Effectiveness and chemical insights: Exploring interactions between nanomicelles and monoterpenoids for head lice treatment.

This study evaluates the pediculicidal activity of nanoformulations containing different binary essential oil component mixtures (eugenol:linalool, 1,8 -cineole:linalool, and eugenol:thymol) using immersion bioassays. These have allowed us to evaluate the knockdown time affecting 50% of the individuals (KT50). In addition, the type of interaction between the components in each mixture was established in terms of the combination index (IC). The KT50 values were 6.07; 8.83; 7.17 and 27.23 h for linalool, 1,8 -cineole, eugenol, and thymol, respectively. For the eugenol:linalool mixtures, the efficacy was lower or equal to that obtained for the nanoformulations of the pure compounds, with values of KT50 about 13.33, 8.16 and 6.71 h for mixtures with ratios 3:1, 1:1 and 1:3, respectively. These mixtures present IC > 1, evidencing antagonistic interaction, which is enhanced with eugenol content. In the case of the binary mixtures of 1,8 -cineole: linalool, KT50 values were similar to those obtained for eugenol:linalool mixtures with similar ratios. In this case, IC assumes values close to unity, suggesting additive interactions independently of the mixture composition. On the other side, mixtures of eugenol:thymol with 1:1 and 1:3 ratios showed values of 9.40 and 32.93 h, while the mixture with a 3:1 ratio showed the greatest effectiveness (KT50 of 4.42 h). Eugenol:thymol mixtures show synergistic interaction (IC < 1) for combinations 3:1 and 1:1, while no interaction was observed for 1:3 combination. This indicates that eugenol enhances thymol activity. These results must be considered an important step forward to the development of effective pediculicidal nanoformulations based on botanical compounds.

Enhanced Stability and Solidification of Volatile Eugenol by Cyclodextrin-Metal Organic Framework for Nasal Powder Delivery.

Eugenol (Eug) holds potential as a treatment for bacterial rhinosinusitis by nasal powder drug delivery. To stabilization and solidification of volatile Eug, herein, nasal inhalable γ-cyclodextrin metal-organic framework (γ-CD-MOF) was investigated as a carrier by gas-solid adsorption method. The results showed that the particle size of Eug loaded by γ-CD-MOF (Eug@γ-CD-MOF) distributed in the range of 10-150 µm well. In comparison to γ-CD and ß-CD-MOF, γ-CD-MOF has higher thermal stability to Eug. And the intermolecular interactions between Eug and the carriers were verified by characterizations and molecular docking. Based on the bionic human nasal cavity model, Eug@γ-CD-MOF had a high deposition distribution (90.07 ± 1.58%). Compared with free Eug, the retention time Eug@γ-CD-MOF in the nasal cavity was prolonged from 5 min to 60 min. In addition, the cell viability showed that Eug@γ-CD-MOF (Eug content range 3.125-200 µg/mL) was non-cytotoxic. And the encapsulation of γ-CD-MOF could not reduce the bacteriostatic effect of Eug. Therefore, the biocompatible γ-CD-MOF could be a potential and valuable carrier for nasal drug delivery to realize solidification and nasal therapeutic effects of volatile oils.

[Isolation and functional characterization of (iso)eugenol O-methyltransferase (IEMT) gene in Asarum sieboldii].

Methyleugenol is one of the main active constituents in the volatile oil of the traditional Chinese medicine Asari Radix et Rhizoma. It possesses various pharmacological effects such as analgesic, anesthetic, and anti-inflammatory properties. In biosynthesis, the initial precursor phenylalanine is finally converted into methyleugenol through a series of intermediate compounds including coniferyl acid, courmaryl acid, caffeic acid, ferulic acid/ferulic-CoA, coniferyl aldehyde, conferyl alcohol, cnfiferyl acetate, and eugenol/isoeugenol, which are produced through catalysis of a large number of enzymes. Eugenol O-methyltransferase(EOMT) is one of the key enzymes in the biosynthesis pathway, capable of methylating eugenol on the para-site hydroxyl group of the benzene ring, thereby generating methyleugenol. Here, an(iso)eugenol O-methyltransferase(IEMT) gene was cloned for the first time from Asarum siebo-ldii, holding an open reading frame that consisted of 1 113 bp and encoded a protein containing 370 amino acid residues. Bioinformatics analysis results showed that this protein was equipped with the characteristic structural domains of methyltransferases such as S-adenosylmethionine(SAM) binding sites and dimerization domains. The prokaryotic expression recombinant plasmid pET28a(+)-AsIEMT was constructed, and the candidate protein was induced and purified. In vitro enzyme assays confirmed that AsIEMT had dual functions. The enzyme could catalyze the production either of methyleugenol from eugenol or of methylisoeugenol from isoeugenol, although the latter was more prevalent. When isoeugenol was used as the substrate, the kinetics parameters K_m and V_(max) of catalytic reaction were(0.90±0.06) mmol·L~(-1) and(1.32±0.04)nmol·s~(-1)·mg~(-1), respectively. This study expanded our understandings of critical enzyme genes involved in phenylpropanoid metabolic pathways, and would facilitate the elucidation of quality formation mechanisms of the TCM Asari Radix et Rhizoma.

Investigation of the effects of isoeugenol-based phenolic compounds on migration and proliferation of HT29 colon cancer cells at cellular and molecular level.

Colorectal cancer is a type of cancer encountered worldwide and ranks third among all cancer types in terms of incidence. Polyphenols have been shown to have a wide range of biological functions, including a significant impact on cancer start, development, and promotion through regulating many signaling pathways. The aim of this study was to investigate the anticancer effects of isoeugenol based compounds 1, 2 on HT29 colorectal cancer cell line in vitro. MTT test and scratch assay were carried out to determine the effect of these compounds on HT29 cell proliferation and migration respectively. In addition, mRNA expression levels of apoptosis and metastasis-related genes (p53, Bcl2, Bax, Caspase 3, Caspase7, Caspase8, Caspase9, HIF1-α, VEGF, MMP-2, MMP-9) were examined by quantitative real-time PCR. The results indicated that 1 and 2 inhibited HT29 cell proliferation and induced apoptosis by increasing the Bax/Bcl2 ratio and Caspase-9 and Caspase-3 mRNA expression. In conclusion, the results of this study showed that the treatment of these compounds significantly suppressed the mRNA expressions of metastasis-related genes such as Matrix Metalloproteinase-2, Matrix Metalloproteinase-9, Vascular Endothelial Growth Factor and Hypoxia­Inducible Factor 1α.

Antibacterial Potent of Acetylated and Non-Acetylated Clove Bud Essential Oils and Their Main Compounds.

Clove bud is a medicinal plant used traditionally in Asia for the treatment of various disease. Previously, Clove oil is a potential source of an antimicrobial compounds especially vis-a-vis bacterial pathogens. However, the compound responsible for this activity remains to be investigated. Essential oil (EO) clove, acetylated essential oil clove, eugenol, and acetyleugenol were evaluate as an antibacterial potential agent against Staphyloccocus aureus (SE), Escherichia coli (EC) and Pseudomonas aeruginosa (PA). Essential oil containing eugenol was extracted from buds of Eugenia caryophyllata commonly named clove (Syzygium aromaticum (L.) (Family Myrtaceae) by a simple hydrodistillation. The analysis of the essential oils (EOs) using gas chromatography-mass spectrometry (GC-MS) shows eugenol as the major constituent with 70.14 % of the total. The Eugenol was isolated from the EO using chemical treatment. Afterwards, the EO and eugenol were converted to acetylated EO and acetyleugenol, respectively using acetic anhydride. The antibacterial result revealed that all compounds showed a strong activity against the three strains. The Staphyloccocus aureus and Pseudomonas aeruginosa were extremely sensitive against eugenol with an inhibition diameters of 25 mm. The MIC values of eugenol versus S. aureus and P. aeruginosa were 0.58 and 2.32 mg/mL, respectively, while the MIB values were 2.32 mg/mL and 9.28 mg/mL.

In Vitro Antiviral Potential, Antioxidant, and Chemical Composition of Clove (Syzygium aromaticum) Essential Oil.

Viral infections are spread all around the world. Although there are available therapies, their safety and effectiveness are constrained by their adverse effects and drug resistance. Therefore, new natural antivirals have been used such as essential oils, which are natural products with promising biological activity. Accordingly, the present study aimed to identify the components of clove (Syzygium aromaticum) essential oil (EOCa) and verify its antioxidant and antiviral activity. The oil was analyzed using GC/MS, and the antioxidant capacity was evaluated as a function of the radical scavenging activity. A plaque reduction test was used to measure the antiviral activity against herpes simplex virus (HSV-1), hepatitis A virus (HAV), and an adenovirus. GC/MS analysis confirmed the presence of eugenol as the main component (76.78%). Moreover, EOCa had powerful antioxidant activity with an IC50 of 50 µg/mL. The highest antiviral potential was found against HAV, with a selectivity index (SI) of 14.46, while showing poor selectivity toward HSV-1 with an SI value of 1.44. However, no relevant effect was detected against the adenovirus. The antiviral activity against HAV revealed that its effect was not related to host cytotoxicity. The findings imply that EOCa can be utilized to treat diseases caused by infections and free radicals.

A Comprehensive in vitro and in silico Assessment on Inhibition of CYP51B and Ergosterol Biosynthesis by Eugenol in Rhizopus oryzae.

Mucormycosis, also known as Zygomycosis, is a disease caused by invasive fungi, predominantly Rhizopus species belonging to the Order of Mucorales. Seeing from the chemistry perspective, heterocyclic compounds with an "azole" moiety are widely employed as antifungal agent for minimising the effect of mucormycosis as a prescribed treatment. These azoles serve as non-competitive inhibitors of fungal CYP51B by predominantly binding to its heme moiety, rendering its inhibition. However, long-term usage and abuse of azoles as antifungal medicines has resulted in drug resistance among certain fungal pathogens. Hence, there is an unmet need to find alternative therapeutic compounds. In present study, we used various in vitro tests to investigate the antifungal activity of eugenol against R. oryzae/R. arrhizus, including ergosterol quantification to test inhibition of ergosterol production mediated antifungal action. The minimum inhibitory concentration (MIC) value obtained for eugenol was 512 µg/ml with reduced ergosterol concentration of 77.11 ± 3.25% at MIC/2 concentration. Further, the molecular interactions of eugenol with fungal CYP51B were meticulously studied making use of proteomics in silico study including molecular docking and molecular dynamics simulations that showed eugenol to be strongly interacting with heme in an identical fashion to that shown by azole drugs (in this case, clotrimazole was evaluated). This is the first of a kind study showing the simulation study of eugenol with CYP51B of fungi. This inhibition results in ergosterol synthesis and is also studied and compared with keeping clotrimazole as a reference.

Eugenol and Other Vanilloids Hamper Caenorhabditis elegans Response to Noxious Heat.

Eugenol, a known vanilloid, was frequently used in dentistry as a local analgesic in addition, antibacterial and neuroprotective effects were also reported. Eugenol, capsaicin and many vanilloids are interacting with the transient receptor potential vanilloid 1 (TRPV1) in mammals and the TRPV1 is activated by noxious heat. The pharmacological manipulation of the TRPV1 has been shown to have therapeutic value. Caenorhabditis elegans (C. elegans) express TRPV orthologs (e.g. OCR-2, OSM-9) and it is a commonly used animal model system to study nociception as it displays a well-defined and reproducible nocifensive behavior. After exposure to vanilloid solutions, C. elegans wild type (N2) and mutants were placed on petri dishes divided in quadrants for heat stimulation. Thermal avoidance index was used to phenotype each tested C. elegans experimental groups. The results showed that eugenol, vanillin and zingerone can hamper nocifensive response of C. elegans to noxious heat (32-35 °C) following a sustained exposition. Also, the effect was reversed 6 h post exposition. Furthermore, eugenol and vanillin did not target specifically the OCR-2 or OSM-9 but zingerone did specifically target the OCR-2 similarly to capsaicin. Further structural and physicochemical analyses were performed. Key parameters for quantitative structure-property relationships (QSPR), quantitative structure-activity relationships (QSAR) and frontier orbital analyses suggest similarities and dissimilarities amongst the tested vanilloids and capsaicin in accordance with the relative anti-nociceptive effects observed.

Anti-oomycetes and immunostimulatory activity of natural plant extract compounds against Saprolegnia spp.: Molecular docking and in-vitro studies.

This study aimed to investigate the effectiveness of five natural plant extract compounds Curcumin (CUR); Eugenol (EUG), Cinnamaldehyde (CIN), Stigmasterol (ST) and Morin (MOR), on two species of Saprolegnia; Saprolegnia parasitica and S. australis. Selective compounds were screened for the minimum inhibitory concentration, first for anti-oomycetes activity and then mycelium growth inhibition, spore germination inhibition and colonisation test. Nitric oxide production and myeloperoxidase activity of the compounds were tested in head kidney leukocytes of rainbow trout, Oncorhynchus mykiss to assess the immunostimulatory potential. Molecular docking of effective compounds was carried out with effector proteins of S. parasitica to investigate the target binding sites. Among all, CUR could completely inhibit zoospore production and significantly (p ≤ .05) inhibit hyphal growth at 16 mg l-1 against S. parasitica and S. australis. CIN at the concentration of 50 mg l-1 completely inhibited hyphal growth of both Saprolegnia spp., although the zoospore production of S. parasitica and S. australis was reduced at 25 mg l-1 and 10 mg l-1. In the case of EUG, significant inhibition of the hyphal growth and germination of S. parasitica zoospores was observed at 50 mg l-1. ST and MOR did not show antioomycetes activity. The molecular docking results were consistent with in vitro studies, possibly due to the binding with the vital proteins (Plasma membrane ATPase, V-type proton ATPase, TKL protein kinase, Host targeting protein 1) of S. parasitica and ultimately inhibiting their activity. CUR and CIN showed increased nitric oxide production at the highest concentration of 250 and 256 mg l-1 but the value was not significant (p ≤ .05) with control. CUR showed significantly higher peroxidase activity (p ≤ .05) at a concentration of 256 mg l-1 though values were significantly similar with concentration from 16 to 128 mg l-1. The nitric oxide and total peroxidase activity of rainbow trout leukocytes in the case of CIN showed a significant difference only at 250 mg l-1 against the control. The results conclude that CUR, CIN showed the better anti-Saprolegnia activity and could be used as phyto-additives in aquaculture. Among all, the inclusion of CUR as phyto-additives will provide additional immunostimulatory activity.

Eugenol-piperine loaded polyhydroxy butyrate/polyethylene glycol nanocomposite-induced apoptosis and cell death in nasopharyngeal cancer (C666-1) cells through the inhibition of the PI3K/AKT/mTOR signaling pathway.

Nasopharyngeal cancer is a malignancy developing from the nasopharynx epithelium due to smoking and nitrosamine-containing foods. Nasopharyngeal cancer is highly endemic to Southeast Asia. Eugenol and piperine have shown many anticancer activities on numerous cancer types, like colon, lung, liver, and breast cancer. In this study, we amalgamated eugenol and piperine loaded with a polyhydroxy butyrate/polyethylene glycol nanocomposite (Eu-Pi/PHB-PEG-NC) for better anticancer results against nasopharyngeal cancer (C666-1) cells. In the current study, nasopharyngeal cancer cell lines C666-1 were utilized to appraise the cytotoxic potential of Eug-Pip-PEG-NC on cell propagation, programmed cell death, and relocation. Eu-Pi/PHB-PEG-NC inhibits cellular proliferation on C666-1 cells in a dose-dependent manner, and when compared with 20 µg/ml, 15 µg/ml of loaded mixture evidently restrained the passage aptitude of C666-1 cells, this was attended with a downregulated expression of mitochondrial membrane potential. Treatment with 15 µg/ml Eu-Pi/PHB-PEG-NC suggestively amplified cell apoptosis in the C666-1 cells. Furthermore, its cleaved caspase-3, 8, and 9 and Bax gene expression was augmented and Bcl-2 gene expression was diminished after Eu-Pi/PHB-PEG-NC treatment. Additionally, our data established that the collective effect of Eu-Pi/PHB-PEG-NC loaded micelles inhibited the expansion of C666-1 cells augmented apoptosis connected with the intrusion of PI3K/Akt/mTOR signaling pathway.

Synthesis of New Hybrid Derivatives from Metronidazole and Eugenol Analogues as Trypanocidal Agents.

BACKGROUND: The search for new drug compounds is always challenging and there are several different strategies that involve the most varied and creative approaches in medicinal chemistry. One of them is the technique of molecular hybridisation: forming a hybrid compound from two or more pharmacophoric subunits. These hybrids may maintain the characteristics of the original compound and preferably show improvements to its pharmacological action, with reduced side effects and lower toxicity when compared to the original components. This study specifically focuses on synthesising hybrid molecules which demonstrate trypanocidal activity against the epimastigote and trypomastigote forms of Trypanosoma cruzi. METHODS: In this context, this study centres on the synthesis of a novel structural scaffold via molecular hybridisation; by using a triazole species to link a metronidazole unit to a eugenol analogue unit, the objective being to combine their therapeutic properties into a new molecular structure. The resulting hybrid molecules were evaluated against T. cruzi which is responsible for high incidences of trypanosomiasis in tropical countries such as Brazil. RESULTS: The results of this study showed an improvement in the anti-parasitic activity of the hybrid compounds with the best result coming from hybrid compounds [8] and [9], which present an activity similar to the control drug benznidazole. The new compounds, utilising a triazole species as a coupling connector, demonstrated promising results and has highlighted the path for planning similar structural patterns to investigate new compounds. CONCLUSIONS: In summary, we can conclude that the synthesised hybrid compounds demonstrate that using a triazole to link metronidazole with natural phenols, produces hybrid molecules that are promising as a new class of compounds of therapeutic interest for further investigation.

Synthesis and Anti-Oomycete Activity of 1-Sulfonyloxy/Acyloxydihydroeugenol Derivatives.

Endeavor to discover biorational natural products-based fungicides, two series (26) of novel 1-sulfonyloxy/acyloxydihydroeugenol derivatives (3a-p and 5a-j) were prepared and assessed for their fungicidal activity against P. capsici Leonian, in vitro. Results of fungicidal activity revealed that, among all compounds, especially compounds 3a, 5c, and 5e displayed the most potent anti-oomycete activity against P. capsici with EC50 values of 69.33, 68.81, and 67.77 mg/L, respectively. Overall, the anti-oomycete activities of 1-acyloxydihydroeugenol derivatives (5a-j) were higher than that of 1-sulfonyloxydihydroeugenol derivatives (3a-p). It is proved that the introduction of the acyl group at hydroxy position of dihydroeugenol is more beneficial to improve its anti-oomycete activity than that of the sulfonyl group. These preliminary results will pave the way for further modification of dihydroeugenol in the development of potential new fungicides.

Inhibitory Effect of Eugenol and trans-Anethole Alone and in Combination with Antifungal Medicines on Candida albicans Clinical Isolates.

One of the most common pathogens among yeasts is Candida albicans, which presents a serious health threat. The study aimed to check the antifungal properties of trans-anethole and eugenol with selected antifungal medicines (AMs) against C. albicans clinical isolates. The checkerboard method was used to tests of interactions between these compounds. Achieved results indicated that eugenol showed synergistic and additive activities with miconazole and econazole against investigated clinical isolates, respectively. Moreover, the combination - trans-anethole - miconazole also showed an additive effect against two clinical isolate. We tried to relate the results to changes in C. albicans cell sheaths under the influence of essential oils compounds (EOCs) performing the Fourier transform infrared spectra analysis to confirm the presence of particular chemical moieties in C. albicans cells. Nevertheless, no strong relationships was observed between synergistic and additive actions of used EOC-AMs combinations and chemical moieties in C. albicans cells.

Design, Synthesis, Antimicrobial Evaluation and in Silico Studies of Eugenol-Sulfonamide Hybrids.

Using molecular hybridization, specific sulfonamide derivatives of eugenol were synthesized with subtle modifications in the allylic chain of the eugenol subunit (and also in the nature of the substituent group in the sulfonamide aromatic ring) which allowed us to study the influence of structural changes on the antimicrobial potential of the hybrids. Antimicrobial test results showed that most of the synthesized hybrid compounds showed good activity with better results than the parent compounds. Molecular docking studies of the hybrids with the essential bacterial enzyme DHPS showed complexes with low binding energies, suggesting that DHPS could be a possible target for the antibacterial sulfonamide-eugenol hybrids. Furthermore, most of the final compounds presented similar docking poses to that of the crystallographic ligand sulfamethoxazole. The results obtained allow us to conclude that these are promising compounds for use as new leads in the search for new antibacterial sulfonamides.

Platinum nanoparticles-embedded raspberry-liked SiO2 for the simultaneous electrochemical determination of eugenol and methyleugenol.

Based on platinum nanoparticle-embedded raspberry-liked SiO2, a sensitive and selective electrochemical sensor was developed for simultaneous determination of eugenol (EU) and methyleugenol (MEU). Raspberry-liked SiO2 (RL-SiO2) was characterized with open pores on the surface, which can be used as a path for utilizing the inner space fully. So, platinum nanoparticles (Pt NPs) could be embedded in the inner and outer surface of RL-SiO2. As a carrier, RL-SiO2 not only avoided the agglomeration of the Pt NPs but also improved the catalytic performance. Therefore, the prepared Pt NPs@RL-SiO2/GCE exhibited excellent electrocatalytic activity for simultaneous determination of EU and MEU; the linearity ranges were 0.50 ~ 60 µmol/L for EU at a working potential of 0.65 V (vs. saturated calomel electrode) and 0.50 ~ 50 µmol/L for MEU at a working potential of 1.10 V; the detection limits were 0.12 µmol/L and 0.16 µmol/L (S/N=3); and the relative standard deviations (RSDs) were 3.2% and 4.5%, respectively. In addition, Pt NPs@RL-SiO2/GCE was successfully applied to the analysis of fish samples; the obtained recoveries were between 92.0 and 107%. Notably, the results conducted on samples were highly consistent with those obtained from high-performance liquid chromatography. It can be concluded that the study provided a simple method for simultaneous electrochemical determination of EU and MEU in fish samples. Schematic illustration of the preparation of RL-SiO2@Pt NPs/GCE for simultaneous determination of eugenol and methyleugenol in fish samples.

Sweet Basil Has Distinct Synthases for Eugenol Biosynthesis in Glandular Trichomes and Roots with Different Regulatory Mechanisms.

Production of a volatile phenylpropene; eugenol in sweet basil is mostly associated with peltate glandular trichomes (PGTs) found aerially. Currently only one eugenol synthase (EGS), ObEGS1 which belongs to PIP family is identified from sweet basil PGTs. Reports of the presence of eugenol in roots led us to analyse other EGSs in roots. We screened for all the PIP family reductase transcripts from the RNA-Seq data. In vivo functional characterization of all the genes in E. coli showed their ability to produce eugenol and were termed as ObEGS2-8. Among all, ObEGS1 displayed highest expression in PGTs and ObEGS4 in roots. Further, eugenol was produced only in the roots of soil-grown plants, but not in roots of aseptically-grown plants. Interestingly, eugenol production could be induced in roots of aseptically-grown plants under elicitation suggesting that eugenol production might occur as a result of environmental cues in roots. The presence of ObEGS4 transcript and protein in aseptically-grown plants indicated towards post-translational modifications (PTMs) of ObEGS4. Bioinformatics analysis showed possibility of phosphorylation in ObEGS4 which was further confirmed by in vitro experiment. Our study reveals the presence of multiple eugenol synthases in sweet basil and provides new insights into their diversity and tissue specific regulation.

Comparison of Aging Resistance and Antimicrobial Properties of Ethylene-Norbornene Copolymer and Poly(Lactic Acid) Impregnated with Phytochemicals Embodied in Thyme (Thymus vulgaris) and Clove (Syzygium aromaticum).

The effects of plant-based extracts on the solar aging and antimicrobial properties of impregnated ethylene-norbornene (EN) copolymer and poly(lactic acid) (PLA) were investigated. In this study, the impregnation yield of polyolefin, lacking in active centers capable of phytochemical bonding, and polyester, abundant in active sides, was measured. Moreover, two different extracts plentiful in phytochemicals-thyme (TE) and clove (CE)-were employed in the solvent-based impregnation process. The effect of thymol and eugenol, the two main compounds embodied in the extracts, was studied as well. Interestingly, oxidation induction times (OIT) for the impregnation of EN with thyme and clove extracts were established to be, respectively, 27.7 and 39.02 min, which are higher than for thymol (18.4 min) and eugenol (21.1 min). Therefore, an aging experiment, mimicking the full spectrum of sunlight, was carried out to investigate the resistance to common radiation of materials impregnated with antioxidative substances. As expected, the experiment revealed that the natural extracts increased the shelf-life of the polymer matrix by inhibiting the degradation processes. The aging resistance was assessed based on detected changes in the materials' behavior and structure that were examined with Fourier-transform infrared spectroscopy, contact angle measurements, color quantification, tensile tests, and hardness investigation. Such broad results of solar aging regarding materials impregnated with thyme and clove extracts have not been reported to date. Moreover, CE was found to be the most effective modifying agent for enabling material with antimicrobial activity against Escherichia coli to be obtained.

High Performance Liquid Chromatography versus Stacking-Micellar Electrokinetic Chromatography for the Determination of Potentially Toxic Alkenylbenzenes in Food Flavouring Ingredients.

Alkenylbenzenes, including eugenol, methyleugenol, myristicin, safrole, and estragole, are potentially toxic phytochemicals, which are commonly found in foods. Occurrence data in foods depends on the quality of the analytical methodologies available. Here, we developed and compared modern reversed-phase high performance liquid chromatography (HPLC) and stacking-micellar electrokinetic chromatography (MEKC) methods for the determination of the above alkenylbenzenes in food flavouring ingredients. The analytical performance of HPLC was found better than the stacking-MEKC method. Compared to other HPLC methods found in the literature, our method was faster (total run time with conditioning of 15 min) and able to separate more alkenylbenzenes. In addition, the analytical methodology combining an optimized methanol extraction and proposed HPLC was then applied to actual food flavouring ingredients. This methodology should be applicable to actual food samples, and thus will be vital to future studies in the determination of alkenylbenzenes in food.

Amino Alcohols from Eugenol as Potential Semisynthetic Insecticides: Chemical, Biological, and Computational Insights.

A series of ß-amino alcohols were prepared by the reaction of eugenol epoxide with aliphatic and aromatic amine nucleophiles. The synthesized compounds were fully characterized and evaluated as potential insecticides through the assessment of their biological activity against Sf9 insect cells, compared with a commercial synthetic pesticide (chlorpyrifos, CHPY). Three derivatives bearing a terminal benzene ring, either substituted or unsubstituted, were identified as the most potent molecules, two of them displaying higher toxicity to insect cells than CHPY. In addition, the most promising molecules were able to increase the activity of serine proteases (caspases) pivotal to apoptosis and were more toxic to insect cells than human cells. Structure-based inverted virtual screening and molecular dynamics simulations demonstrate that these molecules likely target acetylcholinesterase and/or the insect odorant-binding proteins and are able to form stable complexes with these proteins. Encapsulation assays in liposomes of DMPG and DPPC/DMPG (1:1) were performed for the most active compound, and high encapsulation efficiencies were obtained. A thermosensitive formulation was achieved with the compound release being more efficient at higher temperatures.

Suggestions on the Contribution of Methyl Eugenol and Eugenol to Bay Laurel (Laurus nobilis L.) Essential Oil Preservative Activity through Radical Scavenging.

The present study examined the radical scavenging potential of the two benzene derivatives found in the bay laurel essential oil (EO), namely methyl eugenol (MEug) and eugenol (Eug), theoretically and experimentally to make suggestions on their contribution to the EO preservative activity through such a mechanism. Calculation of appropriate molecular indices widely used to characterize chain-breaking antioxidants was carried out in the gas and liquid phases (n-hexane, n-octanol, methanol, water). Experimental evidence was based on the DPPH• scavenging assay applied to pure compounds and a set of bay laurel EOs chemically characterized with GC-MS/FID. Theoretical calculations suggested that the preservative properties of both compounds could be exerted through a radical scavenging mechanism via hydrogen atom donation. Eug was predicted to be of superior efficiency in line with experimental findings. Pearson correlation and partial least square regression analyses of the EO antioxidant activity values vs. % composition of individual volatiles indicated the positive contribution of both compounds to the radical scavenging activity of bay laurel EOs. Eug, despite its low content in bay laurel EOs, was found to influence the most the radical scavenging activity of the latter.