共查询到20条相似文献,搜索用时 31 毫秒
1.
The antibacterial activity and mechanism of silver nanoparticles (Ag-NPs) on Staphylococcus aureus ATCC 6538P were investigated in this study. The experiment results showed the minimum bactericidal concentration (MBC) of
Ag-NPs to S. aureus was 20 μg/ml. Moreover, when bacteria cells were exposed to 50 μg/ml Ag-NPs for 6 h, the cell DNA was condensed to a tension
state and could have lost their replicating abilities. When S. aureus cells were exposed to 50 μg/ml Ag-NPs for 12 h, the cell wall was breakdown, resulting in the release of the cellular contents
into the surrounding environments, and finally became collapsed. And Ag-NPs could reduce the enzymatic activity of respiratory
chain dehydrogenase. Furthermore, the proteomic analysis showed that the expression abundance of some proteins was changed
in the treated bacterial cell with Ag-NPs, formate acetyltransferase increased 5.3-fold in expression abundance, aerobic glycerol-3-phosphate
dehydrogenase decreased 6.5-fold, ABC transporter ATP-binding protein decreased 6.2-fold, and recombinase A protein decreased
4.9-fold. 相似文献
2.
Biodegradable polymers, when reinforced with nanostructures, are considered good sustainable coatings and viable alternatives to replace conventional coatings. In addition, biopesticides are also considered safe, biodegradable and environmentally friendly; therefore there is a growing interest in nanoemulsions based on phytochemical mixtures. In this context, the aim of this study is to aggregate Neem oil nanoemulsions and pectin matrices to produce nanocomposite films, as well as evaluate the nanoemulsions effect on the film properties for coating soybean seeds. Nanoemulsions were characterized assessing their average diameter and stability, while the nanocomposite antifungal, morphology, mechanical and barrier properties were analyzed. In general, the nanoemulsions had an average diameter close to 59 ± 0.61 nm, showed good stability and its addition improved film mechanical properties: reduced stiffness, resistance, and water vapor permeability, and increased extensibility. In addition, Neem oil provided antifungal properties against Aspergillus Flavus and Penicillium Citrinum. The seed coatings promoted a positive effect on the germination process of soybean seeds. Thus, antifungal nanocomposite films from renewable sources were successfully produced. The fungicidal inhibition of Neem oil as a nanoemulsion makes these new materials promising for the production of seed coatings. 相似文献
3.
Antimicrobial, antioxidant, and antiviral activities of flower extracts of Retama raetam Forssk. Webb (Fabaceae) were screened both from standard and isolated Gram-positive and Gram-negative bacteria by solid medium
technique. Oxacillin, Amoxicillin, Ticarcillin, Cefotaxim, and Amphotericin were used as the control agents. The antiviral
activity was evaluated against human cytomegalovirus (HCMV) strain AD-169 (ATCC Ref. VR 538) and coxsackie B virus type 3
(CoxB-3) using a cytopathic effect (CPE) reduction assay. The antioxidant activity was evaluated using two tests: 1,1-diphenyl-2-picrylhydrazyl
(DPPH) free-radical scavenging and the ammonium thiocyanate methods. All extracts were characterized quantitatively for the
presence of polyphenols, flavonoids, and tannins. Of the extracts tested, butanol and ethyl acetate extracts showed important
antibacterial activity against Gram-positive and Gram-negative bacteria but only moderate antifungal activity. Methanol extract
exhibited moderate antiviral activity against HCMV with IC 50 of 250 μg/ml. Ethyl acetate, chloroform, and methanol fractions were found to cause significant free-radical-scavenging effects
in both assays. These results may suggest that R. raetam flowers could be used as a natural preservative ingredient in the food and/or pharmaceutical industries. 相似文献
4.
In the present work, a bionanocomposite for plant crop protection was prepared by non-toxic biocompatible & biodegradable nanomaterials (Cellulose & TiO 2) to utilize its synergistic effects against antimicrobial pathogens. The commercially available microcrystalline cellulose has been reduced to a nanometric scale regime using acid hydrolysis, while the standard TiO 2 nano-powder of particle size ~20 nm has been used to prepare their nanocomposite (NC). The antibacterial studies via agar well diffusion method demonstrated that after 72 h of incubation, parent nanomaterials Ncell and TiO 2 were not showing any activity against phytopathogens X. campestris pv. campestris, and Clavibacter while the nanocomposite's NC's were still effective depicting both bacteriostatic and bactericidal actions. However, the bacterial growth of biocontrol P. fluorescence was not affected by Ncell, TiO 2 NPs and NC after 72 h of incubation. The antifungal testing results via poison food agar assay method suggest that the nanocomposite, along with Ncell and TiO 2 NPs, exhibited strong inhibition of fungal growth of Phytophthora Spp at 0.125 mg/ml concentration while for F. graminearum, similar effect was observed at 0.25 mg/ml concentration. The nanocomposite has proved its potential by exhibiting longer & stronger synergistic effects against plant pathogens as a good antimicrobial agent for protection of agricultural crops. 相似文献
5.
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
6.
Cyanovirin-N (CVN) is a promising antiviral candidate that has an extremely low sequence homology with any other known proteins.
The efficient and soluble expression of biologically functional recombinant CVN (rCVN) is still an obstacle due to insufficient
yield, aggregation, and abnormal modification. Here, we describe an improved approach to preparing native rCVN from Escherichia coli more efficiently. A fusion gene consisting of cvn and sumo (small ubiquitin-related modifier) and a hexahistidine tag was constructed according to the codon bias of the host cell.
This small ubiquitin-related modifier (SUMO)-fused CVN is expressed in the cytoplasm of E. coli in a folded and soluble form (>30% of the total soluble protein), yielding 3 to 4 mg of native rCVN from 1 g of wet cells
to a purity up to 97.6%. Matrix-assisted laser desorption ionization coupled to time-of-flight mass spectrometry and reverse-phase
high-performance liquid chromatographic analysis showed that the purified rCVN was an intact and homogeneous protein with
a molecular weight of 11,016.68 Da. Potent antiviral activity of rCVN against herpes simplex virus type 1 and human immunodeficiency
virus type 1/IIIB was confirmed in a dose-dependent manner at nanomolar concentrations. Thus, the His-SUMO double-fused CVN
provides an efficient approach for the soluble expression of rCVN in the cytoplasm of E. coli, allowing an alternative system to develop bioprocess for the large-scale production of this antiviral candidate. 相似文献
7.
With the purpose of discovering new chemical classes of molecules, in particular those with selective antiviral activity, extracts from plants growing in Reunion Island were systematically evaluated in a chikungunya virus-cell-based assay. The entire ethyl acetate extract obtained from the stem bark of Stillingia lineata ssp. lineata (Euphorbiaceae) exhibited selective antiviral activity against the chikungunya virus with an EC 50 < 0.8 μg/mL, whereas only a weak cytotoxic effect was observed on the host cells. A phytochemical investigation of this extract led to the isolation of tonantzitlolone A and tonantzitlolone B (1 and 2), together with the new 4′-hydroxytonantzitlolone, named tonantzitlolone C (3), which has an uncommon C15-flexibilane skeleton, as well as in the new ent-12α-hydroxy-3,7-dioxoisopimara-8,15-diene (4). Subsequent evaluation for inhibition of chikungunya virus replication in cellulo demonstrated that the 4′-acetoxytonantzitlolone (2) was endowed with antiviral activity against CHIKV. 相似文献
8.
The crude methanolic extract of Andrachne cordifolia Muell. (Euphorbiaceae) and its various fractions in different solvent systems (chloroform, ethyl acetate and n- butanol) were screened for antibacterial and antifungal activities. Crude extract and subsequent fractions demonstrated moderate to excellent antibacterial activities against the tested pathogens. Highest antibacterial activity was displayed by both chloroform and ethyl acetate fractions (100%) followed by the crude extract (68%) against Salmonella typhi. Similarly, crude extract and its subsequent fractions showed mild to excellent activities in antifungal bioassay with maximum (76%) antifungal activity against Microsporum canis by the chloroform fraction followed by the crude extract (65%). 相似文献
9.
Fish‐mint ( Houttuynia cordataThunb .), belonging to family Saururaceae, has long been used as food and traditional herbal medicine. The present study was framed to assess the changes occurring in the essential‐oil composition of H. cordata during annual growth and to evaluate allelopathic, antibacterial, antifungal, and antiacetylcholinesterase activities. The essential‐oil content ranged from 0.06 – 0.14% and 0.08 – 0.16% in aerial parts and underground stem, respectively. The essential oils were analysed by GC‐FID, GC/MS, and NMR ( 1H and 13C). Major constituents of aerial‐parts oil was 2‐undecanone (19.4 – 56.3%), myrcene (2.6 – 44.3%), ethyl decanoate (0.0 – 10.6%), ethyl dodecanoate (1.1 – 8.6%), 2‐tridecanone (0.5 – 8.3%), and decanal (1.1 – 6.9%). However, major constituents of underground‐stem oil were 2‐undecanone (29.5 – 42.3%), myrcene (14.4 – 20.8%), sabinene (6.0 – 11.1%), 2‐tridecanone (1.8 – 10.5%), β‐pinene (5.3 – 10.0%), and ethyl dodecanoate (0.8 – 7.3%). Cluster analysis revealed that essential‐oil composition varied substantially due to the plant parts and season of collection. The oils exhibited significant allelopathic (inhibition: 77.8 – 88.8%; LD50: 2.45 – 3.05 μl/plate), antibacterial ( MIC: 0.52 – 2.08 μl/ml; MBC: bacteriostatic) and antifungal ( MIC: 2.08 – 33.33 μl/ml; MFC: 4.16 – 33.33 μl/ml) activities. The results indicate that the essential oil from H. cordata has a significant potential to allow future exploration and exploitation as a natural antimicrobial and allelopathic agent. 相似文献
10.
Multidrug resistance (MDR) is a serious health threat throughout the world resulting in reduced efficacy of antibacterial, antiparasitic, antiviral, and antifungal drugs. One of the most promising concepts that may represent a good alternative to antibiotics can be the use of bacteriocins obtained from lactic acid bacteria. The L. rhamnosus BTK 20-12 strain was isolated from traditional Armenian naturally fermented salted cheese. The probiotic potential of the strain was approved. It was shown that strain produced at less two bacteriocins (BCN 1 and BCN 2) with different molecular weight (1427 Da and 602.6 Da, respectively). Bacteriocins inhibited the growth of multidrug-resistant bacteria of different etiologies and belong to different taxonomic groups with diverse efficiency and it depends on properties of bacteriocins, as well as from isolation sources of pathogens. Thus, bacteriocins of L. rhamnosus BTK 20-12 have protein-like nature and a broad range of activity and are excellent candidates for the development of new prophylactic and therapeutic substances to complement or replace conventional antibiotics. 相似文献
11.
The crude methanolic extract and subsequent fractions of Teucrium royleanum (Labiatea) were screened for antibacterial and antifungal activities. Against tested pathogens, crude extract and subsequent fractions demonstrated moderate to excellent antibacterial activities. Highest antibacterial activity was displayed by the ethyl acetate fraction against S. typhi (100%), against E.coli (76.7%) and against P. aerugenosa (70.8%) followed by the chloroform fraction against S. typhi (85.7%). Similarly, the crude extract and its subsequent fractions showed mild to excellent activities in the antifungal bioassay with maximum antifungal activity against M. canis (87%) by the chloroform fraction followed by the ethyl acetate (71%) and n-butanol (70%) fractions. 相似文献
12.
Proteins and peptides belonging to the plant immune system can possess natural antibacterial, antifungal and antiviral properties. Due to their broad range of activity and stability, they represent promising novel alternatives to commonly used antifungal agents to fight the emergence of resistant strains. An isolation protocol was optimised to target proteins found in plants’ defence system, and it was applied to white mustard ( Brassica hirta) seeds. Firstly, a ~14 kDa protein with activity against S. cerevisiae was extracted and purified; secondly, the protein was identified as the mustard Napin protein named Allergen Sin a 1. Napin is the name given to seed storage (2S) albumin proteins belonging to the Brassicaceae family. While several Napins have been described for their antimicrobial potential, Sin a 1 has been mainly studied for its allergenic properties. The antimicrobial activity of Sin a 1 is described and characterised for the first time in this study; it possesses antifungal and antiyeast in vitro activity, but no antibacterial activity was recorded. The yeasts Zygosaccharomyces bailii Sa 1403 and Saccharomyces cerevisiae DSM 70449 along with the filamentous fungi Fusarium culmorum FST 4.05 were amongst the most senstitive strains to Sin a 1 (MICs range 3–6 μM). The antimicrobial mechanism of membrane permeabilisation was detected, and in general, the antifungal activity of Sin a 1 seemed to be expressed in a dose-dependent manner. Data collected confirmed Sin a 1 to be a stable and compact protein, as it displayed resistance to α-chymotrypsin digestion, heat denaturation and insensitivity to pH variations and the presence of salts. In addition, the protein did not show cytotoxicity towards mammalian cells. 相似文献
13.
Fluconazole-loaded ethyl cellulose microspheres were prepared by alginate facilitated (water-in-oil)-in-water emulsion technology
and the effects of various processing variables on the properties of microspheres were investigated. Scanning electron microscopy
revealed spherical nature and smooth surface morphology of the microspheres except those prepared at higher concentration
of emulsifiers and higher stirring speeds. The size of microspheres varied between 228 and 592 μm, and as high as 80% drug
entrapment efficiency was obtained depending upon the processing variables. When compared up to 2 h, the drug release in pH
1.2 HCl solution was slower than in pH 7.4 phosphate buffer saline solution. However, this trend was reversed at high shear
conditions. The microspheres provided extended drug release in alkaline dissolution medium and the drug release was found
to be controlled by Fickian-diffusion mechanism. However, the mechanism shifted to anomalous diffusion at high shear rates
and emulsifier concentrations. The aging of microspheres did not influence the drug release kinetics. However, the physical
interaction between drug and excipients affected the drug dissolution behaviors. X-ray diffractometry (X-RD) and differential
scanning calorimetry (DSC) analysis revealed amorphous nature of drug in the microspheres. Fourier transform infrared (FTIR)
spectroscopy indicated stable character of fluconazole in the microspheres. The stability testing data also supported the
stable nature of fluconazole in the microspheres. The fluconazole extracted from 80% drug-loaded formulation showed good in vitro antifungal activity against Candida albicans. Thus, proper control of the processing variables involved in this modified multiple emulsion technology could allow effective
incorporation of slightly water soluble drugs into ethyl cellulose microspheres without affecting drug stability. 相似文献
14.
Three sesquiterpene lactones (centaurepensin=chlorohyssopifolin A, chlorojanerin and 13-acetyl solstitialin A) isolated from the aerial parts of Centaurea solstitialis L. ssp. solstitialis (Asteraceae) were investigated for antimicrobial and antiviral activities. For the antimicrobial activity assessment, both standard and isolated strains of Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus, Candida albicans and C. parapsilosis were employed by the microdilution method. Herpes simplex type-1, a DNA virus, and Parainfluenza, an RNA virus, were employed for the determination of the antiviral activity of these three sesquiterpene lactones using Vero cell lines. Ampicilline, ofloxocine, ketoconazole, fluconazole, acyclovir and oseltamivir were used as the reference drugs. 13-Acetyl solstitialin A displayed remarkable antibacterial activity against isolated strains of E. faecalis at 1 μg/ml concentration, which was close to the effective concentrations of ampicillin. The same compound also showed significant activity against the DNA virus, being as potent as the reference compound acyclovir at maximum and minimum concentrations of 16–<0.00006 μg/ml. This is the first report showing that 13-acetyl solstitialin A possesses significant antiviral activity. 相似文献
15.
Terminalia arjuna Wight & Arn. (Combretaceae) is a tree having an extensive medicinal potential. The plant is used traditionally in the treatment
of various aliments. T. arjuna is a very good hypocholsteremic, hypolipidemic, anticoagulant, antihypertensive, antithrombotic, antiviral, antifungal and
antibacterial agent Various parts of plant have been investigated for the presence of phytoconstituents and pharmacological
activities. Many useful phytoconstituents have been isolated from T. arjuna. Triterpenoids are mainly responsible for cardiovascular properties. Tannins and flavonoids are responsible for its anticancer
properties. The present review summarizes the ethnic use, pharmacological activities of the extracts and phytoconstituents
of T. arjuna for last 90 years. 相似文献
16.
The pollution of raw surface and underground water with pharmaceutical compounds has an impact on increasing the resistance of pathogenic microorganisms. Environmental challenges include investigating a novel and cost-effective therapeutic approach for the bactericidal treatment of water supplies. Ethyl acetate extracts from three marine algae (Caulerpa racemosa, Codium fragile, and Cystoseira myrica) obtained from the Red Sea (Hurghada, Egypt) were used for the green synthesis of TiO2 nanoparticles (TiO2-NPs). A highly crystalline nanoparticle structure with a stable tetragonal anatase structure was obtained; the mean concentrations were 2.43 to 6.09?×?108 NPs/mL and the average particle size was 125–131 nm. In ultrapure water, the TiO2-NPs were confirmed to be a stable solution following zeta potential analysis. UV light (λ?=?350 nm) for 2 h was used to activate the TiO2-NPs before the antibacterial activity tests. The application of UV-activated TiO2-NPs for 4 h treatments demonstrated promising bactericidal activity, with a 73.08% reduction in Salmonella typhi and a 91.51% reduction in Enterobacter ludwigii. Antibiofilm activities against the reference strains Salmonella typhi NCTC 12023/ATTC and Morganella morganii ATCC25829 and the bacterial isolates Klebsiella pneumoniae, Enterobacter ludwigii, and Enterococcus faecium were tested. The TiO2-NPs were nontoxic against the human normal cell line RPE1. Regarding the treatment of total and fecal coliform, in addition to fecal streptococci, in raw surface and underground water, the UV-activated TiO2-NPs prepared from the ethyl acetate extracts of Caulerpa racemosa showed high applicability. The present study offered insights into the nature and development of nontoxic and green TiO2-NP formulations for use as modern antibacterial alternatives against coliforms in aquatic systems. 相似文献
17.
Aqueous, methanol, ethyl acetate, and chloroform extracts of the root, stem, and leaf of Raphanus sativus were studied for antibacterial activity against food-borne and resistant pathogens. All extracts except the aqueous extracts
had significant broad-spectrum inhibitory activity. The ethyl acetate extract of the root had the potent antibacterial activity,
with a minimum inhibitory concentration (MIC) of 0.016–0.064 mg/ml and a minimum bactericidal concentration (MBC) of 0.016–0.512 mg/ml
against health-damaging bacteria. This was followed by the ethyl acetate extracts of the leaf and stem with MICs of 0.064–0.256
and 0.128–0.256 mg/ml, respectively and MBCs of 0.128–2.05 and 0.256–2.05 mg/ml, respectively. The ethyl acetate extracts
of the different parts of R. sativus retained their antibacterial activity after heat treatment at 100°C for 30 min, and their antibacterial activity was enhanced
when pH was maintained in the acidic range. Hence this study, for the first time, demonstrated that the root, stem, and leaf
of R. sativus had significant bactericidal effects against human pathogenic bacteria, justifying their traditional use as anti-infective
agents in herbal medicines. 相似文献
18.
The aims of this study were to evaluate the antifungal properties of Baccharis glutinosa and Ambrosia confertiflora extracts against Aspergillus flavus, A. parasiticus and Fusarium verticillioides, and to isolate the group of compounds that are responsible for the antifungal activity. Samples of aerial parts from each
plant were extracted with 70% methanol and sequentially partitioned with hexane, ethyl acetate, and n-butanol. The partitioned fractions were evaluated in their capacity to inhibit the radial growth of the three species of
fungi. The active fraction was used for an assay-guided chromatography of antifungal extracts. The results showed that the
extract from B. glutinosa partitioned in ethyl acetate (Bea) showed the highest antifungal activity against the three fungi. Bea completely inhibited
the growth of F. verticillioides at 0.8 mg/ml, whereas the radial growth of A. flavus and A. parasiticus was inhibited 70% at 1.5 mg/ml. The purified antifungal fraction from Bea showed 72, 54, and 52% of antifungal activity,
respectively. 相似文献
19.
Plants are known to produce a plethora of secondary metabolites which are recognized as a useful source of new drugs or drug
leads. Extracts and fractions of Schinus terebinthifolius Raddi (Anacardiaceae), Piper regnellii C.D.C. (Piperaceae), Rumex acetosa L . (Polygonaceae), and Punica granatum L. (Punicaceae) were assessed for their antifungal activity against eight clinical isolates of C. albicans. They were also evaluated for their effect on the adhesion of these C. albicans isolates to buccal epithelial cells (BECs). The ethyl acetate fraction from the leaves of S. terebinthifolius showed promising activity, inhibiting the growth of three C. albicans isolates at 7.8 μg ml −1 and significantly inhibiting their adhesion to BEC at 15 μg ml −1
. In addition, this fraction did not show cytotoxic activity against murine macrophages. The results show the potential of
the plant extracts studied as a source of new antifungal compounds. Further studies are necessary for isolation and characterization
of the active compounds of these plants. 相似文献
20.
Botrytis cinerea, the causal agent of gray mold is one of the major devastating fungal pathogens that occurs in strawberry cultivation and leads to massive losses. Due to the rapid emergence of resistant strains in recent years, an ecofriendly disease management strategy needs to be developed to control this aggressive pathogen. Bacillus velezensis CE 100 exhibited strong antagonistic activity with 53.05% against B. cinerea by dual culture method. In the present study, 50% of culture filtrate supplemented into PDA medium absolutely inhibited mycelial growth of B. cinerea whereas the highest concentration (960 mg/L) of different crude extracts including ethyl acetate, chloroform, and n-butanol crude extracts of B. velezensis CE 100, strongly inhibited mycelial growth of B. cinerea with the highest inhibition of 79.26%, 70.21% and 69.59% respectively, resulting in severe damage to hyphal structures with bulging and swellings. Hence, the antifungal compound responsible was progressively separated from ethyl acetate crude extract using medium pressure liquid chromatography. The purified compound was identified as methyl hippurate by nuclear magnetic resonance and mass spectrometry. The inhibitory effect of methyl hippurate on both spore germination and mycelial growth of B. cinerea was revealed by its dose-dependent pattern. The spore germination rate was completely restricted at a concentration of 3 mg/mL of methyl hippurate whereas no mycelial growth was observed in agar medium supplemented with 4 mg/mL and 6 mg/mL of methyl hippurate by poisoned food method. Microscopic imaging revealed that the morphologies of spores were severely altered by long-time exposure to methyl hippurate at concentrations of 1 mg/mL, 2 mg/mL and 3 mg/mL and hyphae of B. cinerea were severely deformed by exposure to methyl hippurate at concentrations of 2 mg/mL, 4 mg/mL and 6 mg/mL. No significant inhibition on tomato seed germination was observed in treatments with methyl hippurate (2 mg/mL) for both 6 h and 12 h soaking period as compared to the controls. Based on these results, B. velezensis CE 100 could be considered a potential agent for development of environmentally friendly disease control strategies as a consequence of the synergetic interactions of diverse crude metabolites and methyl hippurate. 相似文献
|