Effect of diallyl disulfide on acute gastric mucosal damage induced by alcohol in rats

Protective Effect of Pyrus ussuriensis Maxim. Extract against Ethanol-Induced Gastritis in Rats

Pyrus ussuriensis Maxim (Korean pear) has been used for hundreds of years as a traditional herbal medicine for asthma, cough, and atopic dermatitis in Korea and China. Although it was originally shown to possess anti-inflammatory, antioxidant, and antiatopic properties, its gastroprotective effects have not been investigated. In the present study, we evaluated the protective effects of Pyrus ussuriensis Maxim extract (PUE) against ethanol-induced gastritis in rats. The bioactive compound profile of PUE was determined by gas chromatography mass spectroscopy (GC-MS) and high-performance liquid chromatography (HPLC). The gastroprotection of PUE at different doses (250 and 500 mg/kg body weight) prior to ethanol ingestion was evaluated using an in vivo gastritis rat model. Several endpoints were evaluated, including gastric mucosal lesions, cellular degeneration, intracellular damage, and immunohistochemical localization of leucocyte common antigen. The gastric mucosal injury and ulcer score were determined by evaluating the inflamed gastric mucosa and by histological examination. To identify the mechanisms of gastroprotection by PUE, antisecretory action and plasma prostaglandin E₂ (PGE₂), gastric mucosal cyclic adenosine monophosphate (cAMP), and histamine levels were measured. PUE exhibited significant antioxidant effects with IC₅₀ values of 56.18 and 22.49 µg/mL for 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′- azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) inhibition (%), respectively. In addition, GC/MS and HPLC analyses revealed several bioactive compounds of PUE. Pretreatment with PUE significantly (p < 0.05) decreased the ulcer index by preventing gastric mucosal lesions, erosion, and cellular degeneration. An immunohistochemical analysis revealed that PUE markedly attenuated leucocyte infiltration in a dose-dependent manner. The enhancement of PGE₂ levels and attenuation of cAMP levels along with the inhibition of histamine release following PUE pretreatment was associated with the cytoprotective and healing effects of PUE. In contrast, the downregulation of the H⁺/K⁺ ATPase pathway as well as muscarinic receptor (M₃R) and histamine receptor (H₂R) inhibition was also involved in the gastroprotective effects of PUE; however, the expression of cholecystokinin-2 receptors (CCK₂R) was unchanged. Finally, no signs of toxicity were observed following PUE treatment. Based on our results, we conclude that PUE represents an effective therapeutic option to reduce the risk of gastritis and warrants further study.

A comprehensive understanding about the pharmacological effect of diallyl disulfide other than its anti-carcinogenic activities

Diallyl disulfide (DADS), an oil-soluble sulfur compound that is responsible for the biological effects of garlic, displays numerous biological activities, among which its anti-cancer activities are the most famous ones. In recent years, the pharmacological effects of DADS other than its anti-carcinogenic activities have attracted numerous attentions. For example, it has been reported that DADS can prevent the microglia-mediated neuroinflammatory response and depression-like behaviors in mice. In the cardiovascular system, DADS administration was found to ameliorate the isoproterenol- or streptozotocin-induced cardiac dysfunction via the activation of the nuclear factor E2-related factor 2 (Nrf2) and insulin-like growth factor (IGF)-phosphatidylinositol-3-kinase (PI3K)-protein kinase B (Akt) signaling. DADS administration can also produce neuroprotective effects in animal models of Alzheimer's disease and protect the heart, endothelium, liver, lung, and kidney against cellular or tissue damages induced by various toxic factors, such as the oxidized-low density lipoprotein (ox-LDL), carbon tetrachloride (CCl₄), ethanol, acetaminophen, Cis-Diammine Dichloroplatinum (CisPt), and gentamicin. The major mechanisms of action of DADS in disease prevention and/or treatment include inhibition of inflammation, oxidative stress, and cellular apoptosis. Mechanisms, including the activation of Akt, extracellular signal-regulated kinase 1/2 (ERK1/2), protein kinase A (PKA), and cyclic adenosine monophosphate-response element binding protein (CREB) and the inhibition of histone deacetylases (HDACs), can also mediate the cellular protective effects of DADS in different tissues and organs. In this review, we summarize and discuss the pharmacological effects of DADS other than its anti-carcinogenic activities, aiming to reveal more possibilities for DADS in disease prevention and/or treatment.

The Garlic Compound Z-Ajoene, S-Thiolates COX2 and STAT3 and Dampens the Inflammatory Response in RAW264.7 Macrophages

SCOPE

Garlic (Allium sativum) has been used for centuries as a prophylactic and therapeutic medicinal agent to control inflammation-associated pathologies. To investigate the underlying mechanisms, an in vitro inflammatory model is established using RAW264.7 murine macrophages exposed to low-doses of lipopolysaccharide (LPS) in the presence of garlic compounds allicin and Z-ajoene (ZA), mimicking regular garlic consumption.

METHODS AND RESULTS

Both allicin and Z-ajoene dampen both transcript and protein expression of the pro-inflammatory cytokines IL1β, IL6, and IL12β, and upregulate the expression of the anti-inflammatory cytokine IL10. Protein arrays of selected secreted inflammatory mediators confirm that Z-ajoene has a pronounced down-regulatory effect on LPS-induced inflammatory cytokines and chemokines. Many of these proteins are known targets of the transcription factor signal transducer and activator of transcription 3 (STAT3); and indeed, Z-ajoene or its analogue dansyl-ajoene is found to decrease phosphorylation and nuclear translocation of STAT3, and to covalently modify the protein by S-thiolation at Cys108, Cys367, and Cys687. Z-Ajoene dose-dependently and non-competitively inhibit the activity of cyclooxygenase 2 (COX2), possibly attributed to S-thiolation at Cys9 and Cys299.

CONCLUSION

The characterization of Z-ajoene's activity of targeting and covalently modifying STAT3 and COX2, both important regulators of inflammation, may contribute to the health benefits of regular dietary garlic consumption.

Association Between Lifestyle Factors, Vitamin and Garlic Supplementation, and Gastric Cancer Outcomes: A Secondary Analysis of a Randomized Clinical Trial

IMPORTANCE

The associations of lifestyle factors with gastric cancer (GC) are still underexplored in populations in China. Long-term nutritional supplementation may prevent GC in high-risk populations, but the possible effect modification by lifestyle factors remains unknown.

OBJECTIVE

To evaluate how lifestyle factors, including smoking, alcohol intake, and diet, may change the risk of GC incidence and mortality and whether the effects of vitamin and garlic supplementation on GC are associated with major lifestyle factors.

DESIGN, SETTING, AND PARTICIPANTS

This is a secondary analysis of the Shandong Intervention Trial, a masked, randomized, placebo-controlled trial that aimed to assess the effect of vitamin and garlic supplementations and Helicobacter pylori treatment on GC in a factorial design with 22.3 years of follow-up. The study took place in Linqu County, Shandong province, China, a high-risk area for GC. Data were collected from Jully 1995 to December 2017. Overall, 3365 participants aged 35 to 64 years identified in 13 randomly selected villages who agreed to undergo gastroscopy were invited to participate in the trial and were included in the analysis. Data analysis was conducted from March to May 2019.

INTERVENTIONS

Participants received vitamin and garlic supplementation for 7.3 years, H pylori treatment for 2 weeks (among participants with H pylori ), or placebo.

MAIN OUTCOMES AND MEASURES

The primary outcomes were GC incidence and GC mortality (1995-2017). We also examined the progression of gastric lesions (1995-2003) as a secondary outcome.

RESULTS

Of the 3365 participants (mean [SD] age, 47.1 [9.2] years; 1639 [48.7%] women), 1677 (49.8%) were randomized to receive active vitamin supplementation, with 1688 (50.2%) receiving placebo, and 1678 (49.9%) receiving active garlic supplementation, with 1687 (50.1%) receiving placebo. Overall, 151 GC cases (4.5%) and 94 GC deaths (2.8%) were identified. Smoking was associated with increased risk of GC incidence (odds ratio, 1.72; 95% CI, 1.003-2.93) and mortality (hazard ratio [HR], 2.01; 95% CI, 1.01-3.98). Smoking was not associated with changes to the effects of vitamin or garlic supplementation. The protective effect on GC mortality associated with garlic supplementation was observed only among those not drinking alcohol (never drank alcohol: HR, 0.33; 95% CI, 0.15-0.75; ever drank alcohol: HR, 0.92; 95% CI, 0.55-1.54; P for interaction = .03), and significant interactions were only seen among participants with H pylori (never drank alcohol: HR, 0.31; 95% CI, 0.12-0.78; ever drank alcohol: HR, 0.91; 95% CI, 0.52-1.60; P for interaction = .04). No significant interactions between vitamin supplementation and lifestyle factors were found.

CONCLUSIONS AND RELEVANCE

In this secondary analysis of a randomized clinical trial, smoking was associated with an increased risk of GC incidence and mortality. Not drinking alcohol was associated with a stronger beneficial effect of garlic supplementation on GC prevention. Our findings provide new insights into lifestyle intervention for GC prevention, suggesting that mass GC prevention strategies may need to be tailored to specific population subgroups to maximize the potential beneficial effect.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00339768.

Diallyl Disulfide Suppresses Inflammatory and Oxidative Machineries following Carrageenan Injection-Induced Paw Edema in Mice

Diallyl disulfide (DADS) is the major organosulfur constituent in garlic, with a variety of pharmacological activities including antioxidant and anti-inflammatory. Here, we examined the potential antiedematous impact of DADS- versus carrageenan-mediated paw edema in mice. Carrageenan injection potentiated an inflammatory reaction as presented by the elevated serological C-reactive protein (CRP) levels and transcription of tumor necrosis factor-alpha (TNF-α, Tnfα), interleukin-1 beta (IL-1β, Il1b), interleukin-2 (IL-2, Il2), inducible nitric oxide synthase (iNOS), nitric oxide (NO), cyclooxygenase-2 (COX-2, Ptgs2), prostaglandin E2 (PGE2), monocyte chemoattractant protein-1 (MCP-1, Ccl1), nuclear factor kappa B (NF-κB), and myeloperoxidase (MPO) activity, while interleukin-10 (IL-10) was declined in the injured paw tissue. Additionally, carrageenan elevated lipid peroxidation in terms of malondialdehyde (MDA) and decreased glutathione content (GSH). Remarkably, DADS was found to inhibit the inflammatory signaling, suppressed the developed oxidative damage, and protected the histopathological alterations in the inflamed paw tissue in response to carrageenan injection. Our findings suggest that DADS could be used as an alternative therapy used to alleviate the pathophysiological changes associated with the genesis of paw edema through its potent anti-inflammatory and antioxidant impacts.

Effect of heat-killed Enterococcus faecalis EF-2001 on ethanol-induced acute gastric injury in mice: Protective effect of EF-2001 on acute gastric ulcer

Enterococcus faecalis is a facultative anaerobic gram-positive commensal bacterium common in the gastrointestinal tract of animals and humans. This study aimed to investigate the protective effects of heat-killed E. faecalis EF-2001 (EF-2001) on acute gastric ulcer using a murine model of ethanol (EtOH)-induced acute gastric injury. EF-2001 (20, 40, and 80 mg/kg/day) was administered by oral gavage for 5 days before EtOH treatment (10 mL/kg body weight). EF-2001 effectively attenuated EtOH-induced gastric mucosal injury with reduced gastric mucosal ulcer and histological damage score. Pretreatment of EF-2001 markedly suppressed the phosphorylation of mitogen-activated protein kinases (MAPKs; ERK1/2, JNK, and p38MAPK). In addition, EF-2001 significantly inhibited phosphorylation of nuclear factor kappa B (NF-κB) and subsequently suppressed the upregulation of inducible nitric oxide synthase, cyclooxygenase-2, tumor necrosis factor alpha, interleukin 1 beta, and interleukin 6 in gastric tissues. Taken together, these results suggest that EF-2001 exerts a gastroprotective effect against acute gastric injury, and the underlying mechanism might be associated with the suppression of MAPKs and NF-κB signaling and consequent reduction of pro-inflammatory mediators or cytokines.

Diallyl disulfide attenuates non‑alcoholic steatohepatitis by suppressing key regulators of lipid metabolism, lipid peroxidation and inflammation in mice

Non‑alcoholic steatohepatitis (NASH) is a common clinicopathological condition. Currently, the pathogenesis of NASH remains unknown, and no optimal therapy option currently exists. It has previously been demonstrated that diallyl disulfide (DADS) was capable of attenuating liver dysfunction, as DADS supplementation had a positive impact on liver regeneration, proliferation and oxidative damage. Thus, DADS could serve as a potential therapeutic agent that can protect against the effects of NASH. The present study aimed to evaluate the effect of DADS on NASH and to understand the associated underlying molecular mechanisms. A methionine‑ and choline‑deficient diet (MCD) and high‑fat diet (HFD) are the two common animal models that induce NASH. C57BL/6J mice were fed an MCD for 4 weeks, or an HFD for 20 weeks, in the present study. The mice were treated with or without DADS (20, 50 and 100 mg/kg) for 4 or 20 weeks. For the histopathological examination, hematoxylin and eosin staining, oil red O staining and immunohistochemical analyses were performed using the liver sections. Biochemical assays and ELISA were performed to measure the serum biochemical indicators of hepatic function and inflammatory indicators, respectively. Reverse transcription‑quantitative PCR, immunofluorescence and western blotting were used to detect expression levels of the genes involved in the molecular mechanisms underlying DADS protection. MCD or HFD induced the histological features of NASH in mice, including significant vacuolated hepatocytes, marked inflammatory cell infiltration and severe micro‑ and macro‑vesicular steatosis. Serum alanine transferase and aspartate aminotransferase levels, as well as the contents of liver triglyceride and total cholesterol, were significantly increased in these two models. DADS attenuated these histological and biochemical changes. DADS ameliorated hepatic steatosis by regulating sterol regulatory element‑binding transcription factor 1, apolipoprotein A1, cyclic AMP‑responsive element‑binding protein H and fibroblast growth factor 21. Furthermore, DADS was revealed to prevent lipotoxicity via peroxisome proliferator‑activated receptor α elevation and stearoyl‑coenzyme A desaturase 1 inhibition in HFD‑fed mice. In addition, DADS markedly inhibited lipid peroxidation by modulating malondialdehyde and superoxide dismutase, and it also decreased tumor necrosis factor‑α production, interleukin‑6 production and macrophage influx, as well as suppressing nuclear factor‑κB activation, indicating suppression of MCD‑induced hepatic inflammation. Taken together, the results have shown that DADS exerts beneficial effects on MCD‑ or HFD‑induced NASH by suppressing key regulators of lipid metabolism, lipid peroxidation and inflammation.

Diallyl disulfide attenuated carbon ion irradiation-induced apoptosis in mouse testis through changing the ratio of Tap73/ΔNp73 via mitochondrial pathway

Diallyl disulfide (DADS), a major organosulfur compound derived from garlic, has various biological properties, including anti-cancer effects. However, the protective mechanism of DADS against radiation-induced mouse testis cell apoptosis has not been elucidated. In this study, the magnitude of radiation effects evoked by carbon ion irradiation was marked by morphology changes, significant rise in apoptotic cells, activation expression of p53, up regulation the ratio of pro-apoptotic Tap73/anti-apoptotic ΔNp73, as well as alterations of crucial mediator of the mitochondrial pathway. Interestingly, pretreatment with DADS attenuated carbon ion irradiation-induced morphology damages and apoptotic cells. Additionally, DADS elevated radiation-induced p53 and p21 expression, suggesting that p53 might be involved in the inhibition of cell cycle progression through up regulation of p21. Furthermore, administration with DADS prevented radiation-induced Tap73/ΔNp73 expression and consequently down regulated Bax/Bcl-2 ratio, cytochrome c release and caspase-3 expression, indicating that the balance between Tap73 and ΔNp73 had potential to activate p53 responsive genes. Thus, our results showed that radio protection effect of DADS on mouse testis is mediated by blocking apoptosis through changing the ratio of Tap73/ΔNp73 via mitochondrial pathway, suggesting that DADS could be used as a potential radio protection agent for the testis against heavy-ion radiation.

Prooxidant activity of norbixin in model of acute gastric ulcer induced by ethanol in rats

Free radicals and oxidative stress play a central role in gastric injuries caused by ethanol (EtOH). Antioxidant strategies to counteract EtOH toxicity are highly desirable. Norbixin (NBIX) is a carotenoid with antioxidant potential largely used in the food industry. This study evaluated the NBIX effects in a model of gastric ulcer induced by EtOH in rats. Male Wistar rats received NBIX doses of 0, 10, and 25 mg/kg by gavage 1 h after EtOH administration (0 or 75% solution, 1 mL/200 g of animal). The animals were euthanized 1 h after the NBIX administration, and their stomachs were removed for macroscopic and histopathological analyses, quantification of nonprotein sulfhydryl (NPSH) groups, lipid peroxidation (LPO) levels, and catalase (CAT) activity determination. NBIX increased LPO in gastric mucosa and caused CAT inhibition and NPSH depletion in EtOH-treated animals. Results showed that NBIX did not protect gastric tissue against EtOH damage, and this could be associated to a prooxidant effect.

Antiulcerogenic Activity and Toxicity of Bauhinia holophylla Hydroalcoholic Extract

Several species of Bauhinia are used in traditional medicine for the treatment of gastrointestinal diseases, diabetes, and inflammation, among other conditions. The aim of this study was to investigate the antiulcer effect of a hydroalcoholic extract from the leaves of B. holophylla. The chemical profile of the extract was determined by HPLC-PAD-ESI-IT-MS. A dose-effect relation was constructed using the ethanol-induced gastric ulcer model in male Wistar rats. Histological analyses and studies of antioxidant and anti-inflammatory activities were performed in stomach samples. The involvement of SH compounds, NO, K⁺_ATP channels, and α₂-adrenergic receptors in the gastroprotective effect was evaluated. A toxicity study was performed with a single oral dose of 5000 mg/kg. The extract was composed mainly of cyanoglucoside and flavonol-O-glycosides derivatives of quercetin and myricetin. SH compounds, NO release, K⁺_ATP channel activation, and presynaptic α₂-adrenergic receptor stimulation each proved to be involved in the antiulcer effect. The levels of GSH and activity of GR and GPx were increased, and the levels of TNF-α, IL-6 and IL-10 were modulated. There was an antidiarrheal effect and there were no signs of toxicity. B. holophylla presents antiulcer activity mainly by decreasing oxidative stress and attenuating the inflammatory response, without inducing side effects.