Bergamot essential oil improves CUMS-induced depression-like behaviour in rats by protecting the plasticity of hippocampal neurons.

Bergamot essential oil (BEO) is an extract of the bergamot fruit with significant neuroprotective effect. This study was to investigate the effects and the underlying mechanism of BEO in mitigating depression. GC-MS were used to identify its constituents. Antidepressive properties of BEO were evaluated by sucrose preference test (SPT), force swimming test (FST) and open field test (OFT). Nissl staining was used to determine the number of Nissl bodies in hippocampus (HIPP) of rats. Changes in HIPP dendritic length and dendritic spine density were detected by Golgi-Cox staining. Immunohistochemistry and Western blot were used to detect the postsynaptic density protein-95 (PSD-95) and synaptophysin (SYP) in the HIPP of rats. The enzyme-linked immunosorbent assay was used to determine the 5-hydroxytryptamine (5-HT), insulin-like growth factor 1 (IGF-1) and interleukin-1ß (IL-1ß) in the HIPP, serum and cerebrospinal fluid (CSF) of rats. Inhaled BEO significantly improved depressive behaviour in chronic unpredictable mild stress (CUMS) rats. BEO increased Nissl bodies, dendritic length and spine density, PSD-95 and SYP protein in the HIPP. Additionally, BEO upregulated serum 5-HT, serum and CSF IGF-1, while downregulating serum IL-1ß. Collectively, inhaled BEO mitigates depression by protecting the plasticity of hippocampal neurons, hence, providing novel insights into treatment of depression.

Antiarthritic and Antinociceptive Properties of Ylang-Ylang (Cananga odorata) Essential Oil in Experimental Models.

The aim of this study was to evaluate the effect of ylang-ylang (Cananga odorata) essential oil (YEO) on models of experimental arthritis, persistent inflammation, and nociception in mice. YEO treatment at doses of 100 and 200 mg/kg reduced the infiltration of leukocytes into the joint cavities of mice submitted to zymosan-induced arthritis 6 h and 7 days after arthritis induction. At these doses, YEO treatment reduced the formation of joint edema 4 and 6 h after arthritis induction, and at a dose of 200 mg/kg, YEO treatment reduced mechanical hyperalgesia 3 and 4 h after arthritis induction. At the dose of 200 mg/kg, YEO treatment reduced interleukin-6 (IL-6) levels and cartilage destruction in the zymosan-induced arthritis model, and reduced edema formation and mechanical hyperalgesia in the model of persistent inflammation (21 days) induced by complete Freund's adjuvant (CFA) in mice. YEO treatment at a dose of 200 mg/kg reduced the nociceptive response in experimental models of nociception induced by acetic acid and formalin. The YEO treatment reduced inflammatory parameters in the experimental arthritis model, and presented antiarthritic, anti-hyperalgesic, antinociceptive, and anti-inflammatory properties.

The effect of foliar spraying of some micronutrients and lanthanum on the morphological and physiological characteristics of summer savory (Satureja hortensis L.) under hydroponic and soil conditions.

BACKGROUND: The use of lanthanum (La) as a rare element has increased in agriculture. Summer savory (Satureja hortensis L.) is an herbaceous and medicinal plant that has received attention recently. The present study aimed to investigate the effects of foliar application of zinc (Zn), copper (Cu), manganese (Mn), and La at different growth stages, including vegetative, reproductive, and vegetative to harvest on morphological and physiological traits of S. hortensis under hydroponic and soil conditions in the greenhouse. The study was arranged in a factorial experiment based on a completely randomized design (CRD) with three replications. RESULTS: Results of hydroponic condition showed that foliar application of Cu, Zn, and Mn were the most effective treatments to improve the measured morphological and physiological traits. Moreover, La was not more appropriate in increasing the quantitative and qualitative characteristics. Also, results showed that in soil cultivation, foliar application of micronutrient elements increased the ratio of leaf-to-stems, antioxidant compounds, and the percentage of essential oils, while the application of Mn, Cu, Zn, and La did not have positive effects on the increase in vegetative characteristics in all three stages of foliar application compared with the control treatment. CONCLUSIONS: Cu, Zn, and Mn in appropriate concentrations can increase growth and physiological characteristics of summer savory in hydroponic systems.

Phytochemical and morpho-physiological response of Melissa officinalis L. to different NH4+ to NO3̄ ratios under hydroponic cultivation.

BACKGROUND: The utilization of nutrition management, has recently been developed as a means of improving the growth and production of phytochemical compounds in herbs. The present study aimed to improve the growth, physiological, and phytochemical characteristics of lemon balm (Melissa officinalis L.) using different NH4+ (ammonium) to NO3̄ (nitrate) ratios (0:100, 25:75, 50:50, 75:25 and 100:0) under floating culture system (FCS). RESULTS: The treatment containing 0:100 - NH4+:NO3̄ ratio showed the most remarkable values for the growth and morpho-physiological characteristics of M. officinalis. The results demonstrated that maximum biomass (105.57 g) earned by using the ratio of 0:100 and minimum at 75:25 ratio of NH4+: NO3̄. The plants treated with high nitrate ratio (0:100 - NH4+:NO3̄) showed the greatest concentration of total phenolics (60.40 mg GAE/g DW), chlorophyll a (31.32 mg/100 g DW), flavonoids (12.97 mg QUE/g DW), and carotenoids (83.06 mg/100 g DW). Using the 75:25 - NH4+:NO3̄ ratio caused the highest dry matter (DM), N and K macronutrients in the leaves. The highest antioxidant activity by both DPPH (37.39 µg AAE/mL) and FRAP (69.55 mM Fe++/g DW) methods was obtained in 75:25 - NH4+:NO3̄ treatment. The p-coumaric acid as a main abundant phenolic composition, was detected by HPLC analysis as the highest content in samples grown under 0:100 - NH4+:NO3̄ treatment. Also, the major compounds in M. officinalis essential oil were identified as geranial, neral, geranyl acetate and geraniol by GC analysis. With increasing NO3̄ application, geraniol and geranyl acetate contents were decreased. CONCLUSIONS: The findings of present study suggest that the management of NH4+ to NO3̄ ratios in nutrient solutions could contribute to improving growth, physiological and phytochemical properties of M. officinalis. The plants treated with high nitrate ratio (especially 0:100 - NH4+:NO3̄) showed the greatest effects on improving the growth and production of morpho-physiological and phytochemical compounds. By comprehensively understanding the intricate dynamics among nitrogen sources, plants, and their surroundings, researchers and practitioners can devise inventive approaches to optimize nitrogen management practices and foster sustainable agricultural frameworks.

Investigating foliar application of bulk and nanoparticles titanium dioxide on fennel productivity to mitigate the negative effects of saline irrigation water.

BACKGROUND: Fennel essential oils are fragrance compounds used in food and pharmaceutical sectors. One of the major impediments to expansion of fennel farming in Egypt's reclamation areas is saline water. Titanium dioxide (TiO2) or TiO2 nano particles (TiO2NP) can be utilized to boost the yield of aromatic plants cultivated under saline irrigation water. Saline water, particularly which contains sodium chloride can harm fennel plant; consequently, it was predicted that fennel production would fail in Egypt's reclaimed area, where the primary source of irrigation is groundwater consisting sodium chloride. This study sought to help fennel respond to sodium chloride by applying Ti forms to their leaves in order to reduce the detrimental effects of sodium chloride on them for expanding their production in the newly reclamation areas as a natural source of essential oil. Ti forms were applied as foliar application at 0, 0.1, 0.2 TiO2, 0.1 TiO2NP, and 0.2 TiO2NP, mM under irrigation with fresh water (0.4 dS m-1), or saline water (51.3 mM or 4.7 dS m-1). RESULTS: Plants exposed to 0.1 mM TiO2NP under fresh water resulted in the maximum values of morphological characters, estragole, oxygenated monoterpenes and photosynthetic pigments; while those subjected to 0.1 mM TiO2NP under saline water gave the greatest values of essential oil, proline, antioxidant enzymes and phenols. The greatest amounts of soluble sugars were recorded with 0.2 mM TiO2NP irrigated with saline water. Plants subjected to 0 mM TiO2 under saline water produced the greatest values of flavonoids, hydrogen peroxide and malondialdehyde. CONCLUSION: To mitigate the negative effects of salty irrigation water on fennel plant production, TiO2NP application is suggested as a potential strategy.

Effects of MhMYB1 and MhMYB2 transcription factors on the monoterpenoid biosynthesis pathway in l-menthol chemotype of Mentha haplocalyx Briq.

MAIN CONCLUSION: Transcription factors MhMYB1 and MhMYB2 correlate with monoterpenoid biosynthesis pathway in l-menthol chemotype of Mentha haplocalyx Briq, which could affect the contents of ( -)-menthol and ( -)-menthone. Mentha haplocalyx Briq., a plant with traditional medicinal and edible uses, is renowned for its rich essential oil content. The distinct functional activities and aromatic flavors of mint essential oils arise from various chemotypes. While the biosynthetic pathways of the main monoterpenes in mint are well understood, the regulatory mechanisms governing different chemotypes remain inadequately explored. In this investigation, we identified and cloned two transcription factor genes from the M. haplocalyx MYB family, namely MhMYB1 (PP236792) and MhMYB2 (PP236793), previously identified by our research group. Bioinformatics analysis revealed that MhMYB1 possesses two conserved MYB domains, while MhMYB2 contains a conserved SANT domain. Yeast one-hybrid (Y1H) analysis results demonstrated that both MhMYB1 and MhMYB2 interacted with the promoter regions of MhMD and MhPR, critical enzymes in the monoterpenoid biosynthesis pathway of M. haplocalyx. Subsequent virus-induced gene silencing (VIGS) of MhMYB1 and MhMYB2 led to a significant reduction (P < 0.01) in the relative expression levels of MhMD and MhPR genes in the VIGS groups of M. haplocalyx. In addition, there was a noteworthy decrease (P < 0.05) in the contents of ( -)-menthol and ( -)-menthone in the essential oil of M. haplocalyx. These findings suggest that MhMYB1 and MhMYB2 transcription factors play a positive regulatory role in ( -)-menthol biosynthesis, consequently influencing the essential oil composition in the l-menthol chemotype of M. haplocalyx. This study serves as a pivotal foundation for unraveling the regulatory mechanisms governing monoterpenoid biosynthesis in different chemotypes of M. haplocalyx.

Cell-type specific localization and biological activity of the volatiles from the endemic species Chaerophyllum coloratum L.

MAIN CONCLUSION: New findings are presented for Chaerophyllum coloratum L. on the volatile composition of the essential oil, based on data of hydrosol and fresh plant material, light and electron microscopy of leaves, and cytotoxic and antiviral activity. The widespread Apiaceae family includes many well-known and economically important plants that are cultivated as food or spices. Many produce essential oils and are generally a source of secondary metabolites and compounds that have numerous applications in daily life. In this study, the chemical composition of volatile organic compounds (VOCs), ultrastructure and biological activity of the Mediterranean endemic species Cheaerophyllum coloratum L. are investigated, as literature data for this plant species are generally very scarce. The essential oil and hydrosol were extracted from the air-dried leaves by hydrodistillation and the chemical composition of both extracts was analysed by GC-MS in conjunction with headspace solid-phase microextraction (HS-SPME) of VOCs from the hydrosol and the fresh plant material. In the composition of the essential oil, the oxygenated sesquiterpenes spathulenol and caryophyllene oxide were the most abundant components. In the fresh plant material, non-oxygenated sesquiterpenes dominated, with ß-caryophyllene and germacrene D being the main components. The hydrosol was dominated by monoterpenes, with the oxygenated monoterpene p-cymen-8-ol being the most abundant. Light and electron micrographs of the leaf of C. coloratum show secretory structures, and we hypothesize that glandular leaf trichomes, secretory epidermal cells and secretory canals are involved in the production of volatiles and their secretion on the leaf surface. Since the biological potential of C. coloratum is poorly investigated, we tested its cytotoxic activity on cancer and healthy cell lines and its antiviral activity on plants infected with tobacco mosiac virus (TMV). Our results dealing with the composition, ultrastructure and biological activity show that C. coloratum represent a hidden valuable plant species with a potential for future research.

Antimicrobial properties of essential oil extracted from Schizonepeta annua against methicillin-resistant Staphylococcus aureus via membrane disruption.

Schizonepeta annua (Pall.) Schischk. has long been traditionally employed in China for its anti-inflammatory, antimicrobial, and soothing properties. This study evaluates the antibacterial properties of essential oil extracted from Schizonepeta annua (SEO) and oregano (OEO) against methicillin-resistant Staphylococcus aureus (MRSA). SEO and OEO demonstrated substantial antibacterial efficacy, with SEO exhibiting significantly enhanced antibacterial activity due to its complex composition. Mechanistic investigations revealed that both essential oils disrupt bacterial membrane integrity and biosynthetic pathways, leading to the extrusion of intracellular contents. Metabolomic analyses using GC-Q-TOF-MS highlighted SEO's selective targeting of bacterial membranes, while non-targeted metabolomics indicated significant effects on MRSA's amino acid metabolism and aminoacyl-tRNA biosynthesis. These findings suggest that SEO causes considerable damage to MRSA cell membranes and affects amino acid metabolism, supporting its traditional use and highlighting its potential in treating infections. Our results offer robust theoretical support for SEO's role as an antimicrobial agent and establish a solid foundation for its practical application in combating multidrug-resistant infections.

Nanoemulsions of essential oils against multi-resistant microorganisms: An integrative review.

Microbial resistance to drugs continues to be a global public health issue that demands substantial investment in research and development of new antimicrobial agents. Essential oils (EO) have demonstrated satisfactory and safe antimicrobial action, being used in pharmaceutical, cosmetic, and food formulations. In order to improve solubility, availability, and biological action, EO have been converted into nanoemulsions (NE). This review identified scientific evidence corroborating the antimicrobial action of nanoemulsions of essential oils (NEEO) against antibiotic-resistant pathogens. Using integrative review methodology, eleven scientific articles evaluating the antibacterial or antifungal assessment of NEEO were selected. The synthesis of evidence indicates that NEEO are effective in combating multidrug-resistant microorganisms and in the formation of their biofilms. Factors such as NE droplet size, chemical composition of essential oils, and the association of NE with antibiotics are discussed. Furthermore, NEEO showed satisfactory results in vitro and in vivo evaluations against resistant clinical isolates, making them promising for the development of new antimicrobial and antivirulence drugs.

Evaluation of the activity and mechanisms of oregano essential oil against PRV in vivo and in vitro.

BACKGROUND: The Pseudorabies Virus (PRV) leading to pseudorabies and causes huge economic losses in pig industry. The development of novel PRV variations has diminished the efficacy of traditional vaccinations, and there is yet no medication that can stop the spread of PRV infection. Therefore, PRV eradication is challenging. Oregano essential oil, the plant-based ingredient for medication feed have been shown to has strong anti-herpesvirus activity, but no anti-PRV function has been reported. RESULTS: The current study assessed the anti-pseudorabies virus (PRV) activity of oregano essential oil and explored its mechanisms and most effective components against PRV. Our in vivo findings demonstrated that oregano essential oil could decrease the PRV load in tissues, mitigate tissue lesions, and enhance the survival rate of mice. The potential antiviral mechanism involves augmenting humoral and cellular immune responses in PRV-infected mice. To further investigate the most effective components of oregano essential oil against PRV, an in vitro study was conducted, revealing that oregano essential oil and its main constituents, carvacrol and thymol, all diminished PRV intracellular proliferation in vitro. Carvacrol exhibited the most potent anti-PRV effect, serving as the primary contributor to oregano essential oil's anti-PRV activity. The mechanisms underlying carvacrol's anti-PRV properties include the upregulation of cytokines TNF-α, IFN-ß, IFN-γ, IL-12, and the inhibition of PRV-induced apoptosis in BHK-21 cells. CONCLUSIONS: Our study provides an effective drug for the prevention and control of PRV infection.

Inhibitory effect and mechanism of oregano essential oil on Listeria monocytogenes cells, toxins and biofilms.

Listeria monocytogenes (L. monocytogenes) is a prevalent foodborne pathogen with a remarkable capacity to form biofilms on utensil surfaces. The Listeriolysin O (LLO) exhibits hemolytic activity, which is responsible for causing human infections. In this study, we investigated the inhibitory effect and mechanism of oregano essential oil (OEO) on L. monocytogenes, evaluated the effects on its biofilm removal and hemolytic activity. The minimum inhibitory concentration (MIC) of OEO against L. monocytogenes was 0.03 % (v/v). L. monocytogenes was treated with OEO at 3/2 MIC for 30 min the bacteria was decreased below the detection limit (10 CFU/mL) in PBS and TSB (the initial bacterial load was about 6.5 log CFU/mL). The level of L. monocytogenes in minced pork co-cultured with OEO (15 MIC) about 2.5 log CFU/g lower than that in the untreated group. The inhibitory mechanisms of OEO against planktonic L. monocytogenes encompassed perturbation of cellular morphology, elevation in reactive oxygen species levels, augmentation of lipid oxidation extent, hyperpolarization of membrane potential, and reduction in intracellular ATP concentration. In addition, OEO reduced biofilm coverage on the surface of glass slides by 62.03 % compared with the untreated group. Meanwhile, OEO (1/8 MIC) treatment reduced the hemolytic activity of L. monocytogenes to 24.6 % compared with the positive control. Molecular docking suggested carvacrol and thymol might reduce the hemolytic activity of L. monocytogenes. The results of this study demonstrate that OEO exhibits inhibitory effects against L. monocytogenes, biofilms and LLO, which had potential as natural antimicrobial for the inhibition of L. monocytogenes.

Microbiological studies on Escherichia coli and Klebsiella pneumoniae causing vaginal and urinary tract inflammation; prevalence, antibiotics-resistance and natural products susceptibility.

Great efforts have been made for controlling multidrug-resistant bacteria (MDR). The antibacterial activity of natural products is an effective strategy due to its beneficial effects on human health. This study focused on the isolation, identification, studying the prevalence and the susceptibility of Escherichia coli and Klebsiella spp. to some natural products. After isolation, the isolates primarily identified using biochemical and API tests. Then, the antibiotic susceptibility test was done to reveal the most antibiotics resistant isolates before further identification of Escherichia coli and Klebsiella pneumoniae using phoA and gyrA genes, respectively. Furthermore, the sensitivity of the most antibiotics resistant isolates to apple cider vinegar (ACV), garlic oil (GO), coconut oil (CNO), tea tree oil (TTO), and lavender oil (LO) was estimated. All tested extracts especially ACV and TTO showed good antibacterial activity against MRD selected isolates. Statistical analysis indicated that there was significant difference in ACV and TTO antibacterial response between Escherichia coli and Klebsiella pneumoniae whereas there was no significant difference between natural products activity when tested against Escherichia coli and Klebsiella pneumoniae seperatly. GC-MS spectroscopy analysis revealed the most prominent active constituents present in tested ACV and TTO. Analyzing the 16S rRNA sequence confirmed the two most MRD pathogenic isolates that showed sensitivity to ACV and TTO were Escherichia coli MS1 and Klebsiella pneumoniae MS47, respectively. Essential oils tea tree and apple cider vinegar showed good antibacterial activities against antibiotics-resistant Escherichia coli and Klebsiella pneumoniae causing vaginal and urinary tract inflammation.

Plant protein-based edible films and the effect of phenolic additives.

The use of protein-based films in food preservation has been investigated as an alternative to synthetic plastics in recent years. Being biodegradable, edible, natural, and upcycling from food waste/by-products are the benefits of protein-based edible films. Their use ensures food safety as an alternative to synthetic plastics, and their film-forming properties can be improved with the addition of bioactive compounds. This review summarizes the studies on the changes in certain quality parameters of plant protein-based films, including mechanical, physicochemical, or morphological properties with the use of different forms of phenolic additives (pure phenolics, phenolic extracts, essential oils) and their application in foods during storage. Phenolics affect protein film matrix formation by acting as plasticizers or cross-linking agents and confer additional health benefits by providing bioactive properties to protein films. On the other hand, the effects were more pronounced with the use of their oxidized forms or higher concentrations. Consequently, phenolic additives have great potential to improve protein films, but further studies are still required to investigate the effects and mechanisms of phenolic addition to the protein-based films.

Improving nitrogen content in soil and lemon balm (Melissa officinalis L.) yield by purple nonsulfur bacteria Rhodopseudomonas palustris in two consecutive seasons.

The study was conducted to assess the effects of nitrogen (N)-fixing purple nonsulfur bacteria (PNSB) Rhodopseudomonas palustris TLS06, VNW02, VNW64, and VNS89 on soil fertility, N uptake, essential oil (EO) content, growth, and yield of lemon balm. The experiment followed a completely randomized block design with 9 treatments and 3 replications. The treatments consisted of (i) applying 100% N as the recommended fertilizer rate (RFR), (ii) applying 85% N as RFR, (iii) applying 70% N as RFR, (iv) applying 55% N as RFR, (v) the treatment ii combined with N-PNSB, (vi) the treatment iii combined with N-PNSB, (vii) the treatment iv combined with N-PNSB, (viii) 0% as RFR combined with N-PNSB, and (ix) 0% N as RFR. The results showed that applying N-PNSB increased the plant height, and the number of primary branches in both seasons. In addition, the treatment without N fertilizer combined with N-PNSB increased stem leaf biomass by 41.2 and 50.3% in both seasons as compared with the treatment without neither N fertilizer nor N-PNSB. For soil properties, among treatments without N fertilizer, the treatment with N-PNSB increased concentrations of NH4+, soluble P, and exchangeable K+ by 41.3, 41.4, and 26.8%, respectively, as compared with the treatment without N-PNSB at the end of the second season. Applying 85% N as RFR combined with N-PNSB had a greater yield by 5.78-11.8% as compared with the treatment with 100% N as RFR, and a greater EO content by 23% as compared with the treatment with 85% N as RFR.

Synergistic interactions of essential oil components with antibiotics against multidrug-resistant Corynebacterium striatum.

AIM: In this study, it was aimed to examine the antibacterial activity of the essential oil components (EOCs), carvacrol (CAR), cinnamaldehyde (CIN), thymol (TH), alpha pinene (α-PN), eucalyptol (EU), limonene (LIM), and the antibiotics, linezolid (LZD), vancomycin (VAN), gentamicin (GEN), ciprofloxacin (CIP), clindamycin (CLN), and penicillin (PEN) against 50 multidrug resistant Corynebacterium striatum strains, and the synergistic interactions of CAR and CIN with the antibiotics against 10 randomly selected Coryne. striatum strains to explore synergistic interactions to determine if their combined use could enhance antibiotic activity and potentially reduce resistance. METHODS AND RESULTS: The activity of the EOCs and the antibiotics against Coryne. striatum strains isolated from clinical specimens, was examined by broth microdilution method. The synergistic interactions of the EOCs with the antibiotics against 10 randomly selected Coryne. striatum strains were determined by checkerboard method. EOCs, CIN, and CAR and antibiotics, LZD, VAN, GEN, CIP, and CLN were detected to have antibacterial activity against Coryne. striatum strains alone and either synergistic interactions were observed in combinations of the antibiotics with EOCs. CONCLUSIONS: All Coryne. striatum strains were determined to be susceptible to VAN and LZD and resistant to GEN, PEN, CIP, and CLN. Synergistic interactions were observed in all combinations of antibiotics tested with CAR and CIN.

Amoebicidal activity of essential oils and essential oil-based microemulsions of Aloysia citrodora Ortega ex Pers., Cymbopogon winterianus Jowitt ex Bor, and Ocimum gratissimum L. against Acanthamoeba polyphaga trophozoites.

AIMS: Evaluate the in vitro efficacy of the essential oils derived from Aloysia citrodora (Verbenaceae), Cymbopogon winterianus (Poaceae), and Ocimum gratissimum (Lamiaceae) against Acanthamoeba polyphaga trophozoites. Additionally, microemulsions formulated with these essential oils, along with their major components, were analyzed. METHODS AND RESULTS: The prepared microemulsions were characterized using polarized light microscopy and rheological techniques. The amoebicidal activity was determined by measuring the inhibitory concentration (IC50). Flow cytometry was employed to detect membrane damage and alterations in trophozoites size. The results revealed transparent and thermodynamically stable microemulsions. The essential oil from O. gratissimum exhibited a lower IC50, with values of 280.66 and 47.28 µg ml-1 after 24 and 48 h, respectively. When microemulsions containing essential oils were tested, the IC50 values exhibited a reduction of over 80% after 24 h. Particularly, eugenol, a constituent of the O. gratissimum essential oil, displayed higher amoebicidal activity. The essential oils also caused damage to the cell membrane, resulting in the subsequent death of the trophozoites. CONCLUSIONS: The EOs of A. citrodora, C. winterianus, and O. gratissimum and their microemulsions showed antiparasitic effect against A. polyphaga trophozoites, representing promising alternatives for the treatment of diseases caused by this protozoan.

Antimicrobial activity of eight plant essential oils having antioxidant property against spoilage microbes.

AIMS: To identify efficient, broad-spectrum, and non-toxic preservatives for natural agricultural products, eight essential oils were screened for high inhibitory and antioxidant activities against spoilage microbes. METHODS AND RESULTS: The zone of inhibition test and minimum inhibitory concentration (MIC) assay were performed to assess the antimicrobial activity of eight essential oils against Bacillus subtilis, Staphylococcus aureus, Penicillium, Saccharomyces, and Escherichia coli. Among the eight essential oils, garlic and rose essential oils exhibited the best inhibitory effects, their MICs against the spoilage microbes were 40-640 µl/l and 10-320 µl/l, respectively. In addition, the antioxidant activities of eight essential oils were compared using the DPPH and ABTS radical-scavenging assays and the reducing power assay. Eight essential oils had antioxidant capacity, among which rosemary, thyme, rose, and tea tree essential oils performed the best. Moreover, the combination of thyme and rose exerted stronger antioxidant activity. Therefore, the concentrations of rose and garlic, and thyme essential oils were optimized using response surface methodology to obtain the optimal composite ratios, which were 1254 µl/l, 640 µl/l, and 1228 µl/l for rose, garlic, and thyme, respectively. The DPPH free radical-scavenging rate detected using this formulation was 50.2%, basically consistent with the prediction. Zone of inhibition diameters with the compound essential oil, against five spoilage microbes, were all greater than 45 mm. CONCLUSIONS: The essential oil combination had high antimicrobial, against agricultural product spoilage microbes, and antioxidant activities.

Evaluation of inhibitory activity of essential oils and natural extracts on foodborne viruses.

AIMS: Enteric viruses are recognized as a major concern in health care and in the food sector in Canada. Novel clean-label strategies for controlling enteric viruses are sought in the food industry. In this study, we examined the antiviral potential of plant extracts and essential oils on murine norovirus 1 (MNV-1), hepatitis A virus (HAV), and herpes simplex virus 1 (HSV-1). METHODS AND RESULTS: Inactivation of the viruses by grape seed, blueberry, green tea, and cranberry extracts and by rosemary and thyme essential oils was measured using plaque formation assay. Concentrations ranging from 50 to 200 000 ppm with a contact time of 90 min were tested. Grape seed extract at 10 000 ppm was the most effective (P < 0.05) at reducing MNV-1 and HAV infectious titers, respectively, by 2.85 ± 0.44 log10 and 1.94 ± 0.17 log10. HSV-1 titer was reduced by 3.81 ± 0.40 log10 at 1000 ppm grape seed extract. CONCLUSIONS: Among the plant products tested, grape seed extract was found the most effective at reducing the infectious titers of MNV-1, HAV, and HSV.

Ibuprofen as an adjuvant to conventional antimicrobials and essential oil compounds against skin pathogens.

AIMS: Antimicrobial resistance continues to be a growing concern, resulting in increased use of drug combinations. Antibiotic adjuvants are an emerging strategy that may potentiate an antibiotics efficacy. Ibuprofen's polypharmacological properties have been investigated for their antimicrobial and host-modulating potential. This study aimed to investigate the potential of a novel multidrug combination involving ibuprofen, essential oil compounds (EOCs), and conventional antimicrobials against skin pathogens. METHODS AND RESULTS: The minimum inhibitory concentrations of ibuprofen, conventional antimicrobials, and EOCs were determined and then combined and tested against 14 (reference and clinical) skin pathogens. The cytotoxicity was analysed using the MTT assay, whilst the anti-inflammatory effects were evaluated using lipopolysaccharide activated RAW264.7 murine macrophages. Four pairwise (Ibuprofen and antibiotic) (ΣFIC 0.33-0.50) and three triple (Ibuprofen and antibiotic with EOC) (ΣFIC 0.44-0.47) synergistic antimicrobial interactions were identified. These combinations demonstrated cell viability of 77.59%-100%. No combination significantly reduced nitric oxide production. CONCLUSION: The results from this study provide insight into the potential of a multidrug combination involving ibuprofen with conventional antimicrobials and EOCs against common skin pathogens.

Controlling Staphylococcus aureus biofilm on food contact surfaces: the efficacy of Oliveria decumbens essential oil and its implications on biofilm-related genes.

AIMS: This study aimed to investigate the effect of Oliveria decumbens essential oil (Od-EO) on the phenotypic properties and gene expression of Staphylococcus aureus biofilm on commonly used food contact surfaces. METHODS AND RESULTS: The minimum inhibitory concentration and minimum bactericidal concentration of Od-EO on S. aureus ATCC25923 were determined to be 0.5 and 1 µl/ml, respectively. Crystal violet staining, scanning electron microscopy (SEM), biofilm metabolic activity evaluation, and real-time PCR analysis were used to assess the anti-biofilm properties of Od-EO. The results demonstrated that Od-EO exhibited significant anti-biofilm properties against S. aureus and effectively reduced the metabolic activity of biofilm cells. Furthermore, the inhibitory effects of Od-EO on biofilm formation were more pronounced on stainless steel (SS) compared to high-density polyethylene (HDPE) surfaces. Real-time PCR analysis revealed that Od-EO downregulated the expression of biofilm-related genes (icaA, icaD, clfA, clfB, FnbA, FnbB, and hld) in S. aureus grown on SS, while the expression levels of all studied genes except hld in the biofilm formed on HDPE remained unchanged or increased. CONCLUSIONS: One of the main anti-biofilm mechanisms of the Od-EO on the HDPE is related to the disturbance in the QS of the cells. These findings highlight the potential of Od-EO as an effective agent for controlling and inhibiting S. aureus biofilm in the food industry and its potential use in disinfectant compounds.