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Citrus is one of the main fruit crops cultivated in tropical and subtropical regions worldwide. Approximately half (40–47%) of the fruit mass is inedible and discarded as waste after processing, which causes pollution to the environment. Essential oils (EOs) are aromatic compounds found in significant quantities in oil sacs or oil glands present in the leaves, flowers, and fruit peels (mainly the flavedo part). Citrus EO is a complex mixture of ~400 compounds and has been found to be useful in aromatic infusions for personal health care, perfumes, pharmaceuticals, color enhancers in foods and beverages, and aromatherapy. The citrus EOs possess a pleasant scent, and impart relaxing, calming, mood-uplifting, and cheer-enhancing effects. In aromatherapy, it is applied either in message oils or in diffusion sprays for homes and vehicle sittings. The diffusion creates a fresh feeling and enhances relaxation from stress and anxiety and helps uplifting mood and boosting emotional and physical energy. This review presents a comprehensive outlook on the composition, properties, characterization, and mechanism of action of the citrus EOs in various health-related issues, with a focus on its antioxidant properties. [ABSTRACT FROM AUTHOR]

Despite the discovery and development of an array of antimicrobial agents, multidrug resistance poses a major threat to public health and progressively increases mortality. Recently, several studies have focused on developing promising solutions to overcome these problems. This has led to the development of effective alternative methods of controlling antibiotic-resistant pathogens. The use of antimicrobial agents in combination can produce synergistic effects if each drug invades a different target or signaling pathway with a different mechanism of action. Therefore, drug combinations can achieve a higher probability and selectivity of therapeutic responses than single drugs. In this systematic review, we discuss the combined effects of different antimicrobial agents, such as plant extracts, essential oils, and nanomaterials. Furthermore, we review their synergistic interactions and antimicrobial activities with the mechanism of action, toxicity, and future directions of different antimicrobial agents in combination. Upon combination at an optimum synergistic ratio, two or more drugs can have a significantly enhanced therapeutic effect at lower concentrations. Hence, using drug combinations could be a new, simple, and effective alternative to solve the problem of antibiotic resistance and reduce susceptibility. [ABSTRACT FROM AUTHOR]

Background: Porphyra tenera (Kjellman, 1897) is the most common eatable red seaweed in Asia. In the present study, P. tenera volatile oil (PTVO) was extracted from dried P. tenera sheets that were used as food by the microwave hydrodistillation procedure, after which the characterization of its chemical constituents was done by gas chromatography and mass spectroscopy and its antioxidant potential was evaluated by a number of in vitro biochemical assays such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, nitric oxide (NO) scavenging, superoxide radical scavenging, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging, hydroxyl radical scavenging and reducing power assay and inhibition of lipid peroxidation. Results: A total of 30 volatile compounds comprising about 99.4% of the total volume were identified, of which trans-beta-ionone (20.9%), hexadecanoic acid (9.2%) and 2,6-nonadienal (8.7%) were present in higher quantities. PTVO exhibited strong free radical scavenging activity by DPPH scavenging (44.62%), NO scavenging (28.45%) and superoxide scavenging (54.27%) at 500 µg/mL. Similarly, it displayed strong ABTS radical scavenging (IC value of 177.83 µg/mL), hydroxyl radical scavenging (IC value of 109.70 µg/mL), and moderate lipid peroxidation inhibition activity (IC value of 231.80 µg/mL) and reducing power (IC value of 126.58 µg/mL). PTVO exhibited strong antioxidant potential in a concentration dependent manner and the results were comparable with the BHT and α-tocopherol, taken as the reference standard compounds (positive controls). Conclusions: Taken together, PTVO with potential bioactive chemical compounds and strong antioxidant activity could be utilized in the cosmetic industries for making antioxidant rich anti-aging and sun-screen lotion and in the food sector industries as food additives and preservatives. [ABSTRACT FROM AUTHOR]

This study was outlined to probe chemical composition, antioxidant and free radical scavenging activities ofTaxus cuspidatastem essential oil (TCEO) using different antioxidant models followed by determination of its total phenolic content. The TCEO was obtained by hydrodistillation of stem material using a microwave-assisted extraction technique. Gas chromatography-Mass spectrometry analysis of the TCEO resulted in the determination of 87 different compounds, representing 92.3% of total oil. The oil contained monoand sesquiterpene hydrocarbons, oxygenated monoand sesquiterpenes, diterpenes, phenolics, hydroxy derivatives, steroids, indole derivatives, and fatty acids as its major constituents. The TCEO showed antioxidant capacity as the inhibition of DPPH radical by 92.8%. Also the TCEO had potent inhibitory effect on nitric oxide, superoxide, and hydroxyl radicals by 80.0%, 71.7%, and 73.7%, respectively. Moreover, the TCEO displayed concentration-dependent reducing power ability and remarkable ferric ion-induced lipid peroxidation inhibitory effect in bovine brain extract. In addition, the TCEO yielded 6.5 ± 0.5 mg GAE/g sample equivalent phenolic content. These findings confirm the biological efficacy ofT. cuspidatastem as a potential source of natural antioxidant. [ABSTRACT FROM AUTHOR]

Food contamination with pathogenic microbes have increased dramatically during the last few decades, and going to be a major public health concern in many developing countries. Foodborne pathogens cause severe diseases to human beings including infants. Although a large number of foodbornepathogens exist, the overall increase in the number of infections is of relatively few emerging serotypes and phage types. A variety of foodborne pathogens have risen and fallen within large geographic regions, associated with several meta-outbreaks. Recently the emergence of resistance of foodborne pathogens to the antimicrobial drugs appears to pose a particular health risk. Several reports have indicated that infection due to the consumption of food contaminated with foodborne pathogens is associated with increased risk for invasive illness, and death. In general, antimicrobial drug resistance occurs frequently in zoonotic foodborne pathogens and is largely promoted by using antimicrobial drugs in food practices. Foodborne pathogens have become a matter of great concern because of their rapid dissemination and their ability to readily acquire additional resistance traits to other clinically important antimicrobial drug classes. There has been an increasing interest worldwide on versatile potential of natural products in controlling foodborne pathogens in food commodities using essential oils, especially from plant origin. This review deals with the novel findings on essential oils and their compounds for their possible applications in food industry against the foodborne pathogens.A reliable amount of description on the practical applications of essential oils in food practices has been described. We have also described the chemical nature and mode of action of essential oils. A brief summary on the use of essential oils in food system as future perspectives has also been discussed. Although an adequate information from literature is presented, this review mainly focusses on the food application of essential oils and their active compounds as natural antimicrobial agents. [ABSTRACT FROM AUTHOR]

The seaweed E nteromorpha linza has long been used as a food source rich in natural bioactive compounds in various regions of the world. In the present study, the essential oil from E . linza, extracted by microwave-assisted hydrodistillation, was analyzed for its chemical composition and was evaluated for its free radical-scavenging and antioxidant potential. Gas chromatography and mass spectroscopy revealed the presence of 24 compounds in the seaweed essential oil ( SEO), among which hexadecanoic acid (47.32%), nonadecadiene (18.19%) and azetidine (2.84%) are of medicinal importance. SEO exhibited strong hydroxyl radical-scavenging and superoxide scavenging activity of 91.37 and 53.50%, respectively, at 500 μg/m L. SEO also exhibited strong reducing power (0.90) and inhibited lipid peroxidation by 70.53% at 500 μg/m L. Based on the high antioxidant activities of compounds in SEO, it can be used as a food additive, preservative and dietary supplement to control the deleterious effects of oxidative stress with increased nutritional values. Practical Applications Extensive investigations of free radicals and reactive oxygen species have revealed that these components have adverse effect on biomolecules that cause damage to macromolecules, including proteins, nucleic acids, lipids and carbohydrates, as well as various food products. Seaweeds are a favorable food source that serves as an effective resource for essential oil, which could be an alternative source of natural antioxidants, used as food additives or in food preservation. In this study, SEO from E . linza extracted by microwave-assisted hydrodistillation exhibited significantly high antioxidant and radical-scavenging potential, as well as inhibition of lipid peroxidation. These findings confirm that SEO from E . linza can be used by food industries as an additive, preservative or dietary supplement and as a nutraceutical to control the harmful effects of oxidative stress on food. [ABSTRACT FROM AUTHOR]

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]

The aim of this study was to isolate the Eleutherococcus senticosus seed essential oil ( ESEO) by an efficient microwave extraction method and to determine its antioxidant efficacy as reducing power, lipid peroxidation inhibition, as well as its ability to scavenge free radicals followed by determination of total phenolic content. The gas chromatography-mass spectroscopy analysis of ESEO revealed the presence of 21 different components representing 92.29% of the total oil. The ESEO evoked concentration-dependent reducing power and significant ferric ion-induced lipid peroxidation inhibition. The ESEO also showed significant antioxidant activity as inhibition of 1,1-diphenyl-2-picrylhydrazyl, nitric oxide, superoxide and hydroxyl-free radicals by 71.72, 71.75, 72.87 and 72.36%, respectively. The ESEO yielded 6.02 ± 0.01 mg/g gallic acid equivalent total phenolic content. The present study provides evidence that the ESEO may be considered as a potential source of natural antioxidants. Practical Applications Free radicals play a very important role in food deterioration and disease progression. Plant-based essential oils have wide applications in food preservation, cosmetics and fragrance industry, mainly due to their wide margin of safety and broad range of antioxidant and other biological properties. In this study, the microwave-assisted seed essential oil from Eleutherococcus senticosus showed significant ( P < 0.05) antioxidant and radical-scavenging activities in various experimental models including inhibition of lipid peroxidation and phenolic content. These findings confirm that E. senticosus has potential to be developed into dietary supplements and nutraceuticals. [ABSTRACT FROM AUTHOR]

Abstract: During the past several years, limit of Salmonella infections has been exceeded dramatically. In spite of achieving a low rate infection in Salmonella infections, this microbe has become a challenge in food industry due to its wide-spread distribution worldwide. Salmonella bacteria are not only responsible for mild to severe infections but also they cause life-threatening infections. Salmonella bacteria are zoonotic in nature and hamper the food quality severely as well as being hazardous to human society. Several types of serotypic Salmonella have been reported; however, very less numbers of pathogens are infection responsible. Increase in foodborne infections caused by Salmonella types mainly occurs due to the development of new specific features in Salmonella majority, making them to adapt in any environmental condition. Also the alterations in human society with recent food processing and marketing methodology with live breeders contribute to facilitate these outbreaks. Salmonella resistant to commercial antibiotic drugs has emerged as a great health concern to the consumers. Literature survey has revealed that infection with Salmonella resistant to antibiotics has played a vital role to increased rate in foodborne infectious diseases. Extensive use of antibiotics in food industry against foodborne pathogens or food models has resulted in additional antibiotic resistance to Salmonella which has become a matter of great concern to the public health. There has been an increasing concern worldwide on therapeutic values of natural products. Nature has presented to humanity the gift of vast therapeutic antimicrobial agents of plant origins. There are multitudes of potential useful bioactive substances to be derived from plants. The significance of drugs cannot be over-emphasized with the recent trend of high percentage of resistance of microorganisms to the present day antibiotics. This review provides the informative literature data on antibacterial efficacy of plant essential oils (PEOs) and their volatiles. In addition, the suitability of PEOs and their volatile components for their practical applications in food or food products against Salmonella, a common cause of salmonellosis food poisoning has also been focused. The current knowledge of volatile oils and contents in food model system to control Salmonella has been discussed. Also a brief description on the legal aspects on how to use the volatile oils in food system has been presented, and the area for future research has been proposed. A mode of antibacterial action of PEOs along with their chemical nature has also been described. Although some data on Salmonella-related issues are presented, this review chiefly focused on in vivo practical utilization of plant volatile oils and components in food model-system as natural anti-Salmonella agents. [Copyright &y& Elsevier]

The development of food-borne and infectious diseases has increased globally at an anomalous rate and is combined with emerging social and economic problems. This highlights the need for new and improved antibacterial agents with novel and different mechanisms of action at regular intervals. Some chemical or artificial food additives are considered harmful if they are used beyond their permissible levels. Today, consumers are demanding alternative, green, safer, and natural food additives to increase the shelf life of food. Essential oils (EOs) are concentrated liquid mixtures of volatile compounds with antioxidant and antibacterial properties that can be used as natural, eco-friendly, renewable, and cost-effective additives. The use of combinations of different EOs and their components is a promising strategy to increase the synergistic and additive effects of EOs in foods. In this article, we review the recent literature on EOs concerning the chemical constituents, extraction methods, antioxidant and antibacterial activities, and their mechanisms of action. Additionally, we discuss the synergistic interaction of different EOs and their components, challenges, and future directions of EOs as natural food preservatives, with special emphasis on shelf life extension and applications in the packaging of food products. [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]

Over the past few decades, many pathogenic bacteria have become resistant to existing antibiotics, which has become a threat to infectious disease control worldwide. Hence, there has been an extensive search for new, efficient, and alternative sources of antimicrobial agents to combat multidrug-resistant pathogenic microorganisms. Numerous studies have reported the potential of both essential oils and metal/metal oxide nanocomposites with broad spectra of bioactivities including antioxidant, anticancer, and antimicrobial attributes. However, only monometallic nanoparticles combined with essential oils have been reported on so far with limited data. Bi- and tri-metallic nanoparticles have attracted immense attention because of their diverse sizes, shapes, high surface-to-volume ratios, activities, physical and chemical stability, and greater degree of selectivity. Combination therapy is currently blooming and represents a potential area that requires greater attention and is worthy of future investigations. This review summarizes the synergistic effects of essential oils with other antimicrobial combinations such as mono-, bi-, and tri-metallic nanocomposites. Thus, the various aspects of this comprehensive review may prove useful in the development of new and alternative therapeutics against antibiotic resistant pathogens in the future. [ABSTRACT FROM AUTHOR]

Abstract: The present investigation reports on the chemical composition of Cudrania tricuspidata fruit essential oil (CTEO) and examines its possible antimicrobial mode of action against food-borne pathogenic bacteria. The CTEO was obtained by hydrodistillation of C. tricuspidata fruits using a microwave-assisted extraction technique. Gas chromatography-mass spectrometry analysis of the CTEO resulted in the determination of 29 different compounds, representing 94.46% of the total oil. The CTEO (1000 μg/disc) showed potential antibacterial effect as diameters of inhibition zones (15.0 ± 0.1–21.0 ± 1.0 mm) against the tested food-borne pathogenic bacteria including Bacillus cereus ATCC 13061, Staphylococcus aureus ATCC 12600, Listeria monocytogenes ATCC 7644, Salmonella typhimurium ATCC 43174 and Escherichia coli O157:H7 ATCC 43889. The minimum inhibitory (MIC) and minimum bactericidal (MBC) concentration values of CTEO against the tested bacteria were found in the range of 250–1000 μg/mL, respectively. Also the CTEO had potential inhibitory effect on the cell viability of the tested pathogens at MIC concentration. The SEM analysis showed the inhibitory effect of CTEO as confirmed by considerable morphological alterations on the cell wall B. cereus ATCC 13061 and E. coli O157:H7 ATCC 43889. In addition, the CTEO revealed its mode of action on membrane integrity as confirmed by release of extracellular ATP, loss of 260-nm absorbing materials and leakage of potassium ions against food-borne pathogenic bacteria. These findings suggest that CTEO showed a broad-spectrum of antibacterial efficacy and compromise its mode of action on membrane integrity. [Copyright &y& Elsevier]