Laurus nobilis, Zingiber officinale and Anethum graveolens Essential Oils: Composition, Antioxidant and Antibacterial Activities against Bacteria Isolated from Fish and Shellfish

Antioxidant and antimicrobial effect of sodium alginate nanoemulsion coating enriched with oregano essential oil (Origanum vulgare L.) and Trachyspermum ammi oil (Carum cupticum) on food pathogenic bacteria

Today, microbial contamination in food is one of the major problems of the food industry and public health in general around the world. Foodborne illnesses, such as diarrheal diseases, kill many people around the world each year. The general objective of this study was to evaluate the antioxidant and antibacterial activity of sodium alginate nanoemulsion coating incorporated with oregano essential oil (Origanum vulgare L.) and Trachyspermum ammi oil (Carum cupticum) on Escherichia coli, and Listeria monocytogenes. To achieve this study, fresh chicken meat was used for this experiment. Listeria monocytogenes ATCC 19111 and Escherichia coli ATCC 35218 were obtained from the American Type Culture Collection (Manassas, VA, USA). After the preparation of the essential oil, the chemical composition of this essential oil was determined by using (GC-MS). The physicochemical properties of the nanoemulsion essential oil prepared were characterized and their antimicrobial activity was evaluated. The results showed that the GC-MS analysis of the volatile constituents of the Origanum vulgare essential oil compounds allowed the identification of 19 compounds representing 93.72% of the total oil. The major components detected in Origanum vulgare essential oil were pulegone (49.25%), eucalyptol (18.23%), and menthone (12.37%). About the Carum cupticum essential oil, 21 compounds representing 98.5% of the total oil were identified. The major components detected in Origanum vulgare essential oil were thymol (23.3%), p-cymene (17.5%), and γ-terpinene (16.8%). The best z-average (d.nm) is 483.4 nm (Carum cupticum essential oil + nano) followed by 470.1 nm (nanochitosan). The results of the antimicrobial test showed that the different preparations have a good inhibitory activity for the in vitro growth of Escherichia coli and Listeria monocytogenes. According to the MIC and MBC results of this study, the nanoemulsion also presented a good bacteriostatic activity against the two pathogenic bacteria tested in this study.

Neuroprotective and anti-amnesic effects of Laurus Nobilis essential oil against scopolamine-induced memory deficits in mice brain

ETHNOPHARMACOLOGICAL RELEVANCE

Laurus nobilis L. (Lauraceae family) has been widely used in traditional Tunisian medicine for the treatment of different health problems such as rheumatism and some neurological disorders.

AIM

In this study, the essential oil obtained from Laurus nobilis L. species from Tunisia (LEO) was studied for its chemical composition and anti-amnesic activities on memory impairment caused by scopolamine injection in mice. The major compounds of LEO oil, 1,8-cineole and, α-terpinyl acetate were docked with AChE (Acetylcholinesterase), using Autodock Vina and Discovery Studio visualizer software.

MATERIALS AND METHODS

The Morris water maze (MWM) tests and the Y maze were used to assess the anti-amnesic effects of LEO in mice with scopolamine-induced memory impairments. In brain tissues, the levels of biomarkers, enzyme activity, and protein expression related to the cholinergic system were measured.

RESULTS

Chronic administration of scopolamine led to a significant decline in cognitive performance in both the Morris Water Maze (MWM) and Y maze tests, accompanied by pronounced oxidative damage and a significant increase in acetylcholinesterase activity compared to the other groups. However, compared to the scopolamine group, treatment with LEO (100 mg/kg) significantly enhanced cognitive function and ameliorated the oxidative damage (p < 0.05 versus scopolamine) CONCLUSION: This study demonstrates the beneficial effect of LEO on scopolamine-induced dementia in mice, potentially achieved through the modulation of cholinergic activity and antioxidant properties. The docking analysis of the major compounds, 1,8-cineole and α-terpinyl acetate, further substantiates their potential as memory enhancers.

The synergistic effects of four medicinal plant seeds and chelated minerals on the growth, immunity, and antioxidant capacity of rainbow trout (Oncorhynchus mykiss)

Trace minerals are essential for the normal functioning of all living organisms. In addition, the positive effects of several medicinal plants have been demonstrated in aquaculture. In the present study, we aimed to investigate the effects of a mixture of medicinal plants and test the synergistic effects of medicinal plants and chelated minerals on fish growth and immunity. Thus, in the present experiment we evaluated the combined effects of a commercial chelated mineral source (BonzaFish®) and a mixture of 4 medicinal plants including caraway (Carum carvi), green cumin (Cuminum cyminum), dill (Anethum graveolens), and anise (Pimpinella anisum). Rainbow trout (Oncorhynchus mykiss) fingerlings (n = 225) were fed with five formulated diets, including a control diet (basal diet), Bonza (basal diet + 1 g/kg BonzaFish®), Z-5 (basal diet + 1 g/kg BonzaFish® + 5 g/kg mixture of plant seeds), Z-10 (basal diet + 1 g/kg BonzaFish®+10 g/kg mixture of plant seeds), Z-20 (basal diet+1 g/kg BonzaFish®+20 g/kg mixture of plant seeds) for 6 weeks. In diets including BonzaFish®, 50% of the inorganic mineral premix was replaced by BonzaFish®. Results revealed that fish receiving the Z-20 diet showed the best performance in terms of growth parameters, followed by the Bonza treatment (P < 0.05). The highest protease activity was found in Z-5 and Z-10. RBCs were highest in Z-5, while the highest WBCs and hemoglobin were found in the Bonza treatment followed by Z-20. Stress biomarkers were lowest in the Z-20 treatment. Results showed that Z-20 could elicit the most robust immunological responses of lysozyme activity, ACH50, total Ig, C3, and C4. In conclusion, chelated minerals could be successfully used to replace 50% of mineral premix with no negative impacts on fish growth and together with four medicinal plants, could enhance rainbow trout overall growth performance and immunity.

Phytochemistry and Biological Activities of Essential Oils from Six Aromatic Medicinal Plants with Cosmetic Properties

In this work, the chemical composition and antioxidant and antimicrobial activities of the essential oils (EOs) of six species-Laurus nobilis, Chamaemelum nobile, Citrus aurantium, Pistacia lentiscus, Cedrus atlantica, and Rosa damascena-have been studied. Phytochemical screening of these plants revealed the presence of primary metabolites, namely, lipids, proteins, reducing sugars, and polysaccharides, and also secondary metabolites such as tannins, flavonoids, and mucilages. The essential oils were extracted by hydrodistillation in a Clevenger-type apparatus. The yields are between 0.06 and 4.78% (mL/100 g). The analysis of the chemical composition carried out by GC-MS showed the presence of 30 to 35 compounds and represent between 99.97% and 100% of the total composition of EOs, with a variation in the chemical composition detected at the level of the majority compounds between these species. Indeed, in the EO of Laurus nobilis, 1,8-cineole (36.58%) is the major component. In Chamaemelum nobile EO, the most abundant compound is angelylangelate (41.79%). The EO of Citrus aurantium is rich in linalool (29.01%). The EO of Pistacia lentiscus is dominated by 3-methylpentylangelate (27.83%). The main compound of Cedrus atlantica is β-himachalene (40.19%), while the EO of Rosa damascenaa flowers is rich in n-nonadecane (44.89%). The analysis of the similarity between the EOs of the plants studied by ACH and ACP showed that the chemical composition of the EOs makes it possible to separate these plants into three groups: the first represented by Chamaemelum nobile, because it is rich in oxygenated monoterpenes, the second defined Cedrus atlantica and Rosa damascena, which are rich in sesquiterpenes, and the third gathers Pistacia lentiscus, Laurus nobilis and Citrus aurantium, which are composed of oxygenated sesquiterpenes and monoterpenes (these three species are very close). The study of the antioxidant activity showed that all the EOs tested have a high capacity for scavenging free radicals from DPPH. The EOs of Laurus nobilis and Pistacia lentiscus showed the highest activity, 76.84% and 71.53%, respectively, followed by Cedrus atlantica EO (62.38%) and Chamaemelum nobile (47.98%) then Citrus aurantium EO (14.70%). Antimicrobial activity EO was tested against eight bacterial strains and eight fungal strains; the results showed that EOs exhibit significant bactericidal and fungicidal activities against all the microorganisms tested, of which the MICs of the bacterial strains start with 5 mg/mL, while the MICs of the fungal strains are between 0.60 mg/mL and 5 mg/mL. Thus, these EOs rich in antimicrobial and antioxidant components can serve as a natural alternative; this confirms their use as additives in cosmetics.

Molecular Identification of Bacteria Isolated from Marketed Sparus aurata and Penaeus indicus Sea Products: Antibiotic Resistance Profiling and Evaluation of Biofilm Formation

BACKGROUND

Marketed fish and shellfish are a source of multidrug-resistant and biofilm-forming foodborne pathogenic microorganisms.

METHODS

Bacteria isolated from Sparus aurata and Penaeus indicus collected from a local market in Hail region (Saudi Arabia) were isolated on selective and chromogenic media and identified by using 16S RNA sequencing technique. The exoenzyme production and the antibiotic susceptibility patterns of all identified bacteria were also tested. All identified bacteria were tested for their ability to form biofilm by using both qualitative and quantitative assays.

RESULTS

Using 16S RNA sequencing method, eight genera were identified dominated by Vibrio (42.85%), Aeromonas (23.80%), and Photobacterium (9.52%). The dominant species were V. natrigens (23.8%) and A. veronii (23.80%). All the identified strains were able to produce several exoenzymes (amylases, gelatinase, haemolysins, lecithinase, DNase, lipase, and caseinase). All tested bacteria were multidrug-resistant with a high value of the multiple antibiotic index (MARI). The antibiotic resistance index (ARI) was about 0.542 for Vibrio spp. and 0.553 for Aeromonas spp. On Congo red agar, six morphotypes were obtained, and 33.33% were slime-positive bacteria. Almost all tested microorganisms were able to form a biofilm on glass tube. Using the crystal violet technique, the tested bacteria were able to form a biofilm on glass, plastic, and polystyrene abiotic surfaces with different magnitude.

CONCLUSIONS

Our findings suggest that marketed S. aurata and P. indicus harbor various bacteria with human interest that are able to produce several related-virulence factors.

Thymus musilii Velen. Methanolic Extract: In Vitro and In Silico Screening of Its Antimicrobial, Antioxidant, Anti-Quorum Sensing, Antibiofilm, and Anticancer Activities

Thymus musilii Velen. is a rare plant species cultivated in the Ha'il region (Saudi Arabia) under greenhouse conditions. In this work, we described, for the first time, the phytochemical composition, antimicrobial, antioxidant, anti-quorum sensing, and anticancer activities of T. musilii methanolic extract using both experimental and computational approaches. The obtained results showed the identification of eight small-like peptides and eighteen phyto-compounds by using high-resolution liquid chromatography-mass spectrometry (HR-LCMS) dominated mainly by compounds belonging to isoprenoid, fatty acyl, flavonoid, and alkaloid classes. The tested extracts exhibited high antifungal and antibacterial activity with the mean diameter of growth inhibition zones ranging from 12.33 ± 0.57 mm (Pseudomonas aeruginosa ATCC 27853) to 29.33 ± 1.15 mm (Candida albicans ATCC 10231). Low minimal inhibitory concentrations were recorded for the tested micro-organisms ranging from 0.781 mg/mL to 12.5 mg/mL. While higher doses were necessary to completely kill all tested bacterial and fungal strains. Thyme extract was able to scavenge DPPH^•, ABTS^•+, β-carotene, and FRAP free radicals, and the IC₅₀ values were 0.077 ± 0.0015 mg/mL, 0.040 ± 0.011 mg/mL, 0.287 ± 0.012 mg/mL, and 0.106 ± 0.007 mg/mL, respectively. The highest percentage of swarming and swimming inhibition was recorded at 100 µg/mL with 39.73 ± 1.5% and 25.18 ± 1%, respectively. The highest percentage of biofilm inhibition was recorded at 10 mg/mL for S. typhimurium ATCC 14028 (53.96 ± 4.21%) and L. monocytogenes ATCC 7644 (49.54 ± 4.5 mg/mL). The in silico docking study revealed that the observed antimicrobial, antioxidant, and anticancer activities of the constituent compounds of T. musilii are thermodynamically feasible, notably, such as those of the tripeptides (Asn-Met-His, His-Cys-Asn, and Phe-His-Gln), isoprenoids (10-Hydroxyloganin), and diterpene glycosides (4-Ketoretinoic acid glucuronide).

Chemical Composition and Antimicrobial Activity of Essential Oils from Three Mediterranean Plants against Eighteen Pathogenic Bacteria and Fungi

The chemical composition and antimicrobial activity of essential oils (EOs) obtained from three medicinal plants of the Moroccan flora were evaluated. The chemical composition of EOs of Thymus leptobotrys, Laurus nobilis and Syzygium aromaticum was determined using a gas chromatograph coupled with mass spectrometry. Carvacrol (75.05%) was the main constituent of T. leptobotrys EOs, while 1,8-cineole (31.48%) and eugenol (82.16%) were the predominant components of L. nobilis and S. aromaticum EOs, respectively. The antimicrobial activity of the EOs was evaluated qualitatively and quantitatively against 18 microbial strains pathogenic to humans by using the disc diffusion method, and by measuring the minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC). The EOs of T. leptobotrys were the most active against the strains tested, with inhibitory zone values ranging from 7.00 to 45.00 mm, and MIC and MMC values ranging from 0.312 to 80.00 mg/mL. In many cases, these EOs exhibited higher antibacterial and antifungal activities than the chemical compounds ciprofloxacin and fluconazole, respectively. This high antimicrobial activity can be ascribed to their richness in carvacrol. The EOs of T. leptobotrys, L. nobilis, and S. aromaticum could be considered a promising alternative to replace chemical antimicrobials, and a readily available natural source of bioactive compounds.

The Use of Cinnamon Essential Oils in Aquaculture: Antibacterial, Anesthetic, Growth-Promoting, and Antioxidant Effects

Cinnamon essential oils (EOs) are widely known for their pharmaceutical properties; however, studies investigating the use of these EOs in aquaculture are scarce. The aims of this study were to evaluate the anesthetic effect of bathing silver catfish (Rhamdia quelen) with Cinnamomum cassia EO (CCEO) and its nanoemulsion (NCCEO); the growth-promoting and antioxidant effects of dietary supplementation with CCEO in silver catfish; and the in vitro antibacterial effect of CCEO, NCCEO, and Cinnamomum zeylanicum EO (CZEO) against bacteria isolated from diseased silver catfish. The two cinnamon EOs showed promising antibacterial activity, which was potentiated by the nanoemulsion. CCEO showed satisfactory anesthetic activity in silver catfish, and its nanoemulsion intensified the sedative activity. Supplementation of 1.0 mL CCEO per kg of diet for 60 days increased weight, length, and weight gain when compared to the control group, evidencing the growth-promoting activity of this EO. Dietary supplementation of CCEO for 30 and 60 days also showed an antioxidant effect, as it decreased levels of thiobarbituric acid reactive species and increased the superoxide dismutase activity in the liver of silver catfish. Therefore, cinnamon EOs have a promising use in aquaculture.

Chemical Profile, Antibacterial and Antioxidant Potential of Zingiber officinale Roscoe and Elettaria cardamomum (L.) Maton Essential Oils and Extracts

The aim of this work was to study the chemical composition of the essential oil extracted from ginger rhizomes (Zingiber officinale Roscoe) and cardamom seeds (Elettaria cardamomum (L.) Maton). Using gas chromatography coupled with mass spectrometry (GC/MS), a total of 43 compounds were identified in ginger essential oil and 17 compounds in cardamom. The most abundant components, respectively, were zingiberene (22.18%) and 1.8-cinéol (43.47%). Essential oils, methanol, ethanol and chloroform extracts for both plants were tested against nine bacteria and yeast. The highest sensitivity was noticed against Staphylococcus aureus with a 25 mm inhibition zone. The antioxidant potency of both oils and extracts were measured using DPPH (1,1-diphenyl-2-picryl hydrazyl) free radical scavenging and the ferric reducing power (FRP) method; the ethanolic extract of cardamom fruits exhibited the best results for both tests, with an IC 50 = 0.423 ± 0.015 mg/mL and 95.03 ± 0.076 FRP mg AAE/g.

Biological control of Citrus brown spot pathogen, "Alternaria alternata" by different essential oils

The antifungal effects of laurel, myrtle and peppermint essential oils and their combinations were investigated in vitro on two strains of Alternaria alternata mycelial growth and in vivo on detached Citrus leaf disease incidence. Myrtle essential oil was rich in α-pinene and 1,8-cineole while peppermint essential oil in menthol and menthone. 1,8-Cineole was the main component of the essential oils from laurel, laurel + myrtle and peppermint + laurel. The combined peppermint and myrtle essential oil was characterized by the predominance of menthol and 1,8-cineole. All tested essential oils, incorporated in potato-dextrose agar, inhibited A. alternata mycelial growth and had a fungistatic effect at concentration 3 mg/mL of medium. A great synergism was detected between peppermint and laurel essential oils against the two strains of A. alternata. The combined laurel and peppermint essential oil reduced mycelial growth rates of inoculated detached leaves at concentration above 1.5 mg/mL.

Bay Laurel (Laurus nobilis L.) Essential Oil as a Food Preservative Source: Chemistry, Quality Control, Activity Assessment and Applications to Olive Industry Products

Essential oils (EOs) find application as flavoring agents in the food industry and are also desirable ingredients as they possess preservative properties. The Mediterranean diet involves the use of a lot of herbs and spices and their products (infusions, EOs) as condiments and for the preservation of foods. Application of EOs has the advantage of homogeneous dispersion in comparison with dry leaf use in small pieces or powder. Among them, Laurus nobilis (bay laurel) L. EO is an interesting source of volatiles, such as 1,8-cineole and eugenol, which are known for their preservative properties. Its flavor suits cooked red meat, poultry, and fish, as well as vegetarian dishes, according to Mediterranean recipes. The review is focused on its chemistry, quality control aspects, and recent trends in methods of analysis and activity assessment with a focus on potential antioxidant activity and applications to olive industry products. Findings indicate that this EO is not extensively studied in comparison with those from other Mediterranean plants, such as oregano EO. More work is needed to establish authenticity and activity methods, whereas the interest for using it for the preparation of flavored olive oil or for the aromatization and preservation of table oils must be further encouraged.

Antimicrobial effect of laurel essential oil nanoemulsion on food-borne pathogens and fish spoilage bacteria

This research aimed to apply nanotechnology for nanoformulation of Laurus nobilis essential oil (EO) by ultrasonic emulsification method and characterization of nano-form: particle size, viscosity, polydispersity index, thermodynamic stability, and surface tension. The antimicrobial activity of laurel EO nanoemulsion (LEON) and laurel EO was also investigated against a panel of ten food-borne pathogens and fish spoilage bacteria. The GC-MS analysis of EO revealed that 1,8-Cineole was the main volatile compound. According to disc-diffusion results, LEON was more effective against Gram-positive pathogen bacteria of Staphylococcus aureus and Enterococcus faecalis than EO. Laurel oil demonstrated a higher inhibitory effect against fish spoilage bacteria (6.19 to 18.5 mm). The MICs values of LEON and laurel EO ranged from 6.25 to >25 mg/mL and from 1.56 to >25 mg/mL, respectively. Nanoemulsion and oil exhibited the best bactericidal activity against Pseudomonas luteola. Therefore, LEON can be developed as a natural antimicrobial agent in food industry.

Zingiber officinale: A Systematic Review of Botany, Phytochemistry and Pharmacology of Gut Microbiota-Related Gastrointestinal Benefits

Ginger (Zingiber officinale Rosc.) is a traditional edible medicinal herb with a wide range of uses and long cultivation history. Fresh ginger (Zingiberis Recens Rhizoma; Sheng Jiang in Chinese, SJ) and dried ginger (Zingiberis Rhizoma; Gan Jiang in Chinese, GJ) are designated as two famous traditional Chinese herbal medicines, which are different in plant cultivation, appearances and functions, together with traditional applications. Previous researches mainly focused on the differences in chemical composition between them, but there was no systematical comparison on the similarity concerning research achievements of the two herbs. Meanwhile, ginger has traditionally been used for the treatment of gastrointestinal disorders, but so far, the possible interaction with human gut microbiota has hardly been considered. This review comprehensively presents similarities and differences between SJ and GJ retrospectively, particularly proposing them the significant differences in botany, phytochemistry and ethnopharmacology, which can be used as evidence for clinical application of SJ and GJ. Furthermore, the pharmacology of gut microbiota-related gastrointestinal benefits has also been discussed in order to explore better ways to prevent and treat gastrointestinal disorders, which can be used as a reference for further research.

Synergistic Antioxidant and Antibacterial Advantages of Essential Oils for Food Packaging Applications

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.

Antibacterial, Antifungal, Antimycotoxigenic, and Antioxidant Activities of Essential Oils: An Updated Review

The interest in using natural antimicrobials instead of chemical preservatives in food products has been increasing in recent years. In regard to this, essential oils-natural and liquid secondary plant metabolites-are gaining importance for their use in the protection of foods, since they are accepted as safe and healthy. Although research studies indicate that the antibacterial and antioxidant activities of essential oils (EOs) are more common compared to other biological activities, specific concerns have led scientists to investigate the areas that are still in need of research. To the best of our knowledge, there is no review paper in which antifungal and especially antimycotoxigenic effects are compiled. Further, the low stability of essential oils under environmental conditions such as temperature and light has forced scientists to develop and use recent approaches such as encapsulation, coating, use in edible films, etc. This review provides an overview of the current literature on essential oils mainly on antifungal and antimycotoxigenic but also their antibacterial and antioxidant activities. Additionally, the recent applications of EOs including encapsulation, edible coatings, and active packaging are outlined.

Antifungal, antitoxigenic, and antioxidant activities of the essential oil from laurel (Laurus nobilis L.): Potential use as wheat preservative

Essential oils (EOs) are widely used in the food industry as natural food preservatives to extend product shelf life and as flavoring agents. The aim of this work was to study the chemical profile of the EO from laurel (Laurus nobilis) and its antifungal, antitoxigenic, and antioxidant activities. The extractive yield of the EO from Algerian laurel was 1.13% being 1,8-cineole the most dominant compound (35.5%) by gas chromatography-mass spectrometry analysis. The values of minimum inhibitory concentration and minimum fungicidal concentration (MFC) against Aspergillus flavus were 1.75 and 2 mg/ml, respectively. The production of aflatoxin B1 was inhibited by EO concentrations between 0.25 mg/ml (15% decrease) and 1.50 mg/ml (86% decrease), and it was totally inhibited at the MFC value. The EO showed a wide antifungal spectrum against other species in a dose-dependent manner. In a food-model study, the L. nobilis EO showed remarkable efficacy in fumigated wheat grains, providing from 51.5% to 76.7% protection against A. flavus during 6-month storage. The L. nobilis EO showed good free radical scavenging activity by DPPH assay (IC50 value of 602 μg/ml) and moderate antioxidant activity in the β-carotene bleaching assay (46% inhibition of linoleic acid oxidation). The conclusions of this study justify future research for the application of EO from laurel as a natural preservative to improve food safety and extend shelf life by controlling spoilage and toxigenic molds as well as oxidative damage.

A Comparative Study of the in Vitro Antimicrobial and Synergistic Effect of Essential Oils from Laurus nobilis L. and Prunus armeniaca L. from Morocco with Antimicrobial Drugs: New Approach for Health Promoting Products

Laurus nobilis L. (laurel, Lauraceae) and Prunus armeniaca L. (apricot, Rosaceae) are important industrial crops and display significant biological properties, including antimicrobial activity. In this work, essential oils (EOs) prepared from the leaves of both species from Morocco were evaluated for the first time for possible synergistic in vitro antibacterial and antifungal effects with some conventional antimicrobial drugs, namely fluconazole, ciprofloxacin and vancomycin. Samples were further evaluated for chemical composition by gas chromatography–mass spectrometry (GC-MS). The main volatile compounds detected in L. nobilis were eucalyptol (40.85%), α-terpinyl acetate (12.64%) and methyl eugenol (8.72%), while P. armeniaca was dominated essentially by (Z)-phytol (27.18%), pentacosane (15.11%), nonacosane (8.76%) and benzaldehyde (7.25%). Regarding antimicrobial activity, both EOs inhibited significantly all the microorganisms tested. The EO from L. nobilis had the highest activity, with minimal inhibitory concentrations (MICs) ranging from 1.39 to 22.2 mg/mL for bacteria and between 2.77 and 5.55 mg/mL for yeasts. Conversely, the combination of the studied EOs with ciprofloxacin, vancomycin and fluconazol resulted in a noteworthy decrease in their individual MICs. In fact, of the 32 interactions tested, 23 (71.87%) demonstrated total synergism and 9 (28.12%) a partial synergistic interaction. The EO from L. nobilis exhibited the highest synergistic effect with all the antibiotics used, with fractional inhibitory concentration (FIC) index values in the range of 0.266 to 0.75 for bacteria, and between 0.258 and 0.266 for yeast. The synergistic interaction between the studied EOs and standard antibiotics may constitute promising anti-infective agents useful for treating diseases induced by antibiotic-resistant pathogens.

Effectiveness of five flavored Tunisian olive oils on Anisakis larvae type 1: application of cinnamon and rosemary oil in industrial anchovy marinating process

BACKGROUND

Anisakidosis is caused by the ingestion of raw or undercooked fish or cephalopods containing viable Anisakis larvae. Several natural extracts, oils, essential oils, and their compounds have been tested against Anisakis. In this study the effectiveness of Tunisian olive oil with different spices or plants (cardamom, cinnamon, ginger, laurel, and rosemary) was tested against Anisakis larvae type 1.

RESULTS

For the in vitro test, larvae were submerged separately in the oils mentioned above and observed to check viability. Cinnamon oil was the most effective against parasites with lethal time (LT) scores being LT50  = 1.5 days and LT100  = 3 days, followed by rosemary. Laurel, cardamom, and ginger oils were less effective. For the ex vivo experiment, cinnamon, and rosemary oils were tested in anchovy fillets, previously artificially parasitized. Cinnamon was the most effective against parasites (dead after 4 days) as compared to rosemary (7 days).

CONCLUSION

The use of cinnamon and rosemary-flavored olive oil in the industrial marinating process can be considered as an efficient alternative to the freezing process required by European Regulation EC No 853/2004 to devitalize Anisakis. © 2019 Society of Chemical Industry.

Characterization and Phytotoxicity Assessment of Essential Oils from Plant Byproducts

The present work describes the chemical characterization and the phytotoxicity assessment of essential oils (EOs) obtained from spent materials or pruning waste of four plant species: Zingiber officinale Roscoe used in the juicing industry, Pistacia vera L. var. Bronte used in the food industry, discarded material of industrial hemp (Cannabis sativa L. var. Futura 75), and pruning waste from Cupressus sempervirens L. The phytochemical profile of the EOs was evaluated by gas chromatographic flame ionization detection (GC-FID) and GC-MS analyses, which highlighted the presence of several compounds with a wide range of biological activities. Among them, application possibilities in agriculture were evaluated by studying the phytotoxic activity in vitro against germination and initial radical growth of several seeds such as Raphanus sativus L., Lepidium sativum L., Lactuca sativa L., Solanum lycopersicum L., Lolium multiflorum Lam., and Portulaca oleracea L.

Chemical Composition and Antimicrobial Activity of Laurus nobilis L. Essential Oils from Bulgaria

Laurel, Laurus nobilis L. is an evergreen plant belonging to the Lauraceae family, native to Southern Europe and the Mediterranean area. This is the first report on the composition and bioactivity of laurel essential oil (EO) from Bulgaria. The oil yield was 0.78%, 0.80%, and 3.25% in the fruits, twigs, and leaves, respectively. The main constituents in the fruit EO were 1,8-cineole (33.3%), α-terpinyl acetate (10.3%), α-pinene (11.0%), β-elemene (7.5%), sabinene (6.3%), β-phellandrene (5.2%), bornyl acetate (4.4%), and camphene (4.3%); those in the twig EO were 1,8-cineole (48.5%), α-terpinyl acetate (13.1%), methyl eugenol (6.6%), β-linalool (3.8%), β-pinene (3.4%), sabinene (3.3%) and terpinene-4-ol (3.3%); and the ones in the leaf EO were 1,8-cineole (41.0%), α-terpinyl acetate (14.4%), sabinene (8.8%), methyl eugenole (6.0%), β-linalool (4.9%), and α-terpineol (3.1%). The antibacterial and antifungal properties of laurel EOs were examined according to the agar well diffusion method. The leaf EO showed antibacterial and antifungal activities against almost all strains of the microorganisms tested, whereas the twig EO was only able to inhibit Staphylococcus aureus. Pseudomonas aeruginosa ATCC 9027 and Escherichia coli ATCC 8739 were the bacterial strains that showed the highest resistance to the laurel EO. The results can benefit the EO industry and biopesticide development.

Simultaneous GC-FID Quantification of Main Components of Rosmarinus officinalis L. and Lavandula dentata Essential Oils in Polymeric Nanocapsules for Antioxidant Application

The essential oils (EO) of R. officinalis and L. dentata have been widely used due to their antioxidant activity. However, due to their high volatility, the loading of EO into polymeric nanocapsules (NC) represents an efficient way of retaining their effect in future topical administration. In this way, the quantitative determination of EO incorporated into NC is necessary for simultaneous monitoring of the main components of the EO during the nanoencapsulation process as well as for precise and exact dosing of the components used during the performance of in vitro and in vivo biological tests. In this study, EO were isolated by hydrodistillation in a Clevenger-type apparatus and characterized by GC-MS and GC-FID analyses. The major constituents of EO-R. officinalis were camphor (39.46%) and 1,8-cineole (14.63%), and for EO-L. dentata were 1,8-cineole (68.59%) and β-pinene (11.53%). A new analytical method based on GC-FID for quantification of free and encapsulated EO was developed and validated according to ICH. Linearity, limit of detection and quantification, and intra- and interday precision parameters were determined. The methods were linear and precise for the quantification of the main components of EO. The EO were encapsulated by nanoprecipitation and were analyzed by the GC-FID method validated for their direct quantification. The NC size was 200 nm with homogeneous size distribution. The quantification of the incorporated EO within a NC is an important step in NC characterization. In this way, an encapsulation efficiency of at least 59.03% and 41.15% of total EO-R. officinalis and EO-L. dentata, respectively, was obtained. Simple, repeatable, and reproducible methods were developed as an analytical tool for the simultaneous quantification of the main components of EO loaded in polymeric nanocapsules as well as their monitoring in biological assays.

Evidence of Some Natural Products with Antigenotoxic Effects. Part 2: Plants, Vegetables, and Natural Resin

Cancer is one of the leading causes of death worldwide. The agents capable of causing damage to genetic material are known as genotoxins and, according to their mode of action, are classified into mutagens, carcinogens, or teratogens. Genotoxins are also involved in the pathogenesis of several chronic degenerative diseases, including hepatic, neurodegenerative, and cardiovascular disorders; diabetes; arthritis; cancer; chronic inflammation; and ageing. In recent decades, researchers have found novel bioactive phytocompounds able to counteract the effects of physical and chemical mutagens. Several studies have shown the antigenotoxic potential of different fruits and plants (Part 1). In this review (Part 2), we present a research overview conducted on some plants and vegetables (spirulina, broccoli, chamomile, cocoa, ginger, laurel, marigold, roselle, and rosemary), which are frequently consumed by humans. In addition, an analysis of some phytochemicals extracted from those vegetables and the analysis of a resin (propolis),whose antigenotoxic power has been demonstrated in various tests, including the Ames assay, sister chromatid exchange, chromosomal aberrations, micronucleus, and comet assay, was also performed.

Chemical and Biological Evaluation of Essential Oils from Cardamom Species

To highlight the importance of the spices in the Mediterranean diet, the aim of the paper was to study the essential oil compositions and to clarify the potential differences in the biological activities of the three cardamom species. In the study, we compared the phytochemical profiles and biological activities of essential oils from Elettaria cardamomum, Aframomum corrorima and Amomum subulatum. The oils were analyzed using the GC and GC/MS techniques and were mainly constituted of the oxygenated monoterpenes which represents 71.4%, 63.0%, and 51.0% of all compounds detected in E. cardamomum, A. corrorima and A. subulatum essential oils, respectively, 1,8-cineole was the main common compound between the tree tested volatile oil. The essential oils showed significant antimicrobial activity against Gram-positive and Gram-negative microorganisms tested especially the fungal strains. The Ethiopian cardamom was the most active essential oil with fungal growth inhibition zone ranging from 12.67 to 34.33 mm, MICs values ranging from 0.048 to 0.19 mg/mL, and MBCs values from 0.19 to 1.75 mg/mL. The three tested essential oils and their main component (1,8-cineole) significantly increased the production of elastase and protease production, and motility in P. aeruginosa PAO1 in a dose dependent manner. In fact, at 10 mg/mL concentration, the three essential oils showed more than 50% of inhibition of elastolytic and proteolytic activities in P. aeruginosa PAO1. The same oils inhibited also the violacein production in C. violaceum strain. It was also noticed that at high concentrations, the A. corrorima essential oil significantly inhibited the germination of radish. A thorough knowledge of the biological and safety profiles of essential oils can produce applications of economic importance.

Nanoemulsion of Dill essential oil as a green and potent larvicide against Anopheles stephensi

Indiscriminate use of industrial larvicides causes environment pollution and resistance against the larvicides in mosquitoes. Essential oils (EOs) have many biological activities such as larvicidal effects which have been proposed as new alternatives for industrial ones. Many components of EOs are volatile, thus, should be formulated to retain their activity. Components of Dill EO were identified by GC-MS analysis. Larvicidal activity (LA) of bulk Dill EO (non-formulated) was evaluated against Anopheles stephensi in line with WHO guideline for lab tests. For the first time, nanoemulsions of Dill EO were prepared. Various nanoemulsions having fixed amounts of Dill EO 1.2%, comparable with lethal concentration (LC) at 90% of bulk Dill EO, were prepared having tween 20 (5-30%) with/out ethanol (5-30%). LA of two selected nanoemulsions were then evaluated and compared with that of bulk Dill EO. Five ingredients of oil, with high amounts, were identified as p-Cymenealpha (20.81%), alpha-Phellandrene (20.75%), Carvone (10.97%), Dill ether (9.88%), and cis-Sabinol (3.61%). LC of Dill EO at 50 and 90% were found as 38.8 and 65 ppm, respectively, against 3rd and 4th instar larvae of An. stephensi (Beech-Lab strain). Particle size (PS) ranges of nanoemulsions were 10.7-1880.0 nm. LA of optimum nanoemulsion (PS: 10.7 nm) was significantly better than that of bulk Dill EO. The preparation showed stability against 200 times dilution during larvicidal tests and performed significantly better than the nanoemulsion which was not stable after dilution. To obtain improved efficiency against larvae using nanoemulsions of EOs, the nanoemulsion should be resistant against dilution. Such a stable and green nanoemulsion may be used as alternative to industrial larvicides.

Drug resistance, AmpC-β-lactamase and extended-spectrum β-lactamase-producing Enterobacteriaceae isolated from fish and shrimp

The present study aims to detect the production of extended-spectrum beta-lactamases (ESBL) by enterobacteria isolated from samples of fresh shrimp and fish obtained from the retail trade of the city of Sobral, Ceará State, Brazil. All bacterial isolates were submitted to identification and antimicrobial susceptibility testing using aminopenicillin, beta-lactamase inhibitors, carbapenem, 1st, 2nd, 3rd and 4th generation cephalosporins, and monobactam. Three types of beta-lactamases - ESBL, AmpC and KPC - were investigated. 103 strains were identified, and the most frequent species in shrimp and fish samples was Enterobacter cloacae (n = 54). All the strains were resistant to penicillin and more than 50% of the isolates were resistant to ampicillin and cephalothin. Resistance to three 3rd generation cephalosporins (cefotaxime, ceftriaxone and ceftazidime) and one fourth generation cephalosporin (cefepime) was detected in two isolates of E. cloacae from shrimp samples. Phenotypic detection of AmpC was confirmed in seven strains. The ESBL was detected in two strains of E. cloacae from shrimp samples. No strain showed KPC production. These data can be considered alarming, since food (shrimp and fish) may be carriers of enterobacteria resistant to drugs of clinical interest.

Laurus nobilis: Composition of Essential Oil and Its Biological Activities

Laurus nobilis is native to the southern Mediterranean region and cultivated mainly in Europe and the USA as an ornamental and medicinal plant. The chemical composition of the essential oil (EO) from leaves of L. nobilis, collected in Southern Italy, was studied by GC and GC-MS. In all, 55 compounds were identified, accounting for 91.6% of the total essential oil. 1,8-Cineole (31.9%), sabinene (12.2%), and linalool (10.2%) were the main components. Antimicrobial and antifungal activities of EO and 1,8-cineole were determined in vitro. The cytotoxicity of the EO was evaluated against SH-SY5Y cell line, as well as the influence of the EO on the expression of adenylate cyclase 1 (ADCY1), suggesting possible essential oil effects on the Central Nervous System.