Phytochemical characterization and immunomodulatory effects of aqueous and ethanolic extracts and essential oil of Moroccan Laurus nobilis L. (Lauraceae) on human neutrophils

Abstract

Introduction: The leaves of Moroccan bay laurel (Laurus nobilis L.) have been used in several forms of extracts to cure rheumatic pain due to their anti-inflammatory properties. Our work aimed to evaluate the effects of aqueous and ethanolic extracts, as well as the essential oil (EO) from laurel, on the microbicidal activity of human neutrophils when compared to the effect of eucalyptol. Methods: The extracts (ethanolic and aqueous) were subject to phytochemical profiling and high-performance liquid chromatography (HPLC) analyses. The EO obtained by hydrodistillation from laurel was analyzed by gas chromatography-mass spectrometry (GC-MS). The immunomodulatory effects on neutrophil microbicidal activity of the extracts, EO, and eugenol were carried out by 3-(4,5-diméthylthiazol-2-yl)-2,5-diphényltétrazolium (MTT) assay. Results: The phytochemical analysis of the extracts revealed the presence of flavonoids, coumarins, phenols, flavone aglycones, and tannins. HPLC analysis showed the presence of numerous phenolic molecules such as syringic acid, ferulic acid, gallic acid, caffeine, and quercetin. The chemical composition of EO revealed that the major components were eucalyptol (44.14%), α-terpinyl acetate (11.11%), and β-phellandrene (6.74%). Aqueous and ethanolic extracts and EO revealed a significant and dose-dependent ability to inhibit neutrophils microbicidal activity with maximal inhibition at 200 µg/mL concentration with 30.42%, 24.7%, and 38.13%, respectively (P<0.001). Conclusion: The obtained results revealed the immunomodulatory properties of laurel as a potential natural anti-inflammatory agent that would also allow the development of new anti-inflammatory drugs.

Influence of Thyme Oil Nano-Encapsulated Chitosan on Productivity, Growth Performance, and Meat Quality of Japanese Quails

“…The lack of effects of treatments on different carcass traits agrees with the results of [38,8,9] who found no significant effect of thyme on carcass traits. The abdominal fat weight was affected primarily by the supplements, regardless of dose, being reduced by 41% for chickens fed the thyme supplements and 62% for chickens fed the sumac supplements.…”

“…In this study, thyme essential oil coated with nano-chitosan increased feed intake compared to thyme essential oil alone, and this indicates that nano-encapsulation technology increases the palatability of quails for herbal essential oils. However, this result does not completely correspond to an improvement in body weight gain and FCR of the broilers fed with the chitosan nano-encapsulating thyme essential oils (0.025%, 0.04%, and 0.055% respectively to starter, grower, and finisher diets) in the Nouri, [8] study. Also, Lee et al, [35] used 100 mg/kg of thymol and cinnamaldehyde in a broiler diet but did not find any significant effect on feed intake.…”

“…However, inconsistent results among past and present studies are identified to be conflicting. For instance, there were positive effects of EO on broiler performance as indicated by improving BWG [3][4], FCR [5], enzyme secretion [6] and nutrient digestibility [7] Herbal essential oils can be used as an antibiotic to improve poultry performance, especially in intensive management systems [8]. Thyme (Thymus vulgaris) is commonly used as a spice in human food and has received considerable attention as a beneficial additive in poultry nutrition.…”

“…Thus, such unfavorable reactions may reduce oil efficiency, natural flavors, and sensory quality, lowering palatability and FI, particularly in diets rich in TEO [12]. To increase the delivery and controlled release of active substances, microencapsulation or Nano-Encapsulation technology may entrap them in the core of the membrane wall structure of Nano-capsules or adsorb them onto a carrier [8]. Polyphenol degradation and sluggish gastrointestinal release may be reduced by encapsulating plant extracts in nanoparticles [13].…”

Phytoimmunomodulators: A review of natural modulators for complex immune system

“…Cucumis melo contains a variety of biologically active substances that are essential to plant bioactivities [ 107 ]. Investigations showed that laurel ( Laurus nobilis L) has immunomodulatory capabilities that might make it a promising natural anti-inflammatory agent and enable the creation of novel anti-inflammatory medications [ 108 ].…”