vitro or clinical. In this study, we tried to estimate the risk of an interaction between an ethanol extract of Brazilian green propolis (EEP-B55) and drugs in vitro and in vivo. The activities of CYP1A2, CYP2C9, CYP2C19, CYP2D6, and CYP3A4 were attenuated by EEP-B55 in a concentration-dependent manner, and artepillin C, kaempferide, dihydrokaempferide, isosakuranetin, and kaempferol were estimated to have potential for CYP inhibition. The IC50 values of artepillin C for each CYP were approximately 33-fold higher than its Cmax in the blood of rats after dosing with 5-fold the recommended daily intake of EEP-B55. These findings suggest that liver CYP enzyme activities are not markedly affected by artepillin C at the recommended daily intake of EEP-B55.

Alkyl caffeates improve the antioxidant activity, antitumor property and oxidation stability of edible oil

Caffeic acid (CA) is distributed widely in nature and possesses strong antioxidant activity. However, CA has lower solubility in non-polar media, which limits its application in fat-soluble food. To increase the lipophilicity of natural antioxidant CA, a series of alkyl caffeates were synthesized and their antioxidant and antitumor activities were investigated. The antioxidant parameters, including the induction period, acid value and unsaturated fatty acid content, of the alkyl caffeates in edible oil were firstly investigated. The results indicated that alkyl caffeates had a lower DPPH IC₅₀ (14–23 µM) compared to CA, dibutyl hydroxy toluene (BHT) and Vitamin C (24–51 µM), and significantly inhibited four human cancer cells (SW620, SW480, SGC7901 and HepG2) with inhibition ratio of 71.4–78.0% by a MTT assay. With regard to the induction period and acid value assays, methyl and butyl caffeates had higher abilities than BHT to restrain the oxidation process and improve the stability of edible oil. The addition of ethyl caffeate to oil allowed maintenance of a higher unsaturated fatty acid methyl ester content (68.53%) at high temperatures. Overall, the alkyl caffeats with short chain length (n<5) assessed better oxidative stability than those with long chain length. To date, this is the first report to the correlations among the antioxidant activity, anticancer activity and oxidative stability of alkyl caffeates.

Propolis: a wonder bees product and its pharmacological potentials

Propolis is a natural resinous mixture produced by honey bees from substances collected from parts of plants, buds, and exudates. Due to its waxy nature and mechanical properties, bees use propolis in the construction and repair of their hives for sealing openings and cracks and smoothing out the internal walls and as a protective barrier against external invaders like snakes, lizards, and so forth, or against weathering threats like wind and rain. Bees gather propolis from different plants, in the temperate climate zone mainly from poplar. Current antimicrobial applications of propolis include formulations for cold syndrome (upper respiratory tract infections, common cold, and flu-like infections), wound healing, treatment of burns, acne, herpes simplex and genitalis, and neurodermatitis. Worldwide propolis has a tremendous popularity, but in India the studies over propolis have just started, not extensively reported except few regions of India like Maharashtra, West Bengal, Tamil Nadu, Gujrat, and Madhya Pradesh.

A novel chemoenzymatic synthesis of propyl caffeate using lipase-catalyzed transesterification in ionic liquid

Propyl caffeate has the highest antioxidant capacity in the caffeate alkyl esters family, but industrial production of propyl caffeate is hindered by low yields using either the chemical or enzymatic catalysis method. To set up a high-yield process for obtaining propyl caffeate, a novel chemoenzymatic synthesis method using lipase-catalyzed transesterification of an intermediate methyl caffeate or ethyl caffeate and 1-propanol in ionic liquid was established. The maximum propyl caffeate yield of 98.5% was obtained using lipase-catalyzed transesterification under the following optimal conditions: Novozym 435 as a biocatalyst, [Bmim][CF3SO3] as a medium, a molar ratio of methyl caffeate to 1-propanol of 1:5, a mass ratio of methyl caffeate to lipase of 1:20, and a reaction temperature of 60°C. The two-step conversion of caffeic acid to propyl caffeate via methyl caffeate is an efficient way to prepare propyl caffeate with an overall yield of 82.7%.

Anticancer activity of Indian stingless bee propolis: an in vitro study

Indian stingless bee propolis has a complex chemical nature and is reported to possess various medicinal properties. In the present study, anticancer activity of the ethanolic extract of propolis (EEP) was explored by testing the cytotoxic and apoptotic effect in four different cancer cell lines, namely, MCF-7 (human breast cancer), HT-29 (human colon adenocarcinoma), Caco-2 (human epithelial colorectal adenocarcinoma), and B16F1 (murine melanoma), at different concentrations. Cytotoxicity was evaluated by MTT assay and Trypan blue dye exclusion assay. EEP at a concentration of 250 μg/mL exhibited ≥50% mortality in all cell lines tested (i.e., IC₅₀ value). EEP revealed a concentration and time dependent cytotoxic effect. Apoptosis was estimated by differential staining (ethidium bromide/acridine orange) and TUNEL (deoxynucleotidyl transferase-dUTP nick end labeling) assay. Light microscopy and atomic force microscopy demonstrated morphological features of apoptosis in all the cell lines after treatment with 250 μg/mL EEP for 24 h. Thus, early onset of apoptosis is the reason for anticancer activity of Indian stingless bee propolis. Further, the antioxidant potential of Indian stingless bee propolis was demonstrated to substantiate its anticancer activity.

Evaluation of chemical composition and efficacy of Chinese propolis extract on Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans: An in vitro study

BACKGROUND

Propolis as a natural remedy has maintained its popularity over long periods of time. The aim of this study was to determine the chemical composition in terms of total phenolic compounds and flavonoids present in Chinese propolis and to carry out an in vitro evaluation of its antimicrobial activity and the minimal inhibitory concentrations for Porphyromonas gingivalis (Pg) and Aggregatibacter actinomycetemcomitans (Aa).

MATERIALS AND METHODS

From the ethanolic extract of propolis (EEP), total phenol content was determined by the Folin-Ciocalteau method, flavones and flavonols by the modified aluminum chloride colorimetric method, and flavanones by the 2.4-dinitrophenylhydrazine (2,4-DNP) method. Agar well diffusion assay was used to evaluate the antimicrobial potential of propolis against Pg and Aa. The minimum inhibitory concentration of propolis against the two bacteria was determined using serial tube dilution technique.

RESULTS

The total concentration of phenol in the EEP was 19.44%, flavones and flavonols 2.616%, and flavanones 16.176%. The inhibitory zone depicting antimicrobial activity ranged from 18 to 25 mm for Pg and from 12 to 14 mm for Aa. The concentration range of Chinese propolis that is sensitive to inhibit the growth of Pg was 0.1-0.0125 μg/ml and for Aa it was 0.1-0.025 μg/ml.

CONCLUSION

These data suggest that Chinese propolis has potent antimicrobial activity against the two periodontopathogens, suggesting its possible use as a natural alternative to the widely used synthetic antibiotics for periodontal therapy.

Differences in numbers of termicins expressed in two termite species affected by fungal contamination of their environments

Termicin is a defensin-like antimicrobial peptide of termites that has strong antifungal activity. Fifty-six different termicin mRNAs encoding 46 different peptides were amplified and identified from Odontotermes formosanus (Termitidae), a species that inhabits environments with a large variety of microbial fauna. In contrast, only 38 different termicin mRNAs encoding 21 different peptides were amplified and identified from Reticulitermes chinensis (Rhinotermitidae). All mRNAs were amplified by reverse transcript PCR, with primers designed from reported termicin mRNA sequences. All of these genes showed high intraspecific sequence identity and were found to be highly homologous with other reported termicin genes. These two termite species live in different environments; the latter encounters relatively fewer pathogens in its habitat. We conclude that differences in microenvironmental pressure can affect the number of termicin genes expressed in termite species.

Susceptibility of Trypanosoma evansi to propolis extract in vitro and in experimentally infected rats

Current therapy of Trypanosoma evansi infections is not effective for the vast majority of animals with relapsing parasitemia and clinical signs. Recently, attention is being focused on the antiparasitic activity of propolis. This study evaluated the susceptibility of T. evansi to propolis extract in vitro and in vivo. A dose-dependent trypanocidal activity of propolis extract was observed in vitro. All trypomastigotes were killed 1 h after incubation with 10 μg mL(-1) of the extract. In vivo, the concentrations of 100, 200, 300 and 400 mg kg(-1) administered orally for 10 consecutive days showed no curative effect, and the rats died from the disease. However, rats treated with the two highest concentrations of propolis extract showed higher longevity than the other groups. Based on these data, we concluded that T. evansi is susceptible to propolis in vitro. Despite the lack of curative efficacy observed in vivo at the concentrations tested, the propolis extract can prolong life in rats infected with the protozoan.

Comparison of the effects of Er,Cr:YSGG laser and different cavity disinfection agents on microleakage of current adhesives

The aim of this study was to compare the effect of the Er,Cr:YSGG laser and different cavity disinfection agents on microleakage of an etch-and-rinse and a self-etch adhesive. Class V preparations were completed on the buccal and lingual surfaces of 30 extracted noncarious human molars. The occlusal margin was placed on enamel and the gingival margin on dentin. Preparations were randomly divided into five experimental groups (n = 12); (1) 2% chlorhexidine gluconate (CHX), (2) propolis, (3) ozone, (4) Er,Cr:YSGG laser, and (5) control (no treatment). Each group was divided into two subgroups according to the adhesive system: etch-and-rinse (Adper Single Bond 2), and a self-etch adhesive (All-Bond SE). The preparations were bulk-filled with a resin composite (Arabesk). After storage in distilled water for 24 h the restored teeth were subjected to thermocycling (1,000 cycles; 5-55°C). All specimens were immersed in 0.5% basic fuchsin solution for 24 h and sectioned longitudinally through the centre of the restorations and examined under a stereomicroscope at ×25 magnification. The data were analysed using the Kruskal-Wallis and Mann-Whitney U-tests. No difference was observed between the groups either on enamel or dentin when the etch-and-rinse adhesive was used (p > 0.05). In the self-etch adhesive groups, a significant difference was found only between the laser group and the CHX group on enamel and between the propolis group and the control group on dentin (p < 0.05). Comparing the etch-and-rinse and self-etch adhesives within each group, no differences were found on dentin (p > 0.05). On enamel, a statistically significant difference was found only in the CHX group (p < 0.05). There were no differences in microleakage with the laser and the different cavity disinfectant applications when used with etch-and-rinse adhesive. In the self-etch group there were differences in microleakage depending on the disinfection agent used.