Aqueous Propolis Extract Research Articles

THE PROTECTIVE ROLE OF PROPOLIS AGAINST CHLORPYRIFOS INDUCED OXIDATIVE STRESS AND DNA DAMAGE IN THE LIVER OF MALE ALBINO RATS

Chlorpyrifos (CPF) is a conventional chlorinated organophosphate insecticide, it used widely to control a variety of pests in agriculture and animal farm. Acute and chronic exposure to CPF can elicit several adverse effects including oxidative stress and DNA damage. Twenty-eight rats were divided randomly into four groups of seven rats each. The first group was served as control and received distilled water. The second one received aqueous extract of propolis (100 mg/kg). The third group was administered 2.5 mg/kg of chlorpyrifos (1/30 LD50). The fourth group was received propolis two hours before CPF administration. All animals were orally intubated five days/week for four weeks. Results showed that oral administration of CPF led to a significant increase in liver enzymes alanine aminotransferase (ALAT) and aspartate aminotransferase (ASAT) as well as malondialdehyde (MDA) level beside the percentage of DNA damage in liver tissue were increased in contrast with control group. Decrease in serum cholinesterase (ChE) activity as well as liver reduced glutathione (GSH) level, glutathione-S-transferase (GST), glutathione peroxidase (GPx), and glutathione reductase (GR) activities were observed. Co-administration of propolis to CPFtreated group improved all biochemical parameters towards the control value although this treatment couldn’t normalize it. The data provide evidence for co-administration of propolis to CPFtreated animals ameliorate the oxidative stress and DNA damage revealed the antioxidant property of propolis.

Antimicrobial, antifungal and antioxidant activities of bee glue ethanol and aqueous extracts

Food-borne pathogens is a group of micro-organisms that cause food-borne illness, thus the research for finding effective drugs against this infection is necessary. The purpose of this study determines antibacterial, antioxidant activity antifungal of bee glue ethanol and aqueous extracts. Antibacterial and antifungal activities of extracts were evaluated against food-born (Escherichia coli, Staphylococcus aureus, Bacillus cereus, Vibrio cholerae and Candida albicans) purchased from Boali hospital on by the well diffusion method. Broth serial dilution method was doing to find the Minimal Inhibitory Concentration (MIC) and the agar dilution method to find the Minimal Bacterial Concentration (MBC) of extracts. The antioxidant activity of the extracts assaying by 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Ethanol extract of bee glue was found the most effective against S. aureus strains (inhibition zone=27±0.87 mm) than E. coli strains (inhibition zone=5.5±0.37mm). Aqueous extract of propolis was found the most effective against S. aureus strains (inhibition zone=14.5±0.75 mm) than E. coli strains (inhibition zone=3.5±0.5mm) and C. albicans (inhibition zone=10±0.5 mm). The MIC and MBC values of the extracts ethanol and aqueous most effective against B. cereus strains were 0.3125, 0.625, 0.3125 and 1.25 mg/mL than E. coli strains 0.625, 1. 25, 2.5 and 50 mg/mL. and also for C. albicans was 0.625, 1.25, 1.25 and 2.5 mg/mL. IC50 ethanol and aqueous extracts of propolis were 8±0.25 and 45±1.75, respectively. This study was to assess the Antibacterial, antifungal and antioxidant activities activities of bee glue extracts in in vitro.

CHEMICAL CHARACTERIZATION AND ANTIMICROBIAL ACTIVITY OF JORDANIAN PROPOLIS AND NIGELLA SATIVA SEED OIL AGAINST CLINICALLY ISOLATED MICROORGANISMS

Objective: Increasing use of medicinal plants in the treatment of infectious diseases are due to the development of multi-antibiotics resistant microorganisms, and had alerted our interest in the examination of some natural products. This study was carried out to investigate the antimicrobial activity of Jordanian propolis, black seed oil (Nigella sativa) extract, alone or in combination against clinically isolated microorganisms (bacteria and fungi).Methods: Jordanian propolis samples were collected. Aqueous and alcoholic extractions were done; black seed oil was extracted from Nigella sativa seeds. Seven clinical isolated microorganisms namely: Micrococcus luteus, Bacillus pumilus, Bordetella bronchisptica, Enterococcus fecalis, Bacillus subtilis, and Staphylococcus aureus, and one yeast strain namely Candida albicans were used. The antimicrobial activity was investigated by agar diffusion technique and microplate dilution to determine the MIC.Results: The results indicated that the alcoholic propolis extract showed higher antimicrobial activity than the aqueous propolis extract. The antimicrobial activity of black seed oil was significantly higher than that of the propolis. Mixing propolis with black seed oil showed synergism effects against some microorganisms as Enterococcus fecalis (24±1.1), Bordetella bronchisptica (20±0.9) and Candida albicans (40±2.3), and additive with others as Bacillus subtilis (28±1.8).Conclusion: Black seed oil and propolis might be used as a potential source of safe and effective natural antimicrobial in pharmaceutical and food industries.

Effectiveness of Propolis Aqueous Extract on Chemical Constituents of Calendula Plants

This study was performed in order to investigate how the foliar spray of propolis aqueous extract can influence the vegetative growth and flowering characters, chemical constituents and oil composition of Calendula plants. The aqueous extract was applied at four levels (0, 5, 10, 15 and 20 gL-1). It was revealed that propolis was of a positive effect upon all studied parameters; there was an increase done due to the application of the aqueous extract of propolis. The highest results were obtained due to the application of 5, 10 and 15 g L -1 from the aqueous extract of propolis compared to 20 g L -1 and the control plants. 5 and 10 g L -1 gave the highest records of vegetative characters. While, 15 g L -1 had the highest records of all flowering attributes. In chemical composition optimum results ranged between 10 and 15 gL-1. The highest percentage of the most important components of the essential oil; sesquiterpene hydrocarbons (cadinene, α-Muurolene and Muurolene) and sesquiter phenols (α- cadinol, α-Cadinol (Epi) and α-Muurolol (Epi)) resulted from 15 g L -1. Hence, it could be suggested that propolise aqueous extract could be sprayed on calendula plants at a rate not exceeding 15 g L -1 to get higher results.

Cell viability and apoptotic changes of dental pulp stem cells treated with propolis, chitosan, and their nano counterparts

Aim Biocompatibility of materials used in regenerative endodontics is of prime importance. Thus, this study was conducted to evaluate and compare cytotoxicity and apoptotic changes of propolis, chitosan, and their nano counterparts on dental pulp stem cells. Materials and methods Aqueous and ethanolic extract of propolis, chitosan, propolis nanoparticles, and chitosan nanoparticles were prepared. Dental pulp stem cells were isolated from human third molars and characterized. Cultured cells were incubated with each extract of each material used for 24 and 72 h. Thereafter, cellular viability was assessed using MTT assay and DNA fragmentation using DNA fragmentation laddering assay. Control samples containing only medium were treated similarly. Differences in mean values of cell viability and DNA fragmentation between materials were assessed by using the one-way analysis of variance and Tukey's test. Results Nanoparticles of both materials expressed higher cell viability and lower DNA fragmentation in comparison to their original particles counterpart. Chitosan nanoparticles recorded a lower cytotoxicity and DNA fragmentation after 24 h, which increased by time, meanwhile that of propolis nanoparticles were decreased by time. Type of vehicle was a factor affecting the results of chitosan nanoparticles, while time was the factor affecting propolis nanoparticles. Conclusion Both propolis and chitosan nanoparticles displayed an acceptable biocompatibility and can be used in endodontic regeneration purposes.

Actividad antibacteriana de un extracto acuoso de propóleo del municipio de Irapuato, Guanajuato, México.

El objetivo del presente trabajo fue evaluar la actividad antibacteriana de un extracto acuoso de propóleo. En febrero de 2015 se colectó el propóleo en un apiario ubicado en Irapuato, Guanajuato, México. 300 g de propóleo fueron fraccionados y adicionados a 500 ml de etanol al 70%, en agitación continua por quince días. Por ltración al vacío, se separó la fase líquida, y el etanol contenido en ella fue evaporado en un rotoevaporador accionado a noventa revoluciones por minuto (rpm) y 80 oC. El residuo nal fue resuspendido en agua destilada, obteniéndose así el extracto acuoso. Un extracto de propóleo obtenido con etanol concentrado fue utilizado como control de referencia, además se incluyeron controles de etanol y agua. La actividad antibacteriana de los extractos fue evaluada mediante la técnica de difusión en agar, utilizando cepas de Escherichia coli (ATCC-10536), Salmonella typhimurium (ATCC-13311), Listeria monocytogenes (ATCC-19115) y Staphylococcus aureus (ATCC-11632), desarrolladas en tripticaseina-soya- agar, incubadas a 37 °C por veinticuatro horas (h) y se midió el halo de inhibición al término de dicho tiempo. Solo el extracto etanólico usado como control tuvo actividad antimicrobiana contra S. aureus y L. monocytogenes, más no se encontró respuesta para E. coli y S. typhimurium. El extracto acuoso no tuvo efecto sobre ninguna de las cuatro bacterias evaluadas, concluyéndose que los ingredientes activos del propóleo no son solubles en agua, por lo que se pierden en un proceso de extracción acuosa.

STUDY THE EFFECT OF AQUEOUS EXTRACT OF PROPOLIS ON TRICHOMONAS GALLINAE, IN VITRO

This study was designed to investigate the in vitro inhibitory activity of aqueous extract of propolis (AEP) on the growth of Trichomonas gallinae in comparison to metronidazole. Aqueous extract of propolis inhibited the growth of T. gallinae trophozoites and the level of inhibition varied according to the extract concentration and incubation times. The highest reduction of parasitic growth (100%) was observed in cultures treated with 100 and 75 mg/ ml of propolis aqueous extract after 24 h. The same result was detected in cultures treated with 50 mg/ ml of AEP but after 48h. While Growth reduction by 92.5 and 80% was observed in 25 and 12.5 mg/ml propolis-treated cultures respectively after 96 h. Minimal lethal concentration of aqueous extract of propolis was 50mg /ml after 48 hours.In comparison complete inhibition of parasite growth was obtained by metronidazole (50 µg/ml) after 24hours. Light microscope observations revealed changes of the pear-shaped aspect of the cell as a result of presence of large vacuolations in the cytoplasm of the trophozoites. Our results hold the perspective for the utilization of propolis as an antitrichomonal agent after the complementary in vivo studies.

Synergistic Effects Induced by Combined Treatments of Aqueous Extract of Propolis and Venom.

Background and aimsBreast cancer is a heterogeneous disease and the leading cause of cancer mortality worldwide. Triple negative breast cancer (TNBC) is considered to be one of the most aggressive breast neoplasia due to failure of chemotherapy response. Thus, there is an urgent need of finding alternative therapies for TNBC. This study was designed to evaluate the synergistic effect induced by propolis and bee venom on luminal (MCF-7) and TNBC (Hs578T) cell lines.MethodsIn order to evaluate the synergistic effect of aqueous extract of propolis and bee venom, we treated in combination two breast cancer cell lines: MCF-7(luminal subtype) and Hs578T (TNBC subtype).ResultsOur results indicate that both cell lines exhibited similar sensitivity to the aqueous extract of propolis at a dilution of 0.072–0.09 mg/ml. The results concerning IC50 for bee venom on MCF-7 cells was 1 mg/ml, 20 times higher than 0.05 mg/ml in Hs578T cells. By combining the aqueous extract of propolis with bee venom, we obtained synergistic effects at a higher concentration, which was 5 and 2 times stronger than the two treatments alone.ConclusionOverall, the results from our study indicated that the combination of aqueous extract of propolis and bee venom treatments induced synergistic antiproliferative effects in a concentration-dependent manner in breast cancer cells. Thus we can hypothesize that the combination of honeybee propolis and venom might be involved in signaling pathways that could overcome cells resistance to therapy.

PROPOLIS EXTRACT IN POSTHARVEST CONSERVATION BANANA ' PRATA'

ABSTRACT In the present work were evaluated the effects of propolis coatings of various botanical sources on quality traits of bananas cv. Prata (Musa sapientum L.) stored at room temperature. ´Prata´ bananas were selected and submitted to five postharvest treatments: four coatings applied by immersion in propolis extracts at a concentration of 2.5% (w/v) and a control (without coating). Propolis extracts were applied as 1) a wild type aqueous propolis extract, 2) a wild type hydroalcoholic propolis extract, 3) a rosemary green type hydroalcoholic propolis extract and 4) a red type hydroalcoholic propolis extract. The bananas were evaluated at three-day intervals along 12 days for fresh weight losses, flesh firmness, soluble solids (SS), titratable acidity (TA), the ratio SS/TA and pH. Sensory analyses were performed after three and six days of storage by 55 not trained panelists designed for acceptability. At the end of the twelve-day storage period, bananas coated either with the rosemary green hydroalcoholic extract or with the aqueous extract presented lower fresh weight losses in comparison to the bananas of the control treatment. No differences were determined in relation to flesh firmness and along the storage period TA values decreased and pH values increased in bananas of all treatments. SS contents increased towards the end of the storage period that, consequently, contributed to increases in the SS/TA ratio. The most significant increase in SS/TA ratio was determined in bananas coated with the red type hydroalcoholic extract. Taste panelists did not detect significant differences amongst coated and not coated cv. Prata bananas up to six days of storage.

Recobrimentos comestíveis na conservação pós-colheita de abacate

Objetivou-se neste trabalho avaliar a conservação pós-colheita de abacate agroecológico com uso de própolis e cera vegetal em condição ambiente. O delineamento experimental foi em blocos ao acaso, em parcela subdividida no tempo, utilizando-se os tratamentos: testemunha; cera vegetal (100%); extrato alcoólico e aquoso de própolis (30%), com quatro repetições e quatro frutos por parcela. Os frutos foram mantidos sob condição ambiente e avaliados aos 0, 4, 8 e 12 dias após a aplicação dos tratamentos quanto as características físicas: perda de massa fresca do fruto (%) e rendimento de polpa (%) e a determinação físico-químicas: acidez titulável (AT), expressa em porcentagem de acido cítrico; teor de sólidos solúveis (SS), expresso em °Brix, ratio (SS/AT) e o pH. Verificou-se menor perda de massa fresca de abacate com aplicação de extrato alcoólico de própolis e cara no período de armazenamento em relação aos demais tratamentos. Os frutos do tratamento Testemunha apresentaram maior teor de sólidos solúveis, sendo que não diferiu do tratamento Extrato Aquoso de Própolis, com médias de 9,32 e 8,76 °Brix, respectivamente. Já para o pH, verificou-se maiores médias para os abacates tratados com Cera de Carnaúba, apesar de não diferir dos tratamentos com Extrato Aquoso e Alcoólico de Própolis, com médias de 6,52, 6,41 e 6,23, respectivamente. Conclui-se que o extrato alcoólico de própolis e a cera de carnaúba foram mais efetivos na conservação da massa dos frutos a partir do sexto dia de armazenamento. Durante o armazenamento houve redução significativa do teor de sólidos solúveis dos frutos.

ATIVIDADE AMEBICIDA E CITOTÓXICA DO EXTRATO AQUOSO DE PRÓPOLIS VERDE CONTRA TROFOZOÍTOS E CISTOS DE ACANTHAMOEBA CASTELLANII

The genus Acanthamoeba belongs to the group of free-living amoebae and is widely distributed in the environment. These protists are known to cause severe diseases, including Granulomatous Amebic Encephalitis in immunocompromised patients and amebic keratitis, especially in immunocompetent contact lens wearers. Green Propolis is a resinous and balsamic substance, known in alternative medicine because of its several biological activities. In this study we evaluated the amoebicidal activity of an aqueous extract of green propolis against trophozoites and cysts of Acanthamoeba castellanii. At concentrations of 10 and 20 mg/mL, the extract was able to inactivate 100% of trophozoites in 24 and 48 hours, while at the concentration of 5 mg/ mL, 100% of trophozoites were inactivated in 72 hours. Acanthamoeba cysts were inactivated following 24 hours exposure to the extract at 40 mg/mL. When evaluated on human corneal epithelial (HCE) cells using a MTT-based viability assay, the extract had no significant cytotoxic effect at concentrations of 0.312, 0.625, 1.25 and 2.5 mg/mL. The adhesion test performed showed that the propolis extract reduced the attachment of Acanthamoeba to HCE cells, in a dose-dependent manner. Thus, this study demonstrated the antiparasitic activity of propolis against both forms of Acanthamoeba proving it to be a promising substance especially for the formulation of solutions for disinfection of surfaces, since it showed no toxicity to the HCE cells. However, more studies are needed to understand its mechanism of action.

Evaluation of the in vitro antimicrobial activity of alcoholic solution and aqueous extract of bee propolis against enterococcus faecalis

AIM: The purpose of this study was to analyze the in vitro antimicrobial activity of aqueous and alcoholic extracts of propolis at 1% and 3% concentrations against Enterococcus faecalis (ATCC® 19433). MATERIAL AND METHODS: Initially, the microbial suspension was seeded in a Brain Heart Infusion Agar (BHIA) culture medium, distributed in 20 Petri dishes. Then, 4 soaked filter paper discs were placed on the surface of the inoculated medium of each plate for 1 minute in 1 mL of the following substances: C+ (positive control, n=20): 2% chlorhexidine gel; C- (negative control, n=20): saline solution; S1 (n=10): 1% bee propolis alcoholic solution; S2 (n=10): 3% bee propolis alcoholic solution; E1 (n=10): 1% aqueous propolis extract; E2 (n=10): 3% aqueous propolis extract. One filter paper disc of each (C+, C-, S1 and S2) was placed in a set of 10 Petri dishes, whereas one filter paper disc of each (C+, C-, E1 and E2) was placed in the other set of 10 Petri dishes. RESULTS: The results obtained after incubation at 37°C for 24 hours under microaerobic conditions revealed that S2 showed higher mean levels of microbial growth inhibition as compared to E1, E2 and S1. There were no significantly statically differences between the groups, except for the S2 group and C- group. Mean levels in all other groups were lower than in the C+ group. CONCLUSION: The study concluded that 1% and 3% bee propolis alcoholic solution had lower antibacterial activity against Enterococcus faecalis as compared to 2% chlorhexidine gel.

Anti-inflammatory and ultrastructural effects of Turkish propolis in a rat model of endotoxin-induced uveitis.

Experimental animal models of acute uveitis, an inflammatory eye disease, can be established via endotoxin-induced inflammation. Propolis, a natural substance collected by honeybees from buds and tree exudates, has antioxidant, antibacterial, antiviral, and anti-inflammatory effects. We investigated the effects of propolis, obtained from the Sakarya province of Turkey, on endotoxin-induced uveitis using immunohistochemical, ultrastructural, and biochemical approaches. Male Wistar albino rats (n = 6/group) received intraperitoneal (ip) lipopolysaccharide (LPS) endotoxin (150 μg/kg) followed by aqueous extract of propolis (50 mg/kg ip) or vehicle; two additional groups received either saline (control) or propolis only. After 24 h, aqueous humor (AH) was collected from both eyes of each animal for analysis of tumor necrosis factor-α (TNF-α) and hypoxia-inducible factor-1α (HIF-1α). Right eyeballs were paraffin-embedded for immunohistochemical staining of nuclear factor κB (NF-κB)/p65 and left eyeballs were araldite-embedded for ultrastructural analysis. Treatment of LPS-induced uveitis with propolis significantly reduced ciliary body NF-κB/p65 immunoreactivity and AH levels of HIF-1α and TNF-α. Ultrastructural analysis showed fewer vacuoles and reduced mitochondrial degeneration in the retinal pigment epithelium, as compared to the uveitis group. The intercellular spaces of the inner nuclear layer and outer limiting membrane were comparable with those of the control group; no polymorphonuclear cells or stasis was observed in intravascular or extravascular spaces. This is the first report demonstrating an anti-inflammatory effect of Turkish propolis in a rat model of LPS-induced acute uveitis, suggesting a therapeutic potential of propolis for the treatment of inflammatory ophthalmic diseases.

Haemato-Protective and Hypolipidemic Effects of Aqueous Extract of Libyan Propolis Against Sodium Nitrite Induced Haematotoxicity and Hyperlipidemia in Guinea Pigs

Flavonoids and various phenolics are the most important pharmacologically active constituents in propolis capable of scavenging free radicals. The present work aimed to evaluate the effectiveness of aqueous extract of Libyan propolis as a natural source of antioxidants to minimize the harmful effects of sodium nitrite induced haematotoxicity and hyperlipidemia in Guinea pigs. In this study, Twenty four adult male Guinea pigs were used for this study and divided into four groups. The first group was control group, the 2nd was the propolis group orally received propolis (200 mg/kg body wt), the 3rd was the experimental and received sodium nitrite orally at a dose of 80 mg/kg body weight, the 4th one co-administered sodium nitrite orally at a dose of 80 mg/kg body weight with propolis (200 mg/kg body wt) daily for 35 days. Blood samples were obtained for assessment of haematological parameters and serum lipids profile. In sodium nitrite treated animals, there were severe haematological changes and dyslipidemia. Haematologically, Guinea pigs that received sodium nitrite orally at a dose of 80 mg/kg body weight daily for 35days had significantly (p<0.05) lower red blood cell count, hemoglobin content, haematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, white blood cell count, and platelets count than those in the control animals. On the other hand, mean corpuscular volume of sodium nitrite treated animals was significantly (p<0.05) elevated as compared to the control animals. The serum cholesterol, triglycerides, low density lipids cholesterol, very low density lipids cholesterol concentrations, and the atherogenic ratios based on lipid profile parameters (Castelli’s risk index I, Castelli’s risk index II, atherogenic coefficient and atherogenic index of plasma) were increased and serum high density lipids cholesterol concentration was decreased in sodium nitrite treated group. Co-administration of propolis significantly improved of all haematological and lipid profile parameters, and atherogenic ratios parameters. It can be concluded that, sodium nitrite had adverse effects on haematological, lipid profile parameters, and the atherogenic ratios parameters. Propolis supplementation showed a remarkable amelioration of these abnormalities in sodium nitrite treated male Guinea pigs. It is recommended that the use of sodium nitrite must be limited and use of propolis as antioxidant to prevent the toxic effect. Further studies are necessary to elucidate exact mechanism of protection of haematotoxicity, hyperlipidemia, atherogenic and potential usefulness of aqueous extract of Libyan propolis as a protective agent against sodium nitrite induced haematotoxicity, dyslipidemia and atherogenic in clinical trials.

Inhibitory properties of aqueous ethanol extracts of propolis on alpha-glucosidase.

The objective of the present study was to evaluate the inhibitory properties of various extracts of propolis on alpha-glucosidase from baker's yeast and mammalian intestine. Inhibitory activities of aqueous ethanol extracts of propolis were determined by using 4-nitrophenyl-D-glucopyranoside, sucrose and maltose as substrates, and acarbose as a positive reference. All extracts were significantly effective in inhibiting α-glucosidase from baker's yeast and rat intestinal sucrase in comparison with acarbose (P < 0.05). The 75% ethanol extracts of propolis (75% EEP) showed the highest inhibitory effect on α-glucosidase and sucrase and were a noncompetitive inhibition mode. 50% EEP, 95%, EEP and 100% EEP exhibited a mixed inhibition mode, while water extracts of propolis (WEP) and 25% EEP demonstrated a competitive inhibition mode. Furthermore, WEP presented the highest inhibitory activity against maltase. These results suggest that aqueous ethanol extracts of propolis may be used as nutraceuticals for the regulation of postprandial hyperglycemia.

Antibacterial Effect of Local Propolis Extracts and Pastes Against Enterococcus Faecalis

AIMS:The aim of this study was to determine the antibacterial effect of ethanolic and aqueous extracts and pastes of propolis against Enterococcus faecalis and compare it with that of calcium hydroxide (intracanal medicament) (in vivo and ex vivo). MATERIALS AND METHODS:The antibacterial effect of the 30%,40% ethanolic and aqueous extract of propolis as well as of calcium hydroxide were detected by the turbidity method. The turbidity of the bacterial cultures was measured by light absorption in spectrophotometer and the antibacterial effect of propolis pastes prepared from ethanolic extract as well as that prepared from aqueous extract was examined on teeth and compared with that of calcium hydroxide by colony counting method. The result were analyzed by ANOVA test and Post Hoc tests.

Phenols, flavonoids and antioxidant activity of aqueous and methanolic extracts of propolis (Apis mellifera L.) from Algarve, South Portugal

Propolis is a resinous substance collected by honeybees to seal honeycomb, which has been used in folk medicine due to its antimicrobial and antioxidant properties. In the present study, water and methanol were used to extract phenols and flavonoids from propolis collected in thirteen different areas in the Algarve region during the winter and spring. The ABTS•+, DPPH•, and O2•- scavenging capacity, and metal chelating activity were also evaluated in the propolis samples. Methanol was more effective than water in extracting total phenols (2.93-8.76 mg/mL) (0.93-2.81 mg/mL). Flavones and flavonols were also better extracted with methanol (1.28-2.76 mg/mL) than with water (0.031-0.019 mg/mL). The free radical scavenging activity, ABTS (IC50=0.006-0.036 mg/mL), DPPH (IC50=0.007-0.069 mg/mL) and superoxide (IC50=0.001-0.053 mg/mL), of the samples was also higher in methanolic extracts. The capacity for chelating metal ions was higher in aqueous extracts (41.11-82.35%) than in the methanolic ones (4.33-29.68%). Propolis from three locations of Algarve region were richer in phenols and had better capacity for scavenging free ABTS and DPPH radicals than the remaining samples. These places are part of a specific zone of Algarve known as Barrocal.

Antioxidant Properties and Phenolic Composition of Greek Propolis Extracts

This study was undertaken to determine the total phenols, total flavonoids, and major phenolic compounds in the polar (methanol, 80% methanol, and aqueous) extracts of propolis collected from the Greek mainland (West Macedonia) and the Greek island, Rhodes. The antioxidant properties of the propolis extracts were also evaluated by using free 2,2′-diphenyl-1-picrylhydrazyl radical scavenging assay and ferric reducing antioxidant power assay. The results showed that propolis from West Macedonia was found to be the strongest radical scavenger and ferric reducing agent (mean IC50 0.179 and 0.009 mg/ml, respectively). Methanol (mean IC50 0.181 mg/ml) and 80% methanol extracts (mean IC50 0.138 mg/ml) of propolis from West Macedonia showed higher radical scavenging activity than the synthetic antioxidant butylated hydroxytoluene (mean IC50 0.207 mg/ml), while exhibiting similar levels of reducing activity (IC50 0.0099 mg/ml and 0.0085 mg/ml, respectively) with flavonol quercetin (mean IC50 0.0101 mg/ml). In addition, analysis by high performance liquid chromatography showed that West Macedonia propolis, contained the highest amount of phenolic compounds: phenolic acids (caffeic acid, caffeic acid phenethylester, ferulic acid, p-coumaric acid) and flavonoids (quercetin, galangin, luteolin, apigenin). Caffeic acid (0.639–4.172 mg/g propolis) and galangin (1.317–8.551 mg/g propolis) were found to be the predominant phenolic compounds in these propolis extracts.

English

&nbsp; The inhibition efficiency of aqueous extract of propolis on the corrosion of carbon steel in 35 ppm aluminum sulfate and 10 ppm chloride solution was investigated by weight loss and electrochemical measurements. The corrosion rate of carbon steel and the inhibition efficiency of the propolis were calculated. The results obtained showed that propolis could serve as an effective inhibitor for the corrosion of carbon steel in aqueous media. Inhibition was found to increase with increasing concentration of the extract. The inhibitive action of propolis is discussed on the basis of adsorption of stable complex at the carbon steel surface. Theoretical fitting of different isotherms, Langmuir was tested to clarify the nature of adsorption. Potentiodynamic polarization curves revealed that this extract acts as a mixed type inhibitor and the inhibition efficiency of up to 92% can be obtained. &nbsp; Key words:&nbsp;Corrosion inhibition, propolis extract, carbon steel, 35 ppm aluminum sulfate and 10 ppm chloride solution.

The Beginnings of Modern Research on Propolis in Poland

Propolis studies in Poland were initiated by Professor Stan Scheller in the 1960s. It was a team of Polish researchers who developed a method of introducing hydrophobic ethanol extracts of propolis (EEP) into aqueous solutions, which enabled the study of their biological properties. The studies performed in Poland showed that EEP possesses antioxidant, radioprotective, and immunostimulating properties. It was possible to demonstrate antibacterial activity of propolis on Gram-positive bacteria, virulent Mycobacterium tuberculosis, and protozoa as well as stimulating activity of aqueous extracts of propolis on proliferation of cells in vitro. Polish investigators showed that propolis stimulates regeneration of tissue, acts as antioxidant and radioprotector, has strong immunostimulative properties, affects animals' life span by extending it, and improves intellectual and life functions of the elderly.