Synthesis of some Thymol derivatives for enhanced antibacterial activity

Thymol derivatives were synthesized by condensation reactions implicating its phenolic hydroxyl group. Spectral analysis by 13C, 1H NMR, FT-IR and Mass Spectroscopy confirmed their chemical structures as the following compounds: 2-isopropyl-5-methylphenylformate (1), 2-isopropyl-5-methylphenyl benzoate (2), 5-methyl-2-propylphenyl acetate (3), 2-(2-(2-isopropyl-5-methylphenoxy)ethoxy) ethanol (4) and 2-isopropoxy-1-isopropyl-4-methylbenzene (5). Their antibacterial activity compared to Thymol was assessed by a standard broth microdilution method against five referenced bacterial strains: Escherichia coli a CIP 54127, Salmonella typhimurium an ATCC 133115, Staphylococcus aureus a CIP 4.83, Pseudomonas aeruginosa ATCC 15442 and Klebsiella pneumonia a CIP 104216. Obtained results confirmed enhancement of antibacterial activity of product (5) and moderately of product (3), while products 1, 2 and 4 exhibited low activity comparing to Thymol. These results suggest that the phenolic hydroxyl group of Thymol is involved in the interactions with bacterial structures leading to inhibition of their growth and even killing them at higher doses

Topical co-delivery of indomethacin and nigella sativa L. essential oil in poly-cappa-caprolactone nanoparticles: in vitro study of anti-inflammatory activity

Indomethacin is a potent, nonselective Non-steroidal Antiinflammatory Drug (NSAID) but its low water-solubility precludes its use as topical dosage form. As with other NSAIDs, the systemic delivery is associated with high risk of serious gastrointestinal adverse events including bleeding, ulceration and perforation of stomach and intestines. Here we demonstrate a safer way of administration i.e via topical demonstrating synergistic effects when co-delivered with Nigella sativa L. seeds essential oil (NSSEO) in the form of coencapsulated particles (~200 nm) of poly--caprolactone. The particles showed penetrability across stratum corneum to dermis layer in ex-vivo human skin. Further study in the xyline-induced ear edema in mice was performed, and co-encapsulated particles demonstrated highest antiinflammatory effect compared to indomethacin particles and indomethacin gels. Despite slower onset compared to indomethacin gels, the inflamed ear continued to show reduction in thickness over 8 hours of observation demonstrating synergistic and pro-longed effect contributed by NSSEO. In immunohistochemistry study of CD45+, the mice ears treated with co-encapsulated particles showed considerable reduction in lesions, epidermal-dermal separation and inflammatory cells (lymphocytes and neutrophils) infiltration as compared to other formulation. Based on microscopic evaluation, the anti-inflammatory inhibition effect of co-encapsulated particles is the highest (90%) followed by indomethacin particles (79%) and indomethacin gel (49%). The findings suggest not only skin permeability of indomethacin significantly improved but also the therapeutic effects, all provided by the presence of NSSEO in the particles. This study paves the way to more co-encapsulation of any other contemporary medicines in combination with this wholesome natural oil, NSSEO

Antimicrobial Activity of Nano-Encapsulated Essential Oils: Comparison to Non-Encapsulated Essential Oils

International audienceAs fragile active components, essential oils should be encapsulated to solve several problems linked to their use, including toxicity, miscibility in aqueous medium, time-controlled release, formulations or preparations for various industries (pharmaceuticals, cosmetics, textiles, chemicals, food, etc.). Then, the aim of this study is to perform nano-encapsulation of selected essential oils and to compare their antimicrobial activities with the non-encapsulated ones. Essential oils of Thymus leptobotrys, Thymus satureoides, Pelargonium graveolens, Eugenia Caryophyllata and their major component Eugenol were first encapsulated by the nanoprecipitation technique using Eudragit RS 100 as coating polymer. This results in a final stable milky dispersion of essential oils nanocapsules having a final concentration of 4% (v/v). The formed nanoparticles have 110 nm averages in diameter particle size and possess positive zeta potential (approximately 81 mV). Chemical composition of these encapsulated essential oils was investigated by Gas Chromatography-Mass Spectrometry confirming similarities to the non-encapsulated ones. Antimicrobial assays against five bacterial strains, two yeasts and two moulds, confirm that the prepared nanoparticles exhibit, at a comparative concentration of 0.4% (v/v), relatively less antimicrobial activities (both bacteriostatic and fungistatic) than the non-encapsulated EOs. These results lead us to think to numerous applications of such essential oils particularly in the pharmaceutical and cosmetic domains

Synthesis, structural and crystallographic characterization of new hydrosoluble thymol derivatives with a comparative study of enhanced antioxidant activity

In this study, we synthesized two new Thymol derivatives obtained by reacting Thymol sulfonic acid with respectively two amines: aniline and diethylamine. Spectroscopic analysis by FT-IR, mass spectrometry, (1H, 13C) NMR and XRD elucidated the chemical structure of these two new Thymol derivatives identified as: Diethylammonium 4-hydroxy-5-isopropyl-2-methylbenzenesulfonate (P.1) and Benzenaminium 4-hydroxy-5-isopropyl-2-methylbenzenesulfonate (P.2) obtained respectively with 98% and 52% reaction yields. They match two new Thymol organic salts with specific ionic crystalline form. We investigated a comparative antioxidant activity study based on the DPPH test versus Butyl hydroxy toluene (BHT) as control and Thymol as strating material. The results show that boat synthesized compounds (P.1) and (P.2) are significantly more active with IC50 value 3,44 µg/mL for (P.2) and 6,76 µg/mL for (P.1) versus 21,7 µg/mL for (BHT) and 178.03 µg/mL for Thymol. More interestingly, these two compounds are water soluble and the compound (P.1) was obtained in a good yield reaction (98%)

Photosynthetic Behavior of <i>Argania spinosa</i> (L.) Skeels Induced under Grazed and Ungrazed Conditions

The endemic Moroccan species Argania spinosa is considered the most grazed tree species in its distribution area. Since grazing exerts an important effect on plant performances, we attempted to explore the impact of grazing on A. spinosa. Thus, we performed a comparative field experiment where seasonal variations of gas exchange, photochemical efficiency, relative water content, photosynthetic pigment content, and stomatal features were assessed in grazed and ungrazed trees. The net photosynthetic rate was increased in grazed trees in spring and autumn, the favorable seasons. Enhancement of photosynthetic performance may be due to the high stomatal conductance registered in grazed trees. This mechanism may compensate for the lost leaf area, in order to recover from grazing stress. In addition, grazed trees exhibit a better photochemical efficiency, use water more economically and show lower oxidative stress. However, results obtained in summer show that the compensation mechanism could be limited by summer drought. Since the key to preserving the future of forests is sustainable forest management, our results suggest that proper grazing management can be a control tool to increase plant performance and improve species resilience

Poly (ε-caprolactone) nanoparticles loaded with indomethacin and Nigella Sativa L. essential oil for the topical treatment of inflammation

A. El Asbahani gratefully acknowledges the technical support of Professor Herve Casabianca in the Nigella Sativa L. Seeds Essential Oil extraction and analysis.International audienc

Essential oils: From extraction to encapsulation

International audienceEssential oils are natural products which have many interesting applications. Extraction of essential oils from plants is performed by classical and innovative methods. Numerous encapsulation processes have been developed and reported in the literature in order to encapsulate biomolecules, active molecules, nanocrystals, oils and also essential oils for various applications such as in vitro diagnosis, therapy, cosmetic, textile, food etc. Essential oils encapsulation led to numerous new formulations with new applications. This insures the protection of the fragile oil and controlled release. The most commonly prepared carriers are polymer particles, liposomes and solid lipid nanoparticles

TOPICAL CO-DELIVERY OF INDOMETHACIN AND NIGELLA SATIVA L. ESSENTIAL OIL IN POLY--CAPROLACTONE NANOPARTICLES: IN VIVO STUDY OF ANTI-INFLAMMATORY ACTIVITY.

<p>Indomethacin is a potent, nonselective Non-steroidal Anti-inflammatory Drug (NSAID) but its low water-solubility precludes its use as topical dosage form. As with other NSAIDs, the systemic delivery is associated with high risk of serious gastrointestinal adverse events including bleeding, ulceration and perforation of stomach and intestines. Here we demonstrate a safer way of administration i.e via topical demonstrating synergistic effects when co-delivered with Nigella sativa L. seeds essential oil (NSSEO) in the form of co-encapsulated particles (~200 nm) of poly--caprolactone. The particles showed penetrability across stratum corneum to dermis layer in ex-vivo human skin. Further study in the xyline-induced ear edema in mice was performed, and co-encapsulated particles demonstrated highest anti-inflammatory effect compared to indomethacin particles and indomethacin gels. Despite slower onset compared to indomethacin gels, the inflamed ear continued to show reduction in thickness over 8 hours of observation demonstrating synergistic and pro-longed effect contributed by NSSEO. In immunohistochemistry study of CD45+, the mice ears treated with co-encapsulated particles showed considerable reduction in lesions, epidermal-dermal separation and inflamma?tory cells (lymphocytes and neutrophils) infiltration as compared to other formulation. Based on microscopic evaluation, the anti-inflammatory inhibition effect of co-encapsulated particles is the highest (90%) followed by indomethacin particles (79%) and indomethacin gel (49%). The findings suggest not only skin permeability of indomethacin significantly improved but also the therapeutic effects, all provided by the presence of NSSEO in the particles. This study paves the way to more co-encapsulation of any other contemporary medicines in combination with this wholesome natural oil, NSSEO.</p