Search Results (643)

Oregano (Origanum vulgare L.) and thyme (Thymus mastichina L.) are popular aromatic plants used in the culinary sphere and are known for their antioxidant capacity. This study investigates the variability in the antioxidant capacity and phenolic profiles, focusing on flavonoids and phenolic acids, of oregano and thyme accessions from the Portuguese Bank of Plant Germplasm. The antioxidant capacity was assessed by measurements using the ferric-ion-reducing antioxidant power and DPPH radical scavenging activity assays, Total Phenolic Content, and individual phenolic compounds. Oregano extracts presented the highest total phenolic content (~2152 mg GAE/g DW), while thyme extracts showed the highest ferric-reducing antioxidant powers. However, both aromatic plants (~0.58 mmol TE/g DW) presented similar DPPH radical scavenging capacities. Rosmarinic acid was the major phenolic compound in methanolic extracts from oregano and thyme, but higher amounts were found in thyme (23.11 to 40.45 mg/g DW). The accessions of oregano and thyme showed statistical differences in the phenolic content and antioxidant capacity. This study provides valuable insights into the phenolic profile of Portuguese oregano and thyme, which could constitute potential sources of natural antioxidants and bioactive compounds, to be used by the food industry as natural food additives. Full article

The bacterium Staphylococcus epidermidis is the main cause of most infections related to medical devices and prosthesis. However, current disinfection methods are not satisfactory; a new one is proposed here. S. epidermidis was spiked in a cotton gauze and then treated with supercritical CO₂ mixed with essential oils, such as lemon, cinnamon, oregano, clove, and peppermint, and isolated thymol. The operation took 30 min at 10.0 MPa and 40 °C. Concentrations of 1000, 500, and 200 ppm of the essential oils were used. These additives, which have antimicrobial power by themselves, improved the inactivation with supercritical CO₂. The peppermint essential oil was the most effective. The presence of water from 200 ppm also improved the disinfection. Thus, S. epidermidis total inactivation was achieved with the supercritical CO₂ containing 200 ppm of peppermint essential oil and 200 ppm of water. An evaluation of the gauze before and after disinfection was realized by DSC, FTIR, and SEM. At the optimal conditions, there were no significant physical or chemical changes. Furthermore, no essential oil residuals were found. This disinfection method could be established in the healthcare field as an alternative to toxic liquid chemicals. Full article

Carpesium macrocephalum, a species native to China, Korea, Japan, and Russia, has been used medicinally in the countries of its origin. Though mono- and sesquiterpenoids are known constituents of C. macrocephalum, the complete analysis of essential oils produced by the roots and aerial parts of the plant has not been published until now. The present study discloses considerable differences in the composition and cytotoxic activity of essential oils distilled from roots and shoots of C. macrocephalum. The GC-MS-FID analyses have led to the identification of 131 compounds in all, of which 114 were found in aerial parts and 110 in the roots of the plants. The essential oil distilled from shoots contained a mixture of nerol and thymol methyl ether (c. 26%), neryl isobutyrate (c. 12%) and linalool (c. 9%) as major constituents, whereas alantolactone (c. 29%), thymol methyl ether (c. 7%) and 2,5-dimethoxy-p-cymene (thymohydroquinone dimethyl ether, c. 7%) predominated in the essential oil obtained from the roots. The oils demonstrated weak antibacterial activity against Staphylococcus aureus and, at concentrations up to 2.08 mg/mL (oil from the aerial parts) and up to 3.38 mg/mL (oil from roots), were inactive against Gram-negative bacteria. The essential oil from the roots of the plant demonstrated strong but not selective cytotoxic activity. Full article

Origanum vulgare ssp. hirtum essential oil (OEO) is a natural oil with high therapeutic potential. For some applications, however, the development of novel formulations is still needed to improve the bioavailability and stability of OEO. In this study, we describe the fabrication of an original nanocomposite hydroxypropyl cellulose (HPC) physical hydrogel, containing OEO-loaded polymeric micelles, for topical delivery. The concentration of the main active compounds of OEO—carvacol and thymol—was determined using gas chromatography (GC) analysis. OEO was first encapsulated into Pluronic F127 micelles, and then embedded into HPC gel. Micellar and gel formulations of pure polymers and OEO-containing systems were characterized by dynamic light scattering (DLS) and rheology measurements, respectively. Selected formulations were evaluated for cytotoxicity and antiproliferative activity. The hydrogel formulation of HPC with micellar OEO (8% HPC, 2% F127, 1% OEO) exhibited sustained release of the oil and selectivity towards SH-4 tumor cells (an in vitro model of melanoma). Full article

The aim of this study was to determine the activity of common thyme (Thymus vulgare L.), Greek oregano (Origanum vulgare L. ssp. hirtum), and common oregano (Origanum vulgare L. ssp. vulgare) essential oils (EOs) against selected phytopathogenic microorganisms in relation to their chemical profile. The EOs were obtained from the herbs of 2-year-old plants cultivated in the organic farming system in a temperate climate in Central Europe. The EOs’ composition was determined by GC/MS and GC/FID. The investigated species were represented by the following three chemotypes: ‘thymol’ for common thyme, ‘carvacrol’ for Greek oregano, and mixed ‘caryophyllene oxide + β-caryophyllene’ for common oregano. The antimicrobial activity of the EOs was assessed based on minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC) values. The plant pathogenic bacteria Pseudomonas syringae, Xanthomonas hortorum, Erwinia carotovora, and fungi: Fusarium culmorum, Alternaria alternata, Botrytis cinerea, Epicoccum purpurascens, Cladosporium cladosporioides, Phoma strasseri, and Pythium debaryanum were tested. The EOs revealed a stronger inhibitory effect against fungal growth in comparison to bacterial growth (MIC: 0.016–2 µL/mL for fungi and 0.125–4 µL/mL for bacteria). Common thyme and Greek oregano EOs indicated stronger antimicrobial power than common oregano EO. These results were associated with the chemical profile of the analysed EOs. The growth of examined bacteria and fungi strains (in particular, X. hortorum, F. culmorum, and P. debaryanum) were negatively correlated with the content of phenolic monoterpenes and monoterpene hydrocarbons. Among the tested strains, P. strasseri turned out to be the most sensitive (MIC 0.016 µL/mL) and E. carotovora the most resistant (MIC 0.250–4 µL/mL) to all investigated EOs. Full article

This study determined the antioxidant and antibacterial activities of Thymus schimperi (Ts), Rhamnus prinoides (Rp), and Justicia schimperiana (Js) from Addis Ababa against MDR-Uropathogenic bacteria. Accordingly, Thymus schimperi had the highest total phenolic (TPC), flavonoid (TFC) and proanthocyanidin content. In Ts, the GC-MS analyses predicted 14 bioactive compounds. And among these, hexanedioic acid, bis(2-ethylhexyl) ester, thymol, and o-cymen-5-ol were the most predominant compounds, respectively. Six compounds were also predicted in Rp, where hexanedioic acid, bis(2-ethylhexyl) ester, β-D-glucopyranoside, methyl, and desulphosinigrin were the predominant, respectively. Whereas in the Js extract, five bioactive compounds were predicted, with hexanedioic acid, mono (2-ethylhexyl) ester, debrisoquine, and 8,11,14-heptadecatrienoate, methyl ester being predominant compounds, respectively. The extracts’ TPC showed a strong negative correlation with the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay (r = −0.999; p = 0.023). In addition, the TFC correlated significantly with the ABTS (2,2′-azino-di-(3-ethylbenzthiazoline sulfonic acid)) assay (r = 0.999; p = 0.032). Thymus schimperi showed the highest antibacterial activity against clinical isolates of Escherichia coli and Klebsiella pneumoniae ESBL at 1000 mg/mL, and Ts had the lowest MIC (4 mg/mL) among evaluated extracts against E. coli (ATCC25922). In conclusion, Ts and Rp possess higher predicted bioactive molecules, including antioxidant and antibacterial activities, which are potentially useful in treating urinary tract infections. Full article

Ticks pose a significant threat due to their ability to lay thousands of eggs, which can persist in the environment for extended periods. While the impact of various compounds on adult and larval ticks has been studied, research on their efficacy against tick eggs is limited. This study evaluated the ovicidal activity of commercial acaricides, disinfectants, and natural products against Rhipicephalus annulatus eggs using the egg hatch assay (EHA). Deltamethrin and cypermethrin caused a non-significant inhibition of hatching (IH%), even at concentrations higher than the recommended levels. By contrast, the acaricides chlorpyrifos, phoxim, and amitraz significantly inhibited hatching at all tested concentrations. Ivermectin also demonstrated significant IH% at various concentrations but did not fully inhibit the hatching process. Among the disinfectants tested, Virkon-S^®, TH4, and Chlorox showed insignificant effects, whereas formalin achieved an IH% of only 34.1% at a high concentration of 200 mg/mL. Natural products, carvacrol and thymol, exhibited significant ovicidal activity, with a significant IH%. In a semi-field application, phoxim (0.5 mg/mL) and deltamethrin (0.05 mg/mL) were sprayed on tick eggs on pasture soil from a farm. The results indicated that phoxim-treated eggs had a 40% IH%, while deltamethrin-treated eggs showed only an 8.79% IH%. In conclusion, the acaricides amitraz, phoxim, and chlorpyrifos, as well as the natural products carvacrol and thymol, caused significant toxicity to R. annulatus eggs. Full article

A novel, simple, rapid, and non-expensive analytical method based on square wave voltammogram at Pt-microelectrode coupled with partial least square multivariate calibration was used for the simultaneous quantitation of thymol (THY) and carvacrol (CAR) in thyme and oregano essential oils. Results demonstrated that the multivariate calibration method successfully exploited the first-order advantage, rendering highly satisfactory quantitative figures (average recoveries not statistically different than 100%). Moreover, the results agree well with those obtained from the official analytical method. Last, the method’s environmental sustainability was asserted using the AGREE metric, highlighting its eco-friendly nature. More importantly, the proposed analytical procedure does not require previous sample preparation or electrode surface modification. The results underscore the suitability of the method for determining THY and CAR in essential oils at low concentrations (LOD ~ 7.6 µM) with REP% below 5.6%, meeting the requirements of the green analytical chemistry. Full article

Silica (SiO₂) particles are widely used in various industries due to their chemical inertness, thermal stability, and wear resistance. The present study describes the preparation and potential use of porous hydrophobic and hydrophilic SiO₂ microcapsules (MCs) of a narrow size distribution. First, various layers of SiO₂ micro/nano-particles (M/NPs) were grafted onto monodispersed polystyrene (PS) microspheres of a narrow size distribution. Hydrophobic and hydrophilic sintered SiO₂ MCs were then prepared by removing the core PS from the PS/SiO₂ core–shell microspheres by burning off under normal atmospheric conditions or organic solvent dissolution, respectively. We examined how the size and quantity of the SiO₂ M/NPs influence the MC’s properties. Additionally, we utilized two forms of hollow SiO₂ MC for different applications; one form was incorporated into polymer films, and the other was free-floating. The hydrophobic microcapsules filled with 6% hydrogen peroxide were effective in killing the tomato brown rugose fruit virus (ToBRFV). The hydrophilic microcapsules filled with thymol and thin coated onto polypropylene films were successfully used to prevent mold formation for hay protection. Full article

Consumer demand for high-quality meat has increased. This study aimed to investigate the potential application of cocrystals of thymol and carvacrol in broilers for high-quality meat production. Eight hundred 1-day-old chicks were assigned to four groups fed diets supplemented with 0, 40, 60, and 80 mg/kg of Crystal EO^® (CEO), containing 25% cocrystals of thymol and carvacrol in a 42-d feeding trial. The results showed that dietary CEO supplementation decreased the muscle fiber diameter and increased the muscle fiber density, glycogen content, L*_{45 min} value, and proportion of α-linolenic acid in the breast muscle; dietary 40 and 60 mg/kg of CEO decreased the lactate content, MDA concentration, cooking loss, shear force, and thrombogenicity index and increased the proportion of lauric acid in the breast muscle; dietary 60 and 80 mg/kg of CEO increased the glucose content, total superoxide dismutase, and total antioxidant capacity levels of breast muscle. Citrate synthase activity, free radical scavenging capacity, pH_{24 h} and a*_{45 min} values, and the cystine content in the breast muscle were especially higher in the 60 mg/kg CEO group compared to the control group. Collectively, dietary CEO supplementation improved meat quality and nutritional values and enhanced the antioxidant capacity of broiler meat, with 60 mg/kg of CEO having the greatest effect. Full article

This study focused on the evaluation of the phytotoxic activity of four essential oils (EOs) from the Mediterranean species of Thymus sp. pl., namely Thymus algeriensis Boiss. et Reut., T. ciliatus Desf. subspecies coloratus (Boiss. et Reut.) Batt., T. vulgaris L. ecotype Fasano and T. vulgaris cultivar L. Varico 3, to identify new biomolecules with herbicide potential. The chemical characterization of EOs was performed by GC-MS. The evaluation of the phytotoxicity of the EOs was conducted under in vitro conditions, and the inhibition of germination and seedling growth of Lolium perenne L. and Amaranthus retroflexus L. were assessed. Five concentrations (100, 250, 500, 750 and 1000 µL/100 mL) were considered. Phytochemical analysis revealed a great diversity of compounds. T. algeriensis and T. ciliatus EOs were characterized by the absence of carvacrol and a low content of thymol in T. ciliatus. On the contrary, T. vulgaris ecotype Fasano and T. vulgaris cultivar Varico 3 were characterized by an important content of p-cymene, thymol and carvacrol. All the EOs expressed a potent phytotoxic activity against the tested species. The total inhibition of seed germination and seedling growth were recorded for the highest concentrations of all the EOs. T. vulgaris ecotype Fasano expressed the most effective activity. Full article

In this study, headspace–bar adsorptive microextraction (HS-BAµE) combined with gas chromatography–mass spectrometry (GC-MS) was employed to screen the major biogenic volatile organic compounds (BVOCs) emitted by six different Portuguese shrub species (Erica scoparia L., Cistus ladanifer L., Cistus monspeliensis L., Lavandula stoechas L., Thymus villosus L., and Thymus camphoratus). The HS-BAµE/GC-MS methodology was developed, optimized, and validated using five common monoterpenoids (α-pinene, β-pinene, limonene, 1,8-cineole, and thymol) and one sesquiterpenoid (caryophyllene oxide). Under optimized experimental conditions (microextraction-sorbent phase: activated carbon (CN1), 3 h (35 °C); back-extraction: n-C₆ (1 h)), good efficiencies (>45%), low analytical thresholds (5.0–15.0 µg/L) and suitable linear dynamic ranges (20.0–120.0 µg/L, r² > 0.9872) were achieved, as well as acceptable intra and inter-day precisions (RSD ≤ 30.1%). Benchmarking the proposed methodology, HS-BAµE(CN1), against the reference methodology, HS-SPME(PDMS/DVB), revealed comparable analytical responses and demonstrated excellent reproducibility. Among the six shrub species studied, Thymus camphoratus exhibited the highest emissions of BVOCs from its leaves, notably, 1,8-cineole (4136.9 ± 6.3 µg/g), α-pinene (763.9 ± 0.5 µg/g), and β-pinene (259.3 ± 0.5 µg/g). It was also the only species found to release caryophyllene oxide (411.4 ± 0.3 µg/g). The observed levels suggest that these shrub species could potentially serve as fuel sources in the event of forest fires occurring under extreme conditions. In summary, the proposed methodology proved to be a favorable analytical alternative for screening BVOCs in plants. It not only exhibited remarkable performance but also demonstrated user- and eco-friendliness, cost-effectiveness, and ease of implementation. Full article

Bacterial biofilm on implants may cause inflammation, which disturbs the process of the implant’s integration with the surrounding tissues. Such problems are becoming critical for patients’ health, especially in connection with the presence of antibiotic-resistant bacterial strains. Among the existing alternatives for drug treatments are natural-based substances. This study focused on the examination of silica coatings with curcumin and thymol, which were deposited using the sol-gel method on 3D printouts made of Ti6Al4V ELI. This substrate material is commonly used in medicine. The selective laser melting technique used for the manufacturing of samples was in line with the existing procedures applied for individual orthopedic implants. The examination involved the assessment of the coatings’ morphology, chemical composition, and biological effect. The antibacterial properties were tested using a flow cytometer using Escherichia coli, and the cytotoxicity on Saos-2 cells was assessed using the LIVE/DEAD test. The obtained results showed that it is possible to produce silica sol-gel coatings with the addition of specific natural substances in concentrations assuring a bacteriostatic effect. The produced coatings did not show any cytotoxic effect, which confirms the possibility of using both curcumin and thymol as additives to coatings used in medicine, e.g., for orthopedic implants. Full article

This study evaluates the physicochemical properties, phenolic and flavonoid content, antioxidant activity, and molecular docking interactions of honey from eastern Morocco. Analysis confirmed compliance with European Commission standards, with moisture content ranging from 15.39% to 19.74% and pH between 3.79 and 4.94. Carob honey exhibited the highest protein content (0.42%), polyphenol concentration (720.16 mg gallic acid/kg), flavonoid content (90.5 mg catechin/kg), and antioxidant activity (63.5% DPPH inhibition). Strong correlations were observed between phenolic and flavonoid content and antioxidant properties. Molecular docking identified ethyl phenylacetate and thymol as key compounds with significant interactions with cytochrome c peroxidase, suggesting potential therapeutic effects. DFT calculations supported these findings, indicating these compounds may enhance antioxidant activity. The study highlights the exceptional quality and antioxidant capacity of honey from eastern Morocco, reflecting its unique floral sources and potential as a natural source of antioxidants with therapeutic benefits. Full article

Binary terpenoid-based eutectic systems consisting of the natural substances camphene (CA), fenchol (FE), thymol (TH), menthol (ME), dodecanoic acid (DA), and 1-dodecanol (DO) are synthesized and screened for their Solid–Liquid Equilibrium (SLE) and eutectic compositions. Out of nine eutectic systems, 13 solvent compositions at eutectic points and next to them, in addition to the reference solvent, TH:ME, are synthesized and applied for the solvent extraction of the aromatic aldehydes vanillin (VAN), syringaldehyde (SYR), and p-hydroxybenzaldehyde (HYD) from an acidic aqueous model solution. The extraction efficiency is determined from aldehyde concentrations measured by High-Performance Liquid Chromatography (HPLC), taking into consideration mutual solubility measured by Karl Fischer titration (KF) and a Total Organic Carbon-analysis (TOC). Physicochemical properties, such as the density, viscosity, and stability of the solvents, are evaluated and discussed. Additionally, ¹H-NMR measurements are performed to verify hydrogen bonding present in some of the solvents. The results show that all synthesized eutectic systems have a strong hydrophobic character with a maximum water saturation of ≤2.21 vol.% and solvent losses of ≤0.12 vol.% per extraction step. The hydrophobic eutectic solvents based on CA exhibit lower viscosities, lower mutual solubility, and lower extraction efficiency for the aromatic aldehydes when compared with FE-based solvents. The highest extraction efficiencies for VAN (>95%) and for SYR (>93%) at an extraction efficiency of 92.61% for HYD are achieved by the reference solvent TH:ME (50:50 mol.%). With an extraction efficiency of 93.08%, HYD is most preferably extracted by the FE–DO-solvent (80:20 mol.%), where the extraction efficiencies for VAN and SYR reach their maximum at 93.37% and 90.75%, respectively. The drawbacks of the high viscosities of 34.741 mPas of the TH:ME solvent and 31.801 mPas of the FE–DO solvent can be overcome by the CA–TH solvent, which has a viscosity of 3.436 mPas, while exhibiting extraction efficiencies of 71.92% for HYD, >95% for VAN, and >93% for SYR, respectively. Full article