Antibacterial effect of black seed oil on Listeria monocytogenes

Combined Effect of Nigella sativa and Kefir on the Live Performance and Health of Broiler Chickens Affected by Necrotic Enteritis

Coccidiosis and necrotic enteritis (NE) are prevalent poultry ailments worldwide, leading to decreased live performance and elevated mortality rates without antibiotic usage. This study evaluated Nigella sativa (black cumin) seeds (BCS) and kefir as alternatives to antibiotics for broilers. An in vivo study over a 28-day period, using 384 Cobb 500 male broilers organized into six treatment groups as part of a completely randomized block experimental design was conducted. Each treatment group included eight replicates, with each replicate containing eight birds. The treatments included positive control, negative control, antibiotic control, 5% BCS in feed, 20% kefir in drinking water, and a combination of 5% BCS and 20% kefir. NE was induced in broilers by administering ~5000 oocysts of Eimeria maxima orally on day 14, followed by inoculation with about 108 CFU/mL of Clostridium perfringens (Cp) (strain Cp#4) on days 19, 20, and 21. Live performance metrics including feed intake, body weight gain, and feed conversion were assessed in broilers. Additionally, NE disease outcomes such as lesion scores, mortality rates, and Cp populations in cecum were determined during the study. The BCS, kefir, and the combination had no detrimental effect on broiler live performance. BCS-treated and combination groups had lower NE scores (p > 0.05) in comparison to the positive control and exhibited no significant difference (p > 0.05) from antibiotic control. Additionally, treatment groups and antibiotic control were not significantly different (p > 0.05) in mortality, whereas the BCS and kefir combination significantly reduced (p < 0.05) mortality to 14.1% compared to 31.3% for the positive control. C. perfringens vegetative cells significantly decreased (p < 0.05) in treatments with BCS, kefir, and their combination on days 22 and 28 compared to the positive control. On day 22, Cp sores were significantly lower (p < 0.05) for the kefir and combination treatments compared to the positive control. In conclusion, BCS and kefir successfully reduced C. perfringens infection and mortality without any detrimental impact on broiler live performance with the combined treatment being the most effective. These results suggest that BCS and kefir could serve as potential alternatives to antibiotics in managing NE.

Potential of Essential Oils in the Control of Listeria monocytogenes

Listeria monocytogenes is a foodborne pathogen, the causative agent of listeriosis. Infections typically occur through consumption of foods, such as meats, fisheries, milk, vegetables, and fruits. Today, chemical preservatives are used in foods; however, due to their effects on human health, attention is increasingly turning to natural decontamination practices. One option is the application of essential oils (EOs) with antibacterial features, since EOs are considered by many authorities as being safe. In this review, we aimed to summarize the results of recent research focusing on EOs with antilisterial activity. We review different methods via which the antilisterial effect and the antimicrobial mode of action of EOs or their compounds can be investigated. In the second part of the review, results of those studies from the last 10 years are summarized, in which EOs with antilisterial effects were applied in and on different food matrices. This section only included those studies in which EOs or their pure compounds were tested alone, without combining them with any additional physical or chemical procedure or additive. Tests were performed at different temperatures and, in certain cases, by applying different coating materials. Although certain coatings can enhance the antilisterial effect of an EO, the most effective way is to mix the EO into the food matrix. In conclusion, the application of EOs is justified in the food industry as food preservatives and could help to eliminate this zoonotic bacterium from the food chain.

Novel Slippery Liquid-Infused Porous Surfaces (SLIPS) Based on Electrospun Polydimethylsiloxane/Polystyrene Fibrous Structures Infused with Natural Blackseed Oil

Hydrophobic fibrous slippery liquid-infused porous surfaces (SLIPS) were fabricated by electrospinning polydimethylsiloxane (PDMS) and polystyrene (PS) as a carrier polymer on plasma-treated polyethylene (PE) and polyurethane (PU) substrates. Subsequent infusion of blackseed oil (BSO) into the porous structures was applied for the preparation of the SLIPS. SLIPS with infused lubricants can act as a repellency layer and play an important role in the prevention of biofilm formation. The effect of polymer solutions used in the electrospinning process was investigated to obtain well-defined hydrophobic fibrous structures. The surface properties were analyzed through various optical, macroscopic and spectroscopic techniques. A comprehensive investigation of the surface chemistry, surface morphology/topography, and mechanical properties was carried out on selected samples at optimized conditions. The electrospun fibers prepared using a mixture of PDMS/PS in the ratio of 1:1:10 (g/g/mL) using tetrahydrofuran (THF) solvent showed the best results in terms of fiber uniformity. The subsequent infusion of BSO into the fabricated PDMS/PS fiber mats exhibited slippery behavior regarding water droplets. Moreover, prepared SLIPS exhibited antibacterial activity against Staphylococcus aureus and Escherichia coli bacterium strains.

Slippery Liquid-Infused Porous Polymeric Surfaces Based on Natural Oil with Antimicrobial Effect

Many polymer materials have found a wide variety of applications in biomedical industries due to their excellent mechanical properties. However, the infections associated with the biofilm formation represent serious problems resulting from the initial bacterial attachment on the polymeric surface. The development of novel slippery liquid-infused porous surfaces (SLIPSs) represents promising method for the biofilm formation prevention. These surfaces are characterized by specific microstructural roughness able to hold lubricants inside. The lubricants create a slippery layer for the repellence of various liquids, such as water and blood. In this study, effective antimicrobial modifications of polyethylene (PE) and polyurethane (PU), as commonly used medical polymers, were investigated. For this purpose, low-temperature plasma treatment was used initially for activation of the polymeric surface, thereby enhancing surface and adhesion properties. Subsequently, preparation of porous microstructures was achieved by electrospinning technique using polydimethylsiloxane (PDMS) in combination with polyamide (PA). Finally, natural black seed oil (BSO) infiltrated the produced fiber mats acting as a lubricating layer. The optimized fiber mats' production was achieved using PDMS/PA mixture at ratio 1:1:20 (g/g/mL) using isopropyl alcohol as solvent. The surface properties of produced slippery surfaces were analyzed by various microscopic and optics techniques to obtain information about wettability, sliding behavior and surface morphology/topography. The modified PE and PU substrates demonstrated slippery behavior of an impinged water droplet at a small tilting angle. Moreover, the antimicrobial effects of the produced SLIPs using black seed oil were proven against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli).

Structural Characterization, Antimicrobial Activity, and In Vitro Cytotoxicity Effect of Black Seed Oil

This study was aimed to investigate the structure of bioactive components of black seed oil (BSO) and their antimicrobial and cytotoxic effects. Initially, the structural examination was conducted using various spectroscopic techniques, such as FTIR, TLC, and UV-visible spectroscopy, which are important in determining substituents, functional groups, and the presence of conjugated double bonds in BSO. From the FTIR spectra, a variety of sharp, strong, and weak peaks were specified relating to the main components of thymoquinone (TQ), dithymoquinone, thymohydroquinone, and thymol in BSO. The results of UV-visible spectroscopy confirmed the presence of thymoquinone as a major compound, and conjugated double bonds were also found. In addition, qualitative TLC analysis was used to identify thymoquinone from the methanol-extracted layer in BSO, by calculating the retention factor (R f) value. Furthermore, antimicrobial activity of BSO was studied against various types of bacteria. Strong bacterial inhibitory effects were observed, especially against Bacillus subtilis, with an average inhibition zone of 15.74 mm. Moreover, through the use of the MTT assay in vitro, it was shown that BSO does not exhibit any cytotoxicity towards human peripheral blood mononuclear cells (PBMCs). It was also found from the structural characterization of BSO that the existence of TQ is responsible for potential antibacterial activity without any cytotoxic effects. The main observation of this work is that BSO has antimicrobial activity even against methicillin-resistant Staphylococcus aureus (MRSA).

Determination of some quality properties of "hamsi kaygana" prepared with different additives

This study was aimed to determine the changes of the local anchovy meal which is known as hamsi kaygana in Turkey during cold storage at +4°C ± 1°C. Physicochemical (pH, TVB‐N, TMA‐N, and TBA) shelf life analyses were carried out for hamsi kaygana samples. It was confirmed that the pH values obtained from research groups were within the limit values of the literature. No statistically significant difference was observed (p > .05) between control, stinging nettle, and rosemary groups that were within all created product groups on 12th day of storage, and the observed difference was only present in cumin group (p < .05). Upon examining TVB‐N (Total Volatile Basic Nitrogen) values on 12th day of storage, we saw the lowest TVB‐N value (17.01 ± 0.21 mg/100 g) was at stinging nettle group. However; it was found out that highest TVB‐N value belonged to cumin group with the value of 19.38 ± 0.42 mg/100 g. It was found that 12th day TBA (Thiobarbituric Acid) values of all other groups except control group did not exceed limit values. Among TMA‐N (Trimethylamine Nitrogen) values of all groups on 12th storage period, the lowest value belonged to cumin group samples. While the highest TMA‐N value was found as 14.70 ± 0.30 in control group samples. Therefore, the results showed us that using dried herb and spices in hamsi kaygana production and the storage of the products have an influence on shelf life.

Optimization of Ultrasound Extraction of Cactus Pear(Opuntia ficus indica)Seed Oil Based on Antioxidant Activity and Evaluation of Its Antimicrobial Activity

The purpose of the present study was to determine the optimal ultrasound conditions (amplitude level and time) for the extraction of cactus pear seed oil with the highest antioxidant activity using a closed system. Seed oil was analyzed for yield, antioxidant activity by ABTS and DPPH, and antimicrobial activity. Conventional extraction methods were assessed for comparison. Amplitude level significantly affected antioxidant activity in linear terms (p< 0.0001 DPPH andp< 0.001 ABTS, resp.) so, at lower amplitudes, the higher antioxidant activity was achieved. The optimum ultrasound extraction conditions were of 78% amplitude for 10 min and yielded antioxidant activity values of 66.25 mg AAE/100 g and 289 µmol TE/100 g for ABTS and DPPH, respectively. Compared with conventional extraction methods, ultrasound exhibited lower oil yield and antioxidant activity but had the potential to achieve comparable results if multiple ultrasound extractions are performed in the time needed by conventional methods. Seed oils showed similar antimicrobial activity despite the extraction method and were more effective againstEscherichia coli. The results demonstrated that ultrasound can be an alternative extraction method of seed oils from fruits such as cactus pear.

Synthesis and characterization of crosslinked polyisothiouronium methylstyrene nanoparticles of narrow size distribution for antibacterial and antibiofilm applications

Background

Isothiouronium salts are well known in their variety of antimicrobials activities. The use of polymeric biocides, polymers with antimicrobial activities, is expected to enhance the efficacy of some existing antimicrobial agents, thus minimizing the environmental problems accompanying conventional antimicrobials.

Methods

The current manuscript describes the synthesis and characterization of crosslinked polyisothiouronium methylstyrene (PITMS) nanoparticles (NPs) of narrow size distribution by dispersion co-polymerization of the monomer isothiouronium methylstyrene with the crosslinking monomer ethylene glycol dimetacrylate.

Results and discussion

The effect of total monomer, crosslinker and initiator concentrations on the size and size distribution of the formed NPs was also elucidated. The bactericidal activity of PITMS NPs of 67 ± 8 nm diameter was illustrated for 4 bacterial pathogens: Listeria innocua, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. In order to demonstrate the potential of these PITMS NPs as inhibitor of biofilm formation, polyethylene terephthalate (PET) films were thin-coated with the PITMS NPs. The formed PET/PITMS films reduced the viability of the biofilm of Listeria by 2 orders of magnitude, making the coatings excellent candidates for further development of non-fouling surfaces. In addition, PITMS NP coatings were found to be non-toxic in HaCaT cells.

Conclusions

The high antibacterial activity and effective inhibition of bacterial adsorption indicate the potential of these nanoparticles for development of new types of antibacterial and antibiofilm additives.

Electronic supplementary material

The online version of this article (doi:10.1186/s12951-016-0208-7) contains supplementary material, which is available to authorized users.

Protective efficacy of Nigella sativa seeds and oil against columnaris disease in fishes

Columnaris disease, caused by the bacterium Flavobacterium columnare, is currently the most frequently reported bacterial disease affecting farm-raised channel catfish in the USA. Common treatments against the disease include the use of medicated feed that has led to emergent antibiotic resistant strains of F. columnare. Nigella sativa (Black cumin) is a medicinal herb commonly used by many cultures as a natural remedy for numerous disorders. Recently, we have discovered the antibacterial activity of N. sativa and its oil extract against F. columnare. In this study, we showed N. sativa oil (NSO) strongly inhibited the growth of all of the strains of F. columnare tested and yielded significantly larger zones of inhibition than those produced by oxytetracyclin. We tested the protective effect against columnaris disease in vivo by incorporating NSO (5%) or N. sativa seeds (NSS) (5%) into fish feeds. Fishes (Ictalurus punctatus and Danio rerio) fed amended diets displayed significantly lower mortality than those fed control diets. Per cent mortalities in control groups ranged from 77% to 44% and from 70% to 18% in zebrafish and channel catfish, respectively. A dose study using different NSS concentrations showed that 5% NSS offered the most protection against columnaris disease in channel catfish.

Anti-listerial compounds from Asari Radix

Asari Radix, the roots of Asarum heterotropoides F. Maekawa var. manshuricum F. Maekawa or A. sieboldii F. Maekawa, has traditionally been used for the treatment of various infectious diseases. Since its MeOH extract inhibited the growth of Listeria monocytogenes in a preliminary test, the aim of this study was to isolate and identify the anti-listerial compounds from the plant. Activity-guided fractionation led to the isolation of seven compounds 1-7 from the MeOH extract, and their chemical structures were identified by comparison of the spectroscopic data with those in the literature. Compounds 1-7 exhibited inhibitory activity against all five tested strains of L. monocytogenes with diameter of inhibition zones ranging from 7 to 11 mm in the agar disc diffusion method. Compounds 1-3 and 7 demonstrated potent antimicrobial effects on the L. monocytogenes strains, with MICs between 62.5 and 125 μg/mL. This is the first report that AR possesses inhibitory activity against L. monocytogenes.

Antioxidant and antilisterial effect of seed essential oil and organic extracts from Zizyphus jujuba

Hydrodistilled volatile oil from the seeds of Zizyphus jujuba was analyzed by GC-MS. Twenty three compounds representing 91.59% of the total oil was identified. The oil and organic extracts revealed a great potential of antilisterial effect against all five strains of Listeria monocytogenes ATCC 19111, 19116, 19118, 19166 and 15313. Also the oil had strong detrimental effect on the viable count of the tested bacteria. The samples were also subjected to screening for the antioxidant activity by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radicals scavenging activities assay. In the first case, the IC(50) value of the Z. jujuba essential oil was determined to be 5.21+/-0.01 microg/ml. Among the extracts, the strongest activity was exhibited by the methanol extract with an IC(50) value of 20.44+/-0.18 microg/ml. In the superoxide radicals scavenging activities assay, methanol extract was superior to all other extracts (IC(50)=18.60+/-0.3 microg/ml). Furthermore, the amount of total phenolic compounds was determined. The results indicate that the essential oil and extracts of Z. jujuba could serve as natural antimicrobial and antioxidant agents for the food industry.

Comparison of chemical composition and antibacterial activity of Nigella sativa seed essential oils obtained by different extraction methods

Nigella sativa L. seed essential oils obtained by hydrodistillation (HD), dry steam distillation (SD), steam distillation of crude oils obtained by solvent extraction (SE-SD), and supercritical fluid extraction (SFE-SD) were tested for their antibacterial activities, using the broth microdilution method and subsequently analyzed by gas chromatography and gas chromatography-mass spectrometry. The results showed that the essential oils tested differed markedly in their chemical compositions and antimicrobial activities. The oils obtained by HD and SD were dominated by p-cymene, whereas the major constituent identified in both volatile fractions obtained by SD of extracted oils was thymoquinone (ranging between 0.36 and 0.38 g/ml, whereas in oils obtained by HD and SD, it constituted only 0.03 and 0.05 g/ml, respectively). Both oils distilled directly from seeds showed lower antimicrobial activity (MICs > or = 256 and 32 microg/ml for HD and SD, respectively) than those obtained by SE-SD and SFE-SD (MICs > or = 4 microg/ml). All oil samples were significantly more active against gram-positive than against gram-negative bacteria. Thymoquinone exhibited potent growth-inhibiting activity against gram-positive bacteria, with MICs ranging from 8 to 64 microg/ml.