Ectopic cervical thymus: Recognising the characteristic 'embroidery yarn' appearance on ultrasound.

Introduction: The thymus normally forms in the neck from the third pharyngeal pouch and descends to its normal position in the mediastinum. Arrest of descent or sequestration of thymic tissue can occur at any point along its path leading to an ectopic thymus which can present as a neck mass, usually in the paediatric age group. Purpose and Case Report: Ultrasound is generally performed in the presence of a neck mass in children. Although a characteristic 'starry sky' appearance of the thymus has been described on ultrasound, it is not considered sufficiently specific and cross-sectional imaging with magnetic resonance imaging is usually performed. On magnetic resonance imaging, the ectopic thymus appears as a homogeneous T1 isointense and T2 hyperintense mass and may actually appear ominous due to the tendency of ectopic thymus to sometimes show diffusion restriction unlike the normal thymus. Subsequent invasive biopsy or surgical removal is usually necessary to rule out a neoplastic lesion. In our observation, the ultrasound appearance of thymus is sufficiently distinctive to be confidently diagnosed as ectopic thymic tissue. This appearance is similar to the high-resolution appearance of an embroidery yarn. The reason most radiologists are not aware of the same is because the normal mediastinal thymus is not usually imaged by ultrasound. Conclusion: An accurate diagnosis on ultrasound would mean avoidance of expensive cross-sectional imaging and invasive biopsy or surgical excision in favour of regular non-invasive follow-up ultrasound scans until the lesion involutes in late childhood.

Thymus assessments at birth in echocardiography: a preliminary cohort study.

BACKGROUND: Echocardiography is a tool used in neonatal period to screen for congenital heart defects and to assess the function of the cardiovascular system. It enables obtaining a three-vessel view (3VV) to show how the superior vena cava, the aorta and the pulmonary trunk relate to each other. A 3VV also provides a view of the thymus gland. METHODS: It is a preliminary study. Using the thymus measurements obtained in echocardiography of neonates delivered in one healthcare centre, a total of 1,331 thymus records were collected and statistically analysed. The study was conducted on group of 321 preterm neonates and 1,010 full-term neonates. The superior mediastinal view (three-vessel view, 3VV) was chosen for thymus measurements, with the parallel vascular system, including the superior vena cava, the aorta and the pulmonary trunk, with visible branching to the right and left pulmonary artery. Thymus width, depth and thymic 3VV index were measured. Thymic 3VV index (TI 3VV) is defined as a product of multipling the width and the depth of the thymus in three-vessel view projection. RESULTS: Based on a statistical analysis, a correlation was found of 3VV thymus dimensions and thymic 3VV index with body weight, gestational age and body surface area (BSA). These measurements led to the important finding that the TI 3VV value depends on thymus width and depth, more prominently the latter. The 3VV measurement of thymus depth alone can serve as a screening tool to assess the size of the gland. CONCLUSIONS: Inclusion of thymic measurements in neonatal echocardiography protocol can be used as a screening tool to assess the size of thymus gland.

Shape of the art: TCR-repertoire after allogeneic hematopoietic cell transplantation.

The human adaptive immune repertoire is characterized by specificity and diversity to provide immunity against past and future tasks. Such tasks are mainly infections but also malignant transformations of cells. With its multiple lines of defense, the human immune system contains both, rapid reaction forces and the potential to capture, disassemble and analyze strange structures in order to teach the adaptive immune system and mount a specific immune response. Prevention and mitigation of autoimmunity is of equal importance. In the context of allogeneic hematopoietic cell transplantation (HCT) specific challenges exist with the transfer of cells from the adapted donor immune system to the immunosuppressed recipient. Those challenges are immunogenetic disparity between donor and host, reconstitution of immunity early after HCT by expansion of mature immune effector cells, and impaired thymic function, if the recipient is an adult (as it is the case in most HCTs). The possibility to characterize the adaptive immune repertoire by massively parallel sequencing of T-cell receptor gene rearrangements allows for a much more detailed characterization of the T-cell repertoire. In addition, high-dimensional characterization of immune effector cells based on their immunophenotype and single cell RNA sequencing allow for much deeper insights in adaptive immune responses. We here review, existing - still incomplete - information on immune reconstitution after allogeneic HCT. Building on the technological advances much deeper insights into immune recovery after HCT and adaptive immune responses and can be expected in the coming years.

Arsenic-induced transition of thymic inflammation-to-fibrosis involves Stat3-Twist1 interaction: Melatonin to the rescue.

Groundwater arsenic is a notorious toxicant and exposure to environmentally relevant concentrations persists as a healthcare burden across the world. Arsenic has been reported to jeopardize the normal functioning of the immune system, but there are still gaps in the understanding of thymic T cell biology. Immunotoxic influence of arsenic in thymic integrity demands a potent restorative molecule. The objectives of this study were to examine key signaling cross-talks associated with arsenic-induced immune alterations in the thymus and propose melatonin as a potential candidate against immunological complications arising from arsenic exposure. Swiss albino mice were exposed to sodium arsenite (0.05 mg/L; in drinking water) and melatonin (IP:10 mg/kg BW) for 28 days. Melatonin successfully protected thymus from arsenic-mediated tissue degeneration and maintained immune homeostasis including T cell maturation and proliferation by mitigating oxidative stress through Nrf2 upregulation. Additionally, melatonin exerted ameliorative effect against arsenic-induced apoptosis and inflammation by inhibiting p53-mediated mitochondrial cell death pathway and NF-κB-p65/STAT3-mediated proinflammatory pathway, respectively. For the first time, we showed that arsenic-induced profibrotic changes were inhibited by melatonin through targeting of inflammation-associated EMT. Our findings clearly demonstrate that melatonin can be a viable and promising candidate in combating arsenic-induced immune toxicity with no collateral damage, making it an important research target.

A Japanese Case of Food Protein-induced Enterocolitis Syndrome Caused by Multiple Seafoods.

Food protein-induced enterocolitis syndrome (FPIES) caused by fish and others is prevalent in the Mediterranean regions but is less frequently reported in Japan. This case report describes a 3-year-old Japanese girl who developed FPIES triggered by multiple seafoods, including swordfish, cod, and squid. The diagnosis was confirmed through oral food challenge tests (OFC), which led to repeated vomiting and an increase in thymus and activation-regulated chemokine (TARC) levels. This case highlights the importance of considering fish-induced FPIES in the differential diagnosis of recurrent vomiting in children and suggests the potential utility of TARC levels in diagnosing and monitoring FPIES.

Spindle epithelial tumor with thymus-like elements (SETTLE): a diagnostic challenge with distinct therapeutic implication; case report.

Spindle epithelial tumor with thymus-like elements (SETTLE) is a rare malignant neoplasm of the thyroid gland which is believed to arise from intrathyroidal thymic tissue. It predominantly affects young adults and children presenting with a thyroid mass of variable duration and rarely occurs in adults. It has a high overall survival with a tendency for delayed metastasis. SETTLE is a biphasic lobulated tumor composed of spindle shaped cells along with glandular formations seen on histopathological examination. Despite its typical morphology it is commonly misdiagnosed on histopathology due to its rarity and overlapping morphology with other close mimics such as a carcinoma, synovial sarcoma and thymoma. Herein we report such a case occurring in a middle aged female presenting with a neck mass. She had an initial diagnosis of metastatic poorly differentiated squamous cell carcinoma possibly with an orophayngeal primary in view of co expression of CK, p40 and p16 on immunohistochemistry. The patient underwent surgical resection with modified neck dissection. On review at our hospital it was diagnosed as SETTLE and she remains disease free after a follow-up period of 1 year. Diligent histopathological examination espoused with a judicious panel of IHC markers in conjunction with clinicoradiological findings forms the mainstay of diagnosis. Diffuse and strong p16 immunoexpression has not been documented or evaluated in literature so far, and needs to be explored for its diagnostic utility in this rare entity.

Association between thymus density loss and efficacy in non-small cell lung cancer patients treated with immune checkpoint inhibitors.

Background: Although the thymus undergoes degeneration with the advancement of age, recent studies have continuously revealed that the thymus possesses the potential for regeneration and may reverse this aging trend. Furthermore, an increasing number of studies indicate an association between thymus function and immunotherapy. Considering that lung cancer patients typically undergo chest computed tomography (CT) scans during treatment, this provides convenient conditions for us to observe thymic remodeling through imaging data. Therefore, exploring the changes in the thymus on CT images is of great significance for understanding its relationship with the efficacy of immunotherapy in non-small cell lung cancer (NSCLC) patients. This study investigated the CT imaging characteristics of thymic density changes in patients with advanced NSCLC after immunotherapy. The primary objective was to determine whether changes in thymic density are predictors of response to immunotherapy in patients with NSCLC. Methods: A total of 412 patients with advanced NSCLC who underwent immunotherapy were included. Thymic density measurements were taken initially and after immunotherapy, with the annualized change calculated. Comprehensive analysis, including disease progression, survival, and subgroup assessments, was conducted. The primary outcome was overall survival (OS), and the secondary outcomes were progression-free survival (PFS), objective response rate (ORR) and disease control rate (DCR). Results: The annual change in density of the thymic region ranged from -108 to 108 HU after the initiation of ICIs. Patients were categorized into "loss" or "non-loss" groups (210 vs. 202) based on thymic density changes. Analysis of short-term progression of solid tumors revealed no statistically significant differences in ORR (P=0.55) and DCR (P=0.67) between the two groups. Throughout the entire follow-up period, 41 patients (19.5%) in the "loss" group and 64 patients (31.7%) in the "non-loss" group died. Thymic density reduction was not associated with PFS (P=0.08), but it was positively associated with increased OS (P=0.003). The results were consistent across subgroups. Conclusions: Thymic density changes were observed in nearly all NSCLC patients undergoing immunotherapy, with decreased density associated with longer OS. These findings suggest a potential association between thymic density changes and immune efficacy in NSCLC immunotherapy.

The Effects of Thymus Caramanicus Jalas Extract and Its Main Constituent Carvacrol Against Cisplatin-Induced Nephrotoxicity in Mice.

Background: Cisplatin, an anti-cancer chemotherapy drug, has nephrotoxic effects. Thymus caramanicus Jalas (TCJ) has antioxidant effects due to its main components. Objectives: In the current research, we assessed the impact of TCJ extract and its main compound on cisplatin-induced nephrotoxicity in mice. Methods: Forty-two male mice were used in the study. Depending on their group, the animals received saline, carvacrol (10 mg/kg), or TCJ extract (50, 100, and 150 mg/kg) for 10 days. On the fifth day, mice received cisplatin (7.5 mg/kg, i.p.). After 10 days, serum creatinine (Cr) and blood urea nitrogen (BUN) levels were measured. Additionally, malondialdehyde (MDA) and glutathione (GSH) contents, as well as the activity levels of superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx), and total antioxidant capacity (TAC) were measured in the kidney tissues. The western blotting method was used to determine the kidney's expression of cleaved caspase-3, Bax, Bcl-2, nuclear factor kappa-B (NF-κB), and tumor necrosis factor-alpha (TNF-α). Kidney tissue damage score (KTDS) was assessed using the hematoxylin-eosin (H&E) staining method. Results: Cisplatin significantly increased serum Cr, KTDS, MDA, BUN levels, NF-κB, TNF-α, cleaved caspase-3, and Bax protein expression in the cisplatin group compared to the control group (P < 0.01). Additionally, cisplatin significantly decreased the kidney tissue's TAC and GSH content, activity levels of SOD, catalase, and GPx indicators, and expression of Bcl-2 protein (P < 0.05). TCJ and carvacrol significantly ameliorated these indicators in the cisplatin + TCJ (150 mg/kg) and cisplatin + carvacrol (10 mg/kg) groups compared to the cisplatin group (P < 0.05). Conclusions: TCJ (150 mg/kg) and its main component, carvacrol, could somewhat reduce cisplatin-induced nephrotoxicity through their anti-inflammatory, antioxidant, and anti-apoptotic effects.

Single-cell sequencing has revealed a more complex array of thymic epithelial cells.

Thymic epithelial cells participate in the maturation and selection of T lymphocytes. This review explores recent insights from single-cell sequencing regarding classifying thymic epithelial cells in both normal and neoplastic thymus. Cortical thymic epithelial cells facilitate thymocyte differentiation and contribute to positive selection. Medullary epithelial cells are distinguished by their expression of AIRE. Cells progress from a pre-AIRE state, containing precursors with cortical and medullary characteristics, termed junctional cells. Mature medullary epithelial cells exhibit promiscuous gene expression and after that downregulate AIRE mRNA. Post-AIRE cells can adopt a Hassall corpuscle-like phenotype or exhibit distinctive differentiation characteristics including tuft cells, ionocytes, neuroendocrine cells, and myoid cells.

Nonepisodic angioedema with eosinophilia following a rose-thorn prick injury.

Background: Nonepisodic angioedema with eosinophilia (NEAE) is a condition marked by angioedema and significant eosinophilia and often linked with atopic dermatitis. It predominantly affects young Asian women and occurs more frequently in the autumn and winter. Despite over 100 reported cases, its etiology and pathogenesis remain unclear. Case presentation: A 23-year-old Japanese female florist presented with acute arm swelling following rose-thorn pricks to her hands and fingers in spring. One week later, she developed progressive symmetrical non-pitting edema in her lower legs and a 3 kg weight gain without any rash. She had a history of oral allergy syndrome to apples and pears for which allergen-specific IgE were previously detected. Blood tests showed significant eosinophilia (14,930 cells/µL) and elevated thymus and activation-regulated chemokine (TARC) levels (12,864 pg/mL). Thyroid disease, autoimmune disorders, and hematologic malignancies were ruled out. Normal cardiac markers and a whole-body computed tomography excluded visceral organ involvement. She was diagnosed with NEAE and treated with oral prednisolone, which resolved the edema within 10 days. Prednisolone was tapered gradually on an outpatient basis without recurrence. Conclusion: A review of the literature indicates that NEAE triggered by subcutaneous antigen exposure may not follow the typical age or seasonal patterns. Direct subcutaneous antigen exposure, including rose-thorn pricks, can trigger NEAE. Clinicians should consider NEAE in atypical presentations and thoroughly investigate preceding episodes.

Fetal thymus size in pregnant women with Hashimoto disease.

PURPOSE: This study compared fetal thymic-thoracic ratios and fetal thymus transverse diameter measurements in pregnant women with Hashimoto's thyroiditis (HT) and non-immune hypothyroidism. METHODS: The study included a total of 141 pregnant women in three groups: 41 with HT, 50 with non-immune hypothyroidism, and 50 healthy individuals. Fetal thymus transverse diameter and thymic-thoracic ratio were compared between these groups. RESULTS: The mean fetal thymic-thoracic ratio was greater in pregnant women with HT than in the healthy controls (p = 0.031). Mean fetal thymus transverse diameter showed no statistically significant difference between the groups. CONCLUSIONS: Maternal HT was associated with an increased fetal thymic-thoracic ratio. More comprehensive studies are needed on this subject.

Mechanisms underlying the direct programming of mouse embryonic fibroblasts to thymic epithelial cells by FOXN1.

Thymic epithelial cells (TECs) are crucial to the ability of the thymus to generate T cells for the adaptive immune system in vertebrates. However, no in vitro system for studying TEC function exists. Overexpressing the transcription factor FOXN1 initiates transdifferentiation of fibroblasts into TEC-like cells (iTECs) that support T-cell differentiation in culture or after transplant. In this study, we have characterized iTEC programming at the cellular and molecular level in mouse to determine how it proceeds, and have identified mechanisms that can be targeted for improving this process. These data show that iTEC programming consists of discrete gene expression changes that differ early and late in the process, and that iTECs upregulate markers of both cortical and medullary TEC (cTEC and mTEC) lineages. We demonstrate that promoting proliferation enhances iTEC generation, and that Notch inhibition allows the induction of mTEC differentiation. Finally, we show that MHCII expression is the major difference between iTECs and fetal TECs. MHCII expression was improved by co-culturing iTECs with fetal double-positive T-cells. This study supports future efforts to improve iTEC generation for both research and translational uses.

Thymic epithelial organoids mediate T cell development.

Although the advent of organoids opened unprecedented perspectives for basic and translational research, immune system-related organoids remain largely underdeveloped. Here we established organoids from the thymus, the lymphoid organ responsible for T cell development. We identified conditions enabling thymic epithelial progenitor cell proliferation and development into organoids with diverse cell populations and transcriptional profiles resembling in vivo thymic epithelial cells (TECs) more closely than traditional TEC cultures. Contrary to these two-dimensional cultures, thymic epithelial organoids maintained thymus functionality in vitro and mediated physiological T cell development upon reaggregation with T cell progenitors. The reaggregates showed in vivo-like epithelial diversity and ability to attract T cell progenitors. Thymic epithelial organoids are the first organoids originating from the stromal compartment of a lymphoid organ. They provide new opportunities to study TEC biology and T cell development in vitro, paving the way for future thymic regeneration strategies in ageing or acute injuries.

Recombinant FOXN1 fusion protein increases T cell generation in old mice.

T cell development in the thymus is dependent on the thymic microenvironment, in which thymic epithelial cells (TECs) are the major component. However, TECs undergo both a qualitative and quantitative loss during aging, which is believed to be the major factor responsible for age-dependent thymic atrophy. FOXN1 plays a critical role in TEC development and adult TECs maintenance. We have previously reported that intrathymic injection of a recombinant (r) protein containing murine FOXN1 and a protein transduction domain increases the number of TECs in mice, leading to enhanced thymopoiesis. However, intrathymic injection may not be an ideal choice for clinical applications. In this study, we produced a rFOXN1 fusion protein containing the N-terminal of CCR9, human FOXN1 and a protein transduction domain. When injected intravenously into 14-month-old mice, the rFOXN1 fusion protein enters the thymus and TECs, and enhances thymopoiesis, resulting in increased T cell generation in the thymus and increased number of T cells in peripheral lymphoid organ. Our results suggest that the rFOXN1 fusion protein has the potential to be used in preventing and treating T cell immunodeficiency in older adults.

Microbial and physicochemical changes in green bell peppers treated with ultrasonic-assisted washing in combination with Thymus vulgaris essential oil nanocapsules.

In this study, the effect of Thymus vulgaris essential oil (TVO) nanoemulsion (NE, 500 mg/L) in combination with ultrasound (ultrasound-NE) on the microbial and physiological quality of green bell pepper was investigated. The TVO-NE droplet size and zeta potential were 84.26 nm and - 0.77 mV, respectively. The minimum inhibitory concentrations of the TVO and TVO-NE against E. coli and S. aureus were about 0.07 and 7 g/L, respectively. The NE-ultrasound treatment exhibited the lowest peroxidase activity and respiration rate with no detrimental effect on texture, total phenolic content, antioxidant activity, pH, and TSS. Although the NE-ultrasound treatment showed the highest weight loss and electrolytic leakage, it exhibited the best visual color and appearance. The NE-ultrasound treatment descended the total viable/mold and yeast counts significantly compared to control. Results showed that treating the bell peppers with NE-ultrasound can result in bell peppers with good postharvest quality and extended shelf life.

Selectively T cell phosphorylation activation of azvudine in the thymus tissue with immune protection effect.

Thymus is the important immune organ, responsible for T cell development and differentiation. The lower circulating T counts have been observed in patients who died from COVID-19 compared with survivors. Azvudine, also known as FNC, is a thymus-homing anti-SARS-CoV-2 drug in treating COVID-19 patients. In this study, single-cell transcriptome, proteomics, and parallel reaction monitoring (PRM) were applied to insight into the activation process of FNC in rat and SARS-CoV-2 rhesus monkey thymus. The results indicated that thymic immune cells possess a robust metabolic capacity for cytidine-analogue drugs such as FNC. Key enzymes involved in the FNC phosphorylation process, such as Dck, Cmpk1, and Nme2, were highly expressed in CD4+ T cells, CD8+ T cells, and DP (CD4+ CD8+) cells. Additionally, FNC could upregulate multiple phosphorylated kinases in various cell types while downregulating the phosphatases, phosphoribosyl transferases, and deaminases, respectively. The robust phosphorylation capacity of the thymus for cytidine analogue drug FNC, and the activation effect of FNC on the NAs metabolism system potentially contribute to its enrichment in the thymus and immune protection effect. This suggests that it is crucial to consider the expression level of phosphorylation kinases when evaluating NA drug properties, as an important factor during antiviral drug design.

The chemical composition and the preservative, antimicrobial, and antioxidant effects of Thymus broussonetii Boiss. essential oil: an in vitro and in silico approach.

Introduction: The aim of this study was to evaluate the antioxidant, antimicrobial, and preservative efficacy of Thymus broussonetii Boiss. essential oil (EO) in a topically applied formulation using a challenge test. Methods: The essential oil was extracted from the aerial part of T. broussonetii using hydrodistillation, and the obtained EO was further analyzed by gas chromatography/mass spectrometry (GC/MS). The antioxidant effect of the EO was evaluated using three methods: the inhibition of free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH), ß-carotene-linoleic acid, and the ferric reducing antioxidant power (FRAP) methods. The antimicrobial activity and the minimum inhibitory concentration (MIC) of this EO were assayed by the disk-diffusion method and the broth microdilution method, respectively. The preservative efficacy of T. broussonetii EO was assayed at 1% and 2% (v/w) in a topical cream formulation using a challenge test against standard-specific microorganisms recommended by the European Pharmacopoeia. Furthermore, the identified phytochemical compounds were docked for their effect on nicotinamide adenine dinucleotide phosphate oxidase, human casein kinase 1 alpha 1 (CSNK1A1), glycogen synthase kinase 3, Staphylococcus aureus nucleoside diphosphate kinase, Escherichia coli beta-ketoacyl-[acyl-carrier protein] synthase, Pseudomonas aeruginosa LasR ligand-binding domain, and sterol 14-alpha demethylase (CYP51) from Candida albicans. The ADME/toxicity was predicted by analyzing the absorption, distribution, metabolism, and excretion parameters. Results and discussion: chemical composition of the EO revealed the presence of thymol (63.09%), p-cymene (11%), and γ-terpinene (8.99%) as the major components. The antioxidant assays revealed that the essential oil exhibited strong antioxidant activity, as indicated by the minimum inhibitory concentration IC50 (IC50 = 210 ± 0.3 µg/mL for the DPPH assay, IC50 = 145 ± 0.1 µg/mL for the ß-carotene assay, and IC50 = 84 ± 0.21 µg/mL for the FRAP assay) when compared to quercetin and butylated hydroxytoluene (BHT) as controls. The investigated essential oil exhibited important antimicrobial activity against all the tested microorganisms, and the MICs of the EO against bacteria and fungi were 0.02%-1%. Moreover, the EO of T. broussonetii evaluated at 2% (v/w) in a cream formulation succeeded in satisfying the A criteria for preservation efficacy against S. aureus, E. coli, and Aspergillus brasiliensis but exhibited less efficacy against P. aeruginosa (1.78 log reduction in the number of CFU/g after 7 days of evaluation) and C. albicans (1.09 log reduction in the number of CFU/g after 14 days of evaluation) when compared to the synthetic preservative phenoxyethanol 1% (v/w). In silico results showed that the antimicrobial activity of T. broussonetii EO is mostly attributed to thymol, terpinen-4-ol, and aromadendrene, while the antioxidant activity is attributed to thymol. These results indicate that the EO of T. broussonetii possesses important antimicrobial and antioxidant properties and can, therefore, be used as a natural preservative ingredient in the cosmetic industry.

Thymus in Cardiometabolic Impairments and Atherosclerosis: Not a Silent Player?

The thymus represents a primary organ of the immune system, harboring the generation and maturation of T lymphocytes. Starting from childhood, the thymus undergoes involution, being replaced with adipose tissue, and by an advanced age nearly all the thymus parenchyma is represented by adipocytes. This decline of thymic function is associated with compromised maturation and selection of T lymphocytes, which may directly impact the development of inflammation and induce various autoinflammatory disorders, including atherosclerosis. For a long time, thymus health in adults has been ignored. The process of adipogenesis in thymus and impact of thymic fat on cardiometabolism remains a mysterious process, with many issues being still unresolved. Meanwhile, thymus functional activity has a potential to be regulated, since islets of thymopoeisis remain in adults even at an advanced age. The present review describes the intricate process of thymic adipose involution, focusing on the issues of the thymus' role in the development of atherosclerosis and metabolic health, tightly interconnected with the state of vessels. We also review the recent information on the key molecular pathways and biologically active substances that may be targeted to manipulate both thymic function and atherosclerosis.

Phytochemical Analysis and Antioxidant and Antifungal Activities of Powders, Methanol Extracts, and Essential Oils from Rosmarinus officinalis L. and Thymus ciliatus Desf. Benth.

Chemical residues in food pose health risks such as cancer and liver issues. This has driven the search for safer natural alternatives to synthetic fungicides and preservatives. The aim of this study was to characterize the chemical composition of the essential oils (EO), determine the polyphenolic contents, and evaluate the in vitro antioxidant and antifungal activities of methanol extracts (ME), essential oils (EO), and powders from Rosmarinus officinalis L. (rosemary) and Thymus ciliatus (Desf) Benth. (thyme) from the M'sila region, Algeria. The chemical composition of the EOs was determined by GC-MS. R. officinalis EO was composed of 31 components, mainly camphor (41.22%), camphene (18.14%), and α-pinene (17.49%); T. ciliatus EO was composed of 58 components, mainly, in percentage, α-pinene (22.18), myrcene (13.13), ß-pinene (7.73), ß-caryophyllene (10.21), and germacrene D (9.90). The total phenols and flavonoids were determined spectrophotometrically, and the rosemary ME was found to possess the highest polyphenolic content (127.1 ± 2.40 µg GAE/mg), while the thyme ME had the highest flavonoid content (48.01 ± 0.99 µg QE/mg). The antioxidant activity was assessed using three methods: rosemary ME was the most potent, followed by DPPH (IC50 = 13.43 ± 0.14 µg/mL), ß-carotene/linoleic acid (IC50 = 39.01 ± 2.16 µg/mL), and reducing power (EC50 = 15.03 ± 1.43 µg/mL). Antifungal activity was assessed for 32 pathogenic and foodborne fungi. Four methods were applied to the solid medium. Incorporating the powdered plant into the culture medium (at 10%) reduced the fungal growth to greater than 50% in 21.88% and 6.25% of all fungal isolates, for R. officinalis and T. ciliatus, respectively. The ME, applied by the well diffusion method (0.1 g/mL), was less effective. Different concentrations of EO were tested. Incorporating the EO into the culture medium (1500 µL/L) inhibited 50% of the molds to levels of 50 and 75% for R. officinalis and T. ciliatus, respectively, with the complete inhibition of four fungi. Fumigated EO (15 µL) inhibited 65% of the molds to levels of 65 and 81.25% for R. officinalis and T. ciliatus, respectively, with the complete inhibition of five fungi. There was little to no sporulation in conjunction with the inhibition. Our results revealed some of the potential of the studied plants to fight foodborne molds and presented their promising characteristics as a source of alternatives to chemical pesticides and synthetic preservatives. Further studies are needed to find adequate application techniques in the food safety area.