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1.
Ilkay Orhan Berrin Özçelik Sinem Aslan Murat Kartal Taner Karaoglu Bilge Şener Salih Terzioglu M. Iqbal Choudhary 《Phytochemistry Reviews》2007,6(1):189-196
Purpose of the present study was to evaluate antioxidant, antibacterial, antifungal, and antiviral activities of the petroleum
ether, chloroform, ethyl acetate and methanol extracts as well as the alkaloid fraction of Lycopodium clavatum L. (LC) from Lycopodiaceae growing in Turkey. Antioxidant activity of the LC extracts was evaluated by 1,1-diphenyl-2-picrylhydrazyl
(DPPH) radical-scavenging method at 0.2 mg/ml using microplate-reader assay. Antiviral assessment of LC extracts was evaluated
towards the DNA virus Herpes simplex (HSV) and the RNA virus Parainfluenza (PI-3) using Madin-Darby Bovine Kidney (MDBK) and Vero cell lines. Antibacterial and antifungal activities of the extracts
were tested against standard and isolated strains of the following bacteria; Escherichia coli, Pseudomonas aeruginosa, Proteus mirabilis, Acinobacter baumannii, Klebsiella pneumoniae, Staphylococcus aureus, Bacillus subtilis as well as the fungi; Candida albicans and C. parapsilosis. All of the extracts possessed noteworthy activity against ATCC strain of S. aureus (4 μg/ml), while the LC extracts showed reasonable antifungal effect. On the other hand, we found that only the chloroform
extract was active against HSV (16–8 μg/ml), while petroleum ether and alkaloid extracts inhibited potently PI-3 (16–4 μg/ml
and 32–4 μg/ml, respectively). However, all of the extracts had insignificant antiradical effect on DPPH. In addition, we
also analyzed the content of the alkaloid fraction of the plant by capillary gas chromatography-mass spectrometry (GC-MS)
and identified lycopodine as the major alkaloid. 相似文献
2.
Ángeles Verástegui Julia Verde Santos García Norma Heredia Azucena Oranday Catalina Rivas 《World journal of microbiology & biotechnology》2008,24(7):1249-1252
The in vitro antimicrobial activity against pathogenic bacteria, yeast, and molds were examined in extracts of the Agave species A. lecheguilla, A. picta, A. scabra and A. lophanta using an agar diffusion technique. The extracts of A. picta produced zones of inhibition of 9–13 mm for E. coli, L. monocytogenes, S. aureus, and V. cholerae, while B. cereus and Y. enterocolitica were not inhibited. The other Agave species did not show any detectable inhibitory activity against the bacteria tested; however, all four Agave sp. were inhibitory against all yeast and molds analyzed as evident by 9–20 mm zones of inhibition. The minimum microbicidal
concentration (MMC) of the active extract ranged from 1.8 to 7.0 mg/ml for the sensitive bacteria, and 2.0–3.0 mg/ml for yeast.
In the case of molds, the minimum inhibitory concentration (MIC) of the active extracts ranged from 3.0 to 6.0 mg/ml. Together,
these data suggest that the Agave sp. analyzed are potential antimicrobial candidates with a broad range of activity. 相似文献
3.
A bacterium identified as Pseudomonas fluorescence was isolated from Taxus baccata rhizosphere. Ethyl acetate extract from its culture filtrate yielded an active antimicrobial compound that was purified by
TLC. The active metabolites were resolved by column chromatography on silica gel (60–120 mesh). The compound was further characterized
on the basis of spectral data (UV, IR and 1HNMR), which indicated the presence of an aromatic ring and phenolic functionality. The compound showed significant antimicrobial
activity against two-gram positive bacteria (B. subtilis and S. aureus), four-gram negative bacteria (E. coli, K. pneumoniae, S. flexneri and P. aeruginosa), and one pathogenic fungus (Candida albicans). The minimum inhibitory concentration (MIC) of the compound ranged between 75μg to 250 μg/ml. 相似文献
4.
Senka S. Vidović Ibrahim O. Mujić Zoran P. Zeković Žika D. Lepojević Vesna T. Tumbas Aida I. Mujić 《Food biophysics》2010,5(1):49-58
Considering the growing interest for mushrooms and the demand search of natural antioxidants sources, the aim of this study
was to investigate the antioxidant properties of two edible widely used Boletus species, Boletus edulis, and Boletus auranticus, collected from Istra region in Croatia in late summer 2007. To evaluate the antioxidant properties and content of antioxidant
compounds, scavenging capacity on DPPH˙, OH˙, and O2˙− radicals, reducing power and capacity to inhibit lipid peroxidation has been investigated. It is determined that content
of total phenols (41.82 ± 0.08 mg gallic acid equivalent per gram of dry extract) was higher for B. edulis. Using high performance liquid chromatography/diode array detector analysis, the main antioxidant compound, variegatic acid,
has been detected and quantified. 1,1-Diphenyl-2-picryl-hydrazyl-hydrate assay was used as a preliminary free radical–scavenging
evaluation. By this assay, it has been found that B. edulis dry mushroom extract exhibits 50% of inhibition value at the extract concentration of 0.016 ± 0.0003 mg/ml. The extracts
were capable of reducing iron(III) and, thus, are capable of donating electrons. Using electron paramagnetic resonance spin-trapping
and spin-probing techniques, activity against relevant reactive species, ˙OH and O2˙− radical, was analyzed for both mushroom extracts. Both investigated extracts are determined as good inhibitors for ˙OH radical
reduction, and both exhibited significant capacity for scavenging O2˙− radical and for that could help to prevent or meliorate oxidative damage. Only B. edulis extract prevents lipid peroxidation. Investigated mushroom extracts could represent easily accessible natural antioxidant
resource. 相似文献
5.
R. D. Jebakumar Solomon V. Satheeja Santhi 《World journal of microbiology & biotechnology》2008,24(9):1747-1752
Herbal extracts play an essential role in treating various diseases. The threats in drug resistant pathogenic microbial strains
can be prevented by the un-tapped medicinal principles from plants. The present study has been focused to search for powerful
antimicrobial natural products from Dictyota acutiloba J. Ag. against human enteric pathogens and dermatophytic fungi. Chloroform and acetone extracts of Dictyota acutiloba exhibited antimicrobial activity against methicillin resistant Staphylococcus aureus (MRSA), methicillin susceptible Staphylococcus aureus (MSSA), Enterobacter sp., Pseudomonas aeruginosa MTCC741, Salmonella typhi MTCC733, Bacillus subtilis, Klebsiella pneumoniae MTCC109, Candida albicans and Aspergillus niger MTCC281. Purified compounds A1 and C1 by column chromatography, TLC and HPLC inhibited the gram positive, gram negative bacteria and fungi. MIC of C1 and A1 ranged between 0.5 and 0.9 μg ml−1. The absorption maximum of C1 and A1 was 355 nm. Structural characterization of these purified molecules can lead to the new therapeutic molecule to fight the
pathogenic microorganisms. 相似文献
6.
Sandra I. Pitta-Alvarez Fabricio Medina-Bolivar María A. Alvarez Agustina A. Scambatto Patricia L. Marconi 《In vitro cellular & developmental biology. Plant》2008,44(6):502-507
Berberis buxifolia Lam., known as “Calafate”, is a plant native to Argentina that exhibits antimicrobial activity. This biological activity
is attributed to the isoquinoline alkaloid berberine. The aim of this research was to test the antimicrobial properties of
different extracts of this species, taking berberine as the reference molecule, and to examine if the expression of bacterial
multidrug resistance (MDR) efflux pumps could be responsible for possible resistance mechanisms. To this end, a wild-type
and a mutant strain of Staphylococcus aureus with a defective MDR efflux pump were used and the minimum inhibitory concentrations of the extracts were determined. The
studies were carried out with infusions of in vivo shoots and “Calafate” commercial tea, as well as with the media derived from shoot cultures incubated with different plant
growth regulators (thidiazuron, picloram, and jasmonic acid). As far as antimicrobial activity is concerned, all the extracts
tested were significantly more effective than berberine standard. “Calafate” commercial tea and shoot tea had inhibitory concentrations
similar to the one observed for ampicillin standard. The media from the shoot cultures, however, were significantly more effective
than all the others, particularly the one derived from jasmonic acid, suggesting the presence of compounds that could be acting
synergistically with berberine. There were no differences in antimicrobial activity against the wild-type and the mutant S. aureus; no definite conclusions could be drawn concerning the relationship between MDR pumps and possible pathogen resistance to
extracts of B. buxifolia. 相似文献
7.
Buatong Jirayu Phongpaichit Souwalak Rukachaisirikul Vatcharin Sakayaroj Jariya 《World journal of microbiology & biotechnology》2011,27(12):3005-3008
The aim of this work was to select endophytic fungi from mangrove plants that produced antimicrobial substances. Minimal inhibitory
concentrations (MIC) and minimal bactericidal concentrations (MBC) or minimal fungicidal concentrations (MFC) of crude extracts
from 150 isolates were determined against potential human pathogens by a colorimetric microdilution method. Ninety-two isolates
(61.3%) produced inhibitory compounds. Most of the extracts (28–32%) inhibited Staphylococcus aureus (MIC/MBC 4–200/64–200 μg ml−1). Only two extracts inhibited Pseudomonas aeruginosa (MIC/MBC 200/>200 μg ml−1). 25.5 and 11.7% inhibited Microsporum gypseum and Cryptococcus neoformans (MIC/MFC 4–200/8–200 μg ml−1 and 8–200/8–200 μg ml−1, respectively), while 7.5% were active against Candida albicans (MIC/MFC 32–200/32–200 μg ml−1). None of the extracts inhibited Escherichia coli. The most active fungal extracts were from six genera, Acremonium, Diaporthe, Hypoxylon, Pestalotiopsis, Phomopsis, and Xylaria as identified using morphological and molecular methods. Phomopsis sp. MA194 (GU592007, GU592018) isolated from Rhizophora apiculata showed the broadest antimicrobial spectrum with low MIC values of 8–32 μg ml−1against Gram-positive bacteria, yeasts and M. gypseum. It was concluded that endophytic fungi from mangrove plants are diverse, many produce compounds with antimicrobial activity
and could be suitable sources of new antimicrobial natural products. 相似文献
8.
Dagmar Janovská Pavel Klouček Jan Urban Tomáš Vaněk Vojtěch Rada Ladislav Kokoška 《Biologia》2008,63(5):607-609
The antimicrobial activity of the dichloromethane extract from aerial parts of Leuzea carthamoides DC. was tested in vitro against 19 Staphylococcus aureus strains (ATCC 25923, CNCTC Mau 43/60, clinical isolates). The extract was fractionated by column chromatography on silica
gel into six fractions (petroleum ether, toluene, dichloromethane, ethyl acetate, methanol and water). The minimum inhibitory
concentrations (MICs) of the fractions ranged from 64 to 1024 μg/mL. An ethyl acetate fraction (EA 1) with the widest range
of activity inhibited all of the strains with MIC in the range 128–512 μg/mL. This fraction exhibited potent activity against
strains which showed associated resistance to oxacillin, ciprofloxacin and erythromycin. 相似文献
9.
Rasanthika Nayomi Jayatissa Rohan Prasantha Perera Chamari Madhu Hettiarachchi Pathum Manjula Weerawarna 《Indian journal of microbiology》2012,52(1):83-87
The continuing increase in the incidence of multi drug resistant pathogenic bacteria and shortage of new antimicrobial agents
are the prime driver in efforts to identify the novel antimicrobial classes. In vitro antibacterial activity of 4-phenyl-1-(2-phenylallyl)
pyridinium bromide was tested against Gram positive Staphylococcus aureus, Streptococcus species, Bacillus subtilis, and Gram negative Klebsiella aerogenes and Escherichia coli using disk diffusion method. Among them S. aureus showed strong antibacterial activity (21.99 ± 0.03 mm) while E. coli showed very little activity (8.97 ± 0.06 mm) towards the compound. The MIC of 4-phenyl-1-(2-phenyl-allyl)-pyridinium bromide
for 90% S. aureus was ≤20 μg/ml and was compared with phenoxymethylpenicillin, cloxacillin, erythromycin and vancomycin. When 4-phenyl-1-(2-phenyl-allyl)pyridinium
bromide showed MIC at ≤20 μg/ml, all others showed MIC at ≤100 μg/ml. Strong antibacterial activity of 4-phenyl-1-(2-phenyl-allyl)pyridinium
bromide against S. aureus indicates that there is a possibility to use it as an effective antibacterial agent. 相似文献
10.
This study was undertaken with an objective of testing the antibacterial and antifungal activities of Bauhinia purpurea leaves and identifying the bioactive compounds. The antimicrobial activity of leaf extract was determined in aqueous and organic extracts and the minimum inhibitory concentration (MIC) against six species of pathogenic and non-pathogenic microorganisms: Bacillus subtilis, Staphylococcus aureus, Salmonella typhi, Escherichia coli, Pseudomonas aeruginosa and Candida albicans using the disk diffusion method. The chemical constituents of organic plant extract were separated by thin layer chromatography and purified by column chromatography and further identified by gas chromatography–mass spectrometry (GC–MS) analysis. Significant inhibitory activity was observed with methanol extracts of plant against the test microorganisms while less antibacterial activity was observed in hexane, acetone and aqueous extracts. MIC of B. purpurea extract was ≤1,500 μg/ml against S. aureus and B. subtilis while this extract showed no inhibition against Gram-negative S. typhi, E. coli and P. aeruginosa or against fungus C. albicans. Eleven compounds were identified in B. purpurea leaf extract by GC–MS analysis. The composition of B. purpurea revealed the presence of lupeol, stigmasterol, lanosterol, ergosterol, beta-tocopherol, phytol, hexadeconic acids, hexadeconic acids methyl esters, octadecadienoic acids and octadecatrienoic acid. Stigmasterol and lupeol were the most abundant (34.48 and 15.63 %). Other phytosterols like lanosterol (4.15 %) and ergosterol (2.82 %) were also found to be present in this extract. 相似文献
11.
Pokhrel Naba Raj Adhikari R.P. Baral M.P. 《World journal of microbiology & biotechnology》2002,18(1):69-71
Bauhinia variegata, commonly known as Koiralo is considered as medicinal plant in Nepal and India. The alcoholic extract of this plant was found to have antimicrobial activity against Bacillus subtilis (ATCC 6635) Pseudomonas aeruginosa (ATCC 27853), Salmonella typhi, Shigella dysenteriae, Staphylococcus aureus (ATCC 29213) and Vibrio cholerae. The largest zone of inhibition (18 mm) was found to be exhibited against B. subtilis. For this organism the minimum bactericidal concentration (MBC) of the crude extract was 0.39 mg/ml. The extract was found to be more effective against gram-positive than gram-negative bacteria. The antimicrobial activity of the extract was found to be decreased during purification. 相似文献
12.
Rice dehydrin K-segments have <Emphasis Type="Italic">in vitro</Emphasis> antibacterial activity 总被引:1,自引:0,他引:1
Dehydrins are groups of plant proteins that have been shown to response to various environmental stimuli such as dehydration,
elevated salinity, and low temperature. However, their roles in plant defense against microbes have not been demonstrated.
In an attempt to discover plant antimicrobial proteins, we have screened a rice cDNA library and isolated several cDNAs coding
for dehydrins. Protein extracts from Escherichia coli expressing these cDNAs were tested for their activity against Gram-positive bacteria (Bacillus pumilus, B. subtilis, Staphylococcus aureus, and Sarcina lutea) and Gramnegative bacteria (Escherichia coli and Xanthomonas oryzae pv. oryzae). The results indicate that the crude protein extracts exhibited antibacterial activities against the Gram-positive bacteria.
However, dehydrins purified by immunoaffinity chromatography were not active against the bacteria. To pinpoint the dehydrin
peptides that were responsible for the bactericidal activity, we expressed DNA sequences coding for truncated dehydrins containing
either K- or S-segment and found that K-segment peptides, and not S-segment, were responsible for the antibacterial activities
against Gram-positive bacteria. Antibacterial assay with synthetic K-segments indicated that the peptides inhibited growth
of B. pumilus with minimum inhibition concentration and minimum bactericidal concentration of 130 and 400 μg/ml, respectively. 相似文献
13.
López-Abarrategui C Alba A Lima LA Maria-Neto S Vasconcelos IM Oliveira JT Dias SC Otero-Gonzalez AJ Franco OL 《Current microbiology》2012,64(5):501-505
Marine organisms represent approximately half of the world’s biodiversity by virtue of the sea being an immense reservoir
of bioactive molecules. Here, antimicrobial crude extract activities of different marine invertebrates from the Caribbean
Sea were evaluated. One of the most active, crude extracts was that marine snail Cenchritis muricatus, it was capable of totally inhibiting the development of Staphylococcus aureus and also showed a growth inhibition of 95.9% in Escherichia coli. Aiming to isolate molecules that confirm antimicrobial activity, the crude extract was purified by reversed-phase HPLC C-18
chromatography. Thereafter, one of the obtained fractions preserved this antibacterial activity. Furthermore, SDS-PAGE analysis
(15%) showed the presence of two proteins of molecular masses with approximately 10 and 15 kDa, respectively. The first 19
amino acids of both proteins were sequenced by using Edman degradation, yielding unidentified primary structures compared
against sequences deposited at NCBI databank. This is the first report of antibacterial proteins isolated from the mollusk
Cenchritis muricatus and these proteins could be used as antibiotic alternatives in the aquacultural industry, as well as in agricultural or biomedical
research. 相似文献
14.
Polygonum aviculare (Polygonaceae) is an herb commonly distributed in Mediterranean coastal regions in Egypt and used in folkloric medicine. Organic and aqueous solvent extracts and fractions of P. aviculare were investigated for antimicrobial activities on several microorganisms including bacteria and fungi. Phytochemical constituents of air-dried powered plant parts were extracted using aqueous and organic solvents (acetone, ethanol, chloroform and water). Antimicrobial activity of the concentrated extracts was evaluated by determination of the diameter of inhibition zone against both Gram-negative and Gram-positive bacteria and fungi using paper disc diffusion method.Results of the phytochemical studies revealed the presence of tannins, saponins, flavonoids, alkaloids and sesquiterpenes and the extracts were active against both Gram-negative and Gram-positive bacteria. Chloroform extract gave very good and excellent antimicrobial activity against all tested bacteria and good activity against all tested fungi except Candida albicans. Structural spectroscopic analysis that was carried out on the active substances in the chloroform extract led to the identification of panicudine (6-hydroxy-11-deoxy-13 dehydrohetisane).Evaluation of the antimicrobial activity of panicudine indicated significant activity against all tested Gram-negative and Gram-positive organisms. Panicudine displayed considerable activity against the tested fungi with the exception of C. albicans. Antimicrobial activity of the extracts was unaffected after exposure to different heat treatments, but was reduced at alkaline pH. Studies of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of panicudine on the tested organisms showed that the lowest MIC and the MBC were demonstrated against Salmonella paratyphi, Bacillus subtilis and Salmonella typhi and the highest MIC and MBC were against Staphylococcus aureus. 相似文献
15.
The investigation of the recombinant bovine lactoferrin-derived antimicrobial protein (rBLfA) demonstrates that the inter-lobe
region of bovine lactoferrin contributes to iron binding stability and antimicrobial activity against Staphylococcus aureus. rBLfA containing N-lobe (amino acid residues 1–333) and inter-lobe region (residues 334–344) was expressed in Pichia pastoris at shaking flask and fermentor level. The recombinant intact bovine lactoferrin (rBLf) and N-lobe (rBLfN) were expressed
in the same system as control. The physical–chemical parameters of rBLfA, rBLfN and rBLf including amino acid residues, molecular
weight, isoelectric point, net positive charge and instability index were computed and compared. The simulated tertiary structure
and the calculated surface net charge showed that rBLfA maintained original structure and exhibited a higher cationic feature
than rBLf and rBLfN. The three proteins showed different iron binding stability and antimicrobial activity. rBLfA released
iron in the pH range of 7.0–3.5, whereas rBLfN lost its iron over the pH range of 7.0–4.0 and iron release from rBLf occurred
in the pH range of 5.5–3.0. However, the minimum inhibition concentration of rBLfA against S. aureus ATCC25923 was 6.5 μmol/L, compared with 12.5 and 25 μmol/L that of rBLfN and rBLf, respectively. These results revealed that
S. aureus was more sensitive to rBLfA than rBLfN and rBLf. It appeared that the strong cationic character of inter-lobe region related
positively to the higher anti-S. aureus activity. 相似文献
16.
Milan S. Stanković Olgica Stefanović Ljiljana Čomić Marina Topuzović Ivana Radojević Slavica Solujić 《Central European Journal of Biology》2012,7(4):664-671
In vitro antimicrobial activity of 21 crude extracts obtained from seven taxa of the genus Teucrium (T. chamaedrys, T. montanum, T. arduini, T. polium, T. scordium subsp. scordium, T. scordium subsp. scordioides and T. botrys) was tested against bacterial and fungal species. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration
(MBC) were determined using a microdilution analysis method. Total phenolic content and flavonoid concentrations were measured
spectrophotometrically. Total phenols were determined using Folin-Ciocalteu reagent and their amounts ranged from 28.49 up
to 159.84 mg CA/g of extract (chlorogenic acid equivalent). The amounts of flavonoids ranged from 38.17 up to 190.45 mg RU/g
of extract (rutin equivalent).The plant extracts showed greater potential of antibacterial than antifungal activity. A relationship
was found between total phenolics and biological activity. The highest level of total phenols was measured in the methanol
extracts, which demonstrated higher antimicrobial activity than acetone and ethyl acetate extracts. Staphylococcus aureus ATCC 25923 appeared to be the most sensitive organism. Our results indicate that Teucrium spp extracts are rich sources of phenolic compounds and are promising candidates for further development as natural antimicrobial
agents. 相似文献
17.
This study deals with two range-extending brown algae from Tahitian coral reefs, Sargassum mangarevense and Turbinaria ornata; their alginate properties, mannitol and phenolic contents, antioxidant and antimicrobial activities were determined. Turbinaria ornata showed the richest alginate content with the highest extraction yield (19.2 ± 1.3% dw). Their alginates also exhibited the
highest viscosity (50 ± 18 mPa.s), but the M:G ratios (mannuronic acid to glucuronic acid) of alginates (1.25–1.42) were similar
in both species. Alginate yield displayed spatial variations, but no significant seasonal changes. The highest mannitol content
was found in S. mangarevense (12.2 ± 2.1% dw) during the austral winter. With respect to other tropical Fucales, both algae exhibited also a high phenolic
content (2.45–2.85% dw) with significant spatio-temporal variations. Furthermore, high antioxidant activity and activity against
Staphylococcus aureus were also detected in extracts. According to these preliminary results, these two range-extending algae are of key interest
in numerous industrial areas. 相似文献
18.
The antimicrobial activity of several plant extracts obtained from aerial parts of two invasive plants, Hakea sericeae and Hakea salicifolia, was evaluated against both Gram-positive and Gram-negative bacteria, including resistant strains of Staphylococcus aureus and assayed at different minimum inhibitory concentrations (MIC), ranging between 3.5 and 500 μg/mL. The twigs' aqueous extract showed the strongest antimicrobial activity (MIC 7.5–62 μg/mL) against the tested methicilin and vancomycin resistant strains of S. aureus. 相似文献
19.
Ping Su Anders Henriksson Christina Nilsson Hazel Mitchell 《World journal of microbiology & biotechnology》2008,24(9):1837-1842
The aim of this study was to assess the effect of a commercial green tea extract (TEAVIGO™) on the microbial growth of three
probiotic strains (Lactobacillus and Bifidobacterium), as well as three pathogenic bacteria. MIC and co-culture studies were performed. The MICs of the green tea extract against
Staphylococcus aureus and Streptococcus pyogenes (100 μg ml−1) were considerably lower than those against the probiotic strains tested (>800 μg ml−1) and Escherichia coli (800 μg ml−1). In co-culture studies, a synergistic effect of the probiotic strains and the green tea extract was observed against both
Staph. aureus and Strep. pyogenes. Green tea extract in combination with probiotics significantly reduced the viable count of both pathogens at 4 h and by
24 h had completely abolished the recovery of viable Staph. aureus and Strep. pyogenes. These reductions were more significant than the reductions induced by probiotics or green tea extracts used separately.
These results demonstrate the potential for combined therapy using the green tea extract plus probiotics on microbial infections
caused by Staph. aureus and Strep. pyogenes. As probiotics and the green tea extract are derived from natural products, treatment with these agents may represent important
adjuncts to, or alternatives to, conventional antibiotic therapy. 相似文献
20.
HF Santana AA Barbosa SO Ferreira HC Mantovani 《World journal of microbiology & biotechnology》2012,28(2):485-491
Staphylococcus aureus is an important pathogen for both humans and animals, and it has been an ubiquitous etiological agent of bovine mastitis
in dairy farms worldwide. Elimination of S. aureus with classic antibiotics is difficult, and the current study aimed to evaluate the efficacy of ethanolic extracts of propolis
(EEP) against S. aureus cultivated in complex media or milk. EEP (0–0.5 mg ml−1) decreased growth of S. aureus in BHI media and 1 mg ml−1 was bactericidal against washed cell suspensions (107 CFU ml−1). Propolis extracts also killed S. aureus cells resuspended in milk, but the bactericidal dose was at least 20-fold greater. Cultures that were transferred for at
least 60 generations with sub-lethal doses of propolis did not change much their sensibility to EEP. Atomic force microscopy
images revealed changes in morphology and cell size of S. aureus cells exposed to EEP (0.5 mg ml−1). Our results indicate that propolis extracts might be effective against mastitis-causing S. aureus strains in vivo, but milk constituents affect the inhibitory activity of propolis. Considering that propolis-resistance appears
to be a phenotype not easily selected, the use of EEP combined or not with other antimicrobial agents might be useful for
mastitis control in vivo. 相似文献