In Vitro Antimicrobial Activity of Ethanolic Extract of Polish Propolis against Biofilm Forming Staphylococcus epidermidis Strains

In Vitro Antibiofilm Effect of N-Acetyl-L-cysteine/Dry Propolis Extract Combination on Bacterial Pathogens Isolated from Upper Respiratory Tract Infections

Bacterial biofilms play an important role in the pathogenesis of chronic upper respiratory tract infections. In addition to conventional antimicrobial therapy, N-acetyl-L-cysteine (NAC) and propolis are dietary supplements that are often recommended as supportive therapy for upper respiratory tract infections. However, no data on the beneficial effect of their combination against bacterial biofilms can be found in the scientific literature. Therefore, the aim of our study was to investigate the in vitro effect of N-acetyl-L-cysteine (NAC) and dry propolis extract in fixed combinations (NAC/dry propolis extract fixed combination) on biofilm formation by bacterial species isolated from patients with chronic rhinosinusitis, chronic otitis media, and chronic adenoiditis. The prospective study included 48 adults with chronic rhinosinusitis, 29 adults with chronic otitis media, and 33 children with chronic adenoiditis. Bacteria were isolated from tissue samples obtained intraoperatively and identified using the MALDI-TOF Vitek MS System. The antimicrobial activity, synergism, and antibiofilm effect of NAC/dry propolis extract fixed combination were studied in vitro. A total of 116 different strains were isolated from the tissue samples, with staphylococci being the most frequently isolated in all patients (57.8%). MICs of the NAC/dry propolis extract fixed combination ranged from 1.25/0.125 to 20/2 mg NAC/mg propolis. A synergistic effect (FICI ≤ 0.5) was observed in 51.7% of strains. The majority of isolates from patients with chronic otitis media were moderate biofilm producers and in chronic adenoiditis they were weak biofilm producers, while the same number of isolates in patients with chronic rhinosinusitis were weak and moderate biofilm producers. Subinhibitory concentrations of the NAC/propolis combination ranging from 0.625-0.156 mg/mL to 10-2.5 mg/mL of NAC combined with 0.062-0.016 mg/mL to 1-0.25 mg/mL of propolis inhibited biofilm formation in all bacterial strains. Suprainhibitory concentrations ranging from 2.5-10 mg/mL to 40-160 mg/mL of NAC in combination with 0.25-1 mg/mL to 4-16 mg/mL of propolis completely eradicated the biofilm. In conclusion, the fixed combination of NAC and dry propolis extract has a synergistic effect on all stages of biofilm formation and eradication of the formed biofilm in bacteria isolated from upper respiratory tract infections.

Antimicrobial, Antibiofilm and Toxicological Assessment of Propolis

Antimicrobial resistance is a serious problem for the control of infections and infectious diseases. Propolis is a substance produced by honeybees with antimicrobial and antibiofilm properties. To consider propolis as an alternative to the use of antimicrobials for infection control, we assessed its antimicrobial and antibiofilm activities. To assess propolis for topical medical use, toxicological studies were also performed. A Portuguese 70% propolis ethanolic extract was chemically evaluated and studied for antimicrobial activity on staphylococcal field isolates (n = 137) and antibiofilm action (n = 45). Cell toxicological assessment was performed using keratinocytes and fibroblasts. Pinobanksin, chrysin, acacetin, apigenin, pinocembrin, and kaempferol-dimethyl-ether were detected. All 137 isolates were susceptible to 6.68 mg/mL or lower propolis concentration (80% isolates were susceptible to <1 mg/mL). The mean percentage of biofilm inhibition was 71%, and biofilm disruption was 88.5%. Propolis (<1 mg/mL) was well-tolerated by fibroblasts and moderately tolerated by keratinocytes. The combined antimicrobial and antibiofilm effect of propolis, together with its low toxicity to connective tissue and epithelial cells, suggests a good applicability for topical antibacterial treatment. Therefore, propolis seems to be a good alternative to antimicrobials for the treatment of infections with Staphylococcus spp. that deserves to be evaluated in vivo.

Natural Medicine a Promising Candidate in Combating Microbial Biofilm

Studies on biofilm-related infections are gaining prominence owing to their involvement in most clinical infections and seriously threatening global public health. A biofilm is a natural form of bacterial growth ubiquitous in ecological niches, considered to be a generic survival mechanism adopted by both pathogenic and non-pathogenic microorganisms and entailing heterogeneous cell development within the matrix. In the ecological niche, quorum sensing is a communication channel that is crucial to developing biofilms. Biofilm formation leads to increased resistance to unfavourable ecological effects, comprising resistance to antibiotics and antimicrobial agents. Biofilms are frequently combated with modern conventional medicines such as antibiotics, but at present, they are considered inadequate for the treatment of multi-drug resistance; therefore, it is vital to discover some new antimicrobial agents that can prevent the production and growth of biofilm, in addition to minimizing the side effects of such therapies. In the search for some alternative and safe therapies, natural plant-derived phytomedicines are gaining popularity among the research community. Phytomedicines are natural agents derived from natural plants. These plant-derived agents may include flavonoids, terpenoids, lectins, alkaloids, polypeptides, polyacetylenes, phenolics, and essential oils. Since they are natural agents, they cause minimal side effects, so could be administered with dose flexibility. It is vital to discover some new antimicrobial agents that can control the production and growth of biofilms. This review summarizes and analyzes the efficacy characteristics and corresponding mechanisms of natural-product-based antibiofilm agents, i.e., phytochemicals, biosurfactants, antimicrobial peptides, and their sources, along with their mechanism, quorum sensing signalling pathways, disrupting extracellular matrix adhesion. The review also provides some other strategies to inhibit biofilm-related illness. The prepared list of newly discovered natural antibiofilm agents could help in devising novel strategies for biofilm-associated infections.

Nanoemulsion-Based Hydrogels and Organogels Containing Propolis and Dexpanthenol: Preparation, Characterization, and Comparative Evaluation of Stability, Antimicrobial, and Cytotoxic Properties

Recently, nanoemulsion-based gels have become very popular for dermal drug delivery, overcoming the disadvantages of conventional semi-solid drug forms. The aim of this study is to prepare and characterize nanoemulsion-based hydrogels and organogels containing combined propolis and dexpanthenol, and to compare their stability, antimicrobial, and cytotoxicity properties. Within the scope of characterization studies, organoleptic properties, drug content, morphology, pH, gel-sol conversion temperature, spreadability, viscosity, FT-IR, and release properties were evaluated in hydrogels and organogels. The characterization studies carried out were subjected to short-term stability evaluation at room temperature and refrigerator for 3 months. While no phase separation was observed in any of the formulations kept in the refrigerator, phase separation was observed in four formulations kept at room temperature. The release study successfully obtained an extended release for propolis and dexpanthenol. In the antimicrobial susceptibility study, Hydrogel 1 showed activity against S. aureus, while Organogel 1 showed activity against both S. aureus and S. epidermidis. In the cytotoxicity study against HDFa cells, both Hydrogel 1 and Organogel 1 were found to be nontoxic at low doses. These hydrogels and organogels, which contain propolis and dexpanthenol in combination for the first time, are promising systems that can be used in wound and burn models in the future.

The Current Antimicrobial and Antibiofilm Activities of Synthetic/Herbal/Biomaterials in Dental Application

Herbal and chemical products are used for oral care and biofilm treatment and also have been reported to be controversial in the massive trials conducted in this regard. The present review is aimed at evaluating the potential of relevant herbal and chemical products and comparing their outcomes to conventional oral care products and summarizing the current state of evidence of the antibiofilm properties of different products by evaluating studies from the past eleven years. Chlorhexidine gluconate (CHX), essential oils (EOs), and acetylpyridinium chloride were, respectively, the most commonly studied agents in the included studies. As confirmed by all systematic reviews, CHX and EO significantly control the plaque formation and gingival indices. Fluoride is another interesting reagent in oral care products that has shown promising results of oral health improvement, but the evidence quality needs to be refined. The synergy between natural plants and chemical products should be targeted in the future to accede to the formation of new, efficient, and healthy anticaries strategies. Moreover, to discover their biofilm-interfering or biofilm-inhibiting activities, effective clinical trials are needed. In this review article, therapeutic applications of herbal/chemical materials in oral biofilm infections are discussed in recent years (2010-2022).

The Array of Antibacterial Action of Protocatechuic Acid Ethyl Ester and Erythromycin on Staphylococcal Strains

The spread of antibiotic resistance among bacteria has become one of the major health problems worldwide. Methicillin-resistant staphylococcal strains are especially dangerous because they are often resistant to other antibiotics. The increasing insensitivity to macrolides, lincosamides and streptogramin B antibiotics of methicillin-resistant staphylococcal isolates has limited the use of these drugs in therapy. The combination of natural compounds and antibiotics can be considered as an alternative tool to fight multi-drug-resistant pathogen infections. The aim of the presented study was to examine the antibacterial activity of protocatechuic acid ethyl ester–erythromycin combination towards Staphylococcus aureus and Staphylococcus epidermidis strains with various resistance profiles to methicillin and macrolides, lincosamides and streptogramin B (MLS_B) antibiotics. The in-vitro antibacterial potential of the above combination was investigated by minimum inhibitory concentration assays and checkerboard testing. The observed effects were strain dependent, with 8 of 12 tested staphylococcal strains showing an indifferent effect on the natural compound and erythromycin; for 2 strains, the tested combination had an additive effect, while for another 2, the effect was synergistic. Interestingly, the multi-drug-resistant strains were more sensitive to the cooperative action of the protocatechuic acid ethyl ester and the antibiotic.

Propolis characterization and antimicrobial activities against Staphylococcus aureus and Candida albicans: A review

Propolis is a plant-based sticky substance that is produced by honeybees. It has been used traditionally by ancient civilizations as a folk medicine, and is known to have many pharmaceutical properties including antioxidant, antibacterial, antifungal, anti-inflammatory, antiviral, and antitumour effects. Worldwide, researchers are still studying the complex composition of propolis to unveil its biological potential, and especially its antimicrobial activity against a variety of multidrug-resistant microorganisms. This review explores scientific reports published during the last decade on the characterization of different types of propolis, and evaluates their antimicrobial activities against Staphylococcus aureus and Candida albicans. Propolis can be divided into different types depending on their chemical composition and physical properties associated with geographic origin and plant sources. Flavonoids, phenols, diterpenes, and aliphatic compounds are the main chemicals that characterize the different types of propolis (Poplar, Brazilian, and Mediterranean), and are responsible for their antimicrobial activity. The extracts of most types of propolis showed greater antibacterial activity against Gram-positive bacteria: particularly on S. aureus, as well as on C. albicans, as compared to Gram-negative pathogens. Propolis acts either by directly interacting with the microbial cells or by stimulating the immune system of the host cells. Some studies have suggested that structural damage to the microorganisms is a possible mechanism by which propolis exhibits its antimicrobial activity. However, the mechanism of action of propolis is still unclear, due to the synergistic interaction of the ingredients of propolis, and this natural substance has multi-target activity in the cell. The broad-spectrum biological potentials of propolis present it as an ideal candidate for the development of new, potent, and cost-effective antimicrobial agents.

Evaluation of Total Phenolic and Flavonoid Contents, Antibacterial and Antibiofilm Activities of Hungarian Propolis Ethanolic Extract against Staphylococcus aureus

Propolis is a natural bee product that is widely used in folk medicine. This study aimed to evaluate the antimicrobial and antibiofilm activities of ethanolic extract of propolis (EEP) on methicillin-resistant and sensitive Staphylococcus aureus (MRSA and MSSA). Propolis samples were collected from six regions in Hungary. The minimum inhibitory concentrations (MIC) values and the interaction of EEP-antibiotics were evaluated by the broth microdilution and the chequerboard broth microdilution methods, respectively. The effect of EEP on biofilm formation and eradication was estimated by crystal violet assay. Resazurin/propidium iodide dyes were applied for simultaneous quantification of cellular metabolic activities and dead cells in mature biofilms. The EEP1 sample showed the highest phenolic and flavonoid contents. The EEP1 successfully prevented the growth of planktonic cells of S. aureus (MIC value = 50 µg/mL). Synergistic interactions were shown after the co-exposition to EEP1 and vancomycin at 108 CFU/mL. The EEP1 effectively inhibited the biofilm formation and caused significant degradation of mature biofilms (50-200 µg/mL), as a consequence of the considerable decrement of metabolic activity. The EEP acts effectively as an antimicrobial and antibiofilm agent on S. aureus. Moreover, the simultaneous application of EEP and vancomycin could enhance their effect against MRSA infection.

Nonwoven Releasing Propolis as a Potential New Wound Healing Method-A Review

Wound healing poses a serious therapeutic problem. Methods which accelerate tissue regeneration and minimize or eliminate complications are constantly being sought. This paper is aimed at evaluation of the potential use of biodegradable polymer nonwovens releasing propolis as wound healing dressings, based on the literature data. Propolis is honeybee product with antioxidant, antibacterial, antifungal, anticancer, anti-inflammatory, analgesic, and regenerative properties. Controlled release of this substance throughout the healing should promote healing process, reduce the risk of wound infection, and improve aesthetic effect. The use of biodegradable aliphatic polyesters and polyester carbonates as a propolis carrier eliminates the problem of local drug administration and dressing changes. Well-known degradation processes and kinetics of the active substance release allows the selection of the material composition appropriate to the therapy. The electrospinning method allows the production of nonwovens that protect the wound against mechanical damage. Moreover, this processing technique enables adjusting product properties by modifying the production parameters. It can be concluded that biodegradable polymer dressings, releasing a propolis, may find potential application in the treatment of complicated wounds, as they may increase the effectiveness of treatment, as well as improve the patient’s life quality.

A physico-chemical study of the interaction of ethanolic extracts of propolis with bacterial cells

In the present study, an effort has been made to understand the interaction mode of propolis, a natural substance produced by honey bees, with gram-positive and gram-negative bacterial cells by measuring alterations in cell surface physico-chemical properties following the incubation of the cells with different sub-inhibitory concentrations of this antimicrobial agent. Electrophoretic mobility and surface hydrophobicity measurements revealed for the first time that propolis induced substantial changes in the volumetric charge density, electrophoretic softness and degree of hydrophobicity characterizing the outermost surface layer of cells. These changes, which appear to be dose-dependent, seem to be consistent with the increasing accumulation and penetration of the propolis antimicrobial components through the cells extracellular layer. Moreover, electron microscopy observation and the determination of the cell constituents' release demonstrated that propolis at sub-bactericidal concentrations already provoked (at least localized) cell wall damage and/or perturbations. These findings thus suggest that the initial mechanism of action of propolis is most likely structural, resulting from sufficient interaction between the different propolis components and bacterial cell wall structures.

Nanocellulose in Drug Delivery and Antimicrobially Active Materials

In recent years, nanocellulose (NC) has also attracted a great deal of attention in drug delivery systems due to its unique physical properties, specific surface area, low risk of cytotoxicity, and excellent biological properties. This review is focused on nanocellulose based systems acting as carriers to be used in drug or antimicrobial delivery by providing different but controlled and sustained release of drugs or antimicrobial agents, respectively, thus showing potential for different routes of applications and administration. Microorganisms are increasingly resistant to antibiotics, and because, generally, the used metal or metal oxide nanoparticles at some concentration have toxic effects, more research has focused on finding biocompatible antimicrobial agents that have been obtained from natural sources. Our review contains the latest research from the last five years that tested nanocellulose-based materials in the field of drug delivery and antimicrobial activity.

Effect of Ethanol Extracts of Propolis (EEPs) against Staphylococcal Biofilm-Microscopic Studies

Staphylococci growing in the form of biofilm exhibit high resistance to a plethora of antibiotics. The aim of the study was to assess the influence of ethanolic extract of propolis (EEPs) on S. epidermidis ATCC 35984 biofilm using fluorescent microscopy. Propidium iodide (PI) and SYTO 9 were used for differentiation of live and dead cells, and calcofluor white was used to stain the extracellular matrix, the self-produced extracellular polymeric substances (EPS). The outcomes of the research confirm the promising potential of EEPs for eradication of staphylococcal biofilm. However, its activity cannot be classified as fully satisfactory, either in terms of the effectiveness of elimination of bacterial cells or disturbing the EPS structure. A two or even four times higher concentration of EEPs compared to MIC (Minimum Inhibitory Concentration) against planktonic cells (128 µg/mL) was necessary for effective (estimated for 90%) elimination of living cells from the biofilm structure. Unfortunately, even at that concentration of EEPs, the extracellular matrix was only partially disturbed and effectively protected the residual population of living cells of S. epidermidis ATCC 35984. In our opinion, a combination of EEPs with agents disrupting components of EPS, e.g., proteases, lysines, or enzymes degrading extracellular DNA or PIA (polysaccharide intercellular adhesin).

Chemical Profile and Antibacterial Activity of a Novel Spanish Propolis with New Polyphenols also Found in Olive Oil and High Amounts of Flavonoids

Propolis is a natural product obtained from hives. Its chemical composition varies depending on the flora of its surroundings, but nevertheless, common for all types of propolis, they all exhibit remarkable biological activities. The aim of this study was to investigate the chemical composition and antimicrobial activity of a novel Spanish Ethanolic Extract of Propolis (SEEP). It was found that this new SEEP contains high amounts of polyphenols (205 ± 34 mg GAE/g), with unusually more than half of this of the flavonoid class (127 ± 19 mg QE/g). Moreover, a detailed analysis of its chemical composition revealed the presence of olive oil compounds (Vanillic acid, 1-Acetoxypinoresinol, p-HPEA-EA and 3,4-DHPEA-EDA) never detected before in propolis samples. Additionally, relatively high amounts of ferulic acid and quercetin were distinguished, both known for their important therapeutic benefits. Regarding the antimicrobial properties of SEEP, the minimal inhibitory and bactericidal concentrations (MIC and MBC) against Staphylococcus epidermidis strains were found at the concentrations of 240 and 480 µg/mL, respectively. Importantly, subinhibitory concentrations were also found to significantly decrease bacterial growth. Therefore, the results presented here uncover a new type of propolis rich in flavonoids with promising potential uses in different areas of human health.

In vitro estimation of superfluid critical extracts of some plants for their antimicrobial potential, phytochemistry, and GC-MS analyses

BACKGROUND

Along with swift economic evolution and continuous amelioration of lifestyle, people at present are paying more attention to health issues. Synthetic drugs will be compensated with other natural ones that belong to natural origin. Plants have always been considered as sources of several compounds that are used in many fields, especially human and animal health, starting from boosting immunity to the treatment of infectious diseases caused by some pathogenic microbes such as bacteria, fungi as well as viruses. This study aimed to incorporate some types of plants within the antimicrobial portfolio through the examination of different six plants which were Cichorium intybus, Cinnamomum camphora, Commiphora myrrha, Foeniculum vulgare, Nerium oleander, and Spartium junceum. As well, attempting to identify the active constituents of their extracts using GC-MS.

MATERIALS AND METHODS

All selected plants were analyzed to determine their phytochemical composition such as phenolics, alkaloids, flavonoids, terpenoids, and so on. The extraction step was done by sophisticated equipment called supercritical fluid extractor SFE through adjustment of specific conditions include temperature, time, flow rate and pressure to change the behavior of CO2. Testing the antimicrobial activity of each plant extract via agar well diffusion method through the formation of clear zones against a wide range of test microorganisms including both Gram-positive and Gram-negative bacteria as well as yeasts. Finally, attempting to primarily identify the constituents of each plant extract using GC-MS.

RESULTS AND DISCUSSION

The crude extract of F. vulgare showed the highest potency against C. albicans, E. faecalis and S. typhimurium, it contains some unique compounds such as squalene, eugenol and isoeugenol while, Extract of C. intybus showed a moderate activity especially against C. lipolytica and MRSA and it includes Vitamin A like compound which indicates antioxidant property.

CONCLUSION

Conclusively, fennel gave a promising result as a good wide spectrum antimicrobial agent because it contains some compounds act as antimicrobial agents such as eugenol which was used as food preservatives in addition to squalene which acts as an antioxidant and antimycotic agent so, it will be useful especially while it was used in highly purified form excluding all undesirable subcomponents.

Antibacterial Properties of Propolis

Researchers are continuing to discover all the properties of propolis due to its complex composition and associated broad spectrum of activities. This review aims to characterize the latest scientific reports in the field of antibacterial activity of this substance. The results of studies on the influence of propolis on more than 600 bacterial strains were analyzed. The greater activity of propolis against Gram-positive bacteria than Gram-negative was confirmed. Moreover, the antimicrobial activity of propolis from different regions of the world was compared. As a result, high activity of propolis from the Middle East was found in relation to both, Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) strains. Simultaneously, the lowest activity was demonstrated for propolis samples from Germany, Ireland and Korea.

The Anti-Staphylococcal Potential of Ethanolic Polish Propolis Extracts

The principal objective of this study was to determine the anti-staphylococcal potential of ethanol extracts of propolis (EEPs). A total of 20 samples of propolis collected from apiaries located in different regions of Poland were used in the study. The two-fold broth microdilution method revealed some important differences in the antimicrobial activity of investigated EEPs. Up to the concentration of 4096 µg/mL no activity was observed against Gram-negative bacteria (E. coli and P. aeruginosa). Staphylococci exhibited much higher susceptibility. The highest efficiency observed for EEP12 and EEP20 (MIC values ranged between 32 and 256 µg/mL). However, the achievement of bactericidal effect usually required higher concentrations. In the case of clinical isolates of S. aureus MBC values for EEP12 and EEP20 ranged from 512 to 1024 µg/mL. The HPLC analysis revealed that these two products contained a higher concentration of flavonoids (flavonols, flavones, and flavanones) compared to other investigated EEPs. In checkerboard test, a synergistic anti-staphylococcal effect was observed for the action of EEP20 in combination with amikacin, kanamycin, gentamycin, tetracycline, and fusidic acid (all these antibiotics inhibit protein synthesis). Moreover, the investigated EEPs effectively eradicated staphylococcal biofilm. The obtained results clearly confirm the high anti-staphylococcal potential of propolis harvested in Polish apiaries.

Developing natural products as potential anti-biofilm agents

Biofilm is a natural form of bacterial growth ubiquitously in environmental niches. The biofilm formation results in increased resistance to negative environmental influences including resistance to antibiotics and antimicrobial agents. Quorum sensing (QS) is cell-to-cell communication mechanism, which plays an important role in biofilm development and balances the environment when the bacteria density becomes high. Due to the prominent points of biofilms implicated in infectious disease and the spread of multi-drug resistance, it is urgent to discover new antibacterial agents that can regulate biofilm formation and development. Accumulated evidences demonstrated that natural products from plants had antimicrobial and chemo-preventive properties in modulation of biofilm formation in the last two decades. This review will summarize recent studies on the discovery of natural anti-biofilm agents from plants with clear-cut mechanisms or identified molecular addresses, as well as some herbs with unknown mechanisms or unidentified bioactive ingredients. We also focus on the progression of techniques on the extraction and identification of natural anti-biofilm substances. Besides, anti-biofilm therapeutics undergoing clinical trials are discussed. These newly discovered natural anti-biofilm agents are promising candidates which could provide novel strategies for biofilm-associated infections.

Effect of Propolis Preparations on Transepithelial Electrical Potential, Resistance, and Ion Transport in In Vitro Study

Background

Propolis and its ethanol extract show positive germicidal, bacteriostatic, and anti-inflammatory antioxidants and regenerative properties after use on the surface of the skin. Propolis is in common use in production of cosmetics and in folk medicine. The influence of this resinous mixture on ion channels, channels located in skin cells membranes and skin electrical resistance, was not explained.

Objective

The main aim of the study was the evaluation of electrophysiological skin parameters during mechanical and chemical-mechanical stimulation after use of ethanol extract of propolis and propolis ointment in comparison with iso-osmotic Ringer solution.

Methods

Skin fragments were taken from white New Zealand rabbits and distributed into three experimental groups which were incubated in ethanol extract of propolis (EEP), propolis ointment, and Ringer solution. Then they were placed in a Ussing chamber to measure electrophysiological parameters values.

Results

In this study the influence of EEP on changes in value of electrical potential during block of chloride ions transport at the same time was observed. Ethanol propolis extract dissolved in water increases the transepidermal sodium ions transport in contrast to propolis ointment.

Conclusion

The way of preparation cosmetics, which contain propolis, has effects on transepidermal ions transport in the rabbit's skin. The value of skin electrical resistance is changing with penetration depth of active propolis substances contained in cosmetics.

Activity of preparations from Spilanthes oleracea, propolis, Nigella sativa, and black garlic on different microorganisms involved in oral diseases and on total human salivary bacteria: A pilot study

Due to continuous rise in antibiotic resistance, there is a need for alternative treatment options to reduce the levels of oral pathogens for the maintenance of oral as well as overall health. The aim of this study was to evaluate the in vitro antibacterial potential of tinctures of Spilanthes oleracea and propolis, Nigella seed oil, and an ethanolic extract of black garlic on microorganisms involved in oral diseases. Both the minimum inhibitory concentration assay and the minimum bactericidal/fungicidal concentration assay were used in this study. Inhibition effects against total human salivary bacteria were also determined. Our results show that all of the preparations tested had potent antimicrobial activities. When measured 10 min after exposure, even low concentrations of the propolis tincture were found to have killed more than 99% of salivary bacteria, whereas Spilanthes tincture and black garlic extract killed more than 90% and Nigella seed oil more than 60% of the pathogens. This suggests that all preparations are promising candidates for the use in oral health care products and that all have the potential to control biofilm associated infections.

Brazilian propolis mitigates impaired glucose and lipid metabolism in experimental periodontitis in mice

Background

Periodontitis has been implicated as a risk factor for metabolic disorders associated with insulin resistance. Recently, we have demonstrated that orally administered Porphyromonas gingivalis, a representative periodontopathic bacterium, induces endotoxemia via reduced gut barrier function coupled with changes in gut microbiota composition, resulting in systemic inflammation and insulin resistance. Propolis, a resinous substance collected by honeybees from leaf buds and cracks in the bark of various plants, can positively affect metabolic disorders in various experimental models. In this study, we thus aimed to clarify the effect of propolis on impaired glucose and lipid metabolism induced by P. gingivalis administration.

Methods

Eight-week-old male C57BL/6 mice were orally administered P. gingivalis strain W83, propolis ethanol extract powder with P. gingivalis, or vehicle. We then analyzed the expression profile of glucose and lipid metabolism-related genes in the liver and adipose tissues. Serum endotoxin levels were also evaluated by a limulus amebocyte lysate test. In addition, we performed histological analysis of the liver and quantified alveolar bone loss by measuring the root surface area on the lower first molar.

Results

Oral administration of P. gingivalis induced downregulation of genes that improve insulin sensitivity in adipose tissue (C1qtnf9, Irs1, and Sirt1), but upregulation of genes associated with lipid droplet formation and gluconeogenesis (Plin2, Acox, and G6pc). However, concomitant administration of propolis abrogated these adverse effects of P. gingivalis. Consistent with gene expression, histological analysis showed that administered propolis suppressed hepatic steatosis induced by P. gingivalis. Furthermore, propolis inhibited the elevation of serum endotoxin levels induced by P. gingivalis administration. Contrary to the systemic effects, propolis had no beneficial effect on alveolar bone loss.

Conclusion

These results suggest that administration of propolis may be effective in suppressing periodontopathic bacteria-induced metabolic changes that increase the risk of various systemic diseases.

Staphylococcus aureus Typing by Digestion of Protein A Coding Gene Using Bsp143I

BACKGROUND

Protein A is the virulence factors of Staphylococcus aureus rolling in its pathogenesis, and its gene is used for typing. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) with different enzymes has been used for this action.

OBJECTIVES

In this study, we used Bsp143I enzyme for digestion of the gene, coding protein A (spa gene) in S. aureus. The bacteria were isolated from patients and healthy carriers in Gorgan, north of Iran.

PATIENTS AND METHODS

DNAs of 128 S. aureus subjects (53 from healthy carriers and 75 from patients) were extracted and amplified using specific primers of the spa gene. The product was digested by Bsp143I enzyme and its pattern was assessed by gel electrophoresis.

RESULTS

There were seven spa types among the tested S. aureus samples, among which six types differed in the repeated X region of the spa gene, but the seventh type had a deletion on one of BSP143I restriction sites. The frequency of spa types among isolated S. aureus samples as well as healthy carriers was six and five, respectively. S. aureus isolated from wounds showed the most diverse spa types (five) among clinical samples. Types 1, 2 and 4 were observed in all clinical samples, while only one case of type 3 was identified among patients, whereas this type constituted over 32% of the isolates among carriers. We found seven and four spa types among methicillin-resistant S. aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) isolates, respectively.

CONCLUSIONS

Our results showed that typing the spa gene using PCR-RFLP using Bsp143I was an acceptable method for typing S. aureus. Furthermore, this survey showed that the types in healthy carriers and MSSA were more variable than patient and MRSA isolates, respectively. We used the Bsp143I enzyme, which was not used in any previous studies on the spa gene. The results of this study suggested that we can use PCR-RFLP of spa gene by Bsp143I for molecular typing and sequencing of S. aureus, instead of relatively expensive methods. This method is relatively rapid and inexpensive, and can be accomplished in centers with conventional molecular facilities.

Berberine enhances the antibacterial activity of selected antibiotics against coagulase-negative Staphylococcus strains in vitro

Synergistic interactions between commonly used antibiotics and natural bioactive compounds may exhibit therapeutic benefits in a clinical setting. Berberine, an isoquinoline-type alkaloid isolated from many kinds of medicinal plants, has proven efficacy against a broad spectrum of microorganisms. The aim of the presented work was to assess the antibacterial activity of berberine chloride in light of the effect exerted by common antibiotics on fourteen reference strains of Staphylococccus spp., and to evaluate the magnitude of interactions of berberine with these antistaphylococcal antibiotics. In our study minimum inhibitory concentrations (MIC) of berberine chloride against CoNS ranged from 16 to 512 µg/mL. The most noticeable effects were observed for S. haemolyticus ATCC 29970, S. epidermidis ATCC 12228, S. capitis subsp. capitis ATCC 35661, S. galinarium ATCC 700401, S. hominis subsp. hominis ATCC 27844, S. intermedius ATCC 29663 and S. lugdunensis ATCC 49576. The most significant synergistic effect was noticed for berberine in combination with linezolid, cefoxitin and erythromycin. The synergy between berberine and antibiotics demonstrates the potential application of compound combinations as an efficient, novel therapeutic tool for antibiotic-resistant bacterial infections.

The virulence of Streptococcus mutans and the ability to form biofilms

In some diseases, a very important role is played by the ability of bacteria to form multi-dimensional complex structure known as biofilm. The most common disease of the oral cavity, known as dental caries, is a top leader. Streptococcus mutans, one of the many etiological factors of dental caries, is a microorganism which is able to acquire new properties allowing for the expression of pathogenicity determinants determining its virulence in specific environmental conditions. Through the mechanism of adhesion to a solid surface, S. mutans is capable of colonizing the oral cavity and also of forming bacterial biofilm. Additional properties enabling S. mutans to colonize the oral cavity include the ability to survive in an acidic environment and specific interaction with other microorganisms colonizing this ecosystem. This review is an attempt to establish which characteristics associated with biofilm formation--virulence determinants of S. mutans--are responsible for the development of dental caries. In order to extend the knowledge of the nature of Streptococcus infections, an attempt to face the following problems will be made: Biofilm formation as a complex process of protein-bacterium interaction. To what extent do microorganisms of the cariogenic flora exemplified by S. mutans differ in virulence determinants "expression" from microorganisms of physiological flora? How does the environment of the oral cavity and its microorganisms affect the biofilm formation of dominant species? How do selected inhibitors affect the biofilm formation of cariogenic microorganisms?

Structure and antioxidant activity of polyphenols derived from propolis

Propolis is a potential source of natural antioxidants such as phenolic acids and flavonoids. Its wide biological effects have been known and used since antiquity. In the modern world natural substances are sought which would be able to counteract the effects of antioxidative stress, which underlies many diseases, such as cancer, diabetes and atherosclerosis. This paper aims to present the antioxidative activity of phenolic acids and flavonoids present in Polish propolis and the relationship between their chemical structure and antioxidative activity influencing its medicinal properties. Data concerning the biological activity of propolis are summarized here, including its antibacterial, anti-inflammatory, anticarcinogenic, antiatherogenic, estrogenic effects, as well as AIDS- counteracting and reparative-regenerative function.

Susceptibility of Staphylococcus aureus clinical isolates to propolis extract alone or in combination with antimicrobial drugs

The objective of this study was to assess in vitro the antimicrobial activity of ethanolic extract of Polish propolis (EEPP) against methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates. The combined effect of EEPP and 10 selected antistaphylococcal drugs on S. aureus clinical cultures was also investigated. EEPP composition was analyzed by a High Performance Liquid Chromatography (HPLC) method. The flavonoid compounds identified in Polish Propolis included flavones, flavonones, flavonolols, flavonols and phenolic acids. EEPP displayed varying effectiveness against twelve S. aureus strains, with minimal inhibitory concentration (MIC) within the range from 0.39 to 0.78 mg/mL, determined by broth microdilution method. The average MIC was 0.54 ± 0.22 mg/mL, while calculated MIC₅₀ and MIC₉₀ were 0.39 mg/mL and 0.78 mg/mL, respectively. The minimum bactericidal concentration (MBC) of the EEPP ranged from 0.78 to 3.13 mg/mL. The in vitro combined effect of EEPP and 10 antibacterial drugs was investigated using disk diffusion method-based assay. Addition of EEPP to cefoxitin (FOX), clindamycin (DA), tetracycline (TE), tobramycin (TOB), linezolid (LIN), trimethoprim+sulfamethoxazole (SXT), penicillin (P), erythromycin (E) regimen, yielded stronger, cumulative antimicrobial effect, against all tested S. aureus strains than EEPP and chemotherapeutics alone. In the case of ciprofloxacin (CIP) and chloramphenicol (C) no synergism with EEPP was observed.

The biological activity of propolis-containing toothpaste on oral health environment in patients who underwent implant-supported prosthodontic rehabilitation

The soft and periodontal tissues surrounding dental implants are particularly susceptible to bacteria invasion and inflammatory reactions due to complex histological structures. This study was carried out to investigate the influence of a propolis-containing hygienic agent on selected oral health parameters, oral microflora, and the condition of periodontal health. Sixteen subjects who underwent an oral rehabilitation with dental implants were selected and randomly assigned into two groups, which received a newly formulated propolis-containing toothpaste (3% (CA)) or a negative control without an active ingredient (CC). Approximal plaque index (API), oral hygiene index (OHI, debris component), and sulcus bleeding index (SBI) were assessed in three subsequent stages. During the first and last examinations, the swabs were employed for microbiological inoculation. Propolis-containing toothpaste was found to be distinctively effective in improving oral health and the occurrence of gingivitis triggered by dental plaque. The qualitative and quantitative changes in oral bacteria spectrum were observed. Antibacterial measures containing propolis might be used as a natural adjuvant to other active substances in individuals with a high risk of periodontal problems against pathogenic oral microflora.