Taurine, a conditionally essential amino acid, ameliorates arsenic-induced cytotoxicity in murine hepatocytes

Combined non-targeted and targeted metabolomics reveals the mechanism of delaying aging of Ginseng fibrous root

Background: The fibrous root of ginseng (GFR) is the dried thin branch root or whisker root of Ginseng (Panax ginseng C. A. Mey). It is known for its properties such as tonifying qi, producing body fluid, and quenching thirst. Clinically, it is used to treat conditions such as cough, hemoptysis, thirst, stomach deficiency, and vomiting. While GFR and Ginseng share similar metabolites, they differ in their metabolites ratios and efficacy. Furthermore, the specific role of GFR in protecting the body remains unclear. Methods: We employed ultra-high performance liquid chromatography-triple quadrupole mass spectrometry to examine alterations in brain neurotransmitters and elucidate the impact of GFR on the central nervous system. Additionally, we analyzed the serum and brain metabolic profiles of rats using ultra-high performance liquid chromatography-quadrupole-orbitrap mass spectrometry to discern the effect and underlying mechanism of GFR in delaying aging in naturally aged rats. Results: The findings of the serum biochemical indicators indicate that the intervention of GFR can enhance cardiovascular, oxidative stress, and energy metabolism related indicators in naturally aging rats. Research on brain neurotransmitters suggests that GFR can augment physiological functions such as learning and memory, while also inhibiting central nervous system excitation to a certain degree by maintaining the equilibrium of central neurotransmitters in aged individuals. Twenty-four abnormal metabolites in serum and seventeen abnormal metabolites in brain could be used as potential biomarkers and were involved in multiple metabolic pathways. Among them, in the brain metabolic pathways, alanine, aspartate and glutamate metabolism, arginine and proline metabolism, histidine metabolism, and tyrosine metabolism were closely related to central neurotransmitters. Butanoate metabolism improves energy supply for life activities in the aging body. Cysteine and methionine metabolism contributes to the production of glutathione and taurine and played an antioxidant role. In serum, the regulation of glycerophospholipid metabolism pathway and proline metabolism demonstrated the antioxidant capacity of GFR decoction. Conclution: In summary, GFR plays a role in delaying aging by regulating central neurotransmitters, cardiovascular function, oxidative stress, energy metabolism, and other aspects of the aging body, which lays a foundation for the application of GFR.

The Protective Effects of Taurine, a Non-essential Amino Acid, Against Metals Toxicities: A Review Article

Taurine is a non-proteinogenic amino acid derived from cysteine. It is involved in several phenomena such as the regulation of growth and differentiation, osmoregulation, neurohormonal modulation, and lipid metabolism. Taurine is important because of its high levels in several tissues such as the central nervous system (CNS), heart, skeletal muscles, retinal membranes, and platelets. In this report, we present the functional properties of taurine indicating that it has potential effects on various metal toxicities. Therefore, a comprehensive literature review was performed using the Scopus, PubMed, and Web of Science databases. According to the search keywords, 61 articles were included in the study. The results indicate that taurine protects tissues against metal toxicity through enhancement of enzymatic and non-enzymatic antioxidant capacity, modulation of oxidative stress, anti-inflammatory and anti-apoptotic effects, involvement in different molecular pathways, and interference with the activity of various enzymes. Taken together, taurine is a natural supplement that presents antitoxic effects against many types of compounds, especially metals, suggesting public consumption of this amino acid as a prophylactic agent against the incidence of metal toxicity.

pH-responsive and targeted delivery of chrysin via folic acid-functionalized mesoporous silica nanocarrier for breast cancer therapy

Cancer is a disease of global importance. In order to mitigate conventional chemotherapy-related side effects, phytochemicals with inherent anticancer efficacy have been opted. However, the use of nanotechnology is essential to enhance the bioavailability and therapeutic efficacy of these phytochemicals. Herein, we have formulated folic acid conjugated polyacrylic acid capped mesoporous silica nanoparticles (∼47.6 nm in diameter) for pH-dependent targeted delivery of chrysin to breast cancer (MCF-7) cells. Chrysin loaded mesoporous silica nanoparticles (Chr- mSiO2@PAA/FA) have been noted to induce apoptosis in MCF-7 cells through oxidative insult and mitochondrial dysfunction with subsequent G1 arrest. Further, in tumor bearing mice, intravenous incorporation of Chr-mSiO2@PAA/FA has been noticed to enhance the anti-neoplastic effects of chrysin via tumor site-specific accumulation. Enhanced cytotoxicity of chrysin contributed towards in vivo tumor regression, restoration of normalized tissue architecture and maintenance of healthy body weight. Besides, no serious systemic toxicity was manifested in response to Chr-mSiO2@PAA/FA administration in vivo. Thus, the study evokes about the anticancer potentiality of chrysin and its increased therapeutic activity via incorporation into folic acid conjugated mesoporous silica nanoparticles, which may hold greater impact in field of future biomedical research.

Therapeutic efficacy of N-acetylcysteine and zinc sulphate against di-(2-ethylhexyl) phthalate-induced testicular oxido-nitrergic stress in male Wistar rat

The therapeutic efficacy of N-acetylcysteine (NAC) and zinc sulphate on di-(2-ethylhexyl) phthalate (DEHP)-induced testicular oxido-nitrergic stress in rats was investigated in 36 male Wistar rats (170 ± 10 g) randomly assigned into one of six groups (n = 6). Group 1 (control) received 2.5 ml/kg of distilled water for 42 days, while group 2 (vehicle) received 2.5 ml/kg of corn oil for 42 days. Groups 3,4,5, and 6 were administered DEHP (750 mg/kg/day) for 21 days, after which groups 4, 5, and 6 received zinc sulphate (0.5 mg/kg/day), NAC (100 mg/kg/day), and zinc sulphate (0.5 mg/kg/day) + NAC (100 mg/kg/day) for an additional 21 days respectively. After the experimental period, the animals were euthanized by light thiopental sodium, and their testes were carefully dissected out for histological and biochemical assays. The result shows a significant alteration in testicular levels of malondialdehyde, nitric oxide, antioxidant enzymes, total antioxidant capacity, sulphydryl levels, dehydrogenases and testicular architecture following the administration of DEHP. These effects were reversed by coadministration of NAC and zinc sulphate in the study. We therefore concluded that the combined effects of NAC and ZnSO4 effectively improved testicular antioxidant status and reduced testicular nitregic stress, thus improving testicular architecture and functions.

Taurine as a Natural Antioxidant: From Direct Antioxidant Effects to Protective Action in Various Toxicological Models

Natural antioxidants have received tremendous attention over the last 3 decades. At the same time, the attitude to free radicals is slowly changing, and their signalling role in adaptation to stress has recently received a lot of attention. Among many different antioxidants in the body, taurine (Tau), a sulphur-containing non-proteinogenic β-amino acid, is shown to have a special place as an important natural modulator of the antioxidant defence networks. Indeed, Tau is synthesised in most mammals and birds, and the Tau requirement is met by both synthesis and food/feed supply. From the analysis of recent data, it could be concluded that the direct antioxidant effect of Tau due to scavenging free radicals is limited and could be expected only in a few mammalian/avian tissues (e.g., heart and eye) with comparatively high (>15-20 mM) Tau concentrations. The stabilising effects of Tau on mitochondria, a prime site of free radical formation, are characterised and deserve more attention. Tau deficiency has been shown to compromise the electron transport chain in mitochondria and significantly increase free radical production. It seems likely that by maintaining the optimal Tau status of mitochondria, it is possible to control free radical production. Tau's antioxidant protective action is of great importance in various stress conditions in human life, and is related to commercial animal and poultry production. In various in vitro and in vivo toxicological models, Tau showed AO protective effects. The membrane-stabilizing effects, inhibiting effects on ROS-producing enzymes, as well as the indirect AO effects of Tau via redox balance maintenance associated with the modulation of various transcription factors (e.g., Nrf2 and NF-κB) and vitagenes could also contribute to its protective action in stress conditions, and thus deserve more attention.

Accumulation, transformation and subcellular distribution of arsenite associated with five carbon nanomaterials in freshwater zebrafish specific-tissues

Although carbon nanomaterials (CNMs) commonly exist throughout the aquatic environment, their effect on arsenic (As) distribution and toxicity is unclear. In this study, arsenite accumulation, transformation, subcellular distribution, and enzyme activity were assessed in adult zebrafish (Danio rerio) intestines, heads and muscles, following co-exposure to arsenite and CNMs with different structures (single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), fullerene (C₆₀), graphene oxide (GO), and graphene (GN)). Results show that GN and GO promoted As toxicity in D. rerio, as carriers increasing total As accumulation in the intestine, resulting in arsenite adsorbed by GO and GN being released and transformed mainly into moderately-toxic monomethylarsonic acid (MMA), which was mostly distributed in organelles and metallothionein-like proteins (MTLPs). Moreover, GO and GN influenced As species distribution in D. rerio due to the excellent electron transfer ability. However, the effect was marginal for SWCNT, MWCNT and C₆₀, because of the different structure and suspension stability in fish-culture water. In addition, in the muscle and head tissues, As was mainly distributed in cellular debris in the forms of dimethylarsinic acid (DMA) and arsenobetaine (AsB). These findings help better understand the influence of CNMs on the mechanism of As toxicity in natural aquatic environments.

Role of Dietary Amino Acids and Nutrient Sensing System in Pregnancy Associated Disorders

Defective implantation is related to pregnancy-associated disorders such as spontaneous miscarriage, intrauterine fetal growth restriction and others. Several factors proclaimed to be involved such as physiological, nutritional, environmental and managemental that leads to cause oxidative stress. Overloading of free radicals promotes oxidative stress, and the internal body system could not combat its ability to encounter the damaging effects and subsequently leading to pregnancy-related disorders. During pregnancy, essential amino acids display important role for optimum fetal growth and other necessary functions for continuing fruitful pregnancy. In this context, dietary amino acids have received much attention regarding the nutritional concerns during pregnancy. Arginine, glutamine, tryptophan and taurine play a crucial role in fetal growth, development and survival while ornithine and proline are important players for the regulation of gene expression, protein synthesis and angiogenesis. Moreover, amino acids also stimulate the mammalian target of rapamycin (mTOR) signaling pathway which plays a central role in the synthesis of proteins in placenta, uterus and fetus. This review article explores the significances of dietary amino acids in pregnancy development, regulation of nutrient-sensing pathways such as mTOR, peroxisome proliferator-activated receptors (PPARs), insulin/insulin-like growth factor signaling pathway (IIS) and 5' adenosine monophosphate-activated protein kinase (AMPK) which exhibit important role in reproduction and its related problems. In addition, the antioxidant function of dietary amino acids against oxidative stress triggering pregnancy disorders and their possible outcomes will also be enlightened. Dietary supplementation of amino acids during pregnancy could help mitigate reproductive disorders and thereby improving fertility in animals as well as humans.

Role of taurine, its haloamines and its lncRNA TUG1 in both inflammation and cancer progression. On the road to therapeutics? (Review)

For one century, taurine is considered as an end product of sulfur metabolism. In this review, we discuss the beneficial effect of taurine, its haloamines and taurine upregulated gene 1 (TUG1) long non‑coding RNA (lncRNA) in both cancer and inflammation. We outline how taurine or its haloamines (N‑Bromotaurine or N‑Chlorotaurine) can induce robust and efficient responses against inflammatory diseases, providing insight into their molecular mechanisms. We also provide information about the use of taurine as a therapeutic approach to cancer. Taurine can be combined with other chemotherapeutic drugs, not only mediating durable responses in various malignancies, but also circumventing the limitations met from chemotherapeutic drugs, thus improving the therapeutic outcome. Interestingly, the lncRNA TUG1 is regarded as a promising therapeutic approach, which can overcome acquired resistance of cancer cells to selected strategies. In this regard, we can translate basic knowledge about taurine and its TUG1 lncRNA into potential therapeutic options directed against specific oncogenic signaling targets, thereby bridging the gap between bench and bedside.

Taurine and hesperidin rescues carbon tetrachloride-triggered testicular and kidney damage in rats via modulating oxidative stress and inflammation

AIMS

This study assessed the prophylactic or therapeutic effects of taurine (TR) and/or hesperidin (HES) on carbon tetrachloride (CCl₄) induced acute kidney and testicular injury in rats.

MAIN METHODS

Rats were randomly divided into nine experimental groups including control; corn oil; CCl₄; HES/CCl₄; TR/CCl₄; HES + TR/CCl₄; CCl₄/HES; CCl₄/TR; and CCl₄/HES + TR groups. CCl₄ was intraperitoneally injected with a single dose of 2 ml /kg b.w. HES and TR were orally gavaged twice weekly 100 mg/kg b.w. for four weeks. Kidney function, inflammatory response, sexual hormones, and oxidative stress indicators were assessed. Histomorphological and immune-histochemical studies of the inflammatory marker nuclear factor kappa (NF-κB) in renal and testicular tissues were performed.

KEY FINDINGS

The results showed that the TR and/or HES treatment significantly suppressed CCl₄ induced rise of urea, uric acid, potassium, and follicle-stimulating hormone levels. However, significant restoration of sodium, testosterone, and luteinizing hormone was apparent in CCl₄ exposed rats received HES and/or TR. Also, the HES and/or TR treatment significantly rescues CCl₄ induced oxidative stress and inflammation. Moreover, the HES and/or TR dosing significantly repaired the CCl₄ evoked altered renal and testicular architecture and suppressed NF-κB immunoexpression. Notably, alleviating CCl₄ induced renal and testicular damage was more effective in the prophylactic groups than the therapeutic groups. Also, most of the estimated parameters of the HES + TR group did not significantly vary from those of single TR or HES.

SIGNIFICANCE

In conclusion, HES or TR could efficiently guard against CCl₄ nephro-and reprotoxic effects, but both bioactive combinations afford only a limited synergistic outcome.

Single or combined protective and therapeutic impact of taurine and hesperidin on carbon tetrachloride-induced acute hepatic injury in rat

Currently, hepatic injury due to environmental pollutants extremely threatens human health and elicits great concern. Hence, there is a high global interest to find natural novel formulation products with potent hepatoprotective activity to combat liver disease. Hence, we evaluated the protective or therapeutic effect of hesperidin (HSP) and taurine (TAU), individually and in combination, on carbon tetrachloride (CCl₄)-induced acute hepatic injury in rats. The pre- or posttreatment by HSP and/or TAU significantly depressed CCl₄-induced elevation of alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, gamma-glutamyl transferase, total bilirubin, direct bilirubin, indirect bilirubin, malondialdehyde, globulins (α1, α2, β, and γ), albumin/globulin ratio, triglycerides, total cholesterol, high-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, low-density lipoprotein cholesterol, nitric oxide, and myeloperoxidase levels. Also, the pre- or posttreatment by HSP and/or TAU significantly minimized CCl₄-induced reduction of superoxide dismutase, catalase, reduced glutathione, and albumin concentrations. Furthermore, the protective or therapeutic administration of HSP and/or TAU markedly restored the CCl₄-induced altered hepatic architecture, depleted glycogen, and DNA contents. Notably, alleviating CCl₄-induced hepatotoxicity was more prominent in the protective groups than the therapeutic groups. More importantly, most of biochemical and histopathological parameters of HSP+TAU did not significantly differ from those of separate TAU or HSP neither before nor after CCl₄ exposure. Conclusively, HSP or TAU could be candidate protective agents against CCl₄ hepatotoxic impacts but the combination of both bioactive offers only a limited synergistic effect. Graphical abstract.

Taurine supplementation abates cirrhosis-associated locomotor dysfunction

AIM OF THE STUDY

Hepatic encephalopathy and hyperammonemia is a clinical complication associated with liver cirrhosis. The brain is the target organ for ammonia toxicity. Ammonia-induced brain injury is related to oxidative stress, locomotor activity dysfunction, and cognitive deficit, which could lead to permanent brain injury, coma and death if not appropriately managed. There is no promising pharmacological intervention against cirrhosis-associated brain injury. Taurine (TAU) is one of the most abundant amino acids in the human body. Several physiological and pharmacological roles have been attributed to TAU. TAU may act as an antioxidant and is an excellent neuroprotective agent. This study aimed to evaluate the effect of TAU supplementation on cirrhosis-associated locomotor activity disturbances and oxidative stress in the brain.

MATERIAL AND METHODS

Rats underwent bile duct ligation (BDL) surgery, and plasma and brain ammonia level, plasma biochemical parameters, and rats' locomotor function were monitored. Furthermore, brain tissue markers of oxidative stress were assessed.

RESULTS

It was found that plasma and brain ammonia was increased, and markers of liver injury were significantly elevated in the cirrhotic group. Impaired locomotor activity was also evident in BDL rats. Moreover, an increase in brain tissue markers of oxidative stress was detected in the brain of cirrhotic animals. It was found that TAU supplementation (50, 100, and 200 mg/kg, gavage) alleviated brain tissue markers of oxidative stress and improved animals' locomotor activity.

CONCLUSIONS

These data suggest that TAU is a potential protective agent against cirrhosis-associated brain injury.

Ameliorative effects of taurine against diabetes: a review

Diets in rats and humans have shown promising results. Taurine improved glucagon activity, promoted glycemic stability, modified glucose levels, successfully addressed hyperglycemia via advanced glycation end-product control, improved insulin secretion and had a beneficial effect on insulin resistance. Taurine treatment performed well against oxidative stress in brain, increased the secretion of required hormones and protected against neuropathy, retinopathy and nephropathy in diabetes compared with the control. Taurine has been observed to be effective in treatments against diabetic hepatotoxicity, vascular problems and heart injury in diabetes. Taurine was shown to be effective against oxidative stress. The mechanism of action of taurine cannot be explained by one pathway, as it has many effects. Several of the pathways are the advanced glycation end-product pathway, PI3-kinase/AKT pathway and mitochondrial apoptosis pathway. The worldwide threat of diabetes underscores the urgent need for novel therapeutic measures against this disorder. Taurine (2-aminoethane sulfonic acid) is a natural compound that has been studied in diabetes and diabetes-induced complications.

Oxidation Resistance of the Sulfur Amino Acids: Methionine and Cysteine

Sulfur amino acids are a kind of amino acids which contain sulfhydryl, and they play a crucial role in protein structure, metabolism, immunity, and oxidation. Our review demonstrates the oxidation resistance effect of methionine and cysteine, two of the most representative sulfur amino acids, and their metabolites. Methionine and cysteine are extremely sensitive to almost all forms of reactive oxygen species, which makes them antioxidative. Moreover, methionine and cysteine are precursors of S-adenosylmethionine, hydrogen sulfide, taurine, and glutathione. These products are reported to alleviate oxidant stress induced by various oxidants and protect the tissue from the damage. However, the deficiency and excess of methionine and cysteine in diet affect the normal growth of animals; thereby a new study about defining adequate levels of methionine and cysteine intake is important.

Ammonia-induced mitochondrial dysfunction and energy metabolism disturbances in isolated brain and liver mitochondria, and the effect of taurine administration: relevance to hepatic encephalopathy treatment

INTRODUCTION

Ammonia-induced oxidative stress, mitochondrial dysfunction, and energy crisis are known as some the major mechanisms of brain injury in hepatic encephalopathy (HE). Hyperammonemia also affects the liver and hepatocytes. Therefore, targeting mitochondria seems to be a therapeutic point of intervention in the treatment of HE. Taurine is an abundant amino acid in the human body. Several biological functions including the mitochondrial protective properties are attributed to this amino acid. The aim of this study is to evaluate the effect of taurine administration on ammonia-induced mitochondrial dysfunction.

MATERIAL AND METHODS

Isolated mice liver and brain mitochondria were exposed to different concentrations of ammonia (1, 5, 10, and 20 mM) and taurine (1, 5, and 10 mM), and several mitochondrial indices were assessed.

RESULTS

It was found that ammonia inhibited mitochondrial dehydrogenases activity caused collapse of mitochondrial membrane potential (MMP), induced mitochondrial swelling (MPP), and increased reactive oxygen species (ROS) in isolated liver and brain mitochondria. Furthermore, a significant amount of lipid peroxidation (LPO), along with glutathione (GSH) and ATP depletion, was detected in ammonia exposed mitochondria. Taurine administration (5 and 10 mM) mitigated ammonia-induced mitochondrial dysfunction.

CONCLUSIONS

The current investigation demonstrates that taurine is instrumental in preserving brain and liver mitochondrial function in a hyperammonemic environment. The data suggest taurine as a potential protective agent with a therapeutic capability against hepatic encephalopathy and hyperammonemia.

Hydrophilic interaction and reversed-phase ultra-performance liquid chromatography TOF-MS for metabolomic analysis of Veratrum nigrum-induced cardiotoxicity

The acute cardiotoxicity induced by Veratrum nigrum (VN) is explored by analyzing heart tissue metabolic profiles in mouse models and applying reversed-phase liquid chromatography mass spectrometry and hydrophilic interaction liquid chromatography mass spectrometry that are based on ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry. An animal model of acute heart injury was established in mice via intra-gastric administration of VN. Then, electrocardiogram and echocardiograph monitoring of cardiac function and pathological examination were performed on mice in both the control and VN groups, and it was verified that acute heart injury was caused. Meanwhile, comparing the results of the control and VN groups, we detected 36 differential endogenous metabolites of heart tissue, including taurine, riboflavin, purine and lipids, which are related to many possible pathways such as purine metabolism, taurine and hypotaurine metabolism and energy metabolism. Our study provides a scientific approach for evaluating and revealing the mechanisms of VN-induced cardiotoxicity via the metabolomic strategy.

Taurine treatment preserves brain and liver mitochondrial function in a rat model of fulminant hepatic failure and hyperammonemia

Ammonia-induced mitochondrial dysfunction and energy crisis is known as a critical consequence of hepatic encephalopathy (HE). Hence, mitochondria are potential targets of therapy in HE. The current investigation was designed to evaluate the role of taurine treatment on the brain and liver mitochondrial function in a rat model of hepatic encephalopathy and hyperammonemia. The animals received thioacetamide (400mg/kg, i.p, for three consecutive days at 24-h intervals) as a model of acute liver failure and hyperammonemia. Several biochemical parameters were investigated in the serum, while the animals' cognitive function and locomotor activity were monitored. Mitochondria was isolated from the rats' brain and liver and several indices were assessed in isolated mitochondria. Liver failure led to cognitive dysfunction and impairment in locomotor activity in the rats. Plasma and brain ammonia was high and serum markers of liver injury were drastically elevated in the thioacetamide-treated group. An assessment of brain and liver mitochondrial function in the thioacetamide-treated animals revealed an inhibition of succinate dehydrogenase activity (SDA), collapsed mitochondrial membrane potential, mitochondrial swelling, and increased reactive oxygen species (ROS). Furthermore, a significant decrease in mitochondrial ATP was detected in the brain and liver mitochondria isolated from thioacetamide-treated animals. Taurine treatment (250, 500, and 1000mg/kg) decreased mitochondrial swelling, ROS, and LPO. Moreover, the administration of this amino acid restored brain and liver mitochondrial ATP. These data suggest taurine to be a potential protective agent with therapeutic capability against hepatic encephalopathy and hyperammonemia-induced mitochondrial dysfunction and energy crisis.

Protective Effects of S-Adenosylmethionine and Its Combinations With Taurine and/or Betaine Against Lipopolysaccharide or Polyinosinic-polycytidylic Acid-induced Acute Hepatotoxicity

BACKGROUND

Several mechanisms for the pathogenesis of many liver diseases are related with oxidative stress, endotoxins, and infections by many microorganisms. These can lead to chronic hepatitis, cirrhosis, and even liver cancer. The aim of this study was to evaluate the effects of S-adenosylmethionine (SAMe) and its combinations with taurine and/or betaine against hepatotoxicites induced by lipopolysaccharide (LPS) or polyinosinic-polycytidylic acid (polyI:C).

METHODS

RAW 264.7 macrophage cells and seven-week-old male C57BL/6 mice were pretreated with SAMe (SAM or AdoMet), taurine, and/or betaine. In order to mimic hepatic injury like endotoxemia or viral infection, cells and mice were treated with LPS or polyI:C. Concentrations of glutathione (GSH), mRNA expressions of GSH synthesizing enzymes, and inflammatory markers were measured by biochemical assays and quantitative real-time PCR.

RESULTS

In RAW 264.7 cells and mice, pretreatment of SAMe alone or SAMe with taurine and/or betaine attenuated the decrease in GSH levels and mRNA expressions of GSH synthesizing enzymes. In addition, pretreatment of SAMe with taurine and/or betaine prevented the excessive increase in inflammatory mediators produced by LPS or polyI:C treatment.

CONCLUSIONS

Treatment with SAMe in combination with taurine and betaine, would have anti-oxidant functions in addition to anti-inflammatory action against bacterial and/or viral inflammation.

Selective Pro-Apoptotic Activity of Novel 3,3'-(Aryl/Alkyl-Methylene)Bis(2-Hydroxynaphthalene-1,4-Dione) Derivatives on Human Cancer Cells via the Induction Reactive Oxygen Species

Selective induction of apoptosis in cancer cells barring the normal cells is considered as an effective strategy to combat cancer. In the present study, a series of twenty-two (22) synthetic 3,3'-(aryl/alkyl-methylene)bis(2-hydroxynaphthalene-1,4-dione) bis-lawsone derivatives were assayed for their pro-apoptotic activity in six different cell lines (five cancerous and one normal) using MTT assay. Out of these 22 test compounds, 1j was found to be the most effective in inducing apoptosis in human glioma cells (CCF-4) among the different cell lines used in the study. The activity of this compound, 1j, was then compared to a popular anticancer drug, cisplatin, having limited usage because of its nephrotoxic nature. In this study, 1j derivative showed much less toxicity to the normal kidney cells compared to cisplatin, thus indicating the superiority of 1j as a possible anticancer agent. This compound was observed to induce apoptosis in the glioma cells by inducing the caspase dependent apoptotic pathways via ROS and downregulating the PI3K/AKT/mTOR pathway. Estimation of different oxidative stress markers also confirms the induction of oxidative stress in 1j exposed cancer cells. The toxicity of 1j compound toward cancer cells was confirmed further by different flow cytometrical analyses to estimate the mitochondrial membrane potential and cell cycle. The sensitivity of malignant cells to apoptosis, provoked by this synthetic derivative in vitro, deserves further studies in suitable in vivo models. These studies not only identified a novel anticancer drug candidate but also help to understand the metabolism of ROS and its application in cancer treatment.

Arsenic and nicotine co-exposure lead to some synergistic effects on oxidative stress and apoptotic markers in young rat blood, liver, kidneys and brain

Arsenic and nicotine exposure has been a major health concern globally. Individually both these toxicants increase the risk to various diseases including cancers. However, limited information exists on the co-exposure. In this study, we evaluate the effects of their individual and combined exposure and if co-exposure to these toxicants might have a synergism or antagonism. Male rats were exposed to a very low dose of arsenic (25 ppm in drinking water) or nicotine (0.25 mg/kg, sub-cutaneously) for a period of 5 months and post exposure various biochemical variables indicative of oxidative stress and apoptosis evaluated. Almost all glutathione linked enzymes showed marked alteration in individual as well as co-exposure treated groups. While serum creatinine and apoptosis indicator, lactate dehydrogenase (LDH) were significantly increased in both treatments, an additive effect was noted in co-exposure group. A similar trend was also seen in brain and liver but not in kidneys. Gene expression studies showed marked reduction in catalase, Cu-Zn SOD, GST, there was a significant up regulation in Bax, caspase 3 in various tissues along with urinary 8-OHdG levels, indicative of DNA damage and apoptosis. Interestingly, a decrease in liver arsenic concentration was noted in co-exposed group compared to arsenic alone exposed group. In conclusion, the present study suggests that arsenic and nicotine exhibited significant toxicity during individual exposure whereas co-exposure to these toxins showed variable conditions (indicative of both synergism and antagonism) in male rats.

N-acetylcysteine protects against cadmium-induced oxidative stress in rat hepatocytes

Cadmium (Cd) is a well-known hepatotoxic environmental pollutant. We used rat hepatocytes as a model to study oxidative damage induced by Cd, effects on the antioxidant systems, and the role of N-acetylcysteine (NAC) in protecting cells against Cd toxicity. Hepatocytes were incubated for 12 and 24 h with Cd (2.5, 5, 10 µM). Results showed that Cd can induce cytotoxicity: 10 µM resulted in 36.2% mortality after 12 h and 47.8% after 24 h. Lactate dehydrogenase, aspartate aminotransferase, and alanine aminotransferase activities increased. Additionally, reactive oxygen species (ROS) generation increased in Cd-treated hepatocytes along with malondialdehyde levels. Glutathione concentrations significantly decreased after treatment with Cd for 12 h but increased after 24 h of Cd exposure. In contrast, glutathione peroxidase activity significantly increased after treatment with Cd for 12 h but decreased after 24 h. superoxide dismutase and catalase activities increased at 12 h and 24 h. glutathione S-transferase and glutathione reductase activities decreased, but not significantly. Rat hepatocytes incubated with NAC and Cd simultaneously had significantly increased viability and decreased Cd-induced ROS generation. Our results suggested that Cd induces ROS generation that leads to oxidative stress. Moreover, NAC protects rat hepatocytes from cytotoxicity associated with Cd.

Taurine supplementation reduces oxidative stress and protects the liver in an iron-overload murine model

We previously demonstrated that iron overload induces liver damage by causing the formation of reactive oxygen species (ROS). Taurine is a potent free radical scavenger that attenuates the damage caused by excessive oxygen free radicals. Therefore, the aim of the present study was to investigate whether taurine could reduce the hepatotoxicity of iron overload with regard to ROS production. Mice were intraperitoneally injected with iron 5 days/week for 13 weeks to achieve iron overload. It was found that iron overload resulted in liver dysfunction, increased apoptosis and elevated oxidative stress. Taurine supplementation increased liver taurine levels by 40% and led to improved liver function, as well as a reduction in apoptosis, ROS formation and mitochondrial swelling and an attenuation in the loss of the mitochondrial membrane potential. Treatment with taurine mediated a reduction in oxidative stress in iron-overloaded mice, attenuated liver lipid peroxidation, elevated antioxidant enzyme activities and maintained reduced glutathione levels. These results indicate that taurine reduces iron-induced hepatic oxidative stress, preserves liver function and inhibits hepatocyte apoptosis. Therefore, taurine may be a potential therapeutic drug to reduce liver damage caused by iron overload.

An update on oxidative stress-mediated organ pathophysiology

Exposure to environmental pollutants and drugs can result in pathophysiological situations in the body. Research in this area is essential as the knowledge on cellular survival and death would help in designing effective therapeutic strategies that are needed for the maintenance of the normal physiological functions of the body. In this regard, naturally occurring bio-molecules can be considered as potential therapeutic targets as they are normally available in commonly consumed foodstuffs and are thought to have minimum side effects. This review article describes the detailed mechanisms of oxidative stress-mediated organ pathophysiology and the ultimate fate of the cells either to survive or to undergo necrotic or apoptotic death. The mechanisms underlying the beneficial role of a number of naturally occurring bioactive molecules in oxidative stress-mediated organ pathophysiology have also been included in the review. The review provides useful information about the recent progress in understanding the mechanism(s) of various types of organ pathophysiology, the complex cross-talk between these pathways, as well as their modulation in stressed conditions. Additionally, it suggests possible therapeutic applications of a number of naturally occurring bioactive molecules in conditions involving oxidative stress.

Oxidative stress: the mitochondria-dependent and mitochondria-independent pathways of apoptosis

Oxidative stress basically defines a condition in which prooxidant-antioxidant balance in the cell is disturbed; cellular biomolecules undergo severe oxidative damage, ultimately compromising cells viability. In recent years, a number of studies have shown that oxidative stress could cause cellular apoptosis via both the mitochondria-dependent and mitochondria-independent pathways. Since these pathways are directly related to the survival or death of various cell types in normal as well as pathophysiological situations, a clear picture of these pathways for various active molecules in their biological functions would help designing novel therapeutic strategy. This review highlights the basic mechanisms of ROS production and their sites of formation; detail mechanism of both mitochondria-dependent and mitochondria-independent pathways of apoptosis as well as their regulation by ROS. Emphasis has been given on the redox-sensitive ASK1 signalosome and its downstream JNK pathway. This review also describes the involvement of oxidative stress under various environmental toxin- and drug-induced organ pathophysiology and diabetes-mediated apoptosis. We believe that this review would provide useful information about the most recent progress in understanding the mechanism of oxidative stress-mediated regulation of apoptotic pathways. It will also help to figure out the complex cross-talks between these pathways and their modulations by oxidative stress. The literature will also shed a light on the blind alleys of this field to be explored. Finally, readers would know about the ROS-regulated and apoptosis-mediated organ pathophysiology which might help to find their probable remedies in future.

D-saccharic acid 1,4-lactone protects diabetic rat kidney by ameliorating hyperglycemia-mediated oxidative stress and renal inflammatory cytokines via NF-κB and PKC signaling

Increasing evidence suggests that oxidative stress is involved in the pathogenesis of diabetic nephropathy (DN) and this can be attenuated by antioxidants. D-Saccharic acid 1,4-lactone (DSL) is known for its detoxifying and antioxidant properties. Our early investigation showed that DSL can ameliorate alloxan (ALX) induced diabetes mellitus and oxidative stress in rats by inhibiting pancreatic β-cell apoptosis. In the present study we, therefore, investigated the protective role of DSL against renal injury in ALX induced diabetic rats. ALX exposure (at a dose of 120 mg/kg body weight, i. p., once) elevated the blood glucose level, serum markers related to renal injury, the production of reactive oxygen species (ROS), and disturbed the intra-cellular antioxidant machineries. Oral administration of DSL (80 mg/kg body weight) restored all these alterations close to normal. In addition, DSL could also normalize the aldose reductase activity which was found to increase in the diabetic rats. Investigating the mechanism of its protective activity, we observed the activation of different isoforms of PKC along with the accumulation of matrix proteins like collagen and fibronectin. The diabetic rats also showed nuclear translocation of NF-κB and increase in the concentration of inflammatory cytokines in the renal tissue. The activation of mitochondria dependent apoptotic pathway was observed in the diabetic rat kidneys. However, treatment of diabetic rats with DSL counteracted all these changes. These findings, for the first time, demonstrated that DSL could ameliorate renal dysfunction in diabetic rats by suppressing the oxidative stress related signalling pathways.

The prophylactic role of D-saccharic acid-1,4-lactone against hyperglycemia-induced hepatic apoptosis via inhibition of both extrinsic and intrinsic pathways in diabetic rats

Sustained hyperglycemia and increased oxidative stress play major roles in the development of secondary complications in diabetes including liver injury. Dietary supplement of antioxidants is effective in preventing oxidative stress mediated tissue damage in diabetic pathophysiology. D-Saccharic acid 1,4-lactone (DSL), a derivative of D-glucaric acid, is present in many dietary plants and is known for its detoxifying and antioxidant properties. Our early investigation showed that DSL can ameliorate alloxan (ALX) induced diabetes mellitus and oxidative stress in rats by inhibiting pancreatic β-cell apoptosis. In the present study we investigated the protective role of DSL against hepatic dysfunction in ALX induced diabetic rats. ALX exposure elevated the blood glucose, serum ALP and ALT levels, the production of reactive oxygen species (ROS), and disturbed the intra-cellular antioxidant machineries. Oral administration of DSL restored all these alterations close to normal. By investigating the mechanism of its protective activity, we observed that DSL prevented hyperglycemia induced hepatic apoptosis by inhibiting both extrinsic and intrinsic pathways. Results showed that in the liver tissue, diabetes promoted a significant increase of TNF-α/TNF-R1 and led to the activation of caspase-8 and t-Bid. In addition, ALX exposure reciprocally regulated Bcl-2 family protein expression, disturbed mitochondrial membrane potential, and subsequently released cytochrome c from mitochondria to cytosol. As a consequence, a significant increase in caspase-3 expression was observed in the liver of diabetic animals. However, treatment of diabetic rats with DSL counteracted these changes, making it a promising approach in lessening diabetes mediated tissue damage.

Taurine ameliorates alloxan-induced diabetic renal injury, oxidative stress-related signaling pathways and apoptosis in rats

Hyperglycemia-induced oxidative stress plays a vital role in the progression of diabetic nephropathy. The renoprotective nature of taurine has also been reported earlier; but little is known about the mechanism of this beneficial action. The present study has, therefore, been carried out to explore in detail the mechanism of the renoprotective effect of taurine under diabetic conditions. Diabetes was induced in rats by alloxan (single i.p. dose of 120 mg/kg body weight) administration. Taurine was administered orally for 3 weeks (1% w/v in drinking water) either from the day on which alloxan was injected or after the onset of diabetes. Alloxan-induced diabetic rats showed a significant increase in plasma glucose, enhanced the levels of renal damage markers, plasma creatinine, urea nitrogen and urinary albumin. Diabetic renal injury was associated with increased kidney weight to body weight ratio and glomerular hypertrophy. Moreover, it increased the productions of reactive oxygen species, enhanced lipid peroxidation and protein carbonylation in association with decreased intracellular antioxidant defense in the kidney tissue. In addition, hyperglycemia enhanced the levels of proinflammatory cytokins (TNF-α, IL-6, IL-1β) and Na(+)--K(+)-ATPase activity with a concomitant reduction in NO content and eNOS expression in diabetic kidney. Investigation of the oxidative stress-responsive signaling cascades showed the upregulation of PKCα, PKCβ, PKCε and MAPkinases in the renal tissue of the diabetic animals. However, taurine administration decreased the elevated blood glucose and proinflammatory cytokine levels, reduced renal oxidative stress (via decrease in xanthine oxidase activity, AGEs formation and inhibition of p47phox/CYP2E1 pathways), improved renal function and protected renal tissue from alloxan-induced apoptosis via the regulation of Bcl-2 family and caspase-9/3 proteins. Taurine supplementation in regular diet could, therefore, be beneficial to regulate diabetes-associated renal complications.

Antidiabetic effect of taurine in cultured rat skeletal l6 myotubes

Taurine (2-aminoethanesulfonic acid), a sulfur-containing β-amino acid, is found in all animal cells at millimolar concentrations and has been reported to show various health promoting activities including antidiabetic properties. The beneficial effects of taurine in diabetes mellitus have been known. However, the exact mechanism of hypoglycemic action of taurine is not properly defined. In this study, we investigated antidiabetic effect of taurine in the cell culture system using rat skeletal muscle cells. In cultured rat skeletal L6 myotubes, we studied the effect of taurine (0-100 μM) on glucose uptake to plasma membrane from the aspects of AMP-activated protein kinase (AMPK) signaling. Taurine stimulated glucose uptake in a dose-dependent manner by activating AMPK signaling. From these results, it may suggest that taurine show antidiabetic effect by stimulating insulin-independent glucose uptake in rat skeletal muscle.

Iron induces hepatocytes death via MAPK activation and mitochondria-dependent apoptotic pathway: beneficial role of glycine

In the present study we investigated the beneficial role of glycine in iron (FeSO₄) induced oxidative damage in murine hepatocytes. Exposure of hepatocytes to 20 μM FeSO₄ for 3 hours enhanced reactive oxygen species (ROS) generation and induced alteration in biochemical parameters related to hepatic oxidative stress. Investigating cell signalling pathway, we observed that iron (FeSO₄) intoxication caused NF-κB activation as well as the phosphorylation of p38 and ERK MAPKs. Iron (FeSO₄) administration also disrupted Bcl-2/Bad protein balance, reduced mitochondrial membrane potential, released cytochrome c and induced the activation of caspases and cleavage of PARP protein. Flow cytometric analysis also confirmed that iron (FeSO₄) induced hepatocytes death is apoptotic in nature. Glycine (10 mM) supplementation, on the other hand, reduced all the iron (FeSO₄) induced apoptotic indices. Combining, results suggest that glycine could be a beneficial agent against iron mediated toxicity in hepatocytes.

Ameliorative effects of taurine against methimazole-induced cytotoxicity in isolated rat hepatocytes

Methimazole is used as an antithyroid drug to control the symptoms of hyperthyroidism and maintain patients in a euthyroid state. Administration of this drug is associated with agranulocytosis and hepatotoxicity, which are the two most significant adverse effects. The present investigation was conducted to study the protective role of taurine against cytotoxicity induced by methimazole and its proposed reactive intermediary metabolite, N-methylthiourea, in an in vitro model of isolated rat hepatocytes.

At different points in time, markers such as cell viability, reactive oxygen species (ROS) formation, lipid peroxidation, mitochondrial membrane potential, and hepatocyte glutathione content were evaluated.

Treating hepatocytes with methimazole resulted in cytotoxicity characterized by the reduction in cell viability, an increase in ROS formation and lipid peroxidation, mitochondrial membrane potential collapse, and a reduction in cellular glutathione content. Furthermore, a significant amount of oxidized glutathione (GSSG) was formed when rat hepatocytes were treated with methimazole. N-methylthiourea toxicity was accompanied by a reduction in cellular GSH content, but no significant changes in lipid peroxidation, ROS formation, GSSG production, or changes in mitochondrial membrane potential were detected. Administration of taurine (200 μM) effectively reduced the toxic effects of methimazole or its metabolite in isolated rat hepatocytes.

Tertiary butyl hydroperoxide induced oxidative damage in mice erythrocytes: Protection by taurine

The present study was undertaken to investigate the protective role of taurine, against t-butyl hydroperoxide (TBHP) induced oxidative stress in murine erythrocytes. Erythrocytes were treated either with TBHP alone or with taurine, followed by TBHP exposure. TBHP-induced oxidative stress increased methemoglobin formation, lipid peroxidation and protein carbonylation in erythrocytes. The same exposure, however, depleted cellular GSH content and altered the activities of the antioxidant enzymes as well as of methemoglobin reductase; reduced activities of Ca(+) and Na(+)/K(+) ATPase and intracellular ATP levels. Taurine transport inhibitor, β-alanine, treated erythrocytes showed increased phosphatidylserine externalization and ROS formation on TBHP exposure and taurine could not revert the effect. TBHP exposure increased intracellular calcium and upregulated the level of calpain. Administration of taurine could, however, prevent the TBHP induced oxidative imbalance. Electron micrographs of erythrocytes showed changed morphology with an increase in the number of echinocytes. Taurine treatment could restore the normal levels of the antioxidant enzymes and metabolites of the erythrocytes. Results suggest that the oxidative insult introduced in erythrocytes by TBHP administration is prevented by taurine mainly via membrane stabilization.

Traditional extract of Pithecellobium dulce fruits protects mice against CCl(4) induced renal oxidative impairments and necrotic cell death

The present study has been carried out to investigate the role of the aqueous extract of the fruits of Pithecellobium dulce (AEPD) against carbon tetrachloride (CCl(4)) induced renal oxidative injury in mice. HPLC analysis shows that AEPD contains phenolics, flavonoids and saponins as the major active components. Creatinine and blood urea nitrogen (BUN) levels were assayed to determine renal protective action of AEPD in CCl(4)-induced renal pathophysiology. Its antioxidant activity was determined by measuring radical scavenging activity, antioxidant enzymes activities, GSH content, protein carbonylation and lipid peroxidation. In addition, FACS analysis, DNA fragmentation and histological studies were carried out to determine its effect in CCl(4) induced renal oxidative injury and cell death. CCl(4) exposure increased the intracellular reactive oxygen species production, decreased intracellular antioxidant defence, reduced mitochondrial membrane potential, attenuated the intracellular ATP content and caused renal cell death mainly via the necrotic pathway as revealed by DNA fragmentation analysis. Treatment with AEPD both prior and post to the toxin exposure protected the organ from CCl(4) induced oxidative insult. Histological studies also support our results. Combining, results suggest that the protective role of AEPD against CCl(4) induced renal oxidative impairments is probably due to the antioxidative properties present in its active constituents.

Radiation protection following nuclear power accidents: a survey of putative mechanisms involved in the radioprotective actions of taurine during and after radiation exposure

There are several animal experiments showing that high doses of ionizing radiation lead to strongly enhanced leakage of taurine from damaged cells into the extracellular fluid, followed by enhanced urinary excretion. This radiation-induced taurine depletion can itself have various harmful effects (as will also be the case when taurine depletion is due to other causes, such as alcohol abuse or cancer therapy with cytotoxic drugs), but taurine supplementation has been shown to have radioprotective effects apparently going beyond what might be expected just as a consequence of correcting the harmful consequences of taurine deficiency per se. The mechanisms accounting for the radioprotective effects of taurine are, however, very incompletely understood. In this article an attempt is made to survey various mechanisms that potentially might be involved as parts of the explanation for the overall beneficial effect of high levels of taurine that has been found in experiments with animals or isolated cells exposed to high doses of ionizing radiation. It is proposed that taurine may have radioprotective effects by a combination of several mechanisms: (1) during the exposure to ionizing radiation by functioning as an antioxidant, but perhaps more because it counteracts the prooxidant catalytic effect of iron rather than functioning as an important scavenger of harmful molecules itself, (2) after the ionizing radiation exposure by helping to reduce the intensity of the post-traumatic inflammatory response, and thus reducing the extent of tissue damage that develops because of severe inflammation rather than as a direct effect of the ionizing radiation per se, (3) by functioning as a growth factor helping to enhance the growth rate of leukocytes and leukocyte progenitor cells and perhaps also of other rapidly proliferating cell types, such as enterocyte progenitor cells, which may be important for immunological recovery and perhaps also for rapid repair of various damaged tissues, especially in the intestines, and (4) by functioning as an antifibrogenic agent. A detailed discussion is given of possible mechanisms involved both in the antioxidant effects of taurine, in its anti-inflammatory effects and in its role as a growth factor for leukocytes and nerve cells, which might be closely related to its role as an osmolyte important for cellular volume regulation because of the close connection between cell volume regulation and the regulation of protein synthesis as well as cellular protein degradation. While taurine supplementation alone would be expected to exert a therapeutic effect far better than negligible in patients that have been exposed to high doses of ionizing radiation, it may on theoretical grounds be expected that much better results may be obtained by using taurine as part of a multifactorial treatment strategy, where it may interact synergistically with several other nutrients, hormones or other drugs for optimizing antioxidant protection and minimizing harmful posttraumatic inflammatory reactions, while using other nutrients to optimize DNA and tissue repair processes, and using a combination of good diet, immunostimulatory hormones and perhaps other nontoxic immunostimulants (such as beta-glucans) for optimizing the recovery of antiviral and antibacterial immune functions. Similar multifactorial treatment strategies may presumably be helpful in several other disease situations (including severe infectious diseases and severe asthma) as well as for treatment of acute intoxications or acute injuries (both mechanical ones and severe burns) where severely enhanced oxidative and/or nitrative stress and/or too much secretion of vasodilatory neuropeptides from C-fibres are important parts of the pathogenetic mechanisms that may lead to the death of the patient. Some case histories (with discussion of some of those mechanisms that may have been responsible for the observed therapeutic outcome) are given for illustration of the likely validity of these concepts and their relevance both for treatment of severe infections and non-infectious inflammatory diseases such as asthma and rheumatoid arthritis.

Protective role of D-saccharic acid-1,4-lactone in alloxan induced oxidative stress in the spleen tissue of diabetic rats is mediated by suppressing mitochondria dependent apoptotic pathway

The present study investigated the role of D-saccharic acid 1,4-lactone (DSL) in the spleen tissue of alloxan (ALX) induced diabetic rats. Diabetes was induced in rats by injecting ALX (at a dose of 120 mg/kg body weight) intraperitoneally in sterile normal saline. Elevated levels of blood glucose, glycosylated Hb and TNFα decreased levels of plasma insulin and disturbed intra-cellular antioxidant machineries were detected in ALX exposed animals. Oral administration of DSL at a dose of 80 mg/kg body weight, however, restored these alterations in diabetic rats. Studies on the mechanism of ALX-induced diabetes showed that hyperglycemia caused disruption of mitochondrial membrane potential in the spleen, released cytochrome C in the cytosol, activated caspase 3 and ultimately led to apoptotic cell death. Results suggest that DSL possesses the ability of protecting the spleen tissue from ALX-induced hyperglycemia and thus could act as an anti-diabetic agent in lessening diabetes associated spleen dysfunction.

Protective effects of green and white tea against benzo(a)pyrene induced oxidative stress and DNA damage in murine model

In the current investigation, the ameliorative effect of green tea (GT) and white tea (WT) against benzo(a)pyrene (BaP) induced oxidative stress and DNA damage has been studied in the livers and lungs of Balb/c mice. A single dose of BaP (125 mg/kg, b.w. orally) increased the levels of lipid peroxidation (LPO) and decreased endogenous antioxidants such as superoxide dismutase (SOD), glutahione reductase (GR), catalase (CAT), and glutathione (GSH) significantly. Pretreatment with GT and WT for 35 days before a single dose of BaP elevated the decreased activity of GR, SOD, and CAT in liver tissue and also tended to normalize the levels of GSH and LPO in both hepatic and pulmonary tissues. The percentage of DNA in comet tail and 8-hydroxy-2'-deoxyguanosine levels reflected the decreasing pattern of DNA damage from the BaP-treated group to the groups that received pretreatment with GT and WT. Our study concludes that both GT and WT are effective in combating BaP induced oxidative insult and DNA damage. However, WT was found to be more protective than GT with respect to CAT (only in the liver), percentage of DNA in comet tail (only in the lungs), GST activity, and GSH content in both the tissues.

Taurine exerts hypoglycemic effect in alloxan-induced diabetic rats, improves insulin-mediated glucose transport signaling pathway in heart and ameliorates cardiac oxidative stress and apoptosis

Hyperlipidemia, inflammation and altered antioxidant profiles are the usual complications in diabetes mellitus. In the present study, we investigated the therapeutic potential of taurine in diabetes associated cardiac complications using a rat model. Rats were made diabetic by alloxan (ALX) (single i.p. dose of 120mg/kg body weight) and left untreated or treated with taurine (1% w/v, orally, in water) for three weeks either from the day of ALX exposure or after the onset of diabetes. Animals were euthanized after three weeks. ALX-induced diabetes decreased body weight, increased glucose level, decreased insulin content, enhanced the levels of cardiac damage markers and altered lipid profile in the plasma. Moreover, it increased oxidative stress (decreased antioxidant enzyme activities and GSH/GSSG ratio, increased xanthine oxidase enzyme activity, lipid peroxidation, protein carbonylation and ROS generation) and enhanced the proinflammatory cytokines levels, activity of myeloperoxidase and nuclear translocation of NFκB in the cardiac tissue of the experimental animals. Taurine treatment could, however, result to a decrease in the elevated blood glucose and proinflammatory cytokine levels, diabetes-evoked oxidative stress, lipid profiles and NFκB translocation. In addition, taurine increased GLUT 4 translocation to the cardiac membrane by enhanced phosphorylation of IR and IRS1 at tyrosine and Akt at serine residue in the heart. Results also suggest that taurine could protect cardiac tissue from ALX induced apoptosis via the regulation of Bcl2 family and caspase 9/3 proteins. Taken together, taurine supplementation in regular diet could play a beneficial role in regulating diabetes and its associated complications in the heart.

Involvement of both intrinsic and extrinsic pathways in hepatoprotection of arjunolic acid against cadmium induced acute damage in vitro

Cadmium (Cd) is one of the ubiquitous environmental pollutants and is responsible for various organ pathophysiology including hepatic disorders. It is extremely toxic even in low concentrations and bioaccumulate in organisms. The present study has been carried out to investigate the cytoprotective role of arjunolic acid (AA), a tri terpenoid saponin, against Cd induced oxidative impairment and cell death in murine hepatocytes. Administration of cadmium (30 μM), in the form of chloride (CdCl(2)) for 2h, significantly enhanced the ALT, ALP and LDH leakage, increased reactive oxygen species (ROS) production, reduced hepatocytes viability and altered the antioxidant status of hepatocytes by reducing intracellular GSH level, anti-oxidant enzymes activity and increasing intracellular GSSG and lipid peroxidation. Evidence for Cd-induced nature of cell death was sought by flow cytometric analysis. Signal transduction studies revealed that Cd markedly increased the levels of caspase-9, -8, -3, Fas and Bid, decreased mitochondrial membrane potential, enhanced cytochrome c release in the cytosol, disturbed the Bcl-2 family protein balance, cleaved PARP protein and ultimately led to apoptotic cell death. Results showed that Cd could trigger both intrinsic and extrinsic apoptotic pathways. In addition, Cd markedly increased NF-κB nuclear translocation in association with IKKα/β phosphorylation and IκBα degradation. Simultaneous treatment with AA (200 μM), however, reduced Cd-induced oxidative stress, attenuated the nuclear translocation of NF-κB and protects the hepatocytes from Cd-induced apoptotic death. Combining, data suggest that Cd-induced hepatic dysfunction and apoptosis might be supported by the ROS formation and mediated via the activation of NF-κB. AA treatment, on the other hand, reduced Cd-induced oxidative stress, attenuated the activation of NF-κB and mitochondrion-dependent and independent apoptotic signaling pathways.

Protective role of a coumarin-derived schiff base scaffold against tertiary butyl hydroperoxide (TBHP)-induced oxidative impairment and cell death via MAPKs, NF-κB and mitochondria-dependent pathways

The present study investigated the antioxidant signalling mechanism of a coumarin-derived schiff base (CSB) scaffold against tert-butylhydroperoxide (TBHP) induced oxidative insult in murine hepatocytes. CSB possesses DPPH and other free radical scavenging activities. TBHP reduced cell viability and intracellular antioxidant status accompanied by an increase in intracellular ROS production in hepatocytes. TBHP also activated phospho-ERK1/2, phospho-p38 and NF-κB, altered the Bcl-2/Bad ratio, reduced mitochondrial membrane potential, released cytochrome C and activated caspase 3, suggesting that TBHP induced oxidative stress responsive cell death via apoptotic pathway. FACS analysis and DNA fragmentation studies also confirmed the apoptotic cell death in TBHP exposed hepatocytes. Treatment with CSB effectively reduced these adverse effects by preventing the oxidative insult, alteration in the redox-sensitive signalling cascades and mitochondrial events. Combining, results suggest that antioxidant property of CSB make the molecule to be a potential protective measure against oxidative insult, cytotoxicity and cell death.