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• Extracellular mycosynthesis of Co 3 O 4 NPs and ZnO NPs using Aspergillus sojae MCFF. • Physicochemical and morphological properties of Co 3 O 4 NPs and ZnO NPs. • Significant antibacterial efficiency of Co 3 O 4 NPs and ZnO NPs against foodborne pathogens. • Assessment of morphological changes of bacterial cells using microscopic analysis. Foodborne pathogenic bacteria cause a wide range of infectious diseases that pose a serious threat to human health worldwide with significant social and economic consequences. Nano metal oxides have attracted paramount attention owing to their remarkable antimicrobial potency. Microbial synthesis of metal oxide nanoparticles has gained prominence due to cost-effectiveness, biocompatibility, and environmental friendliness. This study reports extracellular mycosynthesis of two nano metal oxides mediated by Aspergillus sojae mycelial cell-free filtrate (MCFF). A. sojae MCFF was reacted with cobalt chloride hexahydrate and zinc nitrate hexahydrate for the preparation of Co 3 O 4 NPs and ZnO NPs, respectively. After reacting with each metal salt, A. sojae MCFF changed from transparent to greyish-brown and white-milky suspensions, indicating the mycosynthesis of Co 3 O 4 NPs and ZnO NPs, respectively. Physicochemical and morphological properties of the two nano metal oxides were determined using various characterization techniques, involving XRD, FTIR, EDX, DLS, zeta potential analysis, XPS, and electron microscopy. The two nano metal oxides exhibited antibacterial potency against three foodborne pathogens. Co 3 O 4 NPs had zones of inhibition (ZOI) of 19.33 ± 0.58, 20.67 ± 0.58, and 22.67 ± 0.58 mm against Escherichia coli (ATCC 43889), Salmonella enterica Serovar Typhimurium (ATCC 43174), and Staphylococcus aureus (ATCC 12600), respectively. Whereas ZnO NPs had ZOI of 15.67 ± 0.58, 15.67 ± 0.58, and 14.33 ± 0.58 mm against the three foodborne pathogens, respectively. The intact morphological structures of the bacterial cells collapsed following exposure to A. sojae -mediated Co 3 O 4 NPs and ZnO NPs, with some cells having irregular, twisted, and rough surfaces. The current study concluded that A. sojae mycelia acted as potential biological entity for the biosynthesis of Co 3 O 4 NPs and ZnO NPs. A. sojae -derived Co 3 O 4 NPs and ZnO NPs can be potential candidates for use as antimicrobial nano metal oxides in food and pharmaceutical industries. [Display omitted] [ABSTRACT FROM AUTHOR]

Herein, Fe3O4nanoparticles synthesized using aqueous extract of corn ear leaves were investigated for proteasome inhibitory activity, antioxidant activity, synergistic antibacterial, and anticandidal potential. The UV-Vis spectrum displayed an absorption band at 355 nm that indicated the formation of nano-sized Fe3O4particles. Vibrating sample magnetometer analysis revealed its superparamagnetic nature. Fe3O4nanoparticles exhibited strong proteasome inhibitory potential and antioxidant activity and exerted strong synergistic antibacterial and anticandidal activity. Its significant proteasome inhibitory potential could be useful in cancer treatment and drug delivery. Furthermore, strong antioxidant, antibacterial, and anticandidal activity make them a promising candidate for biomedical and pharmaceutical applications. [ABSTRACT FROM AUTHOR]

This study was conducted to extract essential oil from an edible seaweed, Undaria pinnatifida, and determine its chemical constituents, antibacterial and antioxidant potential. Gas chromatography and mass spectroscopy analysis of the U. pinnatifida essential oil (UPEO) revealed 26 volatile compounds comprising a total of 97.03%. Fatty acids such as tetradecanoic acid (31.32%) and hexadecanoic acid (22.39%) were present in the highest amount, followed by 3-hexen-1-ol (5.67%), erythritol (4.73%), 4-imidazolidinone (4.40%) and (9Z)-hexadec-9-enoic acid (4.37%). UPEO displayed potent antibacterial activity (9.5-11.0 mm inhibition zone), an MIC of 12.5-25.0 mg/mL and an MBC of 25.0 mg/mL. UPEO also exhibited strong hydroxyl radical scavenging (IC50 85.54 µg/mL), reducing power (IC0.5 178.82 µg/mL) and superoxide radical scavenging (IC50 260.89 µg/mL) potential. Taken together, these results indicate that UPEO could be an economical and safe resource for natural antioxidant and antibacterial compounds that can be utilized in food processing, cosmetics and pharmaceutical sectors. Practical Applications Seaweeds are a rich source of natural bioactive compounds with various medicinal properties. The essential oils extracted from an edible seaweed, U. pinnatifida, could serve as an alternative source of natural antioxidant compounds with the potential for use as food additives and in food preservation and cosmetics. Use of this compound could minimize the use of synthetic antioxidant compounds that trigger health hazards. Furthermore, the bioactive compounds present in the UPEO could serve as a source of natural antibiotics against both Gram positive and Gram negative pathogenic bacteria. [ABSTRACT FROM AUTHOR]

This paper investigated the green synthesis of silver nanoparticles (AgNPs) using aqueous extract of silky hairs of corn (Zea mays L.) which is a waste material of the crop, as both a reducing and stabilising/capping agent. The AgNPs were characterised by UV-visible spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), thermogravimetric analysis (TGA), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The average size of AgNPs was found to be 249.12 nm. The AgNPs displayed strong antibacterial activity against five different foodborne pathogenic bacteria with diameter of inhibition zones ranged between (9.23 - 12.81 mm). It also exhibited potent synergistic antibacterial activity together with standard antibiotics, kanamycin (10.6 - 13.65 mm inhibition zones) and rifampicin (10.02 - 12.86 mm inhibition zones) and anticandidal activity with amphotericin b (10.57 - 13.63 mm inhibition zones). The AgNPs exhibited strong antioxidant activity in terms of nitric oxide scavenging (IC50 91.56 µg/mL), ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging (IC50 115.75 µg/mL), DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging (IC50 385.87 µg/mL), and reducing power (IC0.5 23.14 µg/mL). This study demonstrated the synthesis of spherical AgNPs with strong antibacterial, anticandidal and antioxidant properties that could potentially be utilised in the biomedical, cosmetic, food and pharmaceutical industries. [ABSTRACT FROM AUTHOR]

The present study was conducted to synthesize silver chloride nanoparticles using the aqueous extract of outer peel of peach fruit (Prunus persicaL.) and to evaluate its antibacterial activity, synergistic antibacterial and anticandidal potential against five foodborne pathogenic bacteria and five pathogenicCandidaspecies respectively along with its antioxidant potential. The synthesized silver chloride nanoparticles (PE-AgClNPs) were visually confirmed with surface plasmon resonance peak at 440 nm upon UV–Vis spectroscopy analysis. Furthermore, the morphology, elemental composition and crystallinity nature were also characterized. PE-AgClNPs displayed strong antibacterial potentials (9.01–10.83 mm inhibition zone) against foodborne pathogenic bacteria and increased synergistic effect with kanamycin and rifampicin. PE-AgClNPs also displayed strong anticandidal synergistic activity with standard amphotericin b (10.51–14.01 mm inhibition zones), along with strong free radical scavenging and reducing power. Based on strong antibacterial and antioxidant capacities, PE-AgClNPs are anticipated to have potential applications in the biomedical and food sector industries. [ABSTRACT FROM PUBLISHER]

This study examined the antibacterial mode of action of T axus cuspidata leaf essential oil ( TCEO) against foodborne pathogenic bacteria. Gas chromatography-mass spectrometry analysis of microwave-extracted TCEO resulted in examination of 34 different compounds, representing 81.63% of the total oil. The TCEO (1,000 μg per disc) showed antibacterial effect against B acillus cereus ATCC 13061, S taphylococcus aureus ATCC 12600, L isteria monocytogenes ATCC 7644, S almonella typhimurium ATCC 43174 and E scherichia coli ATCC 43889 as diameters of inhibition zones (22.0 ± 0.4 to 34.0 ± 1.2 mm). The minimum inhibitory concentration and minimum bactericidal concentration values of TCEO against the tested pathogens were found in the range of 250-1,000 μg/mL. Also, the TCEO had potential inhibitory effect on the viable counts of test pathogens. The TCEO revealed its mode of action on membrane integrity as confirmed by marked release of extracellular adenosine triphosphate, 260 nm absorbing materials and potassium ion efflux. The scanning electron microscopy analysis using TCEO further confirmed severe morphological alterations on the cell membrane of test pathogens. Practical Applications Because of frequent foodborne outbreaks and rising concern of consumers on the use of chemical preservatives in foods, the food industry is emphasizing the use of natural antibacterial agents from plant origin as safe food preservatives. Some selected plant materials are used as natural antimicrobials in food systems to prevent the growth of foodborne pathogens, resulting in the extension of shelf life of processed foods. T axus cuspidata leaf essential oil ( TCEO) is shown by this study to elicit its antibacterial action against foodborne pathogens through membrane permeabilization and can be used to control the growth of several foodborne pathogens. Hence, it is anticipated that TCEO may have greater potential for its practical application as an affective food preservative. [ABSTRACT FROM AUTHOR]

This study investigated the antibacterial mechanism of action of the seed essential oil of Eleutherococcus senticosus ( ESEO) against foodborne pathogenic bacteria. Preliminarily, the ESEO (1000 μg disc−1) showed potential antibacterial effect as diameter of inhibition zones (12.0 ± 0.2-37.0 ± 2.0 mm) against the tested foodborne pathogens. The MIC and MBC values of ESEO against the tested bacteria were found in the range of 125-500 and 500-1000 μg mL−1, respectively. At MIC concentration, the ESEO had potential inhibitory effect on the cell viability of the tested pathogens. In addition, SEM analysis showed the inhibitory effect of ESEO as confirmed by considerable morphological alterations on the cell wall of B. cereus ATCC 13061 and E. coli O157:H7 ATCC 43889. Moreover, the ESEO revealed its mode of action against foodborne pathogens on membrane integrity as confirmed by release of extracellular ATP, 260-nm absorbing materials and leakage of potassium ions. These findings confirm that the ESEO can be used as a potential antibacterial agent in food industry to inhibit the growth of various foodborne pathogens. [ABSTRACT FROM AUTHOR]

This study examined the antibacterial mechanism of action of Taxus cuspidata stem essential oil ( TCEO) against foodborne pathogenic bacteria. The TCEO (2,000 μg/disc) showed potential antibacterial effect as diameters of inhibition zones (32.0 ± 0.47-44.0 ± 0.59 mm) against the tested foodborne pathogens including Bacillus cereus ATCC13061, Listeria monocytogenes ATCC7644, Staphylococcus aureus ATCC12600, Salmonella typhimurium ATCC43174 and Escherichia coli ATCC43889. The minimum inhibitory concentration and minimum bactericidal concentration values of TCEO against the tested bacteria were found in the range of 125-500 μg/m L and 250-1,000 μg/m L, respectively. Also, the TCEO had potential inhibitory effect on the cell viability of B. cereus ATCC 13061 and E. coli ATCC 43889. Moreover, the TCEO revealed its mode of action on membrane integrity as confirmed by marked release of extracellular adenosine 5′-triphosphate, 260-nm absorbing materials and efflux of potassium ions ( K+) against the tested pathogens. Further, scanning electron microscopic analysis also supported the inhibitory effect of TCEO as confirmed by significant morphological alterations on the cell membrane of the tested pathogens, suggesting its potential efficacy as a natural antibacterial agent. Practical Application Currently, because of frequent foodborne outbreaks and the rising concern of consumers on the use of chemical preservatives in foods, the food industry is emphasizing the use of natural antibacterial agents of plant origin as safe food preservatives. Some selected plant materials are used as natural antimicrobials in food systems to prevent the growth of foodborne pathogens, resulting in the extension of the shelf-life of processed foods. This study confirmed that Taxus cuspidata stem essential oil showed its antibacterial mode of action against foodborne pathogens through membrane permeabilization and can be used to control the growth of several foodborne pathogens. Hence, it is anticipated that T. cuspidata stem essential oil may have greater potential for its practical applications as an affective and natural food preservative against food deterioration caused by foodborne pathogens. [ABSTRACT FROM AUTHOR]

This study investigates the antibacterial mechanism of action of Allium sativum rhizome essential oil ( ASEO) against foodborne pathogens. The ASEO was obtained by hydrodistillation of A. sativum rhizome using a microwave-assisted extraction technique. The ASEO (1,000 μg/disk) showed potential antibacterial effect as diameters of inhibition zones against the tested foodborne pathogens including American Type Culture Collection (ATCC) strains Bacillus cereus ATCC 13061, Escherichia coli ATCC 43889, Listeria monocytogenes ATCC 7644, Salmonella Typhimurium ATCC 43174 and Staphylococcus aureus ATCC 12600, which were found in the range of 11.0 ± 0.1-24.0 ± 0.1 mm. The minimum inhibitory concentration ( MIC) and minimum bactericidal concentration ( MBC) values of ASEO against the tested bacteria were found in the range of 62.5-500 μg/mL. At the MIC concentration, ASEO had potential inhibitory effect on the cell viability of the tested bacteria. In addition, the scanning electron microscopy analysis showed the inhibitory effect of ASEO as confirmed by the considerable morphological alterations on the cell walls of B. cereus ATCC 13061 and E. coli ATCC 43889. Moreover, the ASEO revealed its mode of action on membrane integrity as confirmed by the release of extracellular adenosine 5′-triphosphate, 260-nm absorbing materials and potassium ions efflux against tested pathogens. These findings suggest that ASEO showed its effect on membrane permeability and surface characteristics. Practical Applications Foodborne pathogens are the leading causes of illness in the developed countries. These pathogens are responsible for millions of cases of infectious diseases each year, costing billions of dollars in medical care. New foodborne pathogens and foodborne diseases are likely to emerge driven by factors such as pathogen evolution, changes in food manufacturing practices, and changes to the human host status. Fuelled by these concerns, research on biologically active natural compounds to control the foodborne pathogens has escalated to unprecedented levels in recent years. Plant-based antimicrobials such as essential oils have been found to suppress the growth of foodborne pathogens in various in vitro and in vivo models. These findings clearly indicate that essential oil derived from the rhizome of A. sativum confers its mode of action on membrane integrity, hence, could be used as an affective candidate to control the growth of certain important foodborne pathogens in practical applications. [ABSTRACT FROM AUTHOR]

Lannea egregia (Anacardiaceae) and Emilia sonchifolia (Asteraceae) are plants used in traditional medicine in southwestern Nigeria. The essential oils from the leaves of L. egregia and E. sonchifolia were obtained by hydrodistillation and analyzed by gas chromatography–mass spectrometry. Both essential oils were dominated by sesquiterpenoids. The major components in L. egregia leaf essential oil were α-panasinsen (34.90%), (E)-caryophyllene (12.25%), α-copaene (11.39%), and selina-4,11-diene (9.29%), while E. sonchifolia essential oil was rich in γ-himachalene (25.16%), (E)-caryophyllene (15.72%), and γ-gurjunene (8.58%). The essential oils were screened for antimicrobial activity against a panel of bacteria and fungi and displayed minimum inhibitory concentrations ranging from 156 μg/mL to 625 μg/mL. Based on these results, either L. egregia or E. sonchifolia essential oil may be recommended for exploration as complementary antibacterial or antifungal agents. [ABSTRACT FROM AUTHOR]

The biological synthesis of nanoparticles has gained tremendous interest, and plants and plant extracts are preferred over other biological sources for this process because of their rich content of bioactive metabolites. In this study, silver nanoparticles (AgNPs) were produced utilizing the aqueous extract of watermelon rind (WRA), an agricultural waste material under photo exposed condition at room temperature, and tested for their antibacterial, anticandidal and antioxidant activities. The synthesized AgNPs showed surface plasmon resonance at 425 nm with an average size of 109.97 nm. The morphology and elemental composition was confirmed by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX). The Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric and differential thermogravimetric analysis (TG/DTG) confirmed that the bioactive compounds from the WRA extract were involved in the synthesis and capping of AgNPs. X-ray diffraction (XRD) revealed the crystallite nature of the AgNPs. The AgNPs exhibited strong broad spectrum antibacterial activity against five different foodborne bacteria with zones of inhibition 9.12–14.54 mm in diameter. When AgNPs were mixed with kanamycin and rifampicin the mixture exhibited strong antibacterial synergistic activity. The AgNPs also exerted strong synergistic anticandidal activity when they were combined with amphotericin b. The AgNPs had high antioxidant activity and reducing power. Overall, the results confirmed the bio-potentials of the synthesized AgNPs using WRA, which could have applications in the biomedical, cosmetic, pharmaceutical, food preservation and packaging industries. [ABSTRACT FROM AUTHOR]