N-acetylcysteine a possible protector against indomethacin-induced peptic ulcer: crosstalk between antioxidant, anti-inflammatory, and antiapoptotic mechanisms

From lab to nature: Recent advancements in the journey of gastroprotective agents from medicinal chemistry to phytotherapy

Peptic ulcer, affecting 10 % of the global population, results from imbalances in gastric juice pH and diminished mucosal defences. Key underlying factors are non-steroidal anti-inflammatory drugs (NSAIDs) and Helicobacter pylori infection, undermining mucosal resistance. Traditional treatments like proton pump inhibitors (PPIs) and histamine-2 (H2) receptor antagonists exhibit drawbacks such as adverse effects, relapses, and drug interactions. This review extensively explores the ethnomedicinal, synthetic and pharmacological facets of various potential peptic ulcer treatments. Rigorous methodologies involving electronic databases, and chemical structure verification via 'PubChem' and 'SciFinder' enhance the review's credibility. The provided information, spanning medicinal insights to intricate pharmacological mechanisms, establishes a robust groundwork for future research and the development of plant-derived or synthetic molecules for peptic ulcers, offering a promising alternative to conventional therapies.

Protective effects and mechanisms of N-acetylcysteine on indomethacin-induced intestinal injury in a porcine model

This study aimed to investigate the effect of N-acetylcysteine (NAC) on indomethacin (IDMT)-induced intestinal injury in a piglet model and explore the underlying molecular mechanisms. Piglets were randomly divided into 3 treatment groups: (1) control group; (2) IDMT group; (3) NAC+IDMT group. The results showed that NAC administration significantly increased the average daily gain of piglets, attenuated the intestine hyperemia, and restored normal jejunal morphology. Further studies indicated that NAC administration significantly increased plasma citrulline concentration and jejunal villin expression, but decreased the content of proinflammatory cytokines in plasma and jejunum of IDMT-stimulated piglets. NAC administration selectively decreased the proportion of eosinophils but not neutrophils in plasma. Furthermore, NAC administration significantly increased the activities of superoxide dismutase and catalase in plasma but decreased the concentrations of hydrogen peroxide (plasma) and malondialdehyde (plasma and jejunum), as well as the activity of myeloperoxidase (jejunum) when comparing NAC+IDMT group with IDMT group. Gene Ontology analysis showed that the significantly enriched molecular function term was "ubiquitin-like protein ligase binding" for NAC+IDMT versus IDMT differentially regulated genes. In the biological process category, differentially regulated genes of NAC+IDMT versus IDMT were mainly enriched in immune-related terms. The major enrichments for differentially regulated proteins (DRPs) of NAC+IDMT versus IDMT were terms involved in lipid metabolism and immune response. KEGG pathway enrichment analysis showed that "arginine biosynthesis" was a significant enrichment term for the DRPs of NAC+IDMT versus IDMT. Further studies demonstrated that NAC administration up-regulated argininosuccinate synthase 1 mRNA expression and down-regulated arginase mRNA expression in the jejunum of IDMT-stimulated piglets. Moreover, the content of nitric oxide was restored to a normal level with the reduction of nitric oxide synthase activity. NAC administration ameliorated intestinal injury in IDMT-challenged piglets by enhancing antioxidant and anti-inflammatory functions and modulating arginine metabolism in the small intestine.

Integration of transcriptomic and proteomic analyses reveals protective mechanisms of N-acetylcysteine in indomethacin-stimulated enterocytes

Intestinal health is critical for the growth and development of humans and animals. Our previous study has demonstrated that indomethacin (IDMT) could induce intestinal injury in piglets, and N-acetylcysteine (NAC) supplementation contributed to alleviating intestinal injury induced by various stimuli. In this study, we investigated the mechanism of IDMT-induced cell death in IPEC-1 cell lines and explored the role of NAC by using transcriptomic and proteomic analyses. Results showed that cell viability was substantially reduced with the increasing concentrations of IDMT, whereas NAC significantly increased the survival rate of IPEC-1 cells regardless of its addition method. Transcriptomics and proteomics data indicated that terms, such as cell cycle, energy metabolism, and cell proliferation, were significantly enriched by Gene ontology and pathway analyses. Flow cytometer analysis showed that IDMT induced cell cycle arrest at G0/G1 phase. The expression of cell cycle regulatory proteins (CDK1, CCNA2, and CDC45) was decreased by IDMT stimulation. Importantly, NAC treatment repaired IDMT-induced mitochondrial dysfunction by increasing ATP production, decreasing oxygen consumption rate in non-mitochondrial O₂ consumption, and increasing the red/green fluorescence ratio. IDMT stimulation significantly increased caspase-3 expression, which was partially reversed by NAC treatment. These results suggest that IDMT-induced cell death may be attributable to disturbance of the cell cycle processes, mitochondria dysfunction and apoptosis, and NAC could confer a protective effect by restoring the mitochondrial function and inhibiting the apoptosis pathway. This study provides a theoretical basis for the pathogenesis of IDMT-induced intestinal injury and guides the clinic application of NAC.

Multifaceted Effects and Mechanisms of N-Acetylcysteine on Intestinal Injury in a Porcine Epidemic Diarrhea Virus-Infected Porcine Model

SCOPE

This study investigates the potential effects of N-acetylcysteine (NAC) on intestinal injury in a porcine epidemic diarrhea virus (PEDV)-infected porcine model.

METHODS AND RESULTS

Thirty-two piglets are randomly assigned to one of four groups: the control, PEDV, NAC, and NAC+PEDV. Piglets in the NAC+PEDV group are orally administrated with NAC (100 mg (kg·BW)^-1  day^-1 ) for 4 consecutive days after 2 days of PEDV infection. The results show that NAC administration decreases the diarrhea rate and improves intestinal morphology. The concentration of diamine oxidase and intestinal fatty-acid binding protein, as well as IL-1β, IL-8, and TNF-α in the plasma, is decreased by NAC. Intriguingly, NAC administration significantly increases the viral load in the jejunum and ileum and down-regulates the expression of interferon-related genes. Microarray and proteomic analyses show that the differentially expressed genes/proteins between NAC+PEDV and PEDV groups are highly enriched in substance transport. Furthermore, aquaporin 8/10 expression is significantly increased by NAC upon PEDV infection.

CONCLUSION

NAC administration alleviates PEDV-induced intestinal injury by inhibiting inflammatory responses and improving substance transport, but promotes viral replication by inhibiting interferon signaling. These results suggest NAC exhibits multifaceted effects upon PEDV infection, and thus caution is required when using NAC as a dietary supplement to prevent viral infection.

N-Acetylcysteine protects against cobalt chloride-induced endothelial dysfunction by enhancing glucose-6-phosphate dehydrogenase activity

Hypoxia‐induced endothelial dysfunction is known to be involved in the pathogenesis of several vascular diseases. However, it remains unclear whether the pentose phosphate pathway (PPP) is involved in regulating the response of endothelial cells to hypoxia. Here, we established an in vitro model by treating EA.hy926 (a hybrid human umbilical vein cell line) with cobalt chloride (CoCl₂; a chemical mimic that stabilizes HIF‐1α, thereby leading to the development of hypoxia), and used this to investigate the involvement of PPP by examining expression of its key enzyme, glucose‐6‐phosphate dehydrogenase (G6PD). We report that CoCl₂ induces the accumulation of HIF‐1α, leading to endothelial cell dysfunction characterized by reduced cell viability, proliferation, tube formation, and activation of cytokine production, accompanied with a significant decrease in G6PD expression and activity. The addition of 6‐aminonicotinamide (6‐AN) to inhibit PPP directly causes endothelial dysfunction. Additionally, N‐Acetylcysteine (NAC), a precursor of glutathione, was further evaluated for its protective effects; NAC displayed a protective effect against CoCl₂‐induced cell damage by enhancing G6PD activity, and this was abrogated by 6‐AN. The effects of CoCl₂ and the involvement of G6PD in endothelial dysfunction have been confirmed in primary human aortic endothelial cells. In summary, G6PD was identified as a novel target of CoCl₂‐induced damage, which highlighted the involvement of PPP in regulating the response of endothelial cell CoCl₂. Treatment with NAC may be a potential strategy to treat hypoxia or ischemia, which are widely observed in vascular diseases.

The Role of Natural Products in Treatment of Depressive Disorder

Depressive disorder is one of the most common psychiatric syndromes that, if left untreated, can cause many disturbances in a person's life. Numerous factors are involved in depression, including inflammation, brain-derived neurotrophic factor (BDNF), GABAergic system, hypothalamic- pituitary-adrenal (HPA) Axis, monoamine neurotransmitters (serotonin (5-HT), noradrenaline, and dopamine). Common treatments for depression are selective serotonin reuptake inhibitors, tricyclic antidepressants, and monoamine oxidase inhibitors, but these drugs have several side effects such as anxiety, diarrhea, constipation, weight loss, and sexual dysfunctions. These agents only reduce the symptoms and temporarily reduce the rate of cognitive impairment associated with depression. As a result, extensive research has recently been conducted on the potential use of antidepressant and sedative herbs. According to the available data, herbs used in traditional medicine can be significantly effective in reducing depression, depressive symptoms and improving patients' performance. The present study provides a summary of biomarkers and therapeutic goals of depression and shows that natural products such as saffron or genipin have antidepressant effects. Some of the useful natural products and their mechanisms were evaluated. Data on various herbs and natural isolated compounds reported to prevent and reduce depressive symptoms is also discussed.

Anti-ulcerogenic effect of methanolic extract of Elaeagnus conferta Roxb. seeds in Wistar rats

ETHNOPHARMACOLOGICAL RELEVANCE

Elaeagnus conferta Roxb. (Elaeagnaceae) is a subtropical shrub mainly native to India, Vietnam, Malaysia and South China, whose various parts are used for treatment of diabetes, gastric ulcers, pain, oxidative stress and pulmonary disorders. Though the other parts of the plant have been reported for their ethnic use i.e. fruits as astringent locally and for cancer systemically, leaves for body pain and flowers for pain in chest and the seeds are mentioned as edible, there is no report per se on the medicinal use of seeds. Based on the fact that seeds of closely resembling species i.e. Elaeagnus rhamnoides has demonstrated significant anti-gastroulcerative property, the probability of the seeds of E. conferta possessing similar activity seemed quite significant.

AIM OF THE STUDY

Phytochemical investigation and assessment of pharmacological mechanism(s) involved in anti-ulcer effect of methanolic extract of the seeds of E. conferta.

MATERIALS AND METHODS

Bioactive phytoconstituents were isolated by column chromatography. These were identified by spectroscopic techniques including infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) and mass spectrometry. Methanolic extract (MEC) of the seeds was prepared by cold maceration and its anti-ulcerogenic potential was evaluated using indomethacin (50 mg/kg) and water immersion stress models in male rats. The animals were pre-treated with different doses of MEC (400 and 800 mg/kg) and the therapeutic effect was compared with standard drug i.e. ranitidine (RANT; 50 mg/kg). The ameliorative effects of MEC were investigated on gastric juice pH, total acidity, free acidity and ulcer index. The assays of malionaldehyde (MDA), catalase (CAT), superoxide dismutase (SOD), glutathione (GSH) and pro-inflammatory cytokines i.e. interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) were carried out to find out the possible mechanism(s) of protection. Further, histopathological changes were also studied.

RESULTS

Chromatography studies and further confirmation by spectroscopic techniques revealed the presence of four different compounds in MEC i.e oleic acid (1), stearic acid (2), ascorbic acid (3) and quercetin (4). MEC exhibited anti-ulcerogenic effect in dose dependent manner which may be attributed to suppression of pro-inflammatory cytokines (IL-6, TNF-α) and MDA (112.7%), and up-regulation of protective factors such as CAT (90.48%), SOD (92.77%) and GSH (90.01%). Ulcer inhibition, reduction in total and free acidity and increase in gastric juice pH were observed in MEC treated rats as compared to disease control animals. Histopathological findings confirmed decreased cell infiltration, less epithelial cell damage and regeneration of gastric mucosa in dose dependent manner.

CONCLUSIONS

The anti-ulcer effect of MEC may be attributed to its ability to scavenge free radicals and anti-inflammatory property via suppression of TNF-α and IL-6, thus offers a complete and holistic approach for management of peptic ulcer.

An insight on safety, efficacy, and molecular docking study reports of N-acetylcysteine and its compound formulations

N-acetylcysteine (NAC) is considered as the body's major antioxidant molecules with diverse biological properties. In this review, the pharmacokinetics, safety and efficacy report on both the preclinical and clinical summary of NAC is discussed. Both in vitro and in vivo preclinical studies along with the clinical data have shown that NAC has enormous biological properties. NAC is used in the treatment of acetaminophen poisoning, diabetic nephropathy, Alzheimer's disease, schizophrenia, and ulcerative colitis, etc. Numerous analytical techniques, for instance, UPLC, LC-MS, HPLC, RP-IPC are primarily employed for the estimation of NAC in different single and fixed-dose combinations. The molecular docking studies on NAC demonstrate the binding within Sudlow's site-I hydrogen bonds and formation of NAC and BSA complexes. Various hydrophobic and hydrophilic amino acids generally exist in making contact with NAC as NAC-BSA complexes. Docking studies of NAC with the active site of the urease exposed an O-coordinated bond through nickel 3002 and a hydrogen bond through His-138. NAC and its analogs also made the allosteric pockets that helped to describe almost all favorable pose for the chaperone in a complex through the protein. Thus, we intended to highlight the several health benefits of this antioxidant compound and applications in pharmaceutical product development.

Novel molecular mechanisms underlying the ameliorative effect of N-acetyl-L-cysteine against ϒ-radiation-induced premature ovarian failure in rats

Radiotherapy represents a critical component in cancer treatment. However, premature ovarian failure (POF) is a major hurdle of deleterious off-target effects in young females, which, therefore, call for an effective radioprotective agent. The present study aimed to explore the molecular mechanism underlying the protective effects of N-acetyl-L-cysteine (NAC) against γ-radiation-provoked POF. Immature female Sprague-Dawley rats were orally-administered NAC (50 mg/kg) and were exposed to a single whole-body dose of 3.2 Gy ϒ-radiation. NAC administration remarkably reversed abnormal serum estradiol and anti-Müllerian hormone levels by 73% and 40%, respectively while ameliorating the histopathological and ultrastructural alterations-triggered by γ-radiation. Mechanistically, NAC alleviated radiation-induced oxidative damage through significantly increased glutathione peroxidase activity by 102% alongside with decreasing NADPH oxidase subunits (p22 and NOX4) gene expressions by 48% and 38%, respectively compared to the irradiated untreated group. Moreover, NAC administration achieved its therapeutic effect by inhibiting ovarian apoptosis-induced by radiation through downregulating p53 and Bax levels by 33% and 16%, respectively while increasing the Bcl-2 mRNA expression by 135%. Hence, the Bax/Bcl2 ratio and cytochrome c expression were subsequently reduced leading to decreased caspase 3 activity by 43%. Importantly, the anti-apoptotic property of NAC could be attributed to inactivation of MAPK signaling molecules; p38 and JNK, and enhancement of the ovarian vascular endothelial growth factor (VEGF) expression. Taken together, our results suggest that NAC can inhibit radiotherapy-induced POF while preserving ovarian function and structure through upregulating VEGF expression and suppressing NOX4/MAPK/p53 apoptotic signaling.

The prospective curative role of lipoxin A4 in induced gastric ulcer in rats: Possible involvement of mitochondrial dynamics signaling pathway

This study purposed to examine the prospective curative role of lipoxin A₄ (LXA₄ ) in induced gastric ulcer in rats and explore the possible involvement of mitochondrial dynamics signaling pathway. Forty-eight male Wistar rats were divided into four groups: control, indomethacin (IND), IND + omeprazole (IND + Omez), and IND+ LXA₄ groups. At the end of the experiment, the gastric pH, gastric fluid volume, total gastric acidity, ulcer index, and curative index were estimated. The gene expression of mitochondrial related protein 1 and mitofusin 2 were determined. In addition, some mitochondrial parameters include mitochondrial transmembrane potential, complex-I activity and reactive oxygen species were measured. Also, some gastric biochemical parameters, histopathological, and immunohistochemical analyses of the gastric mucosa were determined. We found that IND induced gastric ulcer, as manifested by the biochemical, histopathological, and immunohistochemical analyses. Both Omez and LXA₄ treatment for 15 days alleviated the IND-induced gastric ulcer as explored by ameliorating the biochemical, histopathological, and immunohistochemical findings. We concluded that LXA₄ mitigated the IND-induced gastric ulcer via improving the mitochondrial dynamic imbalance and mitochondrial dysfunction, in addition to its anti-apoptotic, anti-inflammatory, and antioxidant properties.

Agomelatine prevents indomethacin-induced gastric ulcer in rats

BACKGROUND

Gastric ulcer is a very common gastrointestinal disease that may be dangerous and even may lead to death. The current study was conducted to detect the prophylactic effects of agomelatine on indomethacin-induced gastric ulcer.

METHODS

In this study, a total of 5 groups were created as the sham, ulcer, omeprazole, agomelatine 1 mg/kg and agomelatine 5 mg/kg groups. The effects of agomelatine on indomethacin-induced gastric injury were investigated. Total antioxidant and oxidant levels; the oxidant parameters like oxidative stress index and the inflammation markers such as tumor necrosis factor-α, interleukin-1β, interleukin-6 and interleukin-10 levels in stomach tissue were determined by ELISA. In addition, the gastric mucosal injury occurred in stomach wall was examined with histopathological methods.

RESULTS

While the levels of the inflammatory markers, total oxidant status and oxidative stress index increased at an obvious level especially in the indomethacin group, the total antioxidant status levels decreased. It was observed that these parameters were improved at a significant level in agomelatine 1 mg/kg and agomelatine 5 mg/kg groups when compared to ulcer group; and the results were similar to omeprazole group. It was also observed that our histopathological findings were consistent with all our other results.

CONCLUSIONS

The results of this study showed that agomelatine usage in indomethacin-induced gastric ulcer model provides beneficial results.

Rosmarinic Acid Enriched Fraction from Perilla frutescens Leaves Strongly Protects Indomethacin-Induced Gastric Ulcer in Rats

Gastric ulcers are a common problem in upper gastrointestinal tract (GI) disorders. Nonsteroidal anti-inflammatory drugs (NSAIDs) are one of the most aggressive factors leading to inducing gastric ulcers. Natural products with lower toxicity and safety are currently sought as a potential source to minimize the effect of the gastric ulcers. Perilla frutescens or Nga-mon (in Thai) leaves are rich in rosmarinic acid (RA), which has antioxidant, anti-inflammatory, and anticancer effects. This study investigates the protective effect of ethanolic extract (EE) and aqueous fraction (AF) from Perilla frutescens leaves, which are rich in RA, on indomethacin- (IND-) induced gastric ulcer in a rat model. The EE at the doses of 50 and 500 mg/kg body weight, AF at the doses of 50, 250, and 500 mg/kg body weight, or famotidine (a standard drug) were administered for 14 days prior to ulcer induction. The ulceration was performed by intragastric administration of IND. Gross gastric ulcers and biological and histological parameters were examined. The pretreatment with AF had more significant effects than EE, including reduced ulcer index, decreased gastric secretion volume and decreased acidity, but it had an elevated gastric pH relative to the IND-induced gastric ulcer. In a histopathological study, the EE and AF decreased mucosal ulcer, inflammatory infiltration, and degenerative lining cells. The IND-induced expression of inflammatory mediators was significantly attenuated with EE and AF. The experiment also remarkably showed the preservation of mucus and apoptosis protection of EE and AF on a gastric mucosal ulcer. The findings demonstrated that the EE and AF of perilla leaves were capable of protecting the stomach against gastric ulcers induced by IND through anti-inflammatory and antiapoptotic mechanisms that should be further investigated. It is suggested that Perilla frutescens leaf could be a potential alternative source of RA as a therapeutic agent and food supplement for NSAID-induced gastric injuries.

Apple Polyphenol Suppresses Indomethacin-Induced Gastric Damage in Experimental Animals by Lowering Oxidative Stress Status and Modulating the MAPK Signaling Pathway

Indomethacin is a nonsteroid anti-inflammatory drug (NSAID) that is used to alleviate pain and inflammation in clinical medicine. Previous studies indicated that NSAIDs can cause gastrointestinal mucosal complications, and it is associated with mucosal lipid peroxidation and oxidative damage. Based on the evidences, decreasing oxidative stress may be an ideal therapeutic strategy for preventing gastrointestinal ulcer. Apple (Rosaceae Malus sp.) is one of the most commonly consumed fruits worldwide. The abundant polyphenolic constituents have received increasing attention for decades. In both in vivo and in vitro studies, the reports showed that apple polyphenol (AP) seems to provide an indirect antioxidant protection by activating cellular antioxidant enzymes to defend against oxidative stress. To address this issue and develop AP into a healthy improvement supplement, we studied the effect and potential mechanisms of AP in indomethacin-treated animal. The results showed AP can decelerate the gastric lesion, significantly suppress lipid peroxidation, increase the level of glutathione and the activity of catalase, and regulate the MAPK signaling proteins. These findings imply that AP protects the gastric mucosa from indomethacin-caused lesions and the protection is at least partially attributable to its antioxidative properties. This alternative medical function of AP may be a safe and effective intervention for preventing indomethacin-induced gastric complications.

Protective Effect of Two Extracts of Cydonia oblonga Miller (Quince) Fruits on Gastric Ulcer Induced by Indomethacin in Rats

BACKGROUND

In various studies, Cydonia oblonga Miller (quince) has been reported to have many properties such as antioxidant and anti-ulcerative effects. This study has aimed to investigate the protective effects of quince aqueous extract (QAE) and quince hydroalcoholic extract (QHE) on gastric ulcer caused by indomethacin and the relevant macroscopic, histopathology, and biochemical factors in rats.

METHODS

Ten groups of male Wistar rats, six in each, were used in this study. These groups included: normal (distilled water), control (distilled water + indomethacin), reference (ranitidine or sucralfate + indomethacin), and test groups (QAE or QHE + indomethacin) treated with three increasing doses (200, 500, and 800 mg/kg). Extracts and drugs were given orally to rats 1 h before injecting the indomethacin (25 mg/kg, intraperitoneally). Six hours later, the abdomen of rats was exposed, its pylorus was legated, gastric acid content was extracted, and its pH and the amount of pepsin secreted were measured by Anson method. Then, histopathology indices, ulcer area, ulcer index, and myeloperoxidase (MPO) activity were measured in gastric mucus.

RESULTS

Both extracts of quince were effective to reduce the acidity of stomach and pepsin activity. Compared to control group, the average of enzyme activity of MPO was significantly declined in all treated groups. Control group had the highest level of gastric ulcer indices including severity, area, and index while the evaluated parameters had decreased in all extract treated groups although it seems that QAE was somewhat more effective.

CONCLUSIONS

Protective effect of QAE and QHE on gastric ulcer was done by undermining offensive factors including decreasing the secretion of gastric acid and pepsin activity and by strengthening the protective factors of gastric mucus including antioxidant capacity.