The impact of carvacrol on the larval gut bacterial structure and function of Lymantria dispar.

Introduction: The gut bacteria of insects play an important role in regulating their metabolism, immune system and metabolizing pesticides. Our previous results indicate that carvacrol has certain gastric toxic activity on Lymantria dispar larvae and affects their detoxification metabolism at the mRNA level. However, the impact of carvacrol on the gut bacteria of L. dispar larvae has been unclear. Methods: In this study, the 16S rRNA sequencing technology was used to sequence and analyze the gut bacteria of the larvae which were exposed with sublethal concentration (0.297 mg/mL) and median lethal concentration (1.120 mg/mL), respectively. Results: A total of 10 phyla, 16 classes, 47 orders, 72 families, 103 genera, and 135 species were obtained by using a 97% similarity cutoff level. The dominant bacterial phyla in the gut of the L. dispar larvae are Firmicutes and Proteobacteria. The treatment with carvacrol can significantly affect the structure of gut bacteria in the larvae of the L. dispar. At both doses, carvacrol can shift the dominant gut bacteria of the larvae from Proteobacteria to Firmicutes. At the genus level, two doses of carvacrol can significantly enhance the relative abundance of probiotic Lactobacillus in the gut of L. dispar larvae (p ≤ 0.01). Additionally, significant differences were observed among the five bacterial genera Burkholderia-Caballeronia-Paraburkholderia, Anoxybacillus, Pelomonas, Mesorhizobium (p ≤ 0.05). The analysis of α-diversity and ß-diversity indicates that the treatment with carvacrol at two doses significantly affect the bacterial richness and diversity in the larvae. However, the results of functional classification prediction (PICRUSt) indicate that carvacrol significantly down-regulate 7 functions, including Energy metabolism, Cell growth and death, and up-regulate 2 functions, including Carbohydrate metabolism and Membrane transport. The network analysis indicates that the correlation between gut bacteria also has been changed. In addition, the insecticidal activity results of carvacrol against L. dispar larvae with gut bacteria elimination showed that gut bacteria can reduce the insecticidal activity of carvacrol against L. dispar larvae. Discussion: This study provides a theoretical foundation for understanding the role of gut bacteria in detoxifying plant toxins and conferring pesticide resistance.

Early-life immunomodulation by carvacrol delivered in ovo in broiler chickens.

In the first 2 wk after hatching, broiler chickens are vulnerable to enteric pathogens due to underdeveloped gastrointestinal and immune systems. Carvacrol has been reported to improve digestive and immune functions. This study aimed to optimize immune development of broiler chickens by delivering carvacrol in ovo. Effects of 2 in ovo treatments delivered at embryonic day (E)17.5 (saline or carvacrol) were evaluated at 3 stages (E19.5, hatch, and d 14 posthatch). Hatchability, performance parameters, lymphoid organ and yolk sac weights were determined. Histomorphology assessment was performed for jejunal samples at hatch and bursa of Fabricius samples at hatch and d 14. Gene expression of immune-relevant genes was determined for jejunal, bursal, and yolk sac samples over time. At hatch, BW was 0.85% lower (P = 0.02) after in ovo carvacrol delivery compared to the controls. Interactions between in ovo treatment and age were found for gene expression. At hatch, carvacrol treatment resulted in lower expression of proinflammatory cytokines IL-8 and IFN-γ in the yolk sac compared to the controls (P = 0.05 and < .001, respectively) suggesting a potential role for carvacrol-mediated immune modulation. At d 14, carvacrol treatment led to lower expression of proinflammatory cytokine IL-6 in the bursa compared to the controls (P = 0.002). In ovo carvacrol delivery led to bursal histomorphometric changes, including a larger cortex in the bursal follicles (P = 0.03), and a higher cortex/medulla ratio (P = 0.04) compared to the controls, indicating increased B-cell stimulation and maturation. Main effects were found for carvacrol treatment in the jejunum, with overall higher expression of proinflammatory mediators IL-1ß and NF-κB, and anti-inflammatory IL-10 compared to the controls (P = 0.04, 0.02, and 0.02 respectively) from E19.5 to d 14. Age-related main effects showed various alterations in expression dynamics of immune-related genes across all tissues over time. Our findings suggest changes in immune parameters occur as the chicken develops, but these mostly do not interact with in ovo carvacrol treatment. In ovo carvacrol treatment alters immune activity of broiler chickens independent of age.

Repellency, Fumigant Toxicity, Antifeedent and Residual Activities of Coridothymus capitatus and Its Main Component Carvacrol against Red Flour Beetle.

Tribolium castaneum is a challenging pest of stored products, causing significant economic losses. The present study explored the efficacy of Coridothymus capitatus essential oil and its primary constituent, carvacrol, as eco-friendly alternatives for managing this pest. To evaluate their insecticidal potential, repellency, fumigant toxicity, and antifeedant properties, progeny inhibition assays were performed. Carvacrol exhibited superior repellency compared to the essential oil, achieving a 92% repellency rate at 2 mg/cm2. Both compounds demonstrated significant fumigant toxicity against T. castaneum, with LC50 values of 168.47 and 106.5 µL/L for the essential oil and carvacrol, respectively, after 24 h. Carvacrol also outperformed the essential oil in antifeedant activity, inducing an 80.7% feeding deterrence at 1.17 mg/g. Moreover, both treatments effectively suppressed the development of the pest's progeny. These results collectively underscore the potent insecticidal properties of C. capitatus essential oil and carvacrol, particularly carvacrol, as promising candidates for the sustainable management of T. castaneum in stored product protection.

The ameliorative effect of carvacrol on sodium arsenite-induced hepatotoxicity in rats: Possible role of Nrf2/HO-1, RAGE/NLRP3, Bax/Bcl-2/Caspase-3, and Beclin-1 pathways.

Arsenic is a toxic environmental pollutant heavy metal, and one of its critical target tissues in the body is the liver. Carvacrol is a natural phytocompound that stands out with its antioxidant, anti-inflammatory, and antiapoptotic properties. The current study aims to investigate the protective feature of carvacrol against sodium arsenite-induced liver toxicity. Thirty-five Sprague-Dawley male rats were divided into five groups: Control, Sodium arsenite (SA), CRV, SA + CRV25, and SA + CRV50. Sodium arsenite was administered via oral gavage at a dose of 10 mg/kg for 14 days, and 30 min later, CRV 25 or 50 mg/kg was administered via oral gavage. Oxidative stress, inflammation, apoptosis, autophagy damage pathways parameters, and liver tissue integrity were analyzed using biochemical, molecular, western blot, histological, and immunohistological methods. Carvacrol decreased sodium arsenite-induced oxidative stress by suppressing malondialdehyde levels and increasing superoxide dismutase, catalase, glutathione peroxidase activities, and glutathione levels. Carvacrol reduced inflammation damage by reducing sodium arsenite-induced increased levels of NF-κB and the cytokines (TNF-α, IL-1ß, IL-6, RAGE, and NLRP3) it stimulates. Carvacrol also reduced sodium arsenite-induced autophagic (Beclin-1, LC3A, and LC3B) and apoptotic (P53, Apaf-1, Casp-3, Casp-6, Casp-9, and Bax) parameters. Carvacrol preserved sodium arsenite-induced impaired liver tissue structure. Carvacrol alleviated toxic damage by reducing sodium arsenite-induced increases in oxidative stress, inflammation, apoptosis, and autophagic damage parameters in rat liver tissues. Carvacrol was also beneficial in preserving liver tissue integrity.

Carvacrol and Thymol Enhance the Quality of Beni Arouss Buck Semen Stored at 4 °C Thanks to Their Antimicrobial Properties.

This study aims to investigate the impact of carvacrol and thymol on the quality of Beni Arouss buck semen stored in skim milk at 4 °C. Ejaculates were collected from eight Beni Arouss bucks weekly for 11 weeks, pooled, and then divided into three equal parts. Samples were diluted to 400 × 106 sperm/mL in skim milk (control) and skim milk supplemented with a single dose of 200 µM carvacrol and thymol each. Evaluations of sperm motility, viability, abnormalities, membrane integrity, lipid peroxidation, and bacterial growth were conducted at 0, 6, 24, and 48 h of liquid storage at 4 °C. After 48 h of storage, the results indicate that the addition of carvacrol positively influences total and progressive motility and viability. However, it also leads to a decrease in lipid peroxidation and bacterial growth compared to the control group (p < 0.05). Thymol showed similar results to carvacrol, except for progressive motility (p > 0.05). Bacterial growth was negatively correlated with total and progressive motility and viability (p < 0.05), while no correlation between lipid peroxidation and these parameters was observed (p > 0.05). In conclusion, the addition of carvacrol and thymol to skim milk extender moderately improves the quality of Beni Arouss buck semen after 48 h storage at 4 °C due to its antimicrobial activity.

Green enrichment of argan oil (Argania spinosa L.) with thyme (Thymus vulgaris L.) and oregano (Origanum vulgare L.) leaves: Evaluating quality and stability improvements.

This study aimed to assess the impact of enriching argan oil (AO) (Argania spinosa L.) using the maceration technique with thyme (Thymus vulgaris L.) and oregano (Origanum vulgare L.) leaves (TL and OL) at two proportions (5 and 10%). The oxidative stability of the control and enriched oils was examined under accelerated conditions at a temperature of 60 °C for 120 days (4 months). Quality indices (Free fatty acids (FFA), peroxide value (PV), p-anisidine value (p-AV), ultraviolet absoptions (K232 and K270), Rancimat test, fatty acids composition, sensory attributes, simple phenolic contents (SPC) and antioxidant activity (DPPH•) were determined. As a simple, inexpensive and green method, enrichment by maceration yielded advantageous results. Compared to the control (68.05 ± 1.10 mg GAE/kg), the SPC significantly increased in enriched oils reaching notably 250.9 ± 9.1 mg GAE/kg when adding 10% of TL. Also, the enriched oil samples showed the lowest PV, p-AV and ultraviolet absorptions compared with the control. However, no noticeable changes were reported in fatty acids composition and iodine value. In terms of sensory attributes, enrichment by maceration masked the rancid odour caused by oxidation. These scientific discoveries inherently yield economic advantages by enabling the diversification of product offerings, simultaneously catering to a broader market seeking high-quality oils infused with herbs, including both AO and aromatic plants.

Carvacrol-conjugated 3-Hydroxybenzoic Acids: Design, Synthesis, cardioprotective potential against doxorubicin-induced Cardiotoxicity, and ADMET study.

Carvacrol (CA) is a phenolic monoterpene renowned for its diverse pharmacological benefits, particularly its cardioprotective effects. Concurrently, phenolic acids have also demonstrated promise in mitigating drug-induced cardiotoxicity. Focusing on combating doxorubicin-induced cardiotoxicity (DIC), the research aims to synthesize novel cardioprotective agents by combining CA with 3-hydroxybenzoic acid (3HA). Doxorubicin, an anticancer drug, poses cardiovascular risks as its adverse effect, prompting the exploration of hybrid compounds. Various linker molecules, including alkyl and acyl with different carbon lengths, were investigated to understand their impact on bioactivity. In vitro testing on the DOX-induced H9c2 cell death model revealed the effectiveness of a CA conjugate in preserving cardiomyocyte viability. In silico analysis highlighted favorable drug-like properties and low toxicity of the conjugate. This study sheds light on molecular hybridization's potential in developing cardioprotective agents, emphasizing CA's pivotal role in combating DIC.

Carvacrol inhibits the progression of oral submucous fibrosis via downregulation of PVT1/miR-20a-5p-mediated pyroptosis.

Oral submucous fibrosis (OSF) is a precancerous condition in the oral cavity, which is closely related to the myofibroblast conversion of buccal mucosal fibroblasts (BMFs) after chronic consumption of areca nut. Emerging evidence suggests pyroptosis, a form of programmed cell death that is mediated by inflammasome, is implicated in persistent myofibroblast activation and fibrosis. Besides, numerous studies have demonstrated the effects of non-coding RNAs on pyroptosis and myofibroblast activities. Herein, we aimed to target key long non-coding RNA PVT1 with natural compound, carvacrol, to alleviate pyroptosis and myofibroblast activation in OSF. We first identified PVT1 was downregulated in the carvacrol-treated fBMFs and then demonstrated that myofibroblast features and expression of pyroptosis makers were all reduced in response to carvacrol treatment. Subsequently, we analysed the expression of PVT1 and found that PVT1 was aberrantly upregulated in OSF specimens and positively correlated with several fibrosis markers. After revealing the suppressive effects of carvacrol on myofibroblast characterisitcs and pyroptosis were mediated by repression of PVT1, we then explored the potential mechanisms. Our data showed that PVT1 may serve as a sponge of microRNA(miR)-20a to mitigate the myofibroblast activation and pyroptosis. Altogether, these findings indicated that the anti-fibrosis effects of carvacrol merit consideration and may be due to the attenuation of pyroptosis and myofibroblast activation by targeting the PVT1/miR-20a axis.

The preventive effects of natural plant compound carvacrol against combined UVA and UVB-induced endoplasmic reticulum stress in skin damage of rats.

The skin is constantly exposed to a variety of environmental stressors, including ultraviolet (UV) radiation. Exposure of the skin to UV radiation causes a number of detrimental biological damages such as endoplasmic reticulum (ER) stress. The ER stress response is a cytoprotective mechanism that maintains homeostasis of the ER by increasing the capacity of the ER against the accumulation of unfolded proteins in the ER. Carvacrol (CRV) is a monoterpenoid phenol found in essential oils with antimicrobial and anti-inflammatory activities. We investigated for the first time in the literature the potential protective role of CRV against combined UVA and UVB-induced skin damage by targeting the ER stress pathway in a rat model. For this purpose, expressions of Grp78, Perk, Atf6, Ire-1, Chop, Xbp1, Casp12, elF2α, and Traf2 genes related to ER stress were analyzed by RT-PCR and protein expression levels of GRP78, ATF6, CHOP, and XBP1 were determined by ELISA assay in tissue sections taken from the back of the rats. As a result of analysis, it was seen that the expression levels of aforementioned ER stress genes increased significantly in the UVA + UVB irradiated group compared to the control group, while their expression levels decreased markedly by supplementation of CRV in UVA + UVB + CRV group. With regard to expressions of foregoing proteins, their levels escalated notably with UVA + UVB application and decreased markedly by CRV supplementation. In conclusion, present study revealed that CRV ameliorates UVA + UVB-induced ER stress via reducing the expression of mRNA as well as proteins involved in the unfolded protein response (UPR) pathway and inducing apoptosis as evidenced from high Caspase12 level.

Systemic and Lung Inflammation and Oxidative Stress Associated With Behavioral Changes Induced by Inhaled Paraquat Are Ameliorated by Carvacrol.

Paraquat (PQ) is an herbicide toxin that induces injury in different organs. The anti-inflammatory and antioxidant effects of carvacrol were reported previously. The effects of carvacrol and pioglitazone (Pio) alone and their combination on inhaled PQ-induced systemic and lung oxidative stress and inflammation as well as behavioral changes were examined in rats. In this study, animals were exposed to saline (control [Ctrl]) or PQ (PQ groups) aerosols. PQ-exposed animals were treated with 0.03 mg/kg/day dexamethasone (Dexa), 20 and 80 mg/kg/day carvacrol (C-L and C-H), 5 mg/kg/day Pio, and Pio+C-L for 16 days. Inhaled PQ markedly enhanced total and differential white blood cell (WBC) counts, nitric oxide (NO), and malondialdehyde (MDA) levels but decreased catalase (CAT) and superoxide dismutase (SOD) activities and thiol levels both in the bronchoalveolar lavage fluid (BALF) and blood and increased interferon-gamma (INF-γ) and interleukin-10 (IL-10) levels in the BALF (p < 0.001 for all cases) except lymphocyte count in blood which was not significantly changed. The escape latency and traveled distance were increased in the PQ group. However, the time spent in the target quadrant in the Morris water maze (MWM) test and the duration of time latency in the dark room in the shuttle box test were reduced after receiving an electrical shock (p < 0.05-p < 0.001). Inhaled PQ-induced changes were significantly improved in carvacrol, Pio, Dexa, and especially in the combination of the Pio+C-L treated groups (p < 0.05-p < 0.001). Carvacrol and Pio improved PQ-induced changes similar to Dexa, but ameliorative effects produced by combination treatments of Pio+C-L were more prominent than Pio and C-L alone, suggesting a potentiating effect for the combination of the two agents.

Antimicrobial potential of carvacrol against Edwardsiella piscicida in vitro.

With the alarming rise of antibiotic-resistant bacteria, novel antibacterial substances are urgently needed for controlling and treating multidrug-resistant bacterial infections. Edwardsiella piscicida is an important zoonotic enteric pathogen, that can cause systemic hemorrhagic septicemia in fish. Carvacrol, a major terpene of oregano essential oil, has a wide range of antibacterial activities. This study aimed to analyze the effect of carvacrol on the growth and virulence of E. piscicida in vitro. The minimum inhibitory concentration (MIC) of carvacrol against E. piscicida was 125 µg/mL. The sub-inhibitory concentrations of carvacrol significantly decreased the biofilm formation of E. piscicida in a dose dependent manner, whereas increased the hemolytic activity with a negative correlation. The quantitative real-time PCR results showed that carvacrol at sub-MICs downregulated the expression of related virulence genes, including flagellum (fimA, fliC, flgN), hemolysins (ethA, ethB), quorum sensing systems (luxR, qseB), T3SS (esrB, esrC) and T6SS (evpB, evpC). Moreover, carvacrol (≤1/8 MIC) reduced the cytotoxicity, adherence and internalization activities of E. piscicida to the EPC cells. In vivo trial, the diet mixed with carvacrol increased the survival of zebrafish infected with E. piscicida. Overall, these findings suggested that carvacrol might be a promising therapeutic agent against E. piscicida infection in aquaculture.

Protective effect of carvacrol hydrogel on the alveolar bone in rats with periodontitis.

OBJECTIVES: This study aimed to investigate the protective effect and mechanism of carvacrol hydrogel on the alveolar bone in rats with periodontitis. METHODS: A thermosensitive hydrogel supported by carvacrol was prepared using poloxamer and hydroxypropyl methyl cellulose as matrix. SD rats were randomly divided into blank group, periodontitis group, blank hydrogel group, and low-, medium-, and high-dose hydrogel groups. The periodontitis symptoms and the CT structure of the alveolar bone were observed. The changes in liver, spleen, kidney, and periodontal tissues were observed. The related indexes of bone metabolism in serum were detected. The expression of osteoprotegerin (OPG) and nuclear transcription factor-κB (NF-κB) pathway proteins was determined by Western blot. The levels of inflammatory factors were assessed by quantitative reverse transcription polymerase chain reaction (qRT-PCR). RESULTS: Carvacrol hydrogel had good slow release, biocompatibility, and cell adhesion. The periodontitis of rats in the carvacrol hydrogel group was significantly alleviated, the expression of OPG protein in gingival tissue was significantly increased (P<0.01), and the levels of receptor activator of NF-κB ligand (RANKL), receptor activator of NF-κB (RANK), NF-κB protein, and inflammatory factors were significantly decreased (P<0.01). CONCLUSIONS: Carvacrol hydrogel can regulate the OPG and NF-κB pathways, reduce alveolar bone absorption, and improve periodontal inflammation.

Assessment of the antimicrobial and antibiofilm activity of the combination of N-acetyl cysteine and carvacrol against Staphylococcus aureus, the most common orthopedic infectious agent.

BACKGROUND: The increasing prevalence of antibiotic-resistant bacterial infections has led to the search for new approaches. OBJECTIVE: This study aimed to evaluate the effects of carvacrol and N-acetyl cysteine, both individually and in combination, on the planktonic cells and biofilm formations of Staphylococcus aureus, including methicillin-resistant and methicillin-sensitive strains. Additionally, the study sought to perform cytotoxicity tests and chemical characterization to further understand the properties and potential applications of these substances. METHODS: A total of 19 S. aureus strains were included in the study. Minimum inhibitory concentration and minimum bactericidal concentration were determined by assays. Synergy analysis tests were carried out. Cytotoxicity tests were conducted on the fibroblast cell line. Characterization test was performed. RESULTS: While Minimum inhibitory concentration and minimum bactericidal concentration values for carvacrol varied between 250 and 500 µg/ml, these values were in the range of 32-64 mg/ml for N-acetyl cysteine. Biofilm formation activities were identified. A total of eight strains, including six clinical and two standard strains with the highest biofilm-forming ability, were selected for combination studies. The combination of Carvacrol and N-acetyl cysteine exhibited synergistic and partially synergistic effects on the tested planktonic and biofilm strains, and these effects were dose-dependent. Carvacrol was found to be the most active drug at the end of 24, 48, and 72 h. Regarding the synergistic effect of N-acetyl cysteine + carvacrol, it was revealed to exhibit higher activity than N-acetyl cysteine and lower activity than carvacrol. CONCLUSION: The combination of carvacrol and N-acetyl cysteine demonstrated synergistic and partially synergistic effects against both planktonic and biofilm forms of Staphylococcus aureus. These results suggest potential for novel approaches in managing orthopedic infections, warranting further research to explore their therapeutic applications.

Carvacrol improves cognitive dysfunction by decreasing amyloid-ß accumulation and regulating neuroinflammation in ovariectomized renovascular hypertensive rats.

Hypertension contributes to both the development and progression of brain damage and cognitive dysfunction in the postmenopausal period in women. Carvacrol (CAR), which can easily cross the blood-brain barrier, exhibits neuroprotective properties due to its antioxidant, anti-inflammatory, and anti-apoptotic effects. In the present study, we have examined the effect of CAR treatment on learning-memory impairment in a post-menopausal hypertensive rat model that was induced by ovariectomy following two-kidney, one-clip renovascular hypertension surgery. From the third week after the establishment of renovascular hypertension in ovariectomized rats, CAR (40 mg/kg) was administered once daily for consecutive 7 weeks by gastric gavage. Systolic blood pressure was estimated by the tail-cuff method once a week. At the end of the study, cognitive functions were evaluated with behavioral tests and also neurochemical changes were measured in serum, cortex, and hippocampus by ELISA test. Blood pressure was decreased with CAR treatment in hypertensive rats. Serum estrogen levels decreased in ovariectomized rats and did not change with CAR treatment. CAR demonstrated beneficial effects on learning and memory tests as determined by increased recognition index, the number of platforms crossed, and time spent in the target quadrant. Due to CAR treatment, there was a marked reduction in the hippocampal and cortex amyloid-ß, osteopontin, interleukin-6 and tumor necrosis factor-alpha levels, and acetylcholinesterase activity, while an increment in neprilysin and interleukin-10 levels was found. In conclusion, since CAR suppressed amyloid-ß deposition and neuroinflammation in ovariectomized-hypertensive rats, it is thought that it may be protective against memory disorders in postmenopausal hypertensive women.

Evaluation of antifungal and apoptotic effects of linalool, citral, and carvacrol separately and in combination with nystatin against clinical isolates of Pichia kudriavzevii.

Pichia kudriavzevii (formerly Candida krusei) poses a significant threat to immunocompromised patients due to its inherent resistance to various antifungal drugs. This study explored the anticandidal potential of citral, linalool, and carvacrol in combination with nystatin against P. kudriavzevii strains.Using the microdilution method following CLSI guidelines, Minimum Inhibitory Concentrations (MICs) and fungicidal concentrations (MFCs) were determined. Citral exhibited MIC values ranging from 50 to 100 µg/ml, averaging 70.24 ± 16.99 µg/ml, while carvacrol had MIC values of 50 to 100 µg/ml, averaging 86.90 ± 16.99 µg/ml. Linalool demonstrated weaker antifungal activity, with MIC values between 100 and 200 µg/ml, averaging 150 ± 38.73 µg/ml. The study assessed the synergistic effectsof these phenols with nystatin through fractional inhibitory concentration indices (FICIS). In addition, flow cytometry was employed to assess apoptosis induction in P. kudriavzevii cells.Carvacrol displayed a remarkable synergistic effect in combination with nystatin against all 21 isolates tested. Conversely, linalool showed synergy in 17 isolates, while citral exhibited synergy in only 2 isolates. These findings highlight distinct patterns of synergy between the different compounds and nystatin against P. kudriavzevii. Also, Carvacrol emerged as the most potent inducer of apoptosis across all P. kudriavzevii strains, followed by citral and linalool. This suggests that carvacrol not only possesses a stronger antifungal effect but also has a more pronounced ability to trigger programmed cell death in P. kudriavzevii. In conclusion, the study supports the potential of carvacrol, citral and linalool, as anticandidal agents, suggesting their supplementation with nystatin for treating P. kudriavzevii infections.

Carvacrol ameliorates skin allograft rejection through modulating macrophage polarization by activating the Wnt signalling pathway.

Post-transplantation immune rejection remains an important factor for transplant patients. However, conventional immunosuppressants are associated with substantial adverse effects. Natural immunosuppressants present a promising alternative to conventional counterparts, boasting exceptional biological activity, minimal toxicity and reduced side effects. We identified carvacrol as a prospective immunosuppressive agent following T cell proliferation experiment and validated carvacrol's immunosuppressive efficacy in the murine allogeneic skin graft model. T cell proliferation assay was used to screen natural small molecule compounds and the immunosuppressive effect of compounds was evaluated in MHC-mismatched murine allogeneic skin graft model. H&E and immunohistochemical staining were applied to evaluate the pathological grade. Furthermore, flow cytometry was uitlized to analyse the immunophenotype changes of immune cells. Western blotting and q-PCR were used to detect the expression of key molecules in macrophages. In vitro, carvacrol demonstrates significant inhibition of the proliferation of CD4+ T and CD8+ T cells. It notably reduces inflammatory factor expression within the allografts, suppresses T cell differentiation toward Th1 phenotype and expansion. Furthermore, carvacrol prominently hinders M1-type macrophages polarization by activating Wnt signaling. Notably, the anti-rejection efficacy of carvacrol was significantly weakened upon the removal of macrophages in mice using chlorophosphate liposomes. Carvacrol could significantly inhibit T cell proliferation, alleviate graft rejection and has outstanding toxicological safety. The molecular mechanism of the anti-rejection effect of carvacrol is closely related to its mediating activation of macrophage Wnt pathway, inhibiting M1 polarization and inducing T cell differentiation.

Analytical and Antimicrobial Characterization of Zn-Modified Clays Embedding Thymol or Carvacrol.

Carvacrol and thymol are broad-spectrum natural antimicrobial agents. To reduce their volatility and improve their antimicrobial performance, synergistic systems were prepared loading the active molecules in zinc-modified clays. Montmorillonite (MMT) and zeolite (ZEO) were modified with zinc ions (ZnMMT and ZnZEO), with well-known antimicrobial properties, and then with carvacrol or thymol, reaching the 26 ± 3% and 33 ± 2% w/w of loading, respectively. The resulting hybrid materials were characterized by FT-IR, XPS, XRD, TGA, and GC-MS to evaluate carvacrol/thymol release in simulating food matrices. Antimicrobial assays carried out using spoiler and pathogenic bacterial strains showed that the antimicrobial activity of both thymol and carvacrol was largely preserved once they were loaded into Zn-modified clays. However, MMT hybrids showed an antibacterial activity significantly higher than ZEO hybrids at 50 mg/mL of thymol and carvacrol. For this reason, deeper antimicrobial evaluations were carried out only for ZnMMT composites. ZnMMT loaded with thymol or carvacrol produced inhibition zones against most of the target strains, also at 3.12 mg/mL, while the positive controls represented by the single molecule thymol or carvacrol were not active. The hybrid materials can be useful for applications in which the antimicrobial activity of natural molecules need to be displayed over time as requested for the control of microbial pathogens and spoilage bacteria in different applications, such as active packaging, biomaterials, and medical devices.

Behavioral and electrophysiological responses of the male medfly, Ceratitis capitata, to thymol and carvacrol ethers.

BACKGROUND: The Mediterranean fruit fly, Ceratitis capitata, is one of the most economically important insect pests attacking fruits and vegetables in tropical and subtropical areas of the world. Semiochemical-based pest management programs are being used to provide environmentally friendly control methods for medflies. The goals of the current study were to discover potential new, attractive, kairomones by designing, synthesizing, and testing simplified ethers of thymol and carvacrol along with their ether derivatives in short-range attraction assays and electroantennogram (EAG) assays with male C. capitata. To the best of our knowledge, this study represents the first investigation of thymol and carvacrol, and their respective ethers for attractancy to C. capitata, a major agricultural pest worldwide. RESULTS: In short-range attraction bioassays, parent compounds, thymol and carvacrol, along with their propyl, butyl, benzyl, and octyl ethers captured the most male C. capitata. The attraction patterns changed over time and captures were only significant if they were greater than the positive control tea tree oil (TTO) at 90 min. In EAG assays, thymol benzyl, octyl ethers, and carvacrol benzyl ether evoked significantly greater antennal responses than their parent compounds. The EAG responses did not correlate with short-range male attraction. The aliphatic side chains of thymol and carvacrol had a small effect on the activity. Future studies will investigate the long-range attraction of the ethers that elicited large EAG responses. CONCLUSION: This report provides new information for discovering potential kairomones through synthesis and structure-activity studies for sterile male medflies. Thymol, carvacrol, and several of their ether derivatives displayed improved longevity of attraction compared with TTO (a strong medfly attractant), with significantly higher captures than TTO observed at 90 min in laboratory bioassays. Further chemical synthesis of thymol and carvacrol ethers within this series may lead to the development of ethers that are more attractive or persistent than their parent compounds, thymol and carvacrol. © 2024 Society of Chemical Industry. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Development of amphipathic derivatives of thymol and carvacrol as potent broad-spectrum antibacterial agents.

In the current study, to discover novel antibacterial agents, we designed and synthesized 72 carvacrol and thymol derivatives by biomimicking the structure and function of cationic antimicrobial peptides (AMPs). Many of the derivatives showed good antibacterial activity, and compound thy2I exhibited the most potent antibacterial activity with minimum inhibitory concentration (MIC) values ranging from 0.5 µg/mL to 8 µg/mL. Compound thy2I could kill both gram-positive and gram-negative bacteria via a membrane-targeting mechanism of action with a low frequency of resistance. In addition, thy2I had the advantages of good membrane selectivity, low toxicity in vitro and in vivo, and good plasma stability. The in vivo activity results revealed that thy2I exhibited a positive therapeutic effect in a mouse skin abscess model induced by Staphylococcus aureus ATCC29213. After thy2I treatment (10 mg/kg), the bacterial load of the S. aureus-infected abscesses was reduced by approximately 99.65 %. Our study suggests that thy2I may serve as an antibacterial lead for further clinical evaluation.

Protective Effect of Carvacrol against Oxidative Damage in Aged Rats.

BACKGROUND: Aging affects cellular functions and impairs tissue homeostasis. Carvacrol, a polyphenolic compound, has been shown to exert a wide range of pharmacological effects, such as antioxidant, anti-inflammatory, and anticancer characteristics. METHODS: This investigation aimed to evaluate the effect of carvacrol in elderly male rats. Carvacrol at a dose of 15 or 30 mg/kg was administrated daily per os for 60 days to aged rats. The liver, heart, and kidney samples were taken for the analysis of oxidative stress markers. Serum samples were used to evaluate liver enzymes (alanine transaminase (ALT) and aspartate aminotransferase (AST)). RESULTS: The levels of malondialdehyde (MDA) in the liver, heart, and kidney tissues of aged rats were higher. Conversely, the level of thiol was lower in the mentioned tissues than in the young control group. The levels of MDA in the liver, heart, and kidney tissues of aged rats were significantly reduced by carvacrol, which was accompanied by increased levels of total thiol. ALT and AST levels were higher in the serum of aged rats than in the young control ones. Carvacrol decreased ALT and AST levels in the serum of aged rats versus aged control rats. CONCLUSION: Carvacrol can be effective in protecting susceptible aged tissues and organs by increasing antioxidant defenses and decreasing liver enzymes.