Protective Effects of Natural Antioxidants on Inflammatory Bowel Disease: Thymol and Its Pharmacological Properties

Amoebicidal thymol analogues against brain-eating amoeba, Naegleria fowleri

Naegleria fowleri, known as the brain-eating amoeba, is the pathogen parasite that causes primary amoebic meningoencephalitis. None of the currently available therapies are fully effective, mainly due to the inefficacy of pharmacotherapy. In this regard, natural products and related compounds represent a promising strategy for amoebicidal drug discovery. Herein, a series of eight monoterpene phenol derivatives of thymol bearing ester, carbonate, or carbamate moieties were prepared, and screened as potential amoebicidal agents on N. fowleri. The cytotoxicity of these compounds on murine macrophages cell line J774 was also evaluated to assess their selectivity. Compounds 3, 4, 7 and 8 showed significant activity against the N. fowleri trophozoite. Moreover, 4-nitrophenyl thymyl carbonate 8 displayed the highest potency, showing IC50 values of 22.87 and 25.16 μM against N. fowleri trophozoite and cyst stages, respectively, coupled with low cytotoxicity on a mammal cell line. Furthermore, mechanism of action studies revealed that derivative 8 triggered programmed cell death via cytosolic calcium accumulation, mitochondrial alteration, membrane damage, chromatin condensation, and ROS accumulation. In addition, the in-silico ADME analysis indicated that derivative 8 exhibits exceptional drug-likeness meeting all the pharmacokinetic criteria. These results highlight derivative 8 as a promising amoebicidal agent to develop new drugs for the treatment of Naegleria infections.

Phytochemical Analysis, Antioxidant and Antibacterial Activities, Minerals Element Profiling, and Identification of Bioactive Compounds by UPLC-HRMS Orbitrap in Four Aromatic and Medicinal Plants

Four aromatic and therapeutic plants, Thymus vulgaris, Rosmarinus officinalis, Pimpinella anisum, and Foeniculum vulgare, were examined in this comparative study. The objectives were to assess its phytochemical composition; polyphenol, flavonoid, and tannin content; antioxidant and antibacterial activity; bioactive molecule identification; and critical trace element quantification. Its aqueous and organic extracts were examined, focusing on ethanolic extracts. The ethanolic extract's ability to neutralize free radicals was validated by phytochemical studies and antioxidant tests, underscoring their role in preventing oxidative stress. An Ultra-Performance Liquid Chromatography-High-Resolution Mass Spectrometry Orbitrap Exploris 120 (UPLC-HRMS Orbitrap) was used to identify the bioactive chemicals, and the results showed a variety of compounds having antibacterial and antioxidant properties. The important trace elements found in these plants were also measured using a Graphite Furnace-Atomic Absorption Spectrometer (GF-AAS). These components are essential to the biological characteristics of the plants, especially their antioxidant and antibacterial capacities. Among the aqueous extracts, it was observed that Rosmarinus officinalis and Foeniculum vulgare exhibited a MIC of 3.91 µg/mL against Staphylococcus. Additionally, R. officinalis also demonstrated a MIC of 3.91 µg/mL against Escherichia coli. All of the data were interpreted and shown using principal component analysis. The results were grouped and explained using this statistical method, which revealed a strong association between the abundance of antibacterial and antioxidant chemicals in the four plants under investigation.

Thymol inhibits ergosterol biosynthesis in Nakaseomyces glabratus, but differently from azole antifungals

INTRODUCTION

Nakaseomyces glabratus is considered a high priority of attention according to WHO, and also is an important yeast species due to its high rate of intrinsic/acquired resistance against fluconazole. This study aimed at the possible mechanisms of action of thymol, as the promising new antifungal agent, in N. glabratus.

METHODS

Thirty previously identified N. glabratus isolates were selected for investigation of the thymol susceptibility pattern. The antifungal susceptibility test was performed according to the Clinical and Laboratory Standards protocol published as M27-A2 document. Likely changes in the expression pattern of genes involved in the ergosterol biosynthesis pathway were assessed by Real-time PCR assay. The ultrastructure characteristics of thymol-treated yeasts and also the possible interactive proteins, as targets for thymol binding, were performed by transmission electron microscopy (TEM) and reverse molecular docking, respectively.

RESULTS

Minimum inhibitory concentrations ranged between 32-128 µg/mL which were statistically significant between the fluconazole-susceptible and fluconazole-resistant yeast group (P<0. 05). TEM observation results showed that thymol led to peripheral vacuole formation which refers to plasma membrane damage and cell membrane separation from the cell wall. Thymol exhibits antifungal activity against N. glabratus by regulating multiple signaling pathways including ergosterol biosynthesis (ERG1) and HOG (high-osmolarity glycerol) MAPK (mitogen-activated protein kinase) pathways. In consistence with the yielded gene expression patterns, docking evaluation findings also revealed the high affinity of thymol with proteins related to the ERG1 gene. Accordingly, thymol's high affinity to chitin synthase and calcineurin subunit B was noteworthy.

CONCLUSION

Thymol might employ its antifungal effect by involving different pathways comprising ergosterol biosynthesis inhibition but not identical to the azole drugs. It is highly suggested that thymol ruins cell membrane function by decreasing the ergosterol/or chitin content. However, studying more ergosterol biosynthesis-related genes and also the yeast apoptotic responses is highly recommended for future investigations.

Urinary Metabolic Profiling During Epileptogenesis in Rat Model of Lithium-Pilocarpine-Induced Temporal Lobe Epilepsy

Background/Objectives: Temporal lobe epilepsy (TLE) often develops following an initial brain injury, where specific triggers lead to epileptogenesis-a process transforming a healthy brain into one prone to spontaneous, recurrent seizures. Although electroencephalography (EEG) remains the primary diagnostic tool for epilepsy, it cannot predict the risk of epilepsy after brain injury. This limitation highlights the need for biomarkers, particularly those measurable in peripheral samples, to assess epilepsy risk. This study investigated urinary metabolites in a rat model of TLE to identify biomarkers that track epileptogenesis progression across the acute, latent, and chronic phases and elucidate the underlying mechanisms. Methods: Status epilepticus (SE) was induced in rats using repeated intraperitoneal injections of lithium chloride-pilocarpine hydrochloride. Urine samples were collected 48 h, 1 week, and 6 weeks after SE induction. Nuclear magnetic resonance spectrometry was used for metabolomic analysis, and statistical evaluations were performed using MetaboAnalyst 6.0. Differences between epileptic and control groups were represented using the orthogonal partial least squares discriminant analysis (OPLS-DA) model. Volcano plot analysis identified key metabolic changes, applying a fold-change threshold of 1.5 and a p-value < 0.05. Results: The acute phase exhibited elevated levels of acetic acid, dihydrothymine, thymol, and trimethylamine, whereas glycolysis and tricarboxylic acid cycle metabolites, including pyruvic and citric acids, were reduced. Both the acute and latent phases showed decreased theobromine, taurine, and allantoin levels, with elevated 1-methylhistidine in the latent phase. The chronic phase exhibited reductions in pimelic acid, tiglylglycine, D-lactose, and xanthurenic acid levels. Conclusions: These findings highlight stage-specific urinary metabolic changes in TLE, suggesting distinct metabolites as biomarkers for epileptogenesis and offering insights into the mechanisms underlying SE progression.

A Novel Selenium-Based Nanozyme (GSH-Se) Ameliorates Colitis in Mice by Modulating the Nrf2/Keap1 and GPx4 Pathways

Combination of selenium (Se) and glutathione peroxidase (GPx) can reduce the dose of Se used while concurrently exploiting their antioxidative performance, which can be used as a potential treatment for ulcerative colitis. Nanozymes possess higher stability, are more economical, and have more multifunctionalities than natural enzymes and thus could be an ideal approach for their combination. Therefore, this study synthesised a nanozyme using glutathione (GSH) and Se-GSH-Se-and evaluated its alleviating effects on colitis in mice induced by dextran sulphate sodium salt (DSS). Three doses of GSH-Se, 6 mM, 12 mM, and 18 mM were supplemented in DSS-induced colitis in mice. Findings showed that GSH-Se supplementation ameliorated colitis by improving the colonic mucosal integrity, reducing inflammatory responses and oxidative stress, and alleviating gut microbiota imbalance in mice with DSS-induced colitis. Moreover, an in vitro experiment was performed to unravel the molecular mechanism by which GSH-Se ameliorated colitis in mice, based on lipopolysaccharide-induced inflammation in mouse colon epithelial cells. The results suggested that the alleviating effects of GSH-Se on mouse colitis was likely mediated by the activation of the Nrf2/Keap1 (nuclear factor E2-related factor 2/Kelch-like ECH-associated protein 1) and GPx4 signalling pathways.

Unlocking the Potential of Origanum Grosii Essential Oils: A Deep Dive into Volatile Compounds, Antioxidant, Antibacterial, and Anti-Enzymatic Properties within Silico Insights

The present study aimed to comprehensively characterize the volatile compounds from the aerial parts of Origanum grosii and evaluate their potential as antioxidants and enzyme inhibitors through both in vitro and in silico approaches. The essential oil's volatile constituents were identified using Gas Chromatography-Mass Spectrometry (GC-MS) analysis, revealing carvacrol (31 %), p-cymene (18.59 %), thymol (12.31 %), and ɣ-terpinene (10.89 %) as the major compounds. The antioxidant capacity was measured using three distinct assays. Notably, Origanum grosii essential oil (OGEO) exhibited significant antioxidant activity, with IC50 values of 55.40±2.23, 81.65±3.26, and 98.04±3.87 μg/mL in DPPH, ABTS, and FRAP assays, respectively. The antibacterial activity was evaluated against both Gram-positive and Gram-negative bacterial strains, including Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213, Pseudomonas aeruginosa IH, and Listeria monocytogenes ATCC 13932. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using the broth microdilution method. The inhibitory effects of OGEO were also assessed against enzymes implicated in human pathologies, including α-glucosidase, α-amylase, tyrosinase, and acetylcholinesterase (AChE). OGEO demonstrated notable inhibitory activity with IC50 values of 49.72±1.64, 60.28±2.13, 97.14±5.15, and 119.42±2.97 μg/mL against elastase, α-glucosidase, tyrosinase, and α-amylase, respectively. Additionally, OGEO exhibited anti-AChE and anti-BChE effects, with values of 7.49±0.83 and 1.91±0.77 mg GALAE/g, respectively. The MIC values were 0.125 μg/mL for E. coli, P. aeruginosa, and S. aureus, and 0.25 μg/mL for L. monocytogenes, while MBC values ranged from 0.25 to 0.5 μg/mL. Compared to chloramphenicol (MIC: 8-16 μg/mL, MBC: 32-64 μg/mL), OGEO showed significantly stronger antibacterial effects. In silico analysis further supported the strong binding affinities of the major compounds to the target enzymes. Overall, OGEO shows promise as a natural agent with potential applications in the food, pharmaceutical, and cosmetic industries.

Fucoxanthin ameliorates ulcerative colitis by maintaining the epithelial barrier via blocking JAK2/STAT3 signaling pathway

BACKGROUND

The clinical efficacies of Ulcerative colitis (UC) are far from satisfactory. Fucoxanthin (FUC) is a marine carotenoid that is abundant in seaweed and microalgae. It has been reported that FUC can possess anti-inflammatory and antioxidant. However, its mechanism and role in UC is yet to be clarified. This study aimed to investigate the protective effect and potential mechanism of FUC extracted from the diatom Phaeodactylum tricornutm on dextran sodium sulfate (DSS) -induced colitis.

METHODS

Animal UC model was induced by DSS and cellular model was established by TNF-α. Immunohistochemical staining, Western blot, RT-qPCR, and immunofluorescence were used to assess the inflammatory responses and epithelial barrier in vivo and in vitro models.

RESULTS

The results showed that FUC attenuates DSS-induced colitis by ameliorating the epithelial mucosal barrier. Moreover, FUC possessed antioxidant and anti-inflammatory effects on NCM460 cells. JAK/STAT activator RO8191 could reverse these changes.

CONCLUSION

FUC exerted anti-inflammatory and antioxidant effects via the JAK2/STAT3 signaling pathway, and served as a potential therapeutic agent for the treatment of UC.

Fabrication of Thymol-loaded Isabgol/Konjac Glucomannan-based Microporous Scaffolds with Enriched Antioxidant and Antibacterial Properties for Skin Tissue Engineering Applications

An antioxidant, antibacterial, and biocompatible biomaterial is essential to repair skin wounds effectively. Here, we have employed two natural biopolymers, isabgol (ISAB) and konjac glucomannan (KGM), to prepare microporous scaffolds by freezing and lyophilization. The scaffolds are loaded with thymol (THY) to impart potent antioxidant and antibacterial activities. The physicochemical properties of the ISAB+KGM+THY scaffold, like porosity (41.8±2.4 %), swelling, and biodegradation, were optimal for tissue regeneration application. Compared to the control, ISAB+KGM+THY scaffolds promote attachment, migration, and proliferation of L929 fibroblasts. The antioxidant activity of the ISAB+KGM+THY scaffold was significantly improved after loading THY. This would protect the tissues from oxidative damage. The antibacterial activity of the ISAB+KGM+THY scaffold was significantly higher than that of the control, which would help prevent bacterial infection. The vascularization ability of the ISAB+KGM scaffold was not altered by incorporating THY in the ISAB+KGM scaffold. Therefore, a strong antioxidant, antibacterial, and biocompatible nature of the ISAB+KGM+THY scaffold could be useful for various biomedical applications.

Mulberry leaf benefits the intestinal epithelial barrier via direct anti-oxidation and indirect modulation of microbiota in pigs

BACKGROUND

Diarrhea and intestinal dysfunction commonly occur in young mammals, causing malnutrition and growth retardation in both human and livestock. As the traditional Chinese herb, mulberry leaf contains various bioactive compounds and showed several health benefits, such as regulating glucose and lipid metabolism, and modulating gut microbiota. Mulberry leaf exhibits the potential to modulate redox homeostasis and improve gut health, but the function and underlying mechanisms remains elucidative.

PURPOSE

To investigate the benefit of mulberry leaf on intestinal barrier in weanling pigs, illustrate the possible involvement of Keap1-Nrf2 mediated anti-oxidation and gut microbiota.

METHODS

Chemical compositions of mulberry leaf powder (MLP) and mulberry leaf extract (MLE) were determined. The effects of MLP on growth performance, intestinal barrier integrity, anti-oxidative capacity, immune function and gut microbiota were evaluated in weaned pigs. The regulation of redox homeostasis by MLE and the involvement of Keap1-Nrf2 signaling were further determined in H2O2 induced oxidative stress (OS) model in IPEC-J2 cells via determining reactive oxygen species (ROS) production by flow cytometry and related protein abundance by western blot analysis.

RESULTS

In weanling pigs, MLP reduced diarrhea incidence, and increased villus height, intestinal integrity and expression of tight junctions in intestinal mucosa. The improvement of intestinal barrier by MLP was associated with the enhancement in anti-oxidative capacity and the changes in gut microbiota and related short chain fatty acids production. Our study further revealed the direct regulation of MLE on tight junction expressions and ROS production to alleviate H2O2 induced OS in IPEC-J2 cells via the activating Keap1-Nrf2 signaling pathway.

CONCLUSIONS

Mulberry leaf in diet improved epithelial barrier via the direct anti-oxidation through the activation of Keap1-Nrf2 signaling pathway and the indirect modulation of gut microbiota in weaned pigs.

Gastroprotective Efficacy of North African Medicinal Plants: A Review on Their Therapeutic Potential for Peptic Ulcers

Peptic ulcer disease remains a prevalent gastrointestinal disorder worldwide. Current treatments often have limitations, sparking interest in alternative therapies from medicinal plants. This review examines the gastroprotective potential of 54 North African medicinal plants against peptic ulcers. An extensive literature search was conducted, focusing on plants with preclinical and clinical evidence of anti-ulcer efficacy and documented use in North African traditional medicine. The review identified several promising plant species, such as licorice (Glycyrrhiza glabra), chamomile (Matricaria chamomilla), olive (Olea europaea), pomegranate (Punica granatum), Aloe vera, and black seed (Nigella sativa), along with their bioactive constituents, including flavonoids, tannins, and terpenoids. These compounds exhibit gastroprotective properties through multiple mechanisms, such as enhancing the gastric mucosal barrier, inhibiting acid secretion, displaying antioxidant and anti-inflammatory effects, promoting ulcer healing, and combating Helicobacter pylori infection. The evidence presented includes in vitro assays, animal models, and some clinical studies. While many of the 53 plants reviewed demonstrated significant anti-ulcer effects compared to standard drugs, further clinical research is needed to establish efficacy and safety in humans. The synergistic actions of phytochemical mixtures in medicinal plant extracts likely contribute to their therapeutic potential. This review highlights the role these North African medicinal plants may play in the prevention and treatment of peptic ulcers and identifies promising candidates for further research and development of evidence-based botanical therapies.

Oral administration of liposome-encapsulated thymol could alleviate the inflammatory parameters in serum and hippocampus in a rat model of Alzheimer's disease

BACKGROUND

Neuroinflammation is closely related to Alzheimer's Disease (AD) pathology, hence supplements with anti-inflammatory property could help attenuate the progression of AD. This study was conducted to evaluate the potential anti-inflammatory effects of liposome encapsulated thymol (LET), administered orally, in prevention of Alzheimer in a rat model by anti-inflammatory mechanisms.

METHODS

The rats were grouped into six groups (n = 10 animals per group), including Control healthy (Con), Alzheimer's disease (AD) model, AD model treated with free thymol in 40 and 80 mg/kg body weight (TH40 and TH80), AD model treated with LET in 40 and 80 mg/kg of body weight (LET40 and LET80). The behavioral response of step through latency (Passive Avoidance Test), concentrations of interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) and cyclooxygenase-2 (COX-2) and brain-derived neurotrophic factor (BDNF) were assessed in serum and hippocampus.

RESULTS

The results showed that significant increase in concentrations of IL-1β (P = 0.001), IL-6 (P = 0.001), TNF-α (P = 0.001) and COX-2 (P = 0.001) in AD group compared with healthy control rats. AD induction significantly reduced step through latency and revealed deficits in passive avoidance performance. The results also showed the treatment with free thymol especially in higher concentrations and also LTE could decrease serum concentrations of IL-1β (P < 0.05), IL-6 (P < 0.05), TNF-α (P < 0.05), and COX-2 (P < 0.05) and increase BDNF (P < 0.05) compared with control Alzheimer rats in hippocampus and serum. There were also significant correlations between serum and hippocampus concentrations of IL-1β (r2 = 0.369, P = 0.001), IL-6 (r2 = 0.386, P = 0.001), TNF-α (r2 = 0.412, P = 0.001), and COX-2 (r2 = 0.357, P = 0.001). It means a closed and positive relation between serum and hippocampus concentrations of IL-1β, IL-6, TNF-α, and COX-2.

CONCLUSIONS

LET demonstrates its ability to attenuate neuroinflammatory reaction in AD model through suppression of IL-1β, IL-6, and TNF-α and COX-2 indicators. Hence, it can ameliorate AD pathogenesis by declining inflammatory reaction.

Anti-inflammatory effects of thymol: an emphasis on the molecular interactions through in vivo approach and molecular dynamic simulations

Thymol (THY), as the natural monoterpene phenol, acts against oxidative stress and inflammatory processes. This study aimed to evaluate the anti-inflammatory effects and possible molecular mechanisms of THY via formalin-induced mouse and egg albumin-induced chick models alongside molecular docking and molecular dynamic (MD) simulations. THY (7.5, 15, and 30 mg/kg) was investigated, compared to celecoxib and ketoprofen (42 mg/kg), as anti-inflammatory standards. THY dose-dependently and significantly (p < 0.05) decreased paw-licking and edema diameter parameters in formalin (phases I and II) and egg albumin-induced models. Moreover, THY (15 mg/kg) exerted better anti-inflammatory effects in combination with the standard drug ketoprofen than alone and with celecoxib. In silico studies demonstrated elevated binding affinities of THY with cyclooxygenase-2 (COX-2) than the COX-1 enzyme, and the ligand binds at a similar location where ketoprofen and celecoxib interact. The results of MD simulations confirmed the stability of the test ligand. THY exerted anti-inflammatory effects on Swiss mice and young chicks, possibly by interacting with COX-2. As a conclusion, THY might be a hopeful drug candidate for the management of inflammatory disorders.

Exploring the therapeutic potential of cinnamoyl derivatives in attenuating inflammation in lipopolysaccharide-induced Caco-2 cells

Aim: In gastrointestinal (GI) diseases, lipopolysaccharide (LPS) exacerbates gut-barrier dysfunction and inflammation. Cinnamoyl derivatives show potential in mitigating LPS-induced inflammation.Materials & methods: We assessed intestinal epithelial barrier function using Trans-epithelial electrical resistance values and measured inflammatory mediators through real-time PCR and ELISA in Caco-2 cells.Results: LPS treatment increased IL-6, IL-1β, TNF-α, PGE2 and TRL4 expression in Caco-2 cells. Pre-treatment with DM1 (1 or 10 μM) effectively countered LPS-induced TLR4 overexpression and reduced IL-6, IL-1β, TNF-α and PGE2 levels.Conclusion: DM1 holds promise in regulating inflammation and maintaining intestinal integrity by suppressing TLR4 and inflammatory mediators in Caco-2 cells. These findings suggest a potential therapeutic avenue for GI diseases.

Thymol as a Potential Neuroprotective Agent: Mechanisms, Efficacy, and Future Prospects

Neurodegenerative diseases pose a growing global health challenge, with limited effective therapeutic options. Mitochondrial dysfunction, oxidative stress, neuroinflammation, apoptosis, and autophagy are common underlying mechanisms in these diseases. Thymol is a phenolic monoterpene compound that has gained attention for its diverse biological properties, including antioxidant, anti-inflammatory, and immunomodulatory activities. Thymol supplementation could provide potential neuroprotection and improve cognitive deficits, depressant-like effects, learning, and memory impairments in rodents. Mechanistic investigations reveal that the neuroprotective effects of thymol involve the improvement of oxidative stress, mitochondrial dysfunction, and inflammatory response. Several signaling pathways, including mitochondrial apoptotic, NF-κB, AKT, Nrf2, and CREB/BDNF pathways are also involved. In this review, the neuroprotective effects of thymol, the potential molecular mechanisms, safety, applications, and current challenges toward development as a neuroprotective agent were summarized and discussed. We hope that this review provides valuable insights for the further development of this promising natural product as a promising neuroprotective agent.

Gel-Dispersed Nanostructured Lipid Carriers Loading Thymol Designed for Dermal Pathologies

Purpose

Acne vulgaris is one of the most prevalent dermal disorders affecting skin health and appearance. To date, there is no effective cure for this pathology, and the majority of marketed formulations eliminate both healthy and pathological microbiota. Therefore, hereby we propose the encapsulation of an antimicrobial natural compound (thymol) loaded into lipid nanostructured systems to be topically used against acne.

Methods

To address this issue, nanostructured lipid carriers (NLC) capable of encapsulating thymol, a natural compound used for the treatment of acne vulgaris, were developed either using ultrasonication probe or high-pressure homogenization and optimized using 22-star factorial design by analyzing the effect of NLC composition on their physicochemical parameters. These NLC were optimized using a design of experiments approach and were characterized using different physicochemical techniques. Moreover, short-term stability and cell viability using HaCat cells were assessed. Antimicrobial efficacy of the developed NLC was assessed in vitro and ex vivo.

Results

NLC encapsulating thymol were developed and optimized and demonstrated a prolonged thymol release. The formulation was dispersed in gels and a screening of several gels was carried out by studying their rheological properties and their skin retention abilities. From them, carbomer demonstrated the capacity to be highly retained in skin tissues, specifically in the epidermis and dermis layers. Moreover, antimicrobial assays against healthy and pathological skin pathogens demonstrated the therapeutic efficacy of thymol-loaded NLC gelling systems since NLC are more efficient in slowly reducing C. acnes viability, but they possess lower antimicrobial activity against S. epidermidis, compared to free thymol.

Conclusion

Thymol was successfully loaded into NLC and dispersed in gelling systems, demonstrating that it is a suitable candidate for topical administration against acne vulgaris by eradicating pathogenic bacteria while preserving the healthy skin microbiome.

Thymol targeting interleukin 4 induced 1 expression reshapes the immune microenvironment to sensitize the immunotherapy in lung adenocarcinoma

Immune checkpoint blockades are the most promising therapy in lung adenocarcinoma (LUAD). However, the response rate remains limited, underscoring the urgent need for effective sensitizers. Interleukin 4 induced 1 (IL4I1) is reported to have immunoinhibitory and tumor-promoting effects in several cancers. However, the targetable value of IL4I1 in sensitizing the immunotherapy is not clear, and there is a lack of effective small molecules that specifically target IL4I1. Here, we show that silencing IL4I1 significantly remodels the immune microenvironment via inhibiting aryl hydrocarbon receptor (AHR) signaling, thereby enhancing the efficacy of anti-PD-1 antibody in LUAD, which suggests that IL4I1 is a potential drug target for the combination immunotherapy. We then identify thymol as the first small molecule targeting IL4I1 transcription through a drug screening. Thymol inhibits the IL4I1 expression and blocks AHR signaling in LUAD cells. Thymol treatment restores the antitumor immune response and suppresses the progression of LUAD in an orthotopic mouse model. Strikingly, the combination treatment of thymol with anti-PD-1 antibody shows significant tumor regression in LUAD mice. Thus, we demonstrate that thymol is an effective small molecule to sensitize the PD-1 blockade in LUAD via targeting IL4I1, which provides a novel strategy for the immunotherapy of LUAD.

Anti-Inflammatory, Anti-Oxidative and Anti-Apoptotic Effects of Thymol and 24-Epibrassinolide in Zebrafish Larvae

Thymol (THY) and 24-epibrassinolide (24-EPI) are two examples of plant-based products with promising therapeutic effects. In this study, we investigated the anti-inflammatory, antioxidant and anti-apoptotic effects of the THY and 24-EPI. We used zebrafish (Danio rerio) larvae transgenic line (Tg(mpxGFP)ⁱ¹¹⁴) to evaluate the recruitment of neutrophils as an inflammatory marker to the site of injury after tail fin amputation. In another experiment, wild-type AB larvae were exposed to a well known pro-inflammatory substance, copper (CuSO4), and then exposed for 4 h to THY, 24-EPI or diclofenac (DIC), a known anti-inflammatory drug. In this model, the antioxidant (levels of reactive oxygen species-ROS) and anti-apoptotic (cell death) effects were evaluated in vivo, as well as biochemical parameters such as the activity of antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase), the biotransformation activity of glutathione-S-transferase, the levels of glutathione reduced and oxidated, lipid peroxidation, acetylcholinesterase activity, lactate dehydrogenase activity, and levels of nitric acid (NO). Both compounds decreased the recruitment of neutrophils in Tg(mpxGFP)ⁱ¹¹⁴, as well as showed in vivo antioxidant effects by reducing ROS production and anti-apoptotic effects in addition to a decrease in NO compared to CuSO4. The observed data substantiate the potential of the natural compounds THY and 24-EPI as anti-inflammatory and antioxidant agents in this species. These results support the need for further research to understand the molecular pathways involved, particularly their effect on NO.

Geniposide ameliorates dextran sulfate sodium-induced ulcerative colitis via KEAP1-Nrf2 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

The dried fruit of Gardenia jasminoides Ellis (Zhizi in Chinese) is a traditional medicine used for thousands of years in China, Japan and Korea. Zhizi was recorded in Shennong Herbal, as a folk medicine, it reduces fever and treats gastrointestinal disturbance with antiphlogistic effects. Geniposide, an iridoid glycoside, is an important bioactive compound derived from Zhizi and possesses remarkable antioxidant and anti-inflammatory capacities. The pharmacological efficacy of Zhizi is highly related to the antioxidant and anti-inflammatory effects of geniposide.

AIM OF THE STUDY

Ulcerative colitis (UC) is a common chronic gastrointestinal disease as a global public health threat. Redox imbalance is an essential factor in the progression and recurrence of UC. This study aimed to explore the therapeutic effect of geniposide on colitis and uncover the underlying mechanisms of geniposide-mediated antioxidant and anti-inflammatory activities.

EXPERIMENTAL DESIGN

The study design involved investigating the novel mechanism by which geniposide ameliorates dextran sulfate sodium (DSS)-induced colitis in vivo and lipopolysaccharide (LPS)-challenged colonic epithelial cells in vitro.

MATERIALS AND METHODS

The protective effect of geniposide against colitis was evaluated by histopathologic observation and biochemical analysis of colonic tissues in DSS-induced colitis mice. The antioxidant and anti-inflammatory effects of geniposide were evaluated in both DSS-induced colitis mice and LPS-challenged colonic epithelial cells. Immunoprecipitation, drug affinity responsive target stability (DARTS), and molecular docking were performed to identify the potential therapeutic target of geniposide and the potential binding sites and patterns.

RESULTS

Geniposide ameliorated the symptoms of DSS-induced colitis and colonic barrier injury, inhibited pro-inflammatory cytokine expression, and suppressed activation of the NF-κB signaling in colonic tissues of DSS-challenged mice. Geniposide also ameliorated lipid peroxidation and restored redox homeostasis in DSS-treated colonic tissues. In addition, in vitro experiments also showed that geniposide exhibited significant anti-inflammatory and antioxidant activity, as evidenced by suppressed IκB-α and p65 phosphorylation and IκB-α degradation, and enhanced the phosphorylation and transcriptional activity of Nrf2 in LPS-treated Caco2 cells. ML385, a specific Nrf2 inhibitor, abolished the protective effect of geniposide against LPS-induced inflammation. Mechanistically, geniposide could bind to KEAP1, thereby disrupting the interaction between KEAP1 and Nrf2, preventing Nrf2 from degradation and activating the Nrf2/ARE signaling pathway, ultimately suppressing the onset of inflammation caused by redox imbalance.

CONCLUSIONS

Geniposide ameliorates colitis by activation of Nrf2/ARE signaling, while preventing colonic redox imbalance and inflammatory damage, indicating that geniposide can be considered as a promising lead compound for the treatment of colitis.

Oxidative Stress, Inflammation, Gut Dysbiosis: What Can Polyphenols Do in Inflammatory Bowel Disease?

Inflammatory bowel disease (IBD) is a long-term, progressive, and recurrent intestinal inflammatory disorder. The pathogenic mechanisms of IBD are multifaceted and associated with oxidative stress, unbalanced gut microbiota, and aberrant immune response. Indeed, oxidative stress can affect the progression and development of IBD by regulating the homeostasis of the gut microbiota and immune response. Therefore, redox-targeted therapy is a promising treatment option for IBD. Recent evidence has verified that Chinese herbal medicine (CHM)-derived polyphenols, natural antioxidants, are able to maintain redox equilibrium in the intestinal tract to prevent abnormal gut microbiota and radical inflammatory responses. Here, we provide a comprehensive perspective for implementing natural antioxidants as potential IBD candidate medications. In addition, we demonstrate novel technologies and stratagems for promoting the antioxidative properties of CHM-derived polyphenols, including novel delivery systems, chemical modifications, and combination strategies.

Thymol improves autism-like behaviour in VPA-induced ASD rats through the Pin1/p38 MAPK pathway

Inflammation plays an essential role in the pathogenesis of autism spectrum disorder (ASD). Thymol is a bioactive monoterpene isolated from Thymus vulgaris that has anti-inflammatory properties and is helpful in neurodevelopmental disorders. The purpose of this study was to investigate the effects of thymol on autism-like behaviours in rats with VPA-induced ASD and to assess the related molecular mechanisms. In the prefrontal cortex (PFC) of the valproic acid (VPA)-exposed rat model, the levels of Pin1, phosphorylated p38 MAPK, interleukin-1β (IL-1β) and tumour necrosis factor (TNF)-α, were increased, and the levels of PSD95 and synaptophysin (SYP) decreased. After thymol treatment (30 mg/kg), the VPA-induced autism-like behaviours were alleviated. Moreover, thymol also rescued the dysregulated levels of Pin1, phosphorylated p38 MAPK, IL-1β, TNF-α, PSD95, and SYP. In addition, immunofluorescence experiments showed that thymol treatment decreased the correlation between Pin1 and phosphorylated p38 MAPK. Mechanistically, Pin1 knockdown by RNA interference confirmed that Pin1 promotes inflammation via phosphorylation of p38 MAPK in the VPA exposure rat model. In conclusion, thymol improved autism-like behaviours in VPA-induced ASD rats by reducing inflammation and improving neurodevelopment. This effect was mediated by the Pin1/p38 MAPK pathway. These results experimentally provide the potential for thymol in new therapeutic avenues for autism.