Jerzy Stojko

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.

Propolis Induces Chondroitin/Dermatan Sulphate and Hyaluronic Acid Accumulation in the Skin of Burned Wound

Changes in extracellular matrix glycosaminoglycans during the wound repair allowed us to apply the burn model in which therapeutic efficacy of propolis and silver sulfadiazine was compared. Burns were inflicted on four pigs. Glycosaminoglycans isolated from healthy and burned skin were quantified using a hexuronic acid assay, electrophoretic fractionation, and densitometric analyses. Using the reverse-phase HPLC the profile of sulfated disaccharides released by chondroitinase ABC from chondroitin/dermatan sulfates was estimated. Chondroitin/dermatan sulfates and hyaluronic acid were found in all samples. Propolis stimulated significant changes in the content of particular glycosaminoglycan types during burn healing. Glycosaminoglycans alterations after silver sulfadiazine application were less expressed. Propolis maintained high contribution of 4-O-sulfated disaccharides to chondroitin/dermatan sulfates structure and low level of 6-O-sulfated ones throughout the observed period of healing. Propolis led to preservation of significant contribution of disulfated disaccharides especially 2,4-O-disulfated ones to chondroitin sulfates/dermatan sulfates structure throughout the observed period of healing. Our findings demonstrate that propolis accelerates the burned tissue repair by stimulation of the wound bed glycosaminoglycan accumulation needed for granulation, tissue growth, and wound closure. Moreover, propolis accelerates chondroitin/dermatan sulfates structure modification responsible for binding growth factors playing the crucial role in the tissue repair.

Propolis Modifies Collagen Types I and III Accumulation in the Matrix of Burnt Tissue

Wound healing represents an interactive process which requires highly organized activity of various cells, synthesizing cytokines, growth factors, and collagen. Collagen types I and III, serving as structural and regulatory molecules, play pivotal roles during wound healing. The aim of this study was to compare the propolis and silver sulfadiazine therapeutic efficacy throughout the quantitative and qualitative assessment of collagen types I and III accumulation in the matrix of burnt tissues. Burn wounds were inflicted on pigs, chosen for the evaluation of wound repair because of many similarities between pig and human skin. Isolated collagen types I and III were estimated by the surface plasmon resonance method with a subsequent collagenous quantification using electrophoretic and densitometric analyses. Propolis burn treatment led to enhanced collagens and its components expression, especially during the initial stage of the study. Less expressed changes were observed after silver sulfadiazine (AgSD) application. AgSD and, with a smaller intensity, propolis stimulated accumulation of collagenous degradation products. The assessed propolis therapeutic efficacy, throughout quantitatively and qualitatively analyses of collagen types I and III expression and degradation in wounds matrix, may indicate that apitherapeutic agent can generate favorable biochemical environment supporting reepithelization.

Polyphenols from Bee Pollen: Structure, Absorption, Metabolism and Biological Activity

Bee pollen constitutes a natural source of antioxidants such as phenolic acids and flavonoids, which are responsible for its biological activity. Research has indicated the correlation between dietary polyphenols and cardioprotective, hepatoprotective, anti-inflammatory, antibacterial, anticancerogenic, immunostimulating, antianaemic effects, as well as their beneficial influence on osseous tissue. The beneficial effects of bee pollen on health result from the presence of phenolic acids and flavonoids which possess anti-inflammatory properties, phytosterol and linolenic acid which play an anticancerogenic role, and polysaccharides which stimulate immunological activity. Polyphenols are absorbed in the alimentary tract, metabolised by CYP450 enzymes, and excreted with urine and faeces. Flavonoids and phenolic acids are characterised by high antioxidative potential, which is closely related to their chemical structure. The high antioxidant potential of phenolic acids is due to the presence and location of hydroxyl groups, a carboxyl group in the immediate vicinity of ortho-diphenolic substituents, and the ethylene group between the phenyl ring and the carboxyl group. As regards flavonoids, essential structural elements are hydroxyl groups at the C5 and C7 positions in the A ring, and at the C3′ and C4′ positions in the B ring, and a hydroxyl group at the C3 position in the C ring. Furthermore, both, the double bond between C2 and C3, and a ketone group at the C4 position in the C ring enhance the antioxidative potential of these compounds. Polyphenols have an ideal chemical structure for scavenging free radicals and for creating chelates with metal ions, which makes them effective antioxidants in vivo.

Caffeic Acid Phenethyl Ester and Ethanol Extract of Propolis Induce the Complementary Cytotoxic Effect on Triple-Negative Breast Cancer Cell Lines

Chemotherapy of breast cancer could be improved by bioactive natural substances, which may potentially sensitize the carcinoma cells’ susceptibility to drugs. Numerous phytochemicals, including propolis, have been reported to interfere with the viability of carcinoma cells. We evaluated the in vitro cytotoxic activity of ethanol extract of propolis (EEP) and its derivative caffeic acid phenethyl ester (CAPE) towards two triple-negative breast cancer (TNBC) cell lines, MDA-MB-231 and Hs578T, by implementation of the MTT and lactate dehydrogenase (LDH) assays. The morphological changes of breast carcinoma cells were observed following exposure to EEP and CAPE. The IC50 of EEP was 48.35 µg∙mL−1 for MDA-MB-23 cells and 33.68 µg∙mL−1 for Hs578T cells, whereas the CAPE IC50 was 14.08 µM and 8.01 µM for the MDA-MB-231 and Hs578T cell line, respectively. Here, we report that propolis and CAPE inhibited the growth of the MDA-MB-231 and Hs578T lines in a dose-dependent and exposure time-dependent manner. EEP showed less cytotoxic activity against both types of TNBC cells. EEP and, particularly, CAPE may markedly affect the viability of breast cancer cells, suggesting the potential role of bioactive compounds in chemoprevention/chemotherapy by potentiating the action of standard anti-cancer drugs.

Positive Effect of Propolis on Free Radicals in Burn Wounds

Concentration and properties of free radicals in the burn wounds treated with propolis were examined by the use of electron paramagnetic resonance spectroscopy. Magnetic spin-spin interactions and complex free radicals structures in wound beds were studied. The results were compared to those obtained for silver sulphadiazine used as a standard pharmaceutical agent. The changes of free radicals in the matrix of injury with time of exposition on these substances were tested. The aim of this study was to check the hypothesis about the best influence of propolis on the burn wounds healing. It was confirmed that a relatively lower concentration of free radicals exists in the burn wounds treated with propolis. The homogeneously broadened spectra and a complex free radical system characterize the tested tissue samples. The fastening of spin-lattice relaxation processes in the matrix of injury after treatment with propolis and silver sulphadiazine was observed. Practical usefulness of electron paramagnetic resonance spectroscopy in alternative medicine was proved.

Antioxidative properties of bee pollen extracts examined by EPR spectroscopy

Antioxidative Properties of Bee Pollen Extracts Examined by EPR Spectroscopy Bee pollen is a valuable and highly recognized source of exogenous antioxidants. The aim of these studies was to determine the antioxidant capacity of three types of bee pollen extracts: ethanol extracts of bee pollen, pepsin extracts of bee pollen and ethanol extracts of pepsin-digested bee pollen. Their antioxidant properties were determined with the use of electron paramagnetic resonance (EPR) and their ability to quench DPPH free radicals was estimated. The EPR results showed that ethanol extracts of pepsin-digested bee pollen (EEPP) had the highest antioxidative effect and the highest free radical DPPH scavenging potential. The pepsin extracts of bee pollen (PEP) had the weakest antioxidant capacity. The ability to quench DPPH free radicals was also the weakest one for this extract. An average antioxidative effect was recorded for ethanol extracts of bee pollen (EEP). Właściwości Antyoksydacyjne Ekstraktów z Pyłku Pszczelego Badane Metodą Spektroskopii EPR W ostatnim czasie dużo uwagi poświęca się substancjom o działaniu antyoksydacyjnym pochodzenia naturalnego. Cennym i uznanym źródłem egzogennych antyoksydantów jest pszczeli pyłek kwiatowy. W związku z powyższym, przedmiotem badań było oznaczenie aktywności antyoksydacyjnej trzech rodzajów ekstraktów z pyłku pszczelego: ekstraktu etanolowego pyłku pszczelego, ekstraktu pepsynowego pyłku pszczelego oraz ekstraktu etanolowego po uprzednim trawieniu enzymatycznym pepsyną pyłku pszczelego. Właściwości antyoksydacyjne oznaczono metodą elektronowego rezonansu paramagnetycznego (EPR) na podstawie zdolności redukcji wolnego rodnika DPPH. Najwyższą aktywnością antyoksydacyjną oznaczoną metodą EPR charakteryzował się ekstrakt etanolowy po uprzednim trawieniu enzymatycznym pepsyną pyłku pszczelego (EEPP). Dla tego rodzaju ekstraktu zdolność redukcji wolnego rodnika DPPH była najsilniejsza. Z kolei ekstrakt pepsynowy pyłku pszczelego (PEP) cechował się najniższą aktywnością antyoksydacyjną. Zdolność redukcji wolnego rodnika DPPH dla tego ekstraktu była najsłabsza. Pośrednią aktywność antyoksydacyjną spośród badanych ekstraktów wykazano dla ekstraktu etanolowego pyłku pszczelego (EEP).

Propolis modulates vitronectin, laminin, and heparan sulfate/heparin expression during experimental burn healing *

ObjectiveThis study was aimed at assessing the dynamics of vitronectin (VN), laminin (LN), and heparan sulfate/heparin (HS/HP) content changes during experimental burn healing.MethodsVN, LN, and HS/HP were isolated and purified from normal and injured skin of domestic pigs, on the 3rd, 5th, 10th, 15th, and 21st days following thermal damage. The wounds were treated with apitherapeutic agent (propolis), silver sulfadiazine (SSD), physiological salt solution, and propolis vehicle. VN and LN were quantified using an immunoenzymatic assay and HS/HP was estimated by densitometric analysis.ResultsPropolis treatment stimulated significant increases in VN, LN, and HS/HP contents during the initial phase of study, followed by a reduction in the estimated extracellular matrix molecules. Similar patterns, although less extreme, were observed after treatment with SSD.ConclusionsThe beneficial effects of propolis on experimental wounds make it a potential apitherapeutic agent in topical burn management.

Biological Activity of Propolis-Honey Balm in the Treatment of Experimentally-Evoked Burn Wounds

Medicines of biogenic origin with micro-organic, regenerative and analgesic properties are becoming more and more significant in the treatment of burn wounds. These properties are found in apitherapeutics such as propolis and honey—products collected and processed by a honey bee. Their effect on the course of the healing processes is multidirectional. The aim of the study was a histopathological and biochemical analysis of the processes of scar formation in experimentally evoked burn wounds in white pigs treated with the 1% and 3% Sepropol balms containing standardized extracts of propolis and honey. The results were compared with the therapeutic effects obtained with dermazin cream (1% silver sulfadiazine). The level of collagen was determined in the wounds treated with 1% and 3% Sepropol and compared with the collagen level in healthy skin and wounds treated with dermazin. Granulation and regenerated epithelium formation times were compared, with the 3% Sepropol being by far the most effective. The 3% Sepropol also increased the collagen level to 116% with the control sub-groups scoring between 80% and 98%. The results show the healing process of burn wounds in pigs treated with the Sepropol balm starts earlier and has a faster course than the standard dermazin therapy.

Propolis Modulates Fibronectin Expression in the Matrix of Thermal Injury

The aim of the study was to assess the propolis effect on fibronectin metabolism in the course of burn wounds healing process. A model of burn wound healing of pig skin was applied. The amount of the released glycoprotein was assessed by a surface plasmon resonance. The profile of extracted fibronectin components was also assessed by an electrophoresis in polyacrylamide gel, with a subsequent immunodetection by Western Blotting. Propolis burn treatment decreased the release of fibronectin components from healing wounds in relation to damages treated with silver sulfadiazine. The main reason of decreased extraction of fibronectin components from wounds treated with propolis was a substantial decrease of degradation product release of the mentioned glycoprotein, which was observed particularly from the 3rd to 5th day of the repair. Wounds treatment with propolis demonstrated, especially in relation to damages treated with silver sulfadiazine, the decreased release of synthesized fibronectin molecules. The obtained results suggest that propolis modifies fibronectin metabolism in the course of wound healing process. The influence of propolis is reflected in prevention of fibronectin biosynthesis as well as its degradation in the wound area. The above-mentioned metabolic changes may decrease the risk of complications in the repair wounds process.