S-allyl cysteine prevents CCl(4)-induced acute liver injury in rats

Therapeutic effects of S-allyl-L-cysteine in a mouse endometriosis model and its immunomodulatory effects via regulation of T cell subsets and cytokine expression

BACKGROUND

Endometriosis is a female hormone-dependent gynecological disorder characterized by chronic inflammation. Therefore, the development of novel treatment strategies that can diminish the side effects of the long-term use of hormone-based drugs has been emphasized. S-Allyl-L-cysteine (SAC) is the major constituent of aged garlic extracts. Although the therapeutic effects resulting from the antioxidant properties of SAC have been extensively studied in inflammatory diseases, the therapeutic efficacy of SAC in endometriosis has not been described. In this study, we investigated the therapeutic potential of SAC for endometriosis using a mouse model.

METHODS

An endometriosis mouse model was surgically induced, and oral treatment with 30 mg/kg SAC was administered daily for 28 days. The development of endometriotic lesions was assessed by histological analysis, and the expression profiles of adhesion-, apoptosis-, and inflammation-related genes were evaluated by PCR. Flow cytometric analysis of mouse spleen was conducted to assess changes in lymphocyte subpopulations.

RESULTS

SAC treatment significantly inhibited endometriotic lesion growth. Transcriptional expression analysis revealed the antiadhesion and apoptosis-promoting effects of SAC. In particular, SAC showed an effective immune modulatory response by altering splenic CD4+ and CD8+ T cell subsets and inflammatory cytokine production in the spleen and endometriotic lesions.

CONCLUSION

This study newly elucidates the inhibitory effects of SAC on the growth of endometriosis in a mouse model and describes its immunomodulatory effects.

The double-edged role of hydrogen sulfide in the pathomechanism of multiple liver diseases

In mammalian systems, hydrogen sulfide (H2S)-one of the three known gaseous signaling molecules in mammals-has been found to have a variety of physiological functions. Existing studies have demonstrated that endogenous H2S is produced through enzymatic and non-enzymatic pathways. The liver is the body's largest solid organ and is essential for H2S synthesis and elimination. Mounting evidence suggests H2S has essential roles in various aspects of liver physiological processes and pathological conditions, such as hepatic lipid metabolism, liver fibrosis, liver ischemia‒reperfusion injury, hepatocellular carcinoma, hepatotoxicity, and acute liver failure. In this review, we discuss the functions and underlying molecular mechanisms of H2S in multiple liver pathophysiological conditions.

The Enhancing Effects of S-Allylcysteine on Liver Regeneration Are Associated with Increased Expression of mRNAs Encoding IGF-1 and Its Receptor in Two-Thirds Partially Hepatectomized Rats

Two-thirds partial hepatectomy (PHx) was performed in rats, and the differences in effects between S-allylcysteine (SAC) and other sulfur-containing compounds on regeneration of the remaining liver and restoration of the injury were examined. Three days after two-thirds PHx, rats treated with 300 mg/kg/d, per os (p.o.) SAC showed a 1.2-fold increase in liver weight per 100 g body weight compared with saline-treated controls. In contrast, S-methylcysteine (SMC) (300 mg/kg/d, p.o.) or cysteine (Cys) (300 mg/kg/d, p.o.) did not have a regeneration-promoting effect. In the comparison with control rats, the regenerating liver of SAC-treated rats showed a significantly higher 5-bromo-2'-deoxyuridine labeling index on day 1. In contrast, serum alanine aminotransferase activity, which increases following PHx, was significantly inhibited by SAC and SMC (but not Cys) on day 1 after two-thirds PHx. In addition, SAC induced increases in insulin-like growth factor (IGF)-1 and its receptor mRNA expressions at 1 h after two-thirds PHx, and it increased phosphorylation of extracellular signal-regulated kinase (ERK)2 and Akt at 3 h after two-thirds PHx without affecting serum growth hormone levels. These results demonstrate that SAC is a mitogenic effector of normal remnant liver and promotes recuperation of liver function after two-thirds PHx. Moreover, SAC-induced proliferative effects are mediated via increased mRNA expressions of IGF-1 and its receptor and subsequent phosphorylation of ERK2 and Akt.

S-allyl cysteine, an active ingredient of garlic, attenuates acute liver dysfunction induced by lipopolysaccharide/ d-galactosamine in mouse: Underlying mechanisms

In the present study, beneficial effect of S-allyl cysteine (SAC) was evaluated in the lipopolysaccharide/d-galactosamine (LPS/d-Gal) model of acute liver injury (ALI). To mimic ALI, LPS and d-Gal (50 μg/kg and 400 mg/kg, respectively) were intraperitoneally administered and animals received SAC per os (25 or 100 mg/kg/d) for 3 days till 1 hour before LPS/d-Gal injection. Pretreatment of LPS/d-Gal group with SAC-lowered activities of alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase and partially reversed inappropriate alterations of hepatic oxidative stress- and inflammation-related biomarkers including liver reactive oxygen species, malondialdehyde, and hepatic activity of the defensive enzyme superoxide dismutase, ferric reducing antioxidant power (FRAP), toll-like receptor-4 (TLR4), cyclooxygenase 2, NLR family pyrin domain containing 3 (NLRP3), caspase 1, nuclear factor κB (NF-κB), interleukin 1β (IL-1β), IL-6, tumor necrosis factor-α, and myeloperoxidase activity. Additionally, SAC was capable to ameliorate apoptotic biomarkers including caspase 3 and DNA fragmentation. In summary, SAC can protect liver against LPS/d-Gal by attenuation of neutrophil infiltration, oxidative stress, inflammation, apoptosis, and pyroptosis which is partly linked to its suppression of TLR4/NF-κB/NLRP3 signaling.

S-allyl-L-cysteine protects hepatocytes from indomethacin-induced apoptosis by attenuating endoplasmic reticulum stress

Drug‐induced liver injury (DILI) can lead to acute liver failure, a lethal condition which may require liver transplantation. Hepatotoxicity associated with nonsteroidal anti‐inflammatory drugs (NSAIDs) accounts for ~ 10% of all DILI. In the current study, we determined whether indomethacin, one of the most commonly used NSAIDS, induced apoptosis in hepatocytes and investigated the underlying mechanism. Meanwhile, we investigated the protective effect of S‐allyl‐L‐cysteine (SAC), an active garlic derivative, on indomethacin‐induced hepatocyte apoptosis, and its implication on endoplasmic reticulum (ER) stress. We found that indomethacin triggered ER stress, as indicated by the elevated expression of phosphorylated eukaryotic translation initiation factor 2α (eIF2α), C/EBP homologous protein (CHOP) and spliced XBP1 in a rat liver BRL‐3A cell line. Following indomethacin treatment, caspase 3 activation and hepatocyte apoptosis were also observed. Inhibition of ER stress by chemical chaperone 4‐phenyl butyric acid alleviated cell apoptosis caused by indomethacin, indicating that ER stress is involved in indomethacin‐induced hepatocyte apoptosis. Moreover, SAC abated indomethacin‐induced eIF2α phosphorylation, inhibited CHOP upregulation and its nuclear translocation, abrogated the activation of caspase 3 and finally, protected hepatocytes from apoptosis. In conclusion, SAC protects indomethacin‐induced hepatocyte apoptosis through mitigating ER stress and may be suitable for development into a potential new therapeutic agent for the treatment of DILI.

Salidroside protects mice against CCl4-induced acute liver injury via down-regulating CYP2E1 expression and inhibiting NLRP3 inflammasome activation

Salidroside (Sal), a natural phenolic compound isolated from Rhodiola sachalinensis, has been utilized as anti-inflammatory and antioxidant for centuries, however, its effects against liver injury and the underlying mechanisms are unclear. This study was designed to evaluate the protective effects and underlying mechanisms of Sal on carbon tetrachloride (CCl4)-induced acute liver injury (ALI) in mice. C57BL/6 mice were pretreated with Sal before CCl4 injection, the serum and liver tissue were collected to evaluate liver damage and molecular indices. The results showed that Sal pretreatment dose-dependently attenuated CCl4-induced acute liver injury, as indicated by lowering the activities of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT), and inhibiting hepatic pathological damage and apoptosis. In addition, Sal alleviated CCl4-primed oxidative stress and inflammatory response by restoring hepatic glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), and inhibiting cytokines. Finally, Sal also down-regulated the expression of cytochrome P4502E1 (CYP2E1), and Nod-like receptor protein 3 (NLRP3) inflammasome activation in the liver of mice by CCl4. Our study demonstrates that Sal exerts its hepatoprotective effects on ALI through its antioxidant and anti-inflammatory effects, which might be mediated by down-regulating CYP2E1 expression and inhibiting NLRP3 inflammasome activation.

Antioxidant Capacity and Hepatoprotective Role of Chitosan-Stabilized Selenium Nanoparticles in Concanavalin A-Induced Liver Injury in Mice

Selenium nanoparticles (SeNPs) have attracted wide attention for their use in nutritional supplements and nanomedicine applications. However, their potential to protect against autoimmune hepatitis has not been fully investigated, and the role of their antioxidant capacity in hepatoprotection is uncertain. In this study, chitosan-stabilized SeNPs (CS-SeNPs) were prepared by means of rapid ultra-filtration, and then their antioxidant ability and free-radical scavenging capacity were evaluated. The hepatoprotective potential of a spray-dried CS-SeNPs powder against autoimmune liver disease was also studied in the concanavalin A (Con A)-induced liver injury mouse model. CS-SeNPs with size of around 60 nm exhibited acceptable oxygen radical absorbance capacity and were able to scavenge DPPH, superoxide anion, and hydroxyl radicals. The CS-SeNPs powder alleviated Con A-caused hepatocyte necrosis and reduced the elevated levels of serum alanine transaminase, aspartate transaminase, and lactic dehydrogenase in Con A-treated mice. These results suggest that the CS-SeNPs powder protected the mice from Con-A-induced oxidative stress in the liver by retarding lipid oxidation and by boosting the activities of superoxide dismutase, glutathione peroxidase, and catalase, partly because of its ability to improve Se retention. In conclusion, SeNPs present potent hepatoprotective potential against Con A-induced liver damage by enhancing the redox state in the liver; therefore, they deserve further development.

Neuroprotective mechanisms of S-allyl-L-cysteine in neurological disease

S-allyl-L-cysteine (SAC) is a sulfur-containing amino acid present in garlic and exhibits a wide range of biological activities such as antioxidant, anti-inflammatory, and anticancer agent. An earlier study demonstrated that SAC ameliorates oxidative damage in a model of experimental stroke. However, the antioxidant property of SAC does not suffice to explain its beneficial effects in terms of the underlying mechanisms. Endoplasmic reticulum (ER) stress and ER stress-induced cell death have been shown to be involved in various neurological diseases such as brain ischemia, Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis and Huntington's disease. We have previously demonstrated that SAC exerts significant protective effects against ER stress-induced neurotoxicity in cultured rat hippocampal neurons and organotypic hippocampal slice cultures. Recently, we demonstrated that these results are due to the direct suppression of calpain activity via the binding of SAC to this enzyme's Ca²⁺-binding domain. We also found that the protective effects of the side-chain-modified SAC derivatives, S-ethyl-L-cysteine (SEC) and S-propyl-L-cysteine (SPC), against ER stress-induced neurotoxicity were more potent than those of SAC in cultured rat hippocampal neurons. In addition, SAC, SEC and SPC have been shown to decrease the production of amyloid-β peptide in the brains of mice with D-galactose-induced aging. These three hydrophilic cysteine-containing compounds have also been shown to exert neuroprotective effects against dopaminergic neuron injury in a murine model of Parkinson's disease induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). In this review, we aim to provide a current overview of the protective actions of SAC and the SAC-related compounds, SEC and SPC, in neurodegenerative disease and discuss the promise of SAC as a prototype for developing novel therapeutic drugs for neurological diseases.

Prevention of arachidonic acid-induced liver injury by controlling oxidative stress-mediated transglutaminase activation with garlic extracts

Garlic and its sulfur constituents have numerous biological functions, such as antioxidant, anti-inflammatory, anti-microbial, anticancer, antidiabetic and cardioprotective effects. Fatty liver diseases, such as non-alcoholic steatohepatitis, which is characterized by the accumulation of lipids and oxidative stress in hepatocytes and continual liver damage, has attracted much attention, and it is believed that it will become the leading etiology of liver cancer. We have previously reported that the growth-suppressive effects of arachidonic acid (AA), an unsaturated fatty acid known to be a pro-inflammatory precursor, is accompanied by the production of reactive oxygen species followed by the nuclear accumulation and activation of the protein crosslinking enzyme, transglutaminase (TG)2. In this study, we examined the potential role of garlic extracts in preventing the growth-suppressive effects of AA on human hepatic cells. We also aimed to provide a mechanistic insight regarding the association between the hepatoprotective effects of garlic extract and the inhibition of the TG-related crosslinking of nuclear proteins, which is not associated with hepatic lipid partitioning mediated by stearoyl-CoA desaturase-1. Given the critical roles of unsaturated fatty acids in the regulation of cancer cell stemness and immune surveillance in the context of chronic injury, we propose that garlic extracts may serve as a therapeutic option for the prevention of chronic liver injury and inflammation, as well as for the prevention of the carcinogenesis of fatty livers.

Garlic and allopurinol attenuate hepatic apoptosis induced by fipronil in male albino rats

Fipronil (FPN) can induce oxidative tissue damage and may be contemplated as an apoptosis inducer. Our aim is to investigate the possible hepatoprotective roles of garlic or allopurinol (ALP) against fipronil subacute toxicity. Thirty-six mature male albino rats were randomly divided into six groups; the first group was saved as control (C), the 2nd (G) was orally intubated with 500 mg/kg aqueous garlic extract, and the 3rd (A) received 150 mg/L allopurinol in their drinking water. The 4th group (F) was administered 13.277 mg/kg fipronil by gavage, while the 5th (G + F) and 6th (A + F) groups received the same doses of garlic and allopurinol, respectively two hours before fipronil intoxication. Our results revealed that FPN significantly increased the hepatic malondialdehyde, protein carbonyl levels, and the enzymatic activities of superoxide dismutase, catalase, glutathione peroxidase, and xanthine oxidase, but it decreased glutathione-S-transferase compared to the control group. Moreover, FPN exhibited significant up-regulation in the hepatic pro-apoptotic (Bax) and caspase-3 genes expression, down-regulation in the anti-apoptotic (Bcl-2) mRNA gene expression and induced DNA fragmentation. Surprisingly, garlic or allopurinol co-treatment ameliorated the hepatic lipid peroxidation, antioxidants disruption, and apoptosis induced by FPN. In conclusion, garlic and allopurinol relieved the oxidative injury and reduced the fipronil-induced apoptosis probably by improving the tissue antioxidant defense system.

Sulfuric Odor Precursor S-Allyl-l-Cysteine Sulfoxide in Garlic Induces Detoxifying Enzymes and Prevents Hepatic Injury

S-Allyl-l-cysteine sulfoxide (ACSO) is a precursor of garlic-odor compounds like diallyl disulfide (DADS) and diallyl trisulfide (DATS) known as bioactive components. ACSO has suitable properties as a food material because it is water-soluble, odorless, tasteless and rich in bulbs of fresh garlic. The present study was conducted to examine the preventive effect of ACSO on hepatic injury induced by CCl₄ in rats. ACSO, its analogs and garlic-odor compounds were each orally administered via gavage for five consecutive days before inducing hepatic injury. Then, biomarkers for hepatic injury and antioxidative state were measured. Furthermore, we evaluated the absorption and metabolism of ACSO in the small intestine of rats and NF-E2-related factor 2 (Nrf2) nuclear translocation by ACSO using HepG2 cells. As a result, ACSO, DADS and DATS significantly suppressed the increases in biomarkers for hepatic injury such as the activities of aspartate transaminase (AST), alanine transaminase (ALT) and lactate dehydrogenase (LDH), and decreases in antioxidative potency such as glutathione (GSH) level and the activities of glutathione S-transferase (GST) and glutathione peroxidase (GPx). We also found ACSO was absorbed into the portal vein from the small intestine but partially metabolized to DADS probably in the small intestine. In in vitro study, ACSO induced Nrf2 nuclear translocation in HepG2 cells, which is recognized as an initial trigger to induce antioxidative and detoxifying enzymes. Taken together, orally administered ACSO probably reached the liver and induced antioxidative and detoxifying enzymes by Nrf2 nuclear translocation, resulting in prevention of hepatic injury. DADS produced by the metabolism of ACSO in the small intestine might also have contributed to the prevention of hepatic injury. These results suggest potential use of ACSO in functional foods that prevent hepatic injury and other diseases caused by reactive oxygen species (ROS).

Aged garlic extract ameliorates fatty liver and insulin resistance and improves the gut microbiota profile in a mouse model of insulin resistance

Aged garlic extract (AGE) produced by the aging process has various beneficial pharmacological effects. In this study, the effects of AGE on fatty liver, insulin resistance and intestinal microbiota were compared between ddY-H mice, an insulin resistance mouse, and ddY-L mice, normal mice. Mice were fed an AGE-supplemented diet (4% w/w) for 7 weeks. The administration of AGE had no effect on the body weight and dietary intake of both types of mice. In the ddY-H mice, the serum levels of glucose and insulin were increased and glucose tolerance was impaired; however, the administration of AGE ameliorated these abnormal conditions. AGE did not have these effects in ddY-L mice. Triglyceride (TG) accumulation in the liver and fat absorption from the digestive tract were increased in the ddY-H mice; however, the administration of AGE reduced this increase. On the other hand, AGE exerted no such effects in the ddY-L mice. In addition, the gut microbiota has been shown to be closely associated with obesity, diabetes, dyslipidemia and non-alcoholic fatty liver disease in human and animal models. The bacterial composition of the gut microbiota in the feces of the ddY-H mice did not differ from that of the ddY-L mice at 5 weeks of age; however, it was altered in the mice at 9 and 12 weeks of age even when the mice were fed a standard diet. In the ddY-H mice, the relative presence of Lactobacillales was increased, while that of Bifidobacterium, Clostridium cluster XVIII and Prevotella was decreased. The alteration of the bacterial composition in the ddY-H mice was reversed by the administration of AGE; however, this effect of AGE was not observed in the ddY-L mice. On the whole, the findings of this study indicate that AGE improves abnormal fat accumulation and insulin resistance, and also alters the intestinal flora in ddY-H mice, suggesting the possibility that these effects of AGE may be related.

S-Allyl Cysteine Alleviates Hydrogen Peroxide Induced Oxidative Injury and Apoptosis through Upregulation of Akt/Nrf-2/HO-1 Signaling Pathway in HepG2 Cells

Hydrogen peroxide (H₂O₂) mediated oxidative stress leading to hepatocyte apoptosis plays a pivotal role in the pathophysiology of several chronic liver diseases. This study demonstrates that S-allyl cysteine (SAC) renders cytoprotective effects on H₂O₂ induced oxidative damage and apoptosis in HepG2 cells. Cell viability assay showed that SAC protected HepG2 cells from H₂O₂ induced cytotoxicity. Further, SAC treatment dose dependently inhibited H₂O₂ induced apoptosis via decreasing the Bax/Bcl-2 ratio, restoring mitochondrial membrane potential (∆Ψ_m), inhibiting mitochondrial cytochrome c release, and inhibiting proteolytic cleavage of caspase-3. SAC protected cells from H₂O₂ induced oxidative damage by inhibiting reactive oxygen species accumulation and lipid peroxidation. The mechanism underlying the antiapoptotic and antioxidative role of SAC is the induction of the heme oxygenase-1 (HO-1) gene in an NF-E2-related factor-2 (Nrf-2) and Akt dependent manner. Specifically SAC was found to induce the phosphorylation of Akt and enhance the nuclear localization of Nrf-2 in cells. Our results were further confirmed by specific HO-1 gene knockdown studies which clearly demonstrated that HO-1 induction indeed played a key role in SAC mediated inhibition of apoptosis and ROS production in HepG2 cells, thus suggesting a hepatoprotective role of SAC in combating oxidative stress mediated liver diseases.

Amelioration of Single Clove Black Garlic Aqueous Extract on Dyslipidemia and Hepatitis in Chronic Carbon Tetrachloride Intoxicated Swiss Albino Mice

Single clove garlic is the product of atypical bulbing process of garlic under specific conditions. Therefore, the number of researches on single clove garlic bioactivity is limited. Recently, the hepatoprotective effect of single clove garlic has been demonstrated. In this study, we investigated amelioration of single clove black garlic aqueous extract, a processed product from single clove garlic, on dyslipidemia and hepatitis induced by chronic administration of CCl₄. Mice were randomly divided into four groups: control, extract control, CCl₄ intoxication, and coadministrated CCl₄ and extract group. Mice were orally given a dose of 1 ml/kg body weight of CCl₄ for 28 days twice a week to establish chronic liver injury model. To evaluate the hepatoprotective effect of single clove black garlic, mice were cotreated with CCl₄ and single clove black garlic extract (200 mg/kg body weight) via gastric gauge for 30 days. Cotreatment with CCl₄ and extract could improve the changes of body weight, liver weight, and relative liver weight as compared to CCl₄ intoxicated mice. Single clove black garlic ameliorated dyslipidemia and the elevation of ALT and AST levels induced by chronic CCl₄ intoxication. Histological studies revealed that single clove black garlic could prevent mononuclear cells infiltration and hepatocyte necrosis.

Saikosaponin‑d alleviates carbon‑tetrachloride induced acute hepatocellular injury by inhibiting oxidative stress and NLRP3 inflammasome activation in the HL‑7702 cell line

Saikosaponin‑d (SSd) the primary active component of triterpene saponin derived from Bupleurum falcatum L., possesses anti‑inflammatory and antioxidant properties. The present study aimed to examine the potential therapeutic effects of SSd on carbon tetrachloride (CCl4)‑induced acute hepatocellular injury in the HL‑7702 cell line and its underlying mechanisms. HL‑7702 cells were treated with SSd at different doses (0.5, 1 or 2 µmol/l). Cell viability was determined using an MTT assay. Injury was assessed by the levels of serum alanine aminotransferase (ALT) and aspartate transaminase (AST). Oxidative stress was assessed using malondialdehyde (MDA) content and total‑superoxide dismutase (T‑SOD) activity. The expression of nucleotide‑binding domain, leucine‑rich‑containing family, pyrin domain‑containing‑3 (NLRP3), apoptosis‑associated speck‑like protein (ASC), caspase‑1 and high mobility group protein B1 (HMGB1) was assessed by reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) and western blot analysis. Interleukin (IL)‑1β and IL‑18 were determined by RT‑qPCR and ELISA. SSd attenuated the inhibition of cell viability and the high AST and ALT levels induced by CCl4 in HL‑7702 cells. Oxidative stress was induced in HL‑7702 cells by CCl4, as demonstrated by the increase of MDA and the decrease of T‑SOD activity. These changes were reversed by SSd. SSd significantly downregulated the mRNA and protein expression of NLRP3, ASC, caspase‑1, IL‑1β, IL‑18 and HMGB1 induced by CCl4. In conclusion SSd alleviated CCl4‑induced acute hepatocellular injury, possibly by inhibiting oxidative stress and NLRP3 inflammasome activation in the HL‑7702 cell line.

S-allyl-glutathione, a synthetic analogue of glutathione protected liver against carbon tetrachloride toxicity: Focus towards anti-oxidative efficiency

A simple analogue of well known natural antioxidant glutathione (GSH) called S-allyl-glutathione (SAG) was evaluated against carbon tetrachloride (CCl₄)-induced oxidative stress liver injury in rat. Pretreatment of SAG attenuated the CCl₄-toxicity induced elevation of liver injury markers such as enzymes (AST, ALT, GGT, ALP and LDH) and bilirubin in the blood circulation. Such protective effect of SAG resulted in preservation of liver function observed as normal level of total protein and albumin in plasma as well as inhibition of dyslipidemia in liver. In addition, in silico analysis has proved that SAG has strong affinity with the amino acids present in active site of the human cytochrome P450 2E1 and 3A4. Three important mechanisms provided by SAG such as scavenging of reactive oxidants, replenishing of endogenous antioxidants (SOD, catalase, GPx, GSH and vitamin C) and protection of mitochondrial function (oxidative phosphorylation complex activities) are involved in the optimal function of liver against CCl₄-toxicity.

S-allyl-glutathione improves experimental liver fibrosis by regulating Kupffer cell activation in rats

S-allyl-glutathione (SAG) is one of the metabolites of diallyl sulfide (DAS), a component of garlic. DAS has shown preventative effects on carcinogenesis in animal models. However, whether synthetic SAG can improve liver fibrosis has not been investigated. We examined the potential preventive effects of SAG on acute and chronic models of liver fibrosis by chronic carbon tetrachloride (CCl₄) administration. SAG inhibited liver fibrogenesis induced by CCl₄ in a dose-dependent manner and reduced heat shock protein-47 (HSP47), a collagen-specific chaperone, and other fibrosis markers. In fibrosis regression models, after administration of either CCl₄ for 9 wk or dimethyl nitrosamine (DMN) for 6 wk, SAG markedly accelerated fibrolysis in both models. In the regression stage of DMN-treated liver, SAG normalized the ratio of M2 phenotype (expression of mannose receptor) in Kupffer cells (KCs). Consistent with these results, the culture supernatants of SAG-treated M2-phenotype KCs inhibited collagen-_α1(I) chain (COL1A1) mRNA expression in primary culture-activated rat hepatic stellate cells (HSCs). However, SAG did not directly inhibit HSC activation. In an acute model of CCl₄ single injection, SAG inhibited hepatic injury dose dependently consistent with the inhibited the elevation of the bilirubin and ALT levels. These findings suggest that SAG could improve the fibrogenic and fibrolysis cascade via the regulation of excess activated and polarized KCs. SAG may also serve as a preventive and therapeutic agent in fibrosis of other organs for which current clinical therapy is unavailable. NEW & NOTEWORTHY S-allyl-glutathione (SAG) is a metabolite of diallyl sulfide, a component of garlic. SAG increased hepatic glutathione levels and GSH-to-GSSG ratio in normal rats. SAG treatment before or after liver fibrosis from chronic CCl₄ administration improved liver fibrosis and regression. SAG decreased heat shock protein-47 (HSP47), a collagen-specific chaperone, and other fibrosis markers in CCl₄-treated livers. SAG-treated Kupffer cell conditioned medium also inhibited collagen-_α1(I) chain (COL1A1) mRNA expression and other markers in primary culture hepatic stellate cells.

4-Hydroxynonenal metabolites and adducts in pre-carcinogenic conditions and cancer

4-hydroxy-2-nonenal (HNE) is an amazing reactive compound, originating from lipid peroxidation within cells but also in food and considered as a "second messenger" of oxidative stress. Due to its chemical features, HNE is able to make covalent links with DNA, proteins and lipids. The aim of this review is to give a comprehensive summary of the chemical properties of HNE and of the consequences of its reactivity in relation to cancer development. The formation of exocyclic etheno-and propano-adducts and genotoxic effects are addressed. The adduction to cellular proteins and the repercussions on the regulation of cell signaling pathways involved in cancer development are reviewed, notably on the Nrf2/Keap1/ARE pathway. The metabolic pathways leading to the inactivation/elimination or, on the contrary, to the bioactivation of HNE are considered. A special focus is given on the link between HNE and colorectal cancer development, due to its occurrence in foodstuffs and in the digestive lumen, during digestion.

PMK-S005 Alleviates Age-Related Gastric Acid Secretion, Inflammation, and Oxidative Status in the Rat Stomach

Background/Aims

The aim of this study was to evaluate the effect of the synthetic S-allyl-l-cysteine (SAC) PMK-S005 on gastric acid secretion, inflammation, and antioxidant enzymes in aging rats.

Methods

The rats were divided into four groups at 31 weeks of age and were continuously fed a diet containing a vehicle control, PMK-S005 (5 or 10 mg/kg), or lansoprazole (5 mg/kg). Gastric acid secretion and connective tissue thickness of the lamina propria were evaluated at 74 weeks and 2 years of age. Tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and COX-2 levels were measured by using enzyme-linked immunosorbent assays (ELISAs) or Western blot assays. Levels of antioxidant enzymes, including heme oxyganase 1 (HO-1) and NAD(P)H:quinone oxidoreductase 1 (NQO-1), were also measured.

Results

As the rats aged, gastric acid secretion significantly decreased, and the connective tissue of the lamina propria increased. However, 74-week-old rats in the PMK-S005 group exhibited greater levels of gastric acid secretion than those of the control and lansoprazole groups. The increase of TNF-α, IL-1β, and COX-2 expression in 74-week and 2-year-old control rats were inhibited by PMK-S005. In addition, the decrease in HO-1 and NQO-1 protein expression that occurred with aging was inhibited by PMK-S005 in the 74-week-old rats.

Conclusions

These results suggest that PMK-S005 has therapeutic potential as an antiaging agent to ameliorate age-related gastric acid secretion, inflammation, and oxidative stress in the stomach.

New amino acid-Schiff base derived from s-allyl cysteine and methionine alleviates carbon tetrachloride-induced liver dysfunction

In spite of the tremendous stride in modern medicine, conventional drugs used in the hepatotoxic management are mostly inadequate. The present study aims in the synthesis of novel Schiff base compound derived using s-allyl cystiene and methionine. The newly synthesized compound, 2-((2-((2-(allylthio)-1-carboxyethyl)imino)ethylidene)amino)-4-(methylthio)butanoic acid (ACEMB) was characterized using UV-visible spectrophotometer, FTIR, ¹HNMR, and GC-MS. ACEMB showed potent in vitro antioxidant property. Chronic administration of ACEMB prior to CCl₄ intoxication: i) attenuated the leakage of liver injury markers, such as, enzymes (AST, ALT, GGT, ALP and LDH) and biomolecules (bilirubin) into the blood circulation; ii) normalized the concentration of total proteins, albumin and globulin to control level; and iii) protected the liver against dyslipidemia. These effects of ACEMB show the preservation of endoplasmic reticulum function against CCl₄ toxicity in the liver. The protective effect of ACEMB was due to its antioxidant property, which was revealed by reduced oxidative stress (TBARS and HP) and enhanced functions of the endogenous antioxidative system (SOD, catalase, GPx, GST, GSH, vitamin E and C) against CCl₄ intoxication. Also, ACEMB protected the functional activities of the various mitochondrial tricarboxylic acid cycle and oxidative phosphorylation enzymes. The biochemical alterations are in concurrence with the histological observations, wherein ACEMB pretreatment prevented the vacuolation, degeneration of nuclei and necrosis of hepatocytes. In addition, in silico analysis reveals the interaction of ACEMB in the active site of cytochrome P450. ACEMB mediates hepatoprotective effect by substituting itself as an antioxidant and decreasing oxidative stress, thereby diminishing the intracellular organelle dysfunction against CCl₄ toxicity in the liver.

Attenuation of Bleomycin-Induced Pulmonary Fibrosis in Rats with S-Allyl Cysteine

Pulmonary fibrosis is a complex disease with high mortality and morbidity. As there are currently no effective treatments, development of new strategies is essential for improving therapeutic outcomes. S-allyl cysteine (SAC) is a constituent of aged garlic extract that has demonstrated efficacy as an antioxidant and anti-inflammatory agent. The current study examines the effects of SAC on pulmonary fibrosis induced by a single intratracheal instillation of bleomycin (2.5 mg/kg). SAC was administered to rats as 0.15% SAC-containing diet from seven days prior to instillation up until the conclusion of the experiment (14 days post-instillation). SAC significantly reduced collagen mRNA expression and protein deposition (33.3 ± 2.7 μg/mg and 28.2 ± 2.1 μg/mg tissue in vehicle- and SAC-treated rats, respectively), and decreased fibrotic area, as assessed histologically. In the rats’ lungs, SAC also attenuated the increased expression of transforming growth factor-β1 (TGF-β1), a central regulator of myofibroblast recruitment, activation, and differentiation. While bleomycin instillation increased the number of myofibroblasts within the lung mesenchymal area, this change was significantly reduced by SAC treatment. SAC may exert efficacy as an anti-fibrotic by attenuating myofibroblast differentiation through TGF-β1-mediated fibroproliferative processes. Thus, our results indicate SAC may be useful for the prevention or treatment of pulmonary fibrosis.

Protective effect of Allium sativum (garlic) aqueous extract against lead-induced oxidative stress in the rat brain, liver, and kidney

The present investigation was undertaken to evaluate the ameliorative activity of Allium sativum against lead-induced oxidative stress in the brain, liver, and kidney of male rats. Four groups of male Wistar strain rats (100-120 g) were taken: group 1 received 1000 mg/L sodium acetate and group 2 was given 1000 mg/L lead acetate through drinking water for 2 weeks. Group 3 and 4 were treated with 250 mg/kg body weight/day of A. sativum and 500 mg/kg body weight/day of A. sativum, respectively, by oral intubation for a period of 2 weeks along with lead acetate. The rats were sacrificed after treatment and the brain, liver, and kidney were isolated on ice. In the brain, four important regions namely the hippocampus, cerebellum, cerebral cortex, and brain stem were separated and used for the present investigation. Blood was also drawn by cardiac puncture and preserved in heparinized vials at 4 °C for estimation of delta-aminolevulinic acid dehydratase (ALAD) activity. The results showed a significant (p < 0.05) increase in reactive oxygen species (ROS), lipid peroxidation products (LPP), total protein carbonyl content (TPCC), and lead in the selected brain regions, liver, and kidney of lead-exposed group compared with their respective controls. Blood delta-ALAD activity showed a significant (p < 0.05) decrease in the lead-exposed rats. However, the concomitant administration of A. sativum resulted in tissue-specific recovery of oxidative stress parameters namely ROS, LPP, and TPCC. A. sativum treatment also restored the blood delta-ALAD activity back to control. Overall, our results indicate that A. sativum administration could be an effective antioxidant treatment strategy for lead-induced oxidative insult.

S-Allyl cysteine alleviates inflammation by modulating the expression of NF-κB during chromium (VI)-induced hepatotoxicity in rats

Hexavalent chromium (Cr (VI)) is a common environmental pollutant. Cr (VI) exposure can lead to severe damage to the liver, but the preventive measures to diminish Cr (VI)-induced hepatotoxicity need further study. S-allyl cysteine (SAC) is a constituent of garlic ( Allium sativum) and has many beneficial effects to humans and rodents. In this study, we intended to analyze the mechanistic role of SAC during Cr (VI)-induced hepatotoxicity. Male Wistar albino rats were induced with 17 mg/kg body weight to damage the liver. The Cr (VI)-induced rats were treated with 100 mg/kg body weight of SAC as an optimum dosage to treat hepatotoxicity. We observed that the levels of oxidants, lipid peroxidation and hydroxyl radical (OH^•) were increased, and enzymatic antioxidants such as superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase were found to be decreased in Cr (VI)-induced rats. While treated with SAC, the levels of oxidants were decreased and enzymatic antioxidants were significantly ( p < 0.05) increased. Lysosomal enzyme activities were increased in Cr (VI)-induced rats and on treatment with SAC, the activities were significantly decreased. The expressions of nuclear factor-kappa B (p65-NF-κB), tumor necrosis factor α (TNF-α), and inducible nitric oxide synthase (iNOS) were increased during induction with Cr (VI). Subsequent administration of SAC to animals showed a decrease in the expressions of NF-κB, TNF-α, and iNOS. Results obtained from this study clearly demonstrated that SAC protects the liver cells from the Cr (VI)-induced free radical damage.

Dicranostiga leptopodu (Maxim.) Fedde extracts attenuated CCl4-induced acute liver damage in mice through increasing anti-oxidative enzyme activity to improve mitochondrial function

Dicranostiga Leptodu (Maxim.) fedde (DLF), a poppy plant, has been reported have many benefits and medicinal properties, including free radicals scavenging and detoxifying. However, the protective effect of DLF extracts against carbon tetrachloride (CCl₄)-induced damage in mice liver has not been elucidated. Here, we demonstrated that DLF extracts attenuated CCl₄-induced liver damage in mice through increasing anti-oxidative enzyme activity to improve mitochondrial function. In this study, the mice liver damage evoked by CCl₄ was marked by morphology changes, significant rise in lipid peroxidation, as well as alterations of mitochondrial respiratory function. Interestingly, pretreatment with DLF extracts attenuated CCl₄-induced morphological damage and increasing of lipid peroxidation in mice liver. Additionally, DLF extracts improved mitochondrial function by preventing the disruption of respiratory chain and suppression of mitochondrial Na⁺K⁺-ATPase and Ca²⁺-ATPase activity. Furthermore, administration with DLF extracts elevated superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) levels and maintained the balance of redox status. This results showed that toxic protection effect of DLF extracts on mice liver is mediated by improving mitochondrial respiratory function and keeping the balance of redox status, which suggesting that DLF extracts could be used as potential toxic protection agent for the liver against hepatotoxic agent.

Ginseng essence, a medicinal and edible herbal formulation, ameliorates carbon tetrachloride-induced oxidative stress and liver injury in rats

Background

Ginseng essence (GE) is a formulation comprising four medicinal and edible herbs including ginseng (Panax ginseng), American ginseng (Panax quinquefolius), lotus seed (Nelumbo nucifera), and lily bulb (Lilium longiflorum). This study was aimed at investigating the hepatoprotective effect of GE against carbon tetrachloride (CCl₄)-induced liver injury in rats.

Methods

We treated Wistar rats daily with low, medium, and high [0.625 g/kg body weight (bw), 1.25 g/kg bw, and 3.125 g/kg bw, respectively] doses of GE for 9 wk. After the 1^st wk of treatment, rats were administered 20% CCl₄ (1.5 mL/kg bw) two times a week to induce liver damage until the treatment ended.

Results

Serum biochemical analysis indicated that GE ameliorated the elevation of aspartate aminotransferase and alanine aminotransferase and albumin decline in CCl₄-treated rats. Moreover, CCl₄-induced accumulation of hepatic total cholesterol and triglyceride was inhibited. The hepatoprotective effects of GE involved enhancing the hepatic antioxidant defense system including glutathione, glutathione peroxidase, glutathione reductase, glutathione S-transferase, superoxide dismutase, and catalase. In addition, histological analysis using hematoxylin and eosin and Masson's trichrome staining showed that GE inhibited CCl₄-induced hepatic inflammation and fibrosis. Furthermore, immunohistochemical staining of alpha-smooth muscle actin indicated that CCl₄-triggered activation of hepatic stellate cells was reduced.

Conclusion

These findings demonstrate that GE improves CCl₄-induced liver inflammation and fibrosis by attenuating oxidative stress. Therefore, GE could be a promising hepatoprotective herbal formulation for future development of phytotherapy.

New pathways driving the experimental hepatoprotective action of tempol (4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl) against acute hepatotoxicity

PURPOSE

In absence of liver protective drugs, a large number of hepatopathies may arise during drug administration. This study was executed to investigate the possible new pathways underlying the hepatoprotective effect of Tempol (4-hydroxy-2,2,6,6- tetramethylpiperidine-1-oxyl), following oral administration of carbon tetrachloride in mice.

METHODS AND RESULTS

Thirty albino mice were randomized into 3 equal groups. The duration of study was 28 days. The groups were classified as follows: Group I (healthy control): received saline, in the same volume of CCl4 dose, daily, orally, for 14 days, then sacrificed. Group II: received CCl4, as a single oral dose only, of 1 ml/kg body weight, dissolved in olive oil (1:1 v/v), the animals of this group were sacrificed 14 days after CCl4 single dose intoxication. Group III (protective Tempol treated): received a single dose of Tempol, 20mg/kg, orally, daily for 14 days. Two hours after the last Tempol dose, animals of group III received a single oral dose of CCl4. Fourteen days later, animals were scarified to collect blood and liver tissues for analysis. Tempol pretreatment significantly captured elevated levels of ALT and AST activities, lipid peroxidation, total bilirubin and increased total thiol and catalase contents. Notably, it significantly reduced the expression of tumor necrosis factor-alpha (TNF-α), Caspase-3 and endoplasmic reticulum (ER) inositol-requiring enzyme 1(IRE1) mRNAs, which is an ER trans membrane sensor that activates the unfolded protein response (UPR) to maintain the ER and cellular function.

CONCLUSION

Pretreatment with Tempol has potential hepatoprotective effects against acute liver injury, induced by CCl4, through antioxidant and anti-inflammatory activities.

Effects of the dihydrolipoyl histidinate zinc complex against carbon tetrachloride-induced hepatic fibrosis in rats

PURPOSE

This study investigated the effects of an antioxidant, dihydrolipoyl histidinate zinc complex (DHLHZn), on the hepatic fibrosis in the carbon tetrachloride (CCl4) rat model.

METHODS

The animals were divided into three groups: control, CCl4, and CCl4+DHLHZn. A histological assessment of the liver fibrosis was performed using stained liver samples. The oxidative stress and antioxidant levels were evaluated by measuring the malondialdehyde (MDA) and glutathione (GSH) levels in the liver. In addition, cultured human hepatic stellate cells (LI90) were exposed to antimycin-A (AMA) and divided into four groups: control, DHLHZn, AMA, and AMA+DHLHZn. The effects of DHLHZn on AMA-induced fibrosis were evaluated by measuring the expression of transforming growth factor (TGF)-β1 and collagen α1 (I).

RESULTS

The hepatic fibrosis in the CCl4+DHLHZn group was attenuated compared to that in the CCl4 group. The MDA levels in the CCl4+DHLHZn group were significantly lower than those of the CCl4 group, whereas the GSH levels in the CCl4+DHLHZn group were significantly higher than those of the CCl4 group. Furthermore, the relative mRNA expression of TGF-β1 and collagen α1 (I) in the AMA+DHLHZn group was significantly lower than that in the AMA group.

CONCLUSION

DHLHZn may attenuate the hepatic fibrosis induced by CCl4 by decreasing the degree of oxidative stress.

Protective effects of garlic extract, PMK-S005, against nonsteroidal anti-inflammatory drugs-induced acute gastric damage in rats

BACKGROUND

PMK-S005 is synthetic s-allyl-L-cysteine (SAC), a sulfur-containing amino acid, which was initially isolated from garlic. The antioxidant and anti-inflammation activities of SAC have been demonstrated in diverse experimental animal models.

AIMS

The purpose of this study was to investigate the gastroprotective effects of PMK-S005 against NSAIDs-induced acute gastric damage in rats.

METHODS

Eight-week SD rats were pretreated with PMK-S005 (1, 5, or 10 mg/kg) or rebamipide (50 mg/kg) 1 h before administration of NSAIDs including aspirin (200 mg/kg), diclofenac (80 mg/kg), and indomethacin (40 mg/kg). After 4 h, the gross ulcer index, histological index, and gastric mucus level were determined. Myeloperoxidase (MPO), TNF-α, IL-1β, PGE2, and LTB4 levels were estimated in the gastric mucosal tissue by ELISA. Protein expressions of cPLA2, COX-1, and COX-2 were assessed by Western blot analysis.

RESULTS

Pretreatment with PMK-S005 significantly attenuated the NSAIDs-induced gastric damage and increased the gastric mucus level. In addition, PMK-S005 attenuated increases in MPO, TNF-α, and IL-1β production. The expressions of cPLA2 and COX-2 induced by NSAIDs were decreased by PMK-S005 pretreatment. PMK-S005 did not cause suppression of PGE2 synthesis induced by NSAIDs, but LTB4 production was significantly suppressed by PMK-S005. The effects of PMK-S005 were consistently maximized at a concentration of 5 mg/kg, which were frequently superior to those of rebamipide.

CONCLUSIONS

These results strongly suggest that PMK-S005 can be a useful gastroprotective agent against acute gastric mucosal damage by suppressing proinflammatory cytokines, down-regulating cPLA2, COX-2 and LTB4 expression, and increasing the synthesis of mucus.

S-allyl cysteine ameliorates the quality of sperm and provides protection from age-related sperm dysfunction and oxidative stress in rats

Reactive oxygen species play a central role in the pathophysiology of the age-related decrease in male fertility. It has been reported that the total protein of DJ-1 was decreased in a proteomic analysis of seminal plasma from asthenozoospermia patients and a DJ-1 protein acts as a sensor of cellular redox homeostasis. Therefore, we evaluated the age-related changes in the ratio of the oxidized/reduced forms of the DJ-1 protein in the epididymis. In addition, the protective effects of S-allyl cysteine (SAC), a potent antioxidant, were evaluated against sperm dysfunction. Male rats aged 15–75 weeks were used to assess age-associated sperm function and oxidative stress. Sperm count increased until 25 weeks, but then decreased at 50 and 75 weeks. The rate of sperm movement at 75 weeks was decreased to approximately 60% of the rate observed at 25 weeks. Expression of DJ-1 decreased, but oxidized-DJ-1 increased with age. In addition, 4-hydroxy-2-nonenal modified proteins in the epididymis increased until 50 weeks of age. The total number and DNA synthetic potential of the sperm increased until 25 weeks, and then decreased. In rats 75 weeks of age, SAC (0.45% diet) attenuated the decrease in the number, motility, and DNA synthesis of sperm and inhibited the oxidized proteins. These results suggest that SAC ameliorates the quality of sperm subjected to age-associated oxidative stress.

Protective effect of S-allyl-L-cysteine against endoplasmic reticulum stress-induced neuronal death is mediated by inhibition of calpain

Endoplasmic reticulum (ER) stress, implicated in various neurodegenerative processes, increases the level of intracellular Ca(2+) and leads to activation of calpain, a Ca(2+)-dependent cysteine protease. We have shown previously that S-allyl-L-cysteine (SAC) in aged garlic extracts significantly protects cultured rat hippocampal neurons (HPNs) against ER stress-induced neurotoxicity. The neuroprotective effect of SAC was compared with those of the related antioxidant compounds, L-cysteine (CYS) and N-acetylcysteine (NAC), on calpain activity in HPNs and also in vitro. SAC, but not CYS or NAC, reversibly restored the survival of HPNs and increased the degradation of α-spectrin, a substrate for calpain, induced by tunicamycin, a typical ER stress inducer. Activities of μ- and m-calpains in vitro were also concentration dependently suppressed by SAC, but not by CYS or NAC. At submaximal concentration, although ALLN (5 pM), which blocks the active site of calpain, and calpastatin (100 pM), an endogenous calpain-inhibitor protein, additively inhibited μ-calpain activity in vitro in combination with SAC, the effect of PD150606 (25 μM), which prevents interaction of Ca(2+) with the Ca(2+)-binding site of calpain, was unaffected by SAC. In contrast, SAC (1 mM) significantly reversed the effect of PD150606 at a concentration that elicited supramaximal inhibition (100 μM), but did not affect ALLN (1 nM)- and calpastatin (100 nM)-induced inhibition of μ-calpain activity. These results suggest that the protective effects of SAC against ER stress-induced neuronal cell death are not attributable to antioxidant activity, but to suppression of calpain through interaction with its Ca(2+)-binding site.

Hepatoprotective properties of sesamin against CCl4 induced oxidative stress-mediated apoptosis in mice via JNK pathway

Sesamin (Ses), one of the major lignan derived from sesame seeds, has been reported to have many benefits and medicinal properties. However, its protective effects against carbon tetrachloride (CCl4) induced injury in liver have not been clarified. The aim of the present study was to investigate the hepatoprotective effects of sesamin on oxidative stress and apoptosis in mice exposed to CCl4. Our data showed that sesamin significantly prevented CCl4-induced hepatotoxicity in a dose-dependent manner, indicated by both diagnostic indicators of liver damage (serum aminotransferase activities) and histopathological analysis. Moreover, CCl4-induced profound elevation of reactive oxygen species (ROS) production and oxidative stress, as evidenced by increasing of lipid peroxidation level and depleting of the total antioxidant capacity (TAC) in liver, were suppressed by treatment with sesamin. Furthermore, TUNEL assay showed that CCl4-induced apoptosis in mouse liver was significantly inhibited by sesamin. In exploring the underlying mechanisms of sesamin action, we found that activities of caspase-3 were markedly inhibited by the treatment of sesamin in the liver of CCl4 treated mice. Sesamin increased expression levels of phosphorylated Jun N-terminal kinases (JNK) in liver, which in turn inactivated pro-apoptotic signaling events restoring the balance between mitochondrial pro- and anti-apoptotic Bcl-2 proteins and decreasing the release of mitochondrial cytochrome c in liver of CCl4 treated mice. JNK was also involved in the mitochondrial extrinsic apoptotic pathways of sesamin effects against CCl4 induced liver injury by regulating the expression levels of phosphorylated c-Jun proteins, necrosis factor-alpha (TNF-α) and Bak. In conclusion, these results suggested that the inhibition of CCl4-induced apoptosis by sesamin is due at least in part to its anti-oxidant activity and its ability to modulate the JNK signaling pathway.

Effects of S-propargyl-cysteine (SPRC) in caerulein-induced acute pancreatitis in mice

Hydrogen sulfide (H(2)S), a novel gaseous messenger, is synthesized endogenously from L-cysteine by two pyridoxal-5'-phosphate-dependent enzymes, cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE). S-propargyl-cysteine (SPRC) is a slow H(2)S releasing drug that provides cysteine, a substrate of CSE. The present study was aimed to investigate the effects of SPRC in an in vivo model of acute pancreatitis (AP) in mice. AP was induced in mice by hourly caerulein injections (50 µg/kg) for 10 hours. Mice were treated with SPRC (10 mg/kg) or vehicle (distilled water). SPRC was administered either 12 h before or 3 h before the induction of pancreatitis. Mice were sacrificed 1 h after the last caerulein injection. Blood, pancreas and lung tissues were collected and processed to measure the plasma amylase, plasma H(2)S, myeloperoxidase (MPO) activities and cytokine levels in pancreas and lung. The results revealed that significant reduction of inflammation, both in pancreas and lung was associated with SPRC given 3 h prior to the induction of AP. Furthermore, the beneficial effects of SPRC were associated with reduction of pancreatic and pulmonary pro-inflammatory cytokines and increase of anti-inflammatory cytokine. SPRC administered 12 h before AP induction did not cause significant improvement in pancreatic and lung inflammation. Plasma H(2)S concentration showed significant difference in H(2)S levels between control, vehicle and SPRC (administered 3 h before AP) treatment groups. In conclusion, these data provide evidence for protective effects of SPRC in AP possibly by virtue of its slow release of endogenous H(2)S.

Garlic in health and disease

The present article reviews the historical and popular uses of garlic, its antioxidant, haematological, antimicrobial, hepatoprotective and antineoplastic properties and its potential toxicity (from sulfoxide). Garlic has been suggested to affect several cardiovascular risk factors. It has also been shown that garlic and its organic allyl sulfur components are effective inhibitors of the cancer process. Since garlic and its constituents can suppress carcinogen formation, bioactivation and tumour proliferation, it is imperative that biomarkers be established to identify which individuals might benefit most. Garlic powder, aged garlic and garlic oil have demonstrated antiplatelet and anticoagulant effects by interfering with cyclo-oxygenase-mediated thromboxane synthesis. Garlic has also been found to have synergistic effects against Helicobacter pylori with a proton pump inhibitor. The active compound allicin may affect atherosclerosis not only by acting as an antioxidant, but also by other mechanisms, such as lipoprotein modification and inhibition of LDL uptake and degradation by macrophages. Freshly prepared garlic homogenate protects against isoniazid+rifampicin-induced liver injury in experimental animal models. Several mechanisms are likely to account for this protection.

Protective effect of L-carnitine and coenzyme Q10 on CCl₄-induced liver injury in rats

This study provides an information about the mechanisms of liver injury induced by CCl(4), and determines the influence of administration of L-carnitine or/and CoQ10 as prophylactic agents against CCl(4) deteriorative effect. The study was carried out on 80 adult male albino rats divided into eight groups, 10 animals each, as follows: four normal groups (control, treated with L-carnitine, treated with CoQ10, and treated with a combination of Lcarnitine and CoQ10) and four liver injury groups treated with CCl(4) (control, treated with L-carnitine, treated with CoQ10, and treated with a combination of L-carnitine and CoQ10). Liver injury was induced by s.c. injection of a single dose of CCl(4) (1 ml/kg). L-carnitine (50 mg/kg/day) was given i.p. for four successive days 24 hours before CCl(4) injection, and CoQ10 (200 mg/kg) was given as a single i.p. dose 24 hours before CCl(4) injection. Animals were sacrificed 24 hours after CCl(4) injection, blood samples were withdrawn and liver tissue samples were homogenized. The levels of the following parameters were determined: hepatic reduced glutathione, serum ALT and AST, hepatic lipid peroxides, hepatic vitamin C, hepatic and serum total protein, serum albumin, serum sialic acid, serum nitrite, and serum and hepatic total LDH activities and LDH isoenzymes. The obtained data revealed that CCl(4) injection produced a significant decrease in reduced glutathione content, vitamin C, total protein and albumin levels. However, there was a significant increase in serum ALT and AST activities, lipid peroxides, sialic acid, nitric oxide, serum and hepatic total LDH activities. On the other hand, groups treated with L-carnitine or/and CoQ10 prior to CCl(4) injection showed an improvement in most parameters when compared with cirrhotic control group. It has been concluded that L-carnitine and coenzyme Q10 have a pronounced prophylactic effect against liver damage induced by halogenated alkanes such as carbon tetrachloride.

Garlic: nature's protection against physiological threats

Currently reliance on natural products is gaining popularity to combat various physiological threats including oxidative stress, cardiovascular complexities, cancer insurgence, and immune dysfunction. The use of traditional remedies may encounter more frequently due to an array of scientific evidence in their favor. Garlic (Allium sativum) holds a unique position in history and was recognized for its therapeutic potential. Recent advancements in the field of immunonutrition, physiology, and pharmacology further explored its importance as a functional food against various pathologies. Extensive research work has been carried out on the health promoting properties of garlic, often referred to its sulfur containing metabolites i.e. allicin and its derivatives. Garlic in its preparations are effective against health risks and even used as dietary supplements such as age garlic extract (AGE) and garlic oil etc. Its components/formulations can scavenge free radicals and protect membranes from damage and maintains cell integrity. It also provides cardiovascular protection mediated by lowering of cholesterol, blood pressure, anti-platelet activities, and thromboxane formation thus providing protection against atherosclerosis and associated disorders. Besides this, it possesses antimutagenic and antiproliferative properties that are interesting in chemopreventive interventions. Several mechanisms have been reviewed in this context like activation of detoxification phase-I and II enzymes, reactive oxygen species (ROS) generation, and reducing DNA damage etc. Garlic could be useful in preventing the suppression of immune response associated with increased risk of malignancy as it stimulates the proliferation of lymphocytes, macrophage phagocytosis, stimulates the release of interleukin-2, tumor necrosis factor-alpha and interferon-gamma, and enhances natural killer cells. In this paper much emphasis has been placed on garlic's ability to ameliorate oxidative stress, core role in cardiovascular cure, chemopreventive strategies, and indeed its prospective as immune booster.

Purification and characterization of flavin-containing monooxygenase isoform 3 from rat kidney microsomes

Rats are a common animal model for metabolism and toxicity studies. Previously, the enzymatic properties of rat flavin-containing monooxygenase (FMO) 1 purified from hepatic and renal microsomes and that of FMO3 purified from hepatic microsomes were characterized. This study investigated the physical, immunological, and enzymatic properties of FMO3 purified from male rat kidney microsomes and compared the results with those obtained with isolated rat liver FMO3. Renal FMO3 was purified via affinity columns based on the elution of L-methionine (Met) S-oxidase activity and reactivity of the eluted proteins with human FMO3 antibody. In general, Met S-oxidase-specific activity was increased 100-fold through the purification steps. The resulting protein had similar mobility (approximately 56 kDa) as isolated rat liver FMO3 and cDNA-expressed human FMO3 by SDS-polyacrylamide gel electrophoresis. When the isolated kidney protein band was subjected to trypsin digestion and matrix-assisted laser desorption ionization/time of flight mass spectral analysis, 34% of the sequence of rat FMO3 was detected. The apparent K(m) and V(max) values for rat kidney FMO3 were determined using the known FMO substrates Met, seleno-L-methionine, S-allyl-L-cysteine (SAC), and methimazole (N-methyl-2-mercaptoimidazole). The stereoselectivity of the reactions with Met and SAC were also examined using high-performance liquid chromatography. The obtained kinetic and stereoselectivity results were similar to those we obtained in the present study, or those previously reported, for rat liver FMO3. Taken together, the results demonstrate many similar properties between rat hepatic and renal FMO3 forms and suggest that renal FMO3 may play an important role in kidney metabolism of xenobiotics containing sulfur and selenium atoms.

Hepatoprotective effects of Solanum nigrum Linn extract against CCl(4)-induced oxidative damage in rats

Solanum nigrum L. (SN) is an herbal plant that has been used as hepatoprotective and anti-inflammation agent in Chinese medicine. In this study, the protective effects of water extract of SN (SNE) against liver damage were evaluated in carbon tetrachloride (CCl4)-induced chronic hepatotoxicity in rats. Sprague-Dawley (SD) rats were orally fed with SNE (0.2, 0.5, and 1.0 g kg(-1) bw) along with administration of CCl4 (20% CCl4/corn oil; 0.5 mL kg(-1) bw) for 6 weeks. The results showed that the treatment of SNE significantly lowered the CCl4-induced serum levels of hepatic enzyme markers (GOT, GPT, ALP, and total bilirubin), superoxide and hydroxyl radical. The hepatic content of GSH, and activities and expressions of SOD, GST Al, and GST Mu that were reduced by CCl4 were brought back to control levels by the supplement of SNE. Liver histopathology showed that SNE reduced the incidence of liver lesions including hepatic cells cloudy swelling, lymphocytes infiltration, hepatic necrosis, and fibrous connective tissue proliferation induced by CCl4 in rats. Therefore, the results of this study suggest that SNE could protect liver against the CCl4-induced oxidative damage in rats, and this hepatoprotective effect might be contributed to its modulation on detoxification enzymes and its antioxidant and free radical scavenger effects.