Concentrations Of Thymol Research Articles

Synergistic Action of Thymol-citral is Associated with Cell Cycle Arrest and Intracellular ROS Generation in A549 Cells

Objective: NSCLC is the predominant form of lung cancer, often exhibiting resistance to chemotherapy. Thymol and citral have shown promise as anticancer agents in different cancer cell lines but have not been evaluated in combination against NSCLC. Hence, we planned to investigate the anticancer effect of thymol-citral combination and explore its mechanisms of action against A549 cells. Methods: A549 cells were exposed to varying concentrations of thymol and citral, alone and in combination. Cell proliferation, plasma membrane integrity, apoptotic markers, reactive oxygen species (ROS) levels, cell cycle distribution, senescence induction, and migration potential were assessed. Additionally, in vitro safety was evaluated in human bronchial epithelial cells (HBECs) and human red blood cells (RBCs). Results: Thymol and citral showed synergistic action against A549 cells, with a CI value of 0.75. After 24 h, they induced apoptosis, caused G0/G1 phase arrest, and increased ROS levels, suggesting oxidative stress as the mechanism. This combination also induced cell senescence, significantly inhibited A549 cell migration, and was non-toxic to human RBCs and HBECs. Conclusion: Overall, the thymol-citral synergistic combination was found to be a safe and effective therapy option for non-small cell lung cancer.

Dietary Thymol Supplementation Promotes Antioxidant Responses and Thermal Stress Resistance in Rainbow Trout, Oncorhynchus mykiss.

Rainbow trout fingerlings were fed, in triplicate, diets supplemented with 0 (CTL), 50 (50 TM), 100 (100 TM), 200 (200 TM), 400 (400 TM) and 800 (800 TM) mg/kg of thymol, followed by 48 h of thermal stress. Growth performance and humoral immunological parameters showed no significant responses to dietary thymol concentrations. Fish fed 50-400 mg/kg thymol diets had significantly higher survival after heat stress. Plasma cortisol, glucose, hepatic glutathione peroxidase, glutathione reductase and erythrocyte catalase significantly increased after thermal stress, whereas total plasma antioxidant capacity, ascorbate, and hepatic/erythrocyte reduced-glutathione significantly decreased. There were significant elevations in plasma ascorbate and hepatic glutathione reductase in the 50 TM, 100 TM and 200 TM groups; plasma total antioxidant capacity in the 100 TM and 200 TM groups; hepatic glutathione peroxidase in the 200 TM group; and hepatic-reduced glutathione in the 100 TM, 200 TM and 400 TM groups, compared to CTL. The highest hepatic superoxide dismutase and lowest hepatic malondialdehyde were observed in the 100 TM group before heat stress. These parameters significantly increased after thermal stress in the treatment groups, except in the 100 TM and 200 TM groups. Hepatic catalase showed no significant difference among the treatment groups before thermal stress. Hepatic catalase significantly increased after heat stress in all treatment groups, except in the 100 TM group. Erythrocyte superoxide dismutase significantly increased in the 100 TM group before heat stress, whereas erythrocyte malondialdehyde significantly decreased in the 100 TM and 200 TM groups after thermal stress. Based on the results, 100 mg/kg of thymol can promote antioxidant power and thermal stress resistance in rainbow trout.

Extension of shelf life of tomato (Solanum lycopersicum L.) by using a coating of polyhydroxybutyrate-carboxymethyl cellulose-pectin-thymol conjugate.

This study targets explicitly finding an alternative to petroleum-based plastic films that burden the environment, which is a high priority. Hence, polymeric films were prepared with carboxymethyl cellulose (CMC) (4%), pectin (2%), and polyhydroxybutyrate (PHB) (0.5%) with different concentrations of thymol (0.3%, 0.9%, 1.8%, 3%, and 5%) and glycerol as a plasticizer by solution casting technique. The prepared films were tested for mechanical, optical, antimicrobial, and antioxidant properties. Film F5 (CMC+P+PHB+0.9%thymol) showed an excellent tensile strength of 15MPa, Young's modulus of 395MPa, antioxidant activity (AA) (92%), rapid soil biodegradation (21 days), and strong antimicrobial activity against bacterial and fungal cultures such as Klebsiella pneumoniae, Staphylococcus aureus, Escherichia coli, Aspergillus niger, and Aspergillus flavus. The thymol content increase in films F6 (1.8%), F7 (3%), and F8 (5%) displayed a decrease in mechanical properties due to thymol's hydrophobicity. For shelf life studies on tomatoes, F2, a film without thymol (poor antimicrobial and antioxidant activities), F5 (film with superior mechanical, optical, antimicrobial, and antioxidant properties), and F7 (film with low mechanical properties) were selected. Film F5 coatings on tomato fruit enhanced the shelf life of up to 15 days by preventing weight loss, preserving firmness, and delaying changes in biochemical constituents like lycopene, phenols, and AA. Based on the mechanical, optical, antimicrobial, antioxidant, and shelf life results, the film F5 is suitable for active food packaging and preservation. PRACTICAL APPLICATION: The developed active biodegradable composite can be utilized as a coating to extend the shelf life of fruits and vegetables. These coatings are easy to produce and apply, offering a sustainable solution to reduce food waste. On an industrial scale, they can be applied to food products, ensuring longer freshness without any technical challenges.

Thymol-a plant-based monoterpenoid phenol compound of an essential oil for the management of sheath blight disease of rice.

Sheath blight of rice is a global disease that significantly reduces rice yield. This study reports the antifungal activity of an active compound of essential oil, thymol, at different concentrations against Rhizoctonia solani (strain RS-Gvt). In vitro assay results indicated that thymol concentrations (0.5 mg mL-1 and 0.25 mg mL-1) completely inhibited (100%) the mycelial growth of RS-Gvt (p ≤ 0.01). Microscopic observations of thymol-treated mycelium of RS-Gvt at 0.0312 mg mL-1 and above concentrations, revealed a distorted mycelial morphology with deformed hyphae. Hyphae showed a bead-like appearance, reduction in size, and constriction of the hyphae at uneven points with increased hyphal density often entangling with each other. Further, an on-field experiment was conducted to study the field bio-efficacy of thymol for two consecutive Kharif seasons of 2022 and 2023 using a factorial RCBD design. The disease severity was measured as the percent disease index (PDI), and the results of two seasons were pooled. Pathogen (RS-Gvt) and thymol were inoculated in different combinations/methods as main treatments (M1-M3), and concentrations of thymol (0.0625-1.0 mg ML-1) as sub-treatments. The results indicated that all two factors significantly (P = 0.05) influenced the PDI and grain yield. The pooled data of two seasons indicated a significant difference between the main treatments (M1: RS-Gvt + thymol together; M2: thymol sprayed first followed by RS-Gvt; M3: RS-Gvt first followed by thymol spray) on PDI (53.39-59.67) and grain yield (4.16-4.75 t ha-1). M1 exhibited a lower PDI (53.39) and a higher grain yield (4.75 t ha-1) compared to M2 and M3, indicating a protective mode of action of thymol against sheath blight disease of rice. The sub-treatments have shown significant variation in PDI and grain yield. The PDI and grain yield ranged from 33.70 (at 1 mg mL-1) to 66.21 (at 0.0625 mg mL-1) and 4.18 (at 1 mg mL-1) to 5.26 (at 0.0625 mg mL-1) t ha-1, respectively, among the thymol concentrations. This indicates that increasing concentrations of thymol have negatively influenced the PDI and positively impacted the yield. Therefore, the spray of 1 mg mL-1 of thymol at the potential disease-infection stage is most effective in controlling the sheath blight disease of rice. This study provides an alternative green bioactive compound for controlling the sheath blight disease, and thymol can be included in developing eco-friendly integrated disease management practices. © 2024 Society of Chemical Industry.

Konjac glucomannan/microcapsule of thymol edible coating reduces okra pericarp browning by regulating antioxidant activity and ROS synthesis

Okra is susceptible to browning during storage. The effects of konjac glucomannan/microcapsule of thymol edible coating (TKL) on antioxidant activity and reactive oxygen (ROS) synthesis of okra during low-temperature storage were investigated. Thymol edible coating of thymol concentration 40 mg/mL (TKL40) had a regulatory effect on okra browning. After 14 days of storage, compared with the control group, the weight loss rate of TKL was reduced by 5.26 %, the hardness was increased by 24.14 %, and the L⁎ value was increased by 31 %. Moreover, TKL40 increased the scavenging capacity of okra for DPPH and ABTS free radicals, and activated catalase and superoxide dismutase activities by promoting the accumulation of total phenolics and flavonoids. TKL40 also reduced the cell membrane damage of okra during low-temperature storage by reducing the increase of malondialdehyde and H2O2 during okra storage. Meanwhile, it delayed the increase of relative conductivity and the production of O2.-, inhibited the activity of polyphenol oxidase in the late stage, so reduced the combination of polyphenol oxidase and phenolics to reduce the browning. Therefore, TKL40 reduces okra pericarp browning by regulating antioxidant activity and ROS synthesis.

Thymol Enhances Antibiotic Sensitivity and Inhibits Biofilm Formation in Urinary Tract Infection Isolates of Escherichia coli From Gilan Province, Iran

Background: The present study aimed to investigate the effect of thymol on growth inhibition, biofilm inhibition, and antibiotic sensitivity of Escherichia coli isolated from urinary tract infection in Gilan province, Iran. Methods: The disc diffusion and broth microdilution methods were used to investigate the antimicrobial effect of thymol on 30 urinary tract infection isolates of E. coli. Additionally, the time-kill assay was used to investigate the effectiveness of thymol at different time intervals over a period of 24 hours. The anti-biofilm effect of thymol was investigated using the microplate method. Moreover, the effect of thymol on fimH gene expression was investigated. To investigate the effect of thymol on the sensitivity of E. coli isolates to cefotaxime and ciprofloxacin, the checkerboard assay was used. Results: ThymolFF exhibits inhibitory effects on the growth of E. coli isolates and the diameter of the zone of growth inhibition caused by 5 mg of thymol in the studied isolates varied between 15 and 30 mm and minimum inhibitory concentration (MIC) of thymol against MDR E. coli isolates ranged from 1 to 4 mg/mL. Depending on the concentration and the exposure time, bacterial killing was promoted by thymol treatment. The use of thymol decreased the biofilm formation of the isolates by more than 50% compared to the control and also bacterial treatment with thymol led to down-regulation of the fimH gene. Furthermore, enhancing the antibacterial effect of cefotaxime and ciprofloxacin by thymol was demonstrated. Conclusion: The present study found that thymol, a terpenoid of plant origin, exhibited strong killing efficiency, inhibiting the biofilm formation, and enhanced antibiotic sensitivity of E. coli isolated from urinary tract infection.

Modification of the composition of thyme (Thymus vulgaris) essential oil based on the quality of the light

Objective: To identify the changes in the concentration of the main components of thyme (Thymus vulgaris) essential oil in response to five different LED colors. Design/Methodology/Approach: A completely randomized experimental design was used. The design included five treatments (white light; blue light; red light; 75% blue light and 25% red light; and 75% red light and 75% blue light) and 10 repetitions, at a 25 μmol m−2 s−1 luminous intensity, during a 16 h photoperiod. The thyme plants were sown in a pot with a substrate made up of 50% peat, 48% perlite, and 2% vermicompost. Each plant was an experimental unit. The plants were placed in light isolation chambers and subjected to the treatment for 35 days. Results: The concentration of the main molecules in the essential oil recorded considerable changes between treatments: the concentration of thymol (its main component) increased in the white light treatments, as well as in the red light (75%) and blue light (75%) treatments. In addition, the composition of the essential oil resulting from these treatments is different to the composition reported in the references. Study Limitations/Implications: The light intensity used in this experiment was lower than the light intensity required for plant growth; however, it was enough to produce changes in the secondary metabolism. Findings/Conclusions: The changes in the quality of the light modify the composition of the thyme essential oil. Even at a low light intensity (25 µmol m-2 s-1), the changes in the spectrum composition under which the plants grow influence the composition of the essential oil.

Mechanistic insight into the membrane disrupting properties of thymol in Candida species

Candida infection is a major problem in immunocompromised patients and has become a significant public health concern in recent years due to high toxicity, multidrug resistance and unfavourable side effects of conventional antifungal drugs. This study aims to investigate the antifungal efficacy of thymol, a natural monoterpenoid, on the membrane integrity of Candida albicans, Candida glabrata and Candida tropicalis. Minimum inhibitory concentrations (MICs) of thymol were 32 µg/ml, 63 µg/ml, and 125 µg/ml for C. albicans, C. tropicalis and C. glabrata, respectively. The minimum fungicidal concentrations (MFC) were 64 µg/ml, 110 µg/ml and 240 µg/ml, respectively. At MIC, thymol treated cells showed complete suppression of cell growth (growth kinetics, disc diffusion), altered morphology (scanning electron microscopy), leakage of intracellular macromolecules (absorption at 260 nm), significant reduction in ergosterol levels and inhibition of plasma membrane H+-ATPase (Pma1) activity. The disruption of the fungal membranes by thymol was further confirmed by propidium iodide uptake using flow cytometry and confocal microscopy. In silico studies with membrane-bound proteins (lanosterol 14-α demethylase (LDM) and Pma1), showed good binding affinity of −6.3 kcal/mol and −6.7 kcal/mol, respectively, and formed hydrogen bonds with crucial amino acid residues at the active site of target proteins. With low MIC values, negligible host toxicity, desirable ADME properties, thymol has immense potential as a potent antifungal drug that can be used for developing mechanism-based drugs as it has specific binding affinity for specific target proteins. Studies using animal models are required for further validation.

Thymol improves the growth performance of blue foxes by regulating the gut microbiota.

The drawbacks of using antibiotics as feed additives for blue foxes have gradually become apparent; moreover, thymol has wide-spectrum antimicrobial activity and has the potential to replace antibiotics in various animals. However, there are few reports on the effects of thymol on blue foxes. This study aimed to investigate the effects of different concentrations of thymol on the growth performance, apparent nutrient digestibility, serum biochemical indicators, intestinal morphology, and gut microbiota of blue foxes. Twenty-four male blue foxes (120 ± 5 d) of similar weight (6.05 ± 0.16 kg) were randomly divided into 4 groups. 0, 100, 200, and 300 mg/kg thymol were added to the basal diets of groups C, L, M, and H, respectively. Compared with those in the C group, the addition of 100 mg/kg thymol to the diet significantly increased organic matter (OM) digestibility, crude protein (CP) digestibility, immunoglobulin (Ig) A, IgM, the VH of the duodenum, the CD of the jejunum, the VH of the ileum, and the VH/CD of the ileum (P < 0.05) and strongly significantly increased IgG (P < 0.01). The addition of 200 mg/kg thymol to the diet increased the VH/CD of the duodenum (P < 0.05). The addition of 300 mg/kg thymol to the diet significantly increased the VH and CD of the jejunum (P < 0.05). The addition of 200 mg/kg and 300 mg/kg thymol to the diets increased the final weight (FW) (P < 0.05). Adding 100 mg/kg thymol significantly increased the levels of interleukin-4 (IL-4) and catalase (CAT) compared with those in the other groups (P < 0.05). 16S rRNA gene detection revealed that thymol can change the abundances of Bifidobacterium, Fusobacterium, Allobaculum, Streptococcus, Megasphaera, and Lactobacillus in the gut. The addition of thymol to diets can increase the abundance of Bifidobacterium, Fusobacterium, and Allobaculum, which may contribute to improving the growth performance of blue foxes.

Repelência e atividade inseticida mediada por necrose em mosquitos Aedes aegypti expostos ao timol

ABSTRACT The mosquito Aedes aegypti is a major threat to public health because it spreads several arboviruses. Since this insect is an anthropophilic mosquito that has evolved to thrive in urban settings and is common in Brazil and other tropical nations, controlling its population growth is difficult. The two basic methods of control are eradicating its breeding grounds and applying pesticides. There have been reports of pesticide resistance emerging as well as DEET's potential danger for people, particularly youngsters. Therefore, research has been done to find novel insecticides and repellents. In this way, the goal of this research was to assess thymol's insecticidal and repellent activities in Ae. aegypti. Bioassays were performed with eggs, larvae and adults exposed to different concentrations of thymol. The findings demonstrated that thymol has insecticidal effect in both the immature and adult phases, eliminating the larvae in 24 hours. In addition, necrosis was observed in hemocytes, without alteration in the production of nitric oxide by the insects. When evaluating repellency, thymol showed 99.5% of landing inhibition. This leads to the conclusion that thymol can be employed as an active component in the formulation of insecticides and repellents for the Ae. aegypti mosquito.

Effect of nanocomposite alginate-based edible coatings containing thymol-nanoemulsion and/or thymol-loaded nanostructured lipid carriers on the microbial and physicochemical properties of carrot

In this study, the effect of thymol-nanoemulsion (NE) and thymol-loaded nanostructured lipid carriers (NLC) on the physiological and microbial quality of carrot was investigated. The NE and NLC droplet sizes were 86 and 140 nm with encapsulation efficiency of 97 and 94 %, respectively. The minimum inhibitory concentration and minimum bactericidal concentration of thymol decreased in NE and increased in NLC against E. coli and S. aureus. Moreover, thymol-containing coatings exhibited a higher peroxidase activity, total phenolic content, flavonoid content, DPPH radical scavenging activity, pH, and lower respiration rate, TSS, weight loss, and decay with the preference for samples coated with NLC and NE (particularly NLC). The NE and NLC treatments significantly reduced the total viable, mold and yeast, lactic acid bacteria, and Enterobacteriaceae counts compared to the free thymol-containing coating. Results showed that the application of NE and NLC containing alginate-based coating (with the preference for NLC) improved the postharvest quality of carrot and extended its shelf life. Meanwhile, the separate application of these systems gave better results than the simultaneous application of both systems in one sample.

Anti-Helicobacter pylori Effects of Thymus caramanicus Jalas Essential Oils: A New Antimicrobial Approach.

Helicobacter pylori are the principal causative factor in the etiological factors of chronic, active, or type B gastritis; peptic and duodenal ulcers; stomach carcinoma; and epithelial tissue lymphoid malignancies. It infects more than half of the population worldwide. To reduce H. pylori production, pharmacological therapy of H. pylori diseases typically involves using threefold treatment methods. However, as a result of such therapy, antimicrobial resistance is commonly developed. Alternative therapeutics for H. pylori diseases are thus of particular interest. Thyme essential oils (EOs) obtained from T. caramanicus Jalas plants in Iran were tested for antibacterial activity against H. pylori obtained from 320 poultry specimens in this investigation. Antibacterial activity was measured using inhibition zones, minimum inhibitory concentrations (MICs), and minimum bactericidal concentrations (MBCs). The impact of T. caramanicus Jalas essential oils on H. pylori isolate cagA, vacA, and babA2 gene expression was evaluated using a quantitative real-time PCR method (p < 0.05). The chemical content of these EOs varied significantly according to chromatographic examination. Thymol, carvacrol, and terpinene-4-ol are the most abundant components in these EOs. H. pylori was recognized as a Helicobacter species with a 175-bp PCR product of 16S rRNA in 20/20 (100%). According to PCR results, all 20 (100%) isolates belonged to H. pylori. The EOs inhibited H. pylori in a dose-dependent manner, with T. caramanicus Jalas being the most effective, followed by pterygium EOs in decreasing order. At 8 mg/mL of T. caramanicus Jalas EOs, IZs against H. pylori were 27.4 ± 0.42 mm, and at 8 mg/mL of pterygium, IZs against H. pylori were 1 ± 0.02. T. caramanicus Jalas essential oils were used to treat all bacteria, and the findings showed that T. caramanicus Jalas had a substantial inhibitory impact on the expression of cagA, vacA, and babA2 virulence-related genes (p < 0.05). In a dose-dependent manner, the EOs of T. caramanicus Jalas EO demonstrated a high degree of antimicrobial property against H. pylori bacteria. The most efficient EOs were those from T. caramanicus Jalas with relative concentrations of thymol and carvacrol, followed by the coumarin-dominated pterygium EO with reduced antibacterial activity.

Voltammetric techniques for low-cost on-site routine analysis of thymol in the medicinal plant Ocimum gratissimum

The composition of essential oils varies according to culture conditions and climate, which induces a need for simple and inexpensive characterization methods close to the place of extraction. This appears particularly important for developing countries. Herein, we develop an analytical strategy to determine the thymol content in Ocimum Gratissimum, a medicinal plant from Benin. The protocol is based on electrochemical techniques (cyclic and square wave voltammetry) implemented with a low cost potentiostat. Thymol is a phenol derivative and was directly oxidized at the electrode surface. We had to resort to submillimolar concentrations (25–300 μM) in order to minimize production of phenol oligomers that passivate the electrode. We worked first on two essential oils and realized that in one of them the thymol concentration was below our detection method. These results were confirmed by gas chromatography – mass spectrometry. Furthermore, we optimized the detection protocol to analyze an infusion made directly from the leaves of the plant. Finally, we studied whether the cost of the electrochemical cell may also be minimized by using pencil lead as working and counter electrodes.

A Green Method for Nanoencapsulation of Thymol in Chitosan–Gelatin with Antioxidant Capacity

AbstractNanostructures are usually formed by solvent dissolution, but this paper proposes a green-chemistry method for thymol nano-encapsulation based on a chitosan–gelatin bio-copolymer matrix formation that enhances the physical stability to obtain a thymol-modified release system, with antioxidant capacity. Various ratios of chitosan–gelatin, gelatin types A and B, and crosslinkers were evaluated at a constant thymol concentration of 0.5 mg/ml. Gallic acid was chosen as the crosslinker. All batches were ultrasonicated to reduce particle size. The best conditions were obtained using a chitosan–gelatin ratio of 1:4 with type A gelatin, as those nanoparticles had higher physical stability, together with a smaller particle size (316.5 ± 2 nm) and higher thymol encapsulation efficiency (88 ± 3%). Antioxidant capacity was evaluated by DPPH, ABTS (radical inhibition 87.06 ± 4.38%, and 88.5 ± 4.42%, respectively), and a FRAP assay (1084.68 ± 54.32 µM Trolox equivalents). Release profiles were evaluated at two pH values (5.5, 7.0) and environmental temperatures (4, 25 °C). Diffusion was non-Fickian in all treatments. Gelatin type A systems exhibited a major physical stability, influencing the reduction of released thymol significantly. The research findings suggest that this submicronic dispersion can be used as a modified release system with high antioxidant activity and potentially serve as a preservative system during food storage.

Synergistic antimicrobial activity of essential oils in combination with phage endolysin against Salmonella Typhimurium in cooked ground beef

This study was designed to evaluate the antimicrobial activity of selected essential oils (AITC, carvacrol, eugenol, and thymol) in combination with Salmonella phage-encoding endolysin (LysPB32) against Salmonella Typhimurium KCCM 40253 in vitro and in cooked ground beef. The minimum inhibitory concentrations (MICs) of AITC, carvacrol, eugenol, and thymol against S. Typhimurium were determined in the absence and presence of LysPB32 using broth microdilution assay. In vitro antimicrobial susceptibility of S. Typhimurium to the essential oils in combination with LysPB32 was evaluated at 37 °C for 24 h using time-kill curve assay. The N-phenyl-1-napthylamine (NPN) uptake and relative bacterial fitness were measured to evaluate the outer membrane permeability and reproductive success. The morphological alterations of these treated S. Typhimurium cells were observed through a holotomographic 3D microscopy. The MICs of AITC, carvacrol, eugenol, and thymol against S. Typhimurium were significantly decreased from 6.0 to 2.9 mg/mL, 3.0 to 0.8 mg/mL, 2.8 to 0.7 mg/mL, and 1.4 to 0.7 mg/mL, respectively, when treated with LysPB32 (100 μg/mL). The combinations of carvacrol, eugenol, and thymol combined with LysPB32 effectively reduced the numbers of S. Typhimurium to below the detection limit (20 CFU/mL) after 12 h incubation at 37 °C, caused by membrane disruption. The relative bacterial fitness was significantly decreased in S. Typhimurium treated with carvacrol in the absence and presence of LysPB32. The combinations of carvacrol and eugenol with LysPB32 most effectively inhibited the growth of S. Typhimurium in cooked ground beef after 24 h of storage at 37 °C (>2 log reduction) and 7 days of refrigerated storage (>2 log reduction). Therefore, this study could provide the possibility of using the combinations of essential oils and phage endolysin as synergistic antimicrobials and also pave the way for designing effective food preservatives to enhance food safety and quality.

Electrochemical sensing of monoterpene phenols in plant essential oils using a molecularly imprinted polymer dual-template sensor

Monoterpene phenols are naturally occurring aromatic compounds found in plant essential oils, contributing to their distinct flavors, fragrances, and medicinal properties. Thymol and carvacrol, major constituents of thyme and oregano essential oils, have garnered significant attention due to their diverse biological activities. Here, we propose the development of a novel double template molecular imprinted electrochemical sensor (DT-MIP sensor) for the selective and simultaneous detection of thymol and carvacrol. The sensor's performance was optimized by varying the quantity of functional monomer, cross-linker, and template molecules during MIP synthesis. The DT-MIP sensor demonstrated superior recognition properties and high sensitivity, with detection limits of 0.11 μM for carvacrol and 0.24 μM for thymol. Selectivity tests confirmed minimal interference from potential interfering agents. GC-MS analysis validated the sensor's accuracy in detecting thymol and carvacrol concentrations in thyme and oregano essential oils. The simplicity, cost-effectiveness, and portability of the DT-MIP sensor offer promising applications in food quality control, environmental monitoring, and medical diagnostics.

Antioxidant and Antimicrobial Activity of Essential oil Extracted from Trachyspermum Ammi (ajwain) Seeds: an In-vitro Study

The food industry uses essential oils derived from natural sources as flavouring and preservatives. The purpose of this study is to investigate how temperature affects the essential oil extracted from Trachyspermum ammi, seeds which has the best antioxidant and antimicrobial properties, in order to find a green substitute for toxic chemically produced preservatives used in food and pharmaceutical chemistry. Trachyspermum ammi (ajwain seeds) seeds were hydrodistilled at various temperatures (60°C to 90°C). The amount of essential oil was found to decrease on increasing temperature (2.1ml, 1.5 ml and 1.0 ml at 70°C, 80°C, and 90°C respectively). Hence, 70°C was the ideal temperature for extracting the essential oil from ajwain seeds. 25 components were discovered in the essential oil extracted from ajwain seeds by GC-MS technique. The predominant ingredient was shown to be thymol (31.40%). The percentages of scavenger activity against hydrogen peroxide were 70.75%, 86.99%, and 95.28% for 70°C, 80°C, and 90°C respectively. Due to the presence of the largest concentration of thymol (67.66%), the results showed that essential oil extracted at 90°C demonstrated the highest level of antioxidant property. By using the disc diffusion method, the antimicrobial activity of an essential oil made from ajwain seeds was evaluated. MIC50 of standard essential oil of Trachyspermum ammi seeds against gram positive strain was observed 10 µL/mL of culture and 25µL/mL of culture was observed against gram negative bacteria. Essential oil extracted at 70°C showed antimicrobial activity by forming zones of inhibition with diameters including discs of 18.3 mm and 14.36 mm against S. aureus and E. coli, respectively. Essential oil extracted at 80°C produced zones of inhibition with diameters of 18.68 mm and 15.30 mm, respectively. In the case of essential oil extracted at 90°C, the zones of inhibition against S. aureus and E. coli had diameters of 18.690.3 mm and 15.38 mm, respectively. As a result, using Trachyspermum ammi essential oil as a food preservative and the temperature at which it is extracted are unaffected by an increase in extraction temperature. Hence, essential oil obtained from Trachyspermum ammi seeds can be used as green alternative of chemically synthesized toxic preservatives used in food and pharmaceutical chemistry.

Impact of sodium alginate-based film loaded with resveratrol and thymol on the shelf life of cooked sausage and the inoculated Listeria monocytogenes.

In present study, sodium alginate biodegradable films containing different concentrations of resveratrol (RES: 0.002% and 0.004%) or thymol (THY: 0.5% and 1%) and their combinations were prepared, and evaluated for their effects on spoilage-related microbial profile, lipid oxidation, sensory properties, and protective effects against Listeria monocytogenes in beef mortadella sausage during 40 days storage at 4°C. The release rate of phenolic compounds was determined by the Folin-Ciocalteu test. To assess the shelf life of the product, changes in total viable count (TVC), lactic acid bacteria count (LAB), psychrotrophic bacteria count (PTC), pH levels, thiobarbituric acid reactive substances (TBARS) levels, and sensory characteristics (taste, color, odor, and overall acceptability) were evaluated. For the sensory evaluation, a panel of 70 semi-trained judges was selected according to their initial performance. Samples wrapped with sodium alginate films containing 1% THY (alone or combined with different concentrations of RES) exhibited lower bacterial counts compared to other experimental groups at the end of the storage period (6.01-6.35 vs. 6.71-8.17 log10 CFU/g for TVC, 5.37-5.83 vs. 6.07-7.11 log10 CFU/g for LAB, 5.08-5.18 vs. 5.40-7.23 log10 CFU/g for PTC, and 6.53-6.92 vs. 7.23-9.01 log10 CFU/g for inoculated L. monocytogenes). Sodium alginate films containing the combination of 0.004% RES and different concentrations of THY showed higher antioxidant effects than other experimental groups (TBARS values of 1.68-1.99 vs. 2.23-3.80 mg MDA/kg sample). The sodium alginate film containing 0.004% RES + 1% THY exhibited the highest antimicrobial and antioxidant activities and highest sensory scores among all treatments. These findings highlight the potential application of the sodium alginate film containing a combination of RES and THY as an active packaging material with natural preservatives in the meat products industry. This application can effectively extend the shelf life and enhance the microbial safety of clean-label cooked sausages during refrigerated storage.

The Preharvest Application of Essential Oils (Carvacrol, Eugenol, and Thymol) Reduces Fungal Decay in Lemons

Lemon postharvest losses are mainly due to the presence of fungal diseases. Current postharvest decay strategies rely on synthetic chemical fungicides; however, consumers are demanding that fruit is free of any chemical residue. The use of new natural alternatives, including essential oils, is emerging due to their potential antimicrobial activity. Therefore, the aim of this work is the elucidation of the effect of carvacrol, eugenol, and thymol, individually and in combination, applied in preharvest. Three different concentrations (100, 500, and 1000 µL/mL) of carvacrol, eugenol, and thymol were individually applied and in combination in ‘Fino’ and ‘Verna’ lemon cultivars. The fungal incidence (mainly Penicillium digitatum and P. italicum) was evaluated weekly for 35 days. Moreover, the main different quality parameters (weight loss, firmness, colour, total soluble solids, titratable acidity, and total phenolic content) of lemons were evaluated at harvest and after 35 days of cold storage. The results showed that carvacrol at the lowest concentration (100 µL/L) provided the lowest fungal incidence with a non-negative effect on the lemon quality parameters during storage, while the highest concentrations and the combination of essential oils resulted in the opposite effect. Therefore, carvacrol applied at 100 µL/L in preharvest could be an eco-friendly alternative to the current fungicides to control lemon decay, while maintaining their optimal quality.

Minimal Inhibitory Concentrations of Thymol and Carvacrol: Toward a Unified Statistical Approach to Find Common Trends.

Thymol and carvacrol are some of the most important and used components of Essential oils (EOs); they are widely studied, and there are much data available in the literature. Their Minimal Inhibitory Concentration (MIC) values found in the literature from 2005 to present were used to assess the bioactivity toward yeasts, molds, Gram-positive bacteria, and Gram-negative bacteria, as well as on some bacterial species/serotypes (Salmonella sp., Escherichia coli, E. coli O157:H7, lactic acid bacteria, Listeria monocytogenes, Staphylococcus aureus, S. epidermidis, etc.) to find possible common trends or differences between the two compounds and among the tested species. The results were quite interesting and pointed out that there is a common range for the MIC of thymol and carvacrol for some bacterial species (150-400 mg/L), with some exceptions to this generalized statement. In addition, the statistics pointed out that bacteria could experience homogeneous (S. epidermidis, E. coli O157:H7) or heterogeneous trends (for example, Salmonella sp.) depending on the existence of possible sub-species or different experimental set-ups. Moreover, this paper suggests that there are some drawbacks and issues that should be solved for the effective use of EOs, which are the strong variability among the microorganisms and the lack of standard protocols and reference strains.