Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 17 de 17
Filter
Add more filters











Publication year range
1.
Heliyon ; 10(7): e28621, 2024 Apr 15.
Article in English | MEDLINE | ID: mdl-38586359

ABSTRACT

Natural deep eutectic solvents (NADESs) have been considered promising to replace traditional volatile and toxic organic solvents for the extraction of biologically active substances from natural sources. This work applied an efficient and ethanol-exclusion strategy for extraction of phenolic compounds from poplar type propolis using five known NADESs (lactic acid:1,2-propanediol 1:1, lactic acid:fructose 5:1, choline chloride:1,2-propanediol 1:3, choline chloride:1,2-propanediol:water 1:1:1 and betaine:malic acid:water 1:1:6). The selected NADESs' extractability was evaluated by measuring the concentrations of total phenolics and total flavones and flavonols in the propolis extracts obtained, which qualitative chemical composition was further determined in detail by gas chromatography-mass spectrometry (GC-MS) analysis. It demonstrated that the chemical profiles of NADES and 70% ethanolic propolis extracts are similar. To expand the knowledge about the role of the applied solvents in the poplar propolis extraction process, the in vitro antimicrobial, cytotoxic and genotoxic activity of both NADESs and liquid NADES extracts were evaluated. The results revealed that the use of the selected NADESs as an extraction media for phenolic compounds from poplar propolis not only delivered a good extraction yield in some cases, but generally led to the preservation of propolis extracts' biological activity and even to the enhancement of their antimicrobial effect in comparison with the hydroethanolic one. Besides, the tested NADESs except for lactic acid:fructose and betaine:malic acid:water exerted low to negligible toxicity against normal cells treated and apart from lactic acid:fructose the remaining solvents demonstrated concentration-dependent moderate to subtle genotoxicity. There is a probability that not the supramolecular structure of the NADESs, but their components, played a key role for the observed biological effects. The present study has demonstrated an alternative approach for extracting the biologically active complex from poplar type propolis using NADESs, which could be useful for further pharmaceutical and cosmeceutical applications.

2.
Microorganisms ; 11(8)2023 Jul 27.
Article in English | MEDLINE | ID: mdl-37630469

ABSTRACT

Escherichia coli (E. coli) is a ubiquitous microorganism with pathogenic and saprophytic clones. The objective of this study was to evaluate the presence, virulence, antibiotic resistance and biofilm formation of E. coli in three industrial farms in Bulgaria, as well as their adjacent sites related to the utilization of manure (feces, wastewater in a separator, lagoons, means of transport, and soils). The isolation of single bacterial cultures was performed via standard procedures with modifications, and E. coli isolates were identified via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and polymerase chain reaction (PCR). The disk diffusion method was used to assess antimicrobial resistance, and PCR was used to detect genes for antibiotic resistance (GAR) (qnr, aac(3), ampC, blaSHV/blaTEM and erm) and virulence genes (stx, stx2all, LT, STa, F4 and eae). The protocol of Stepanovic was utilized to measure the biofilm formation of the isolates. A total of 84 isolates from different samples (n = 53) were identified as E. coli. Almost all demonstrated antimicrobial resistance, and most of them demonstrated resistance to multiple antibiotics from different classes. No virulence genes coding the Shiga toxin or enterotoxins or those associated with enteropathogenicity were detected. No GAR from those tested for quinolones, aminoglycosides and macrolides were found. However, all isolates that were resistant to a penicillin-class antibiotic (56) had ß-lactamase-producing plasmid genes. All of them had ampC, and 34 of them had blaTEM. A total of 14 isolates formed strongly adherent biofilms. These results in a country where the use of antibiotics for growth promotion and prophylaxis in farms is highly restricted corroborate that the global implemented policy on antibiotics in human medicine and in animal husbandry needs revision.

3.
Antibiotics (Basel) ; 10(8)2021 Aug 04.
Article in English | MEDLINE | ID: mdl-34438990

ABSTRACT

Antimicrobial resistance (AMR) is a worldwide health problem affecting humans, animals, and the environment within the framework of the "One Health" concept. The aim of our study was to evaluate the prevalence of pathogenic strains of the species Escherichia coli (E. coli), their AMR profile, and biofilm-forming potential. The isolated strains from three swine faeces and free lagoons (ISO 16654:2001/Amd 1:2017) were confirmed using Phoenix M50 and 16S rDNA PCR. The antibiotic sensitivity to 34 clinically applied antibiotics was determined by Phoenix M50 and the disc diffusion method, according to the protocols of the CLSI and EUCAST. We confirmed the presence of 16 E. coli isolates, of which 87.5% were multi-drug-resistant and 31.25% performed strong biofilms. The possibility for the carrying and transmission of antibiotic-resistance genes to quinolones (qnr), aminoglycosides (aac(3)), ß-lactamase-producing plasmid genes ampC, and blaSHV/blaTEM was investigated. We confirmed the carrying of blaSHV/blaTEM in one and ampC in seven isolates. The strains were negative for the virulence genes (ETEC (LT, STa, and F4), EPEC (eae), and STEC/VTEC (stx and stx2all)). The results should contribute to the development of effective measures for limitation and control on the use of antibiotics, which is a key point in the WHO action plan.

4.
Nat Prod Res ; 34(19): 2779-2786, 2020 Oct.
Article in English | MEDLINE | ID: mdl-30938183

ABSTRACT

Two new δ-tocotrienol derivatives with oxidized terminal chain: 5,6-dioxo-garcinoic acid (trans-13'-carboxy-5,6-dioxo-δ-tocotrienol) (2) and 5-hydroxy-8b-oxo garcinoic acid (trans-13'-carboxy-5-hydroxy-8b-oxo-δ-tocotrienol) (3), together with one known derivative garcinoic acid (trans-13'-carboxy-δ-tocotrienol) (1) were isolated from a Colombian propolis. Garcinoic acid was found as a propolis constituent for the first time. The isolated compounds and crude ethanolic extract demonstrated high antimicrobial activity against Staphylococcus aureus and Candida albicans (MICs range: 10-39 µg/ml) as well as promising antioxidant potential in DPPH assay. Compound 3 displayed highest radical scavenging activity, even higher than that of dl-α-tocopherol, used as a positive control.


Subject(s)
Anti-Infective Agents/chemistry , Anti-Infective Agents/pharmacology , Propolis/chemistry , Vitamin E/analogs & derivatives , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Antioxidants/chemistry , Antioxidants/pharmacology , Benzopyrans/analysis , Benzopyrans/pharmacology , Candida albicans/drug effects , Colombia , Microbial Sensitivity Tests , Molecular Structure , Staphylococcus aureus/drug effects , Vitamin E/chemistry
5.
Chem Cent J ; 11(1): 113, 2017 Nov 07.
Article in English | MEDLINE | ID: mdl-29116480

ABSTRACT

Many Geum species are known to be rich in biologically active compounds and therefore could be a source of new natural products with pharmacological potential. The medicinal plant Geum urbanum L. is widespread in Bulgaria and has been used in folk medicine. In the present study, the methanol extracts of the roots and aerial parts of G. urbanum and their fractions (petroleum ether, ethyl acetate and n-butanol) were investigated for antibacterial and radical scavenging activity. The ethyl acetate and n-butanol fractions inhibited the growth of Gram-positive pathogenic and opportunistic bacteria from the genus Staphylococcus (MIC EtOAc: 0.078 mg/ml aerial and 0.156 mg/ml roots; MIC n-BuOH: 0.156 mg/ml aerial and 1.25 mg/ml roots) and the species Bacillus cereus stronger than the other extracts and fractions tested (MIC EtOAc: 0.078 mg/ml aerial and 0.156 mg/ml roots; MIC n-BuOH: 0.156 mg/ml aerial and 0.078 mg/ml roots), and showed corresponding radical scavenging activity (EtOAc: EC50 1.5 µg/ml aerial, 0.8 µg/ml roots; n-BuOH: 4.5 µg/ml aerial; 3.7 µg/ml roots). Additionally, their total phenolic content was quantified (% of dry EtOAc fractions of roots 61%, of arial parts 32%; of dry n-BuOH fractions of roots 16%, of arial parts 13%). Seven compounds were isolated and identified spectroscopically from the ethyl acetate extract. Two acetylated ellagic acid rhamnosides were found for the first time in the genus Geum and three others, tormentic acid, niga-ichigoside F1, and 3,3'-di-O-methylellagic acid-4-O-ß-D-glucopyranoside, were newly detected for the species G. urbanum. Our results reveal that G. urbanum L. is a perspective medicinal plant and deserves further, more detailed studies.

6.
Chem Cent J ; 7(1): 158, 2013 Sep 22.
Article in English | MEDLINE | ID: mdl-24053750

ABSTRACT

BACKGROUND: Propolis (bee glue) is a resinous honeybee product having a long history of application in many countries as a traditional remedy for treating wounds, burns, soar throat, stomach disorders, etc. It has been proved to possess beneficial biological effects, including antimicrobial, antioxidant, anti-inflammatory, cytotoxic, antiulcer, and many others. Bees gather propolis from diverse resinous plant parts and in different phytogeographic regions its chemical composition might vary significantly. In this article we report the results of the first study on the chemical profiles of propolis from Oman, its plant origin and antibacterial activity. RESULTS: The chemical profiles of Omani propolis extracts were obtained by GC-MS analysis after silylation. Over 50 individual compounds were identified in the samples, belonging to different compound types: sugars, polyols, hydroxy acids, fatty acids, cardanols and cardols, anacardic acids, flavan derivatives, triterpenes, prenylated flavanones and chalcones. The profiles were dissimilar from other known propolis types. They demonstrate that although Oman is not a large country, the plant sources of propolis vary significantly, even in the same apiary and the same season. Based on chemical profiles, and isolation and identification of major marker compounds (new propolis constituents), new plant sources of propolis were found: Azadiracta indica (neem tree) and Acacia spp. (most probably A. nilotica). The ethanol extracts of the studied propolis samples demonstrated activity against S. aureus (MIC < 100 µg. mL-1) and E. coli (MIC < 380 µg. mL-1). CONCLUSION: Omani propolis is different form the known propolis types and demonstrates significant chemical diversity. Its most important plant source is the resin of Azadirachta indica, and as a result its typical components are С5-prenyl flavanones. Other plant sources have been identified, too, playing some role in resin collection by bees in Oman: Acacia spp. (most probably A. nilotica) and Mangifera indica. The results demonstrate also the potential of Omani propolis as antimicrobial.

7.
Nat Prod Res ; 25(6): 606-13, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21409722

ABSTRACT

From a biologically active extract of Indonesian propolis from East Java, 11 compounds were isolated and identified: four alk(en)ylresorcinols (obtained as an inseparable mixture) (1-4) were isolated for the first time from propolis, along with four prenylflavanones (6-9) and three cycloartane-type triterpenes (5, 10 and 11). The structures of the components were elucidated based on their spectral properties. All prenylflavanones demonstrated significant radical scavenging activity against diphenylpicrylhydrazyl radicals, and compound 6 showed significant antibacterial activity against Staphylococcus aureus. For the first time Macaranga tanarius L. and Mangifera indica L. are shown as plant sources of Indonesian propolis.


Subject(s)
Anti-Bacterial Agents/isolation & purification , Euphorbiaceae/chemistry , Free Radical Scavengers/isolation & purification , Mangifera/chemistry , Propolis/chemistry , Indonesia , Microbial Sensitivity Tests , Molecular Structure
8.
Fitoterapia ; 81(6): 509-14, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20079813

ABSTRACT

From propolis samples from Kenya, two new arylnaphtalene lignans were isolated, tetrahydrojusticidin B 1 and 6-methoxydiphyllin 2, along with four known phenolic compounds 5-8, found for the first time in propolis. The structures of the compounds were elucidated based on their spectral properties. The geranylstilbenes 7 and 8 demonstrated antibacterial activity against S. aureus, and the geranylflavon macarangin 6 possessed antiradical activity against DPPH radicals.


Subject(s)
Anti-Bacterial Agents/isolation & purification , Free Radical Scavengers/isolation & purification , Lignans/isolation & purification , Propolis/chemistry , Kenya , Microbial Sensitivity Tests , Molecular Structure , Naphthalenes/isolation & purification
9.
Nat Prod Commun ; 4(8): 1059-62, 2009 Aug.
Article in English | MEDLINE | ID: mdl-19768983

ABSTRACT

The chemical composition of fresh flowers from Allium ursinum (ramsons, bear's garlic, wild garlic) growing in Bulgaria has been studied. Thymidine (1), adenosine (2), astragalin (kaempferol-3-O-beta-D-glucopyranoside (3), kaempferol-3-O-beta-D-glucopyranosyl-7-O-beta-D-glucopyranoside (4), kaempferol-3-O-beta-D-neohesperoside (5), and kaempferol-3-O-beta-D-neohesperoside-7-O-beta-D-glucopyranoside (6) were isolated from the n-butanol extract and identified by different spectroscopic and spectrometric methods. Thymine (7), uridine (8), uracil (9) and 5-chloro-uridine (10) were detected in the same extract by GC-MS. This is the first report of the occurrence of 1, 2, 4, 7 - 10 in the flowers of A. ursinum. GC-MS of the volatile components of fresh flowers and leaves from the same plant revealed a high content of sulfur compounds, some of which are reported for the first time for A. ursinum. The antimicrobial activities of extracts from fresh flowers and leaves of A. ursinum have been tested; some extracts exhibited moderate antifungal properties.


Subject(s)
Allium/chemistry , Garlic/chemistry , 1-Butanol , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/isolation & purification , Anti-Bacterial Agents/pharmacology , Antifungal Agents/isolation & purification , Antifungal Agents/pharmacology , Bulgaria , Candida albicans/drug effects , Flowers/chemistry , Gas Chromatography-Mass Spectrometry/methods , Kaempferols/isolation & purification , Kaempferols/pharmacology , Oils, Volatile/chemistry , Oils, Volatile/isolation & purification , Oils, Volatile/pharmacology , Plant Extracts/chemistry , Plant Extracts/isolation & purification , Plant Leaves/chemistry , Staphylococcus aureus/drug effects
10.
Pol J Microbiol ; 58(1): 43-7, 2009.
Article in English | MEDLINE | ID: mdl-19469285

ABSTRACT

The antibacterial activity of the medium chain fatty acids and their 1-monoglycerides was evaluated towards several Gram-positive strains belonging to the genera Staphylococcus, Corynebacterium, Bacillus, Listeria and Streptococcus. The 1-monoglycerides were more active than the fatty acids with monolaurin being the most active compound. Interesting effects were observed when the streptococcal strain Streptococcus pyogenes was used as a test microorganism. First, blocking of the hydroxyl groups of the glycerol moiety of monolaurin led to a compound with remarkable antibacterial activity (MIC, 3.9 microg/ml). Secondly, synergistic relationships were observed between monolaurin and monocaprin as well as between monolaurin and the poorly active lauric acid when their two component mixtures were examined. The mixtures in which one of the components was 2-fold more predominant than the other one were much more active than the pure components taken individually. Moreover, the presence of the components in ratio 1:1 was disadvantageous. Synergistic relationships were also found between monolaurin and monomyristin towards Staphylococcus aureus 209 when monomyristin was in the same quantity as monolaurin or in shortage.


Subject(s)
Fatty Acids/pharmacology , Gram-Positive Bacteria/drug effects , Monoglycerides/pharmacology , Anti-Bacterial Agents/pharmacology , Drug Therapy, Combination , Glycerides/pharmacology , Glycerol/chemistry , Laurates/chemistry , Laurates/pharmacology , Lauric Acids/pharmacology , Microbial Sensitivity Tests , Monoglycerides/chemistry , Streptococcus pyogenes/drug effects , Surface-Active Agents/chemistry , Surface-Active Agents/pharmacology
11.
Nat Prod Res ; 23(5): 448-54, 2009.
Article in English | MEDLINE | ID: mdl-19296388

ABSTRACT

Four groups of metabolites from the halophyte plant Stachys maritima Gouan, family Lamiaceae, were investigated: lipids, sterols, volatiles and polar compounds. Most of the metabolites have been previously reported to possess biological activity. Two of the main substances in the volatile fraction--phenidone and naphthalene, unusual for plants--were products of environmental contamination. This is a typical example of how marine pollutants could transfer and threaten terrestrial organisms via the trophic chain. The n-butanol extract possessed a relatively high antibacterial activity against S. aureus and Candida albicans, but was not active against Escherichia coli.


Subject(s)
Ecosystem , Stachys/chemistry , Bulgaria , Sodium Chloride/chemistry , Water/chemistry , Water Pollutants, Chemical
12.
Fitoterapia ; 80(5): 263-6, 2009 Jul.
Article in English | MEDLINE | ID: mdl-19264113

ABSTRACT

From a biologically active extract from the fungus Fomitopsis rosea, two new lanostane triterpenes were isolated, 3alpha-(3'-butylcarboxyacetoxy)oxepanoquercinic acid C 1 and 3alpha-hydroxy-24-methylene-23-oxolanost-8-en-26-carboxylic acid 2, along with three known triterpenes, 3-5, and the epidioxy sterol derivative 6. The structures of the compounds were elucidated based on their spectral properties. All triterpenes demonstrated antibacterial activity against S. aureus but possessed no antiradical activity against DPPH radicals.


Subject(s)
Anti-Bacterial Agents/isolation & purification , Cholesterol Esters/isolation & purification , Coriolaceae/chemistry , Staphylococcus aureus/drug effects , Triterpenes/isolation & purification , Anti-Bacterial Agents/pharmacology , Cholesterol Esters/pharmacology , Triterpenes/pharmacology
13.
Eur J Med Chem ; 44(5): 2211-8, 2009 May.
Article in English | MEDLINE | ID: mdl-18584918

ABSTRACT

A large series of chalcones were synthesized and studied against Staphylococcus aureus and Escherichia coli. Chalcones were either unsubstituted in ring A or possessed 4'-chloro or 3',4',5'-trimethoxy groups. Their other ring B was variously substituted. It was found that the anti-staphylococcal activity of chalcones was related to the energy difference between the two highest occupied molecular orbitals (HOMO and HOMO-1). Presence of hydroxyl group in ring B was not a determinant factor for the anti-staphylococcal activity, but the lipophilicity of ring A of the hydroxyl chalcones was of importance.


Subject(s)
Anti-Bacterial Agents/chemical synthesis , Chalcones/chemical synthesis , Anti-Bacterial Agents/pharmacology , Chalcones/pharmacology , Escherichia coli/drug effects , Models, Molecular , Staphylococcus aureus/drug effects , Structure-Activity Relationship
14.
Pol J Microbiol ; 57(3): 261-5, 2008.
Article in English | MEDLINE | ID: mdl-19004249

ABSTRACT

The antibacterial activity of synthetic aliphatic and aromatic monoacylglycerols (MAGs) was studied against two human pathogens: Staphylococcus aureus and Escherichia coli. The active compounds inhibited selectively S. aureus. The most active compounds amongst them were those with medium size aliphatic chain and aromatic MAGs with electron withdrawing substituents at the aryl ring. The introduction of one or two-carbon spacer between the aryl ring and the carboxylic function did not influence antibacterial effectiveness.


Subject(s)
Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Monoglycerides/chemical synthesis , Monoglycerides/pharmacology , Staphylococcus aureus/drug effects , Molecular Structure
15.
Evid Based Complement Alternat Med ; 3(2): 249-54, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16786055

ABSTRACT

In a new propolis type, red Brazilian propolis, 14 compounds were identified (six of them new for propolis), among them simple phenolics, triterepenoids, isoflavonoids, prenylated benzophenones and a naphthoquinone epoxide (isolated for the first time from a natural source). Three of the major components demonstrated significant antimicrobial activity, and two (obtained as inseparable mixture) possessed radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH).

17.
Z Naturforsch C J Biosci ; 57(7-8): 624-8, 2002.
Article in English | MEDLINE | ID: mdl-12240987

ABSTRACT

Fourteen aromatic and 24 aliphatic acids were determined by GC-MS analysis of acidic fractions obtained from Paeonia peregrina and Paeonia tenuifolia roots. Benzoic acid and its monohydroxy-, dihydroxy- and trihydroxy-derivatives are the main acid components of both Paeonia species. Some fractions could serve as a source of benzoic, 4-hydroxybenzoic, vanillic and gallic acids, as well as of ethyl gallate. The fractions inhibited the growth of Staphylococcus aureus, Escherichia coli and Candida albicans.


Subject(s)
Anti-Infective Agents/chemistry , Candida albicans/drug effects , Escherichia coli/drug effects , Magnoliopsida/chemistry , Plant Extracts/chemistry , Plant Roots/chemistry , Staphylococcus aureus/drug effects , Anti-Bacterial Agents , Anti-Infective Agents/isolation & purification , Gas Chromatography-Mass Spectrometry , Hydrolysis , Plant Extracts/pharmacology
SELECTION OF CITATIONS
SEARCH DETAIL