Evaluation of essential oils from <i>Aloysiapolystachya</i>, <i>Citrus limon</i>, <i>Eucalyptuscinerea</i>, and <i>Laurus nobilis</i>, and(R)-(−)-carvone as natural preservatives in Vienna sausages

This study aimed to evaluate the effect of Laurus nobilis (L. nobilis) essential oil (EOs) (80 mg/kg) on Triton WR-1339-induced dyslipidemia in Wistar rats. The effect of L. nobilis essential oil (80 mg/kg) on lipid and lipoprotein profile was examined on Triton WR-1339-induced dyslipidemia in rats. Furthermore, the phytochemical evaluation was performed by GC-MS. In Addition, the acute toxicity of this EO was evaluated at a dose of 2 g/kg. The results revealed that the main constituents of L. nobilis EO were 1,8-cineole (39.5%), linalool (13.09%), and a-terpineol (11.55%). Furthermore, the EO did not cause any signs of toxicity or mortality, and the acute lethal dose 50 (LD50) was estimated to be higher than 2 g/kg. L. nobilis EO ameliorated lipid parameters and atherogenic indices. In conclusion, the study demonstrates that L. nobilis essential oils possess antidyslipidemic activity in acute model of hyperlipidaemia.

Effect of lavander (Lavandula angustifolia) and laurel (Laurus nobilis) essential oils as anesthesics in rainbow trout (Oncorhynchus mykiss)

Aim. To study the qualitative composition and the quantitative content of the essential oil components from Laurus nobilis L. unripe fruits.Results and discussion. In the essential oil from Laurus nobilis L. unripe fruits 31 compounds were determined; among them 28 substances were identified. A high content was characteristic for spatulenol (1947.1 mg/kg) and betulenol (925.3 mg/kg).Experimental part. The raw material for obtaining the essential oil (unripe fruits) of Laurus nobilis L. was harvested in November 2017 in Alushta and the village of Rybalskoe, Crimea. The component composition of the essential oil of the unripe fruits from Laurus nobilis L. was studied and the constituents of the essential oil were identified by chromato-mass spectrometry using an Agilent Technology 6890N chromatograph. The component composition of the essential oil was revealed by comparing the results obtained with data from the NIST 02 mass spectrum library (more than 174.000 substances).Conclusions. The component composition of the essential oil from Laurus nobilis L. unripe fruits harvested in Ukraine has been studied. Taking into account the set of the biologically active compounds found in the essential oil of Laurus nobilis L. it can be argued that further pharmacognostic studies of fruits of this plant as the medicinal raw material with the predicted pharmacological activity (e.g., antimicrobial and skin cleansing) are promising.

Fabrication and characterization of laurel (laurus nobilis) essential oil nanoemulsion stabilized by sodium caseinate/modified α-cyclodextrin.

Essential oil (EO) of Laurus nobilis, from Tunisian, France and Austrian were screened for their chemical composition, antioxidant and antimicrobial activities and compared. GC-MS analysis showed that leaves of Tunisian L. nobilis had camphor (34.43%), 1,8-cineole (20.21%) and α-terpineol (7%) as major components. France and Austrian EOs had a high content of 1,8-cineole (45.8% and 43.4%, respectively) followed by bornyl acetate (13.8% and 17.7% respectively) and methyl eugenol (7.7% and 10.9% respectively). Antioxidant potential was measured by ABTS and DPPH tests. Tunisian L. nobilis EO showed greater radical scavenging by ABTS activity (IC50=44.8±0.1 mg/L) than the France and Austrian EOs (76.4±3.2 mg/L and 81.4±4.0 mg/L, respectively). However, for DPPH test system, French and Austrian EOs activities were excellent (IC50=176.1±5.1 mg/L and 236.3±2.9 mg/L respectively) then Tunisian L. nobilis EO (IC50=2859.7±99.0 mg/L). A good Antimicrobial activity was observed on the yeasts and fungi for all EOs. Tunisian laurel EO show a better antibacterial activity against gram-negative bacteria (Klebsiella pneumonial, E. coli and Salmonella enterica CMI: 0.004 mg/ml) than gram-positive ones (Bacilus subtilis, Staphylococcus aureus and Listeria monocytogenes CMI: 0.01 mg/ml). A significant antifungal activity of Tunisian EO was also observed against fungi and yeasts species (CMI: 0.004 mg/ml). France essential oil shows better activities against all organisms tested wail Austrian oil activity is more important against yeasts species tested and Mucor ramannianus (fungi). Chemical composition, antimicrobial and antioxidant activity of Tunisian L. nobilis essential oil, were different from that of France and Austrian and it give the opportunity for its uses in new pharmaceuticals and natural therapies of infectious diseases.

Antioxidant activity evaluation of the combination of oregano (Origanum vulgare) and laurel (Laurus nobilis) essential oil as two natural “chain-breaking” antioxidants by direct measurement of sunflower oil oxidation

Insecticidal activities of essential oils from leaves of Laurus nobilis L. from Tunisia, Algeria and Morocco, and comparative chemical composition

The main objective of the present study was to evaluate under laboratory conditions the toxicity of essential oils (EOs) extracted from Mentha suaveolens L. subsp. timija (Briq.) Harley, Chenopodium ambrosioides L. and Laurus nobilis L. against Varroa destructor adult mites. Also, various combinations were prepared by mixing equal concentrations of any two and all three studied EOs and used to evaluate the combinational acaricidal effects of mixtures against adult Varroa mites. The GC/MS analysis indicated that the main chemical compounds of M. suaveolens subsp. timija EO were menthone (40.42%) and pulegone (19.22%), whereas C. ambrosioides EO is rich in α-terpinene (34.08%), isoascaridol (13.6%), p-cymene (10.95%), thymol (10.26%), ascaridole (10.25%) and carvacrol (7.75%). L. nobilis EO is mainly composed with 1,8-cineol (37.5%) and linalool (14.09%). The fumigation bioassays showed that the three tested EOs showed varroacidal toxicity, whereas no mortality has been observed on honey bees that were exposed to their higher concentrations. The highest acaricidal potency was observed with M. suaveolens subsp. timija (LD50 = 3.360 µl/Lair and LD90 = 7.300 µl/Lair). According to the combination index (CI) calculated by CompuSyn software, the ternary blend combination exhibited high synergistic effectiveness with a CI value of 0.343. All combinations have shown favorable dose reduction with DRI indexes greater than one. Our findings suggest that EO combinations tested could present a promising solution to reduce the effective doses of EOs and constitute a promising alternative to synthetic acaricides.

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.

Aedes aegypti is a mosquito and vector of dengue, chikungunya and Zika virus making it a serious global health problem. We aimed to evaluate the chemical composition of the essential oil (EO) of Laurus nobilis leaves obtained at different seasons and its A. aegypti larvicidal activity. The EO was obtained from fresh leaves by hydrodistillation. Larvicidal activity was determined by the larval immersion test. It was identified 37 EO chemical compounds and the major ones were 1,8-cineole and linalool. Seasonal variations affected EO larvicidal activity: spring LC50 was 0.41 mg/mL and LC99 0.77 mg/mL, autumn LC50 was 0.60 mg/mL and LC99 1.37 mg/mL, winter LC50 was 0.66 mg/mL and LC99 3.19 mg/mL and summer LC50 was 0.91 mg/mL and LC99 2.50 mg/mL. The EO extracted during spring showed the highest larvicidal activity on A. aegypti larvae. Our results present a new perspective of L. nobilis EO use as a larvicidal agent.

Cereal production has always been an important component of Tunisian agriculture. However, insect pests are considered as a serious biosecurity threat to Tunisian cereals’ production and industry. Several methods such as fumigation have been used in storage. However, their use is controverted due to human and environmental worries. The main objective of this study was to introduce an ecologically safe method for managing the rust–red flour beetle, Tribolium castaneum. The insecticidal activities of Laurus nobilis have been extensively investigated. Therefore, the L. nobilis leaf essential oil chemical composition, and its insecticidal activity against T. castaneum adults were evaluated. Thus, a preliminary screening tests were designed to assess fumigant toxicity of Laurus nobilis essential oil against T. castaneum adults and to determine median effective concentrations (LC50 value). A second experiment was aimed to test the impact of spaces occupation with semolina and the storage period on essential oil effectiveness. T. castaneum adults were treated with the LC50 concentration and mortalities were assessed after 30, and 60 days of storage under 50% and 100% spaces occupied with semolina. Furthermore, the qualitative contamination of semolina by T. castaneum and the effect of essential oil on semolina characteristics and rheological dough properties were elucidated. Results indicated that the oil exhibited strong fumigant potentialities that depend on the exposure period and percentage of space occupation. The LT50 values for T. castaneum ranged from 70.48 h for 50% space occupation with semolina to 43.44 h for 100% space occupation with semolina. Moreover, we investigated the essential oil impact on semolina characteristics (protein, ash, gluten, and moisture) and rheological dough. Results indicated that the oil exhibited strong fumigant potentialities that depend on the exposure period and percentage of space occupation. It was also revealed that essential oil treatment slightly modified semolina characteristics but did not affect rheological properties that still conformed with ISO standards. The results of this study can be interested in further phytochemical and insecticidal activities of L. nobilis essential oil as alternative fumigants for control of stored semolina without negative effect on the quality of semolina.

The aim of this study was to determine the antifungal activity of the essential oils isolated from three aromatic plants against 13 filamentous fungal strains. The major constituents of Mentha spicata, Thymus vulgaris, and Laurus nobilis essential oils were carvone (52.2%), linalool (78.1%), and 1,8-cineole (45.6%), respectively. There are also some patents suggesting the use of essential oils as natural and safe alternatives to fungicides for plant protection. In the present work, M. spicata essential oil exhibited the strongest activity against all tested fungi in which Fusarium graminearum, F.moniliforme, and Penicillium expansum were the most sensitive to mint oil with lower minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) values of 2.5 μL mL-1 (v/v). Thymus vulgaris essential oil was less active compared to the oil of M. spicata. Aspergillus ochraceus was the most sensitive strain to thyme oil with MIC and MFC values of 2.5 and 5 μL mL-1, respectively. Thymus vulgaris essential oil also exhibited a moderate fungicidal effect against the tested fungi, except for A. niger (MFC >20 μL-1). L. nobilis essential oil showed a similar antifungal activity with thyme oil in which A. parasiticus was the most resistant strain to this oil (MFC >20 μL mL-1). Our findings suggested the use of these essential oils as alternatives to synthetic fungicides in order to prevent pre-and post-harvest infections and ensure product safety.

The essential oil of Laurus nobilis L. was used to test their antinociceptive efficacy. It was applied intraperitoneally (i.p.) to rats subjected to a nociception test (C reflex and spinal wind-up). The results showed that the essential oil applied at higher doses (0.06 mg/Kg) causes a complete abolition of the spinal wind-up, while the C reflex was unchanged, indicating a clear antinociceptive effect. At lower concentrations (0.012 mg/Kg), there was a lowering in the wind-up by 85% within ten minutes of the essential i.p. oil application. Interestingly, there was an effect of naloxone (0.08 mg/Kg i.p.) When applied, a change occurs that almost entirely reversed the antinociception caused by the essential oil from Laurus nobilis. We conclude that there is a significant antinociceptive effect of the essential oil of Laurus nobilis subjected to electric nociception. In addition, it was observed that naloxone reversed the antinociceptive effect (windup) produced by Laurus nobilis.

In the present study, the chemical composition of laurel (Laurus nobilis L.) leaves essential oil (EO) and its antibacterial effect on common food and water-borne pathogenic bacteria were investigated. The results showed that 1.8-cineol (41.1 %), sabinene (6.96 %), α-pinene (5.94 %), humulene epoxide II (5.73 %), and α-terpinenyl acetate (5.72 %) were the main compounds in the Laurus nobilis leaves EO. The EO showed the highest (P < 0.05) antibacterial effect on Enterococcus faecalis (28.0 mm, zone diameter), followed by Escherichia coli O:157 H:7 (27.1 mm) and Salmonella pullorum (25.2 mm). Regarding MIC/MBC ratios, Laurus nobilis EO had a bacteriocidal effect on all tested food and waterborne pathogens except of Listeria monocytogenes.

Chemical profile and inhibition of MDR bacteria by the essential oil of Laurus nobilis L. and its major compound 1,8-cineol