Effect of Laurus nobilis on bacteria and human transforming growth factor-β1

SUMMARY OBJECTIVE: In this study, we aimed to determine the phenolic compounds, the antibacterial activity of extract from Laurus nobilis leaves, and its possible effect on transforming growth factor-β1 expression level in peripheral blood mononuclear cells. METHODS: The phenolic components of Laurus nobilis were identified by the high-performance liquid chromatography method. The antibacterial activity of this extract was determined by disk diffusion and broth microdilution methods. The transforming growth factor-β1 expression was analyzed using the RT-qPCR method. RESULTS: Epicatechin was found in the highest amount and o-coumaric acid in the lowest amount. The half-maximal inhibitory concentration (IC50) was determined to be 55.17 μg/mL. The zones of inhibition and minimum inhibitory concentration for Staphylococcus aureus, Enterococcus faecalis, and Klebsiella pneumoniae were 15, 14, and 8 mm and 125, 250, and 1000 μg/mL, respectively. The change in transforming growth factor-β1 expression levels was found to be statistically significant compared with the control groups (p<0.0001). CONCLUSION: Laurus nobilis extract was found to be effective against bacteria and altered the expression level of transforming growth factor-β1 in peripheral blood mononuclear cells.

Chemical and Enantioselective Analysis of the Essential Oils from Different Morphological Structures of Ocotea quixos (Lam.) Kosterm.

The traditional Ecuadorian spice Ishpingo, characterized by a strong cinnamon-like aroma, is constituted by the dry cupules of Amazonian species Ocotea quixos. Nevertheless, bark and leaves also present aromatic properties and are sometimes used as substitutes. In the present study, the essential oils, distilled from these morphological structures, are comparatively analyzed for their chemical and enantiomeric compositions. A total of 88 components were identified with 2 orthogonal GC columns, whereas 79, corresponding to more than 94%, were also quantified with at least 1 column. Major compounds were (E)-methyl cinnamate in cupules (35.9-34.2%), (E)-cinnamaldehyde in bark (44.7-47.0%), and (E)-cinnamyl acetate (46.0-50.4%) in leaves. For what concerns the enantioselective analysis, 10 chiral terpenes and terpenoids were detected, of which 6 were present as enantiomeric pairs in at least 1 essential oil, the others being enantiomerically pure. Both quantitative and enantioselective analyses were submitted to Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA), where their results confirmed significative difference among the three products.

Evaluation of essential oils as an ecological alternative in the search for control Rhipicephalus microplus (Acari: Ixodidae).

The cattle tick Rhipicephalus microplus is a significant problem for livestock, causing losses of billions of dollars per year. This work aimed to determine the chemical composition of essential oils obtained from Laurus nobilis and Copaifera officinalis and evaluate activity against engorged R. microplus females. Chemical composition analyzed by GC-MS revealed the presence of 39 components accounting for 95.38% of the oil in L. nobilis, the most abundant being 1,8-cineol (25.7%), trans-sabinene-hydrate (20.8%), and α-terpinil acetate (15.0%). Chemical analysis of C. officinalis oil identified 25 components corresponding to 80.5% of the total constituents, where the major compounds were ß-caryophyllene (21.1%), caryophyllene oxide (10.7%), and α-trans-bergamotene (9.3%). Adult immersion test (AIT) showed that L. nobilis essential oil at 5% or 10% caused 80.5% mortality of engorged females after 24 h and reached 96.9% and 100% mortality on the third day after treatment, respectively. While the essential oil from C. officinalis caused 84.7% mortality after six days at 10% and at 5%, achieved approximately 100% mortality rate at the end of the experiment (day 15). Both essential oils and the combination significantly inhibited egg-laying; however, the combination treatment showed higher effectiveness than the isolated oils at 2.5%. A possible synergic action of L. nobilis and C. officinalis against the cattle tick R. microplus is therefore suggested. The present work introduces a potential alternative for the development of a formulation environment-friendly (green pesticide) used to control cattle tick infestations.

Essential oil and fractions isolated of Laurel to control adults and larvae of cattle ticks.

This study, was to evaluate the acaricidal effect of the essential oil (EO) and fractions (FR) obtained from Laurus nobilis leaves on Rhipicephalus (Boophilus) microplus. Eight fractions were obtained, however FR1: sabinene (37.83%), ß-pinene (13.50%), 1,8-cineole (12.66%), α-pinene (12.56%) and FR8: α-terpineol (79.19%) were highlighted as to the larvicidal potential when submitted by Larval Packet Test. The EO was tested by the Adult Immersion Test, at concentrations of 200.00; 100.00 and 50.00 µL/mL caused mortality of engorged females, egg mass reduction and hatching inhibition. Two fractions are shown to be efficient in controlling larvae FR8 (LC50 = 0.13 µL/mL, LC99 = 0.51 µL/mL) and FR1 (LC50 = 0.20 µL/mL, LC99 = 0.56 µL/mL). The fractionation of EO was determinant to elucidate which compounds were responsible for the larvicidal potential. This study opens new perspectives to direct new bioassays with the compounds obtained in the fractionation, since they present high potential on cattle tick larvae.

Laurus nobilis L.: assessment of the cytotoxic and genotoxic potential of aqueous extracts by micronucleus and Allium cepa assays

Laurus nobilis L. is a large shrub belonging to the Lauracea family. Its leaves are widely used for food seasoning as well as in folk medicine. Various studies have demonstrated the antiproliferative, antifungal and antibacterial effects of Laurus nobilis, but no studies have investigated the genotoxic effect of the aqueous extract of the plant. The objective of this study was to analyze the genotoxic potential of an aqueous extract of leaves, using the Allium cepa assay and mouse peripheral blood cell micronucleus test. The results showed that the extract did not have any genotoxic activity, but cytotoxic activity was observed in the two experimental models used. The extract had an antiproliferative effect, detected through the reduction of the mitotic index and the polychromatic/normochromatic erythrocyte (PCE/NCE) ratio. The tests also demonstrated a large number of cells undergoing apoptosis and with nuclear abnormalities related to cell death processes. These results can be explained by the presence of phenolic compounds, saponins, flavonoids and alkaloids, detected in the phytochemical analysis of the extract. Therefore, the extract from L. nobilis in the form generally used by the population does not pose risks related to its genotoxic potential, and also contains components with apoptotic and antigenotoxic potential.

Complete essential oils of Laurus nobilisinducing antinociceptiveaction by opioid mechanism in C-Reflex and spinal Wind-Up model in rat / Aceites esenciales totales de Laurus nobilis inducen acción antinociceptivamediante mecanismo opioide en el modelode Reflejo-C y Wind-Up espinal en ratas

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 (wind-up) produced by Laurus nobilis.

El aceite esencial de Laurus nobilis L. se usó para probar su eficacia antinociceptiva. Se aplicó por vía intraperitoneal (i.p.) a ratas sometidas a una prueba de nocicepción (reflejo-C y wind-up espinal). Los resultados mostraron que el aceite esencial aplicado a dosis más altas (0.06 mg/Kg) abolió completamente el wind-up espinal, mientras que el reflejo-C no cambió, lo que indica un claro efecto antinociceptivo. A concentraciones más bajas (0.012 mg/Kg), hubo una disminución en el wind-up en un 85% dentro de los diez minutos del i.p. la aplicación del aceite esencial. Curiosamente, hubo un efecto de la naloxona (0.08 mg/Kg i.p.) la cual revierte casi por completo la antinocicepción causada por el aceite esencial de Laurus nobilis. Concluimos que existe un efecto antinociceptivo significativo del aceite esencial de Laurus nobilis sometido a nocicepción eléctrica. Además, se observó que la naloxona revirtió el efecto antinociceptivo (wind-up) producido por Laurus nobilis.

Antifungal Activity of Essential Oils Against Candida Species Isolated from Clinical Samples.

We evaluated the in vitro antifungal activity of essential oils obtained from the aromatic plants Laurus nobilis, Thymus vulgaris, Mentha piperita, Cymbopogon citratus and Lippia junelliana against the following Candida species isolated from clinical samples: C. krusei (n = 10); C. albicans (n = 50); C. glabrata (n = 70) and C. parapsilosis (n = 80). The minimal inhibitory concentration (MIC) was determined according to EDef 7.3.1 document from EUCAST. Amphotericin B and fluconazole were the antifungal drugs used as inhibition control. The concentration ranges evaluated were 0.4-800 and 0.03-128 mg l-1 for essential oils and antifungal drugs, respectively. MIC50 and MIC90, mode and ranges were calculated. All the Candida spp. evaluated were susceptible to amphotericin B (MIC ≤ 1 mg l-1), while fluconazole was inactive for C. krusei (MIC ≥ 32 mg l-1) and intermediate for C. glabrata (MIC≤ 32 mg l-1). The essential oils showed antifungal activity on Candida spp. tested with MIC90 values ranging from 0.8 to 800 mg l-1. In general, the most active essential oils were L. nobilis and T. vulgaris (MIC90 0.8-0.16 mg l-1), and the least active was C. officinalis (MIC90 400-800 mg l-1). C. krusei was inhibited by 5/6 of the essential oils evaluated, and C. glabrata was the least susceptible one. This in vitro study confirms the antifungal activity of these six essential oils assayed which could be a potential source of new molecules useful to control fungal infections caused by some Candida species, including those resistant to antifungal drugs.

Antifungal activity, mode of action and anti-biofilm effects of Laurus nobilis Linnaeus essential oil against Candida spp.

OBJECTIVE: The present study demonstrated the antifungal potential of the chemically characterized essential oil (EO) of Laurus nobilis L. (bay laurel) against Candida spp. biofilm adhesion and formation, and further established its mode of action on C. albicans. METHODS: L. nobilis EO was obtained and tested for its minimum inhibitory and fungicidal concentrations (MIC/MFC) against Candida spp., as well as for interaction with cell wall biosynthesis and membrane ionic permeability. Then we evaluated its effects on the adhesion, formation, and reduction of 48hC. albicans biofilms. The EO phytochemical profile was determined by gas chromatography coupled to mass spectrometry (GC/MS). RESULTS: The MIC and MFC values of the EO ranged from (250 to 500) µg/mL. The MIC values increased in the presence of sorbitol (osmotic protector) and ergosterol, which indicates that the EO may affect cell wall biosynthesis and membrane ionic permeability, respectively. At 2 MIC the EO disrupted initial adhesion of C. albicans biofilms (p<0.05) and affected biofilm formation with no difference compared to nystatin (p>0.05). When applied for 1min, every 8h, for 24h and 48h, the EO reduced the amount of C. albicans mature biofilm with no difference in relation to nystatin (p>0.05). The phytochemical analysis identified isoeugenol as the major compound (53.49%) in the sample. CONCLUSIONS: L. nobilis EO has antifungal activity probably due to monoterpenes and sesquiterpenes in its composition. This EO may affect cell wall biosynthesis and membrane permeability, and showed deleterious effects against C. albicans biofilms.