Catechin as an antioxidant in liver mitochondrial toxicity: Inhibition of tamoxifen-induced protein oxidation and lipid peroxidation

Genomic organization and transcription of superoxide dismutase genes (sod1, sod2, and sod3b) and response to diazinon toxicity in platyfish (Xiphophorus maculatus) by using SOD enzyme activity

The aim of this study is to determine the effects of 50% of 96 h LC50 (5.25 ppm) diazinon on the expression of superoxide dismutase (SOD) enzyme genes (sod1, sod2, and sod3b) and SOD enzyme activity at the end of 24, 48, 72, and 96 h in platyfish liver and gill tissues. To this end, we determined the tissue-specific distribution of sod1, sod2, and sod3b genes and performed in silico analyses in platyfish (Xiphophorus maculatus). It was determined that malondialdehyde (MDA) level and SOD enzyme activity were increased in the liver [(43.90 EU mg protein-1 (control), 62.45 EU mg protein-1 (24 h), 73.17 EU mg protein-1 (48 h), 82.18 EU mg protein-1 (72 h), 92.93 EU mg protein-1 (96 h)] and gill [(16.44 EU mg protein-1 (control), 33.47 EU mg protein-1 (24 h), 50.38 EU mg protein-1 (48 h), 64.62 EU mg protein-1 (72 h), 74.04 EU mg protein-1 (96 h)] tissues of platyfish exposed to diazinon, while the expression of the sod genes was down-regulated. The tissue-specific distribution of the sod genes varied, with the tissues and the sod genes expression were being predominant in the liver (628.32 in sod1, 637.59 in sod2, 888.5 in sod3b). Thus, the liver was considered a suitable tissue for further gene expression studies. Based on the phylogenetic analyses, platyfish sod genes can be reported to be orthologs of sod/SOD genes from other vertebrates. Identity/similarity analyses supported this determination. Conserved gene synteny proved that there are conserved sod genes in platyfish, zebrafish, and humans.

Mitochondrial oxidative damage by co-exposure to bisphenol A and acetaminophen in rat testes and its amelioration by melatonin

OBJECTIVE

Human exposure to multiple xenobiotics, over various developmental windows, results in adverse health effects arising from these concomitant exposures. Humans are widely exposed to bisphenol A, and acetaminophen is the most commonly used over-the-counter drug worldwide. Bisphenol A is a well-recognized male reproductive toxicant, and increasing evidence suggests that acetaminophen is also detrimental to the male reproductive system. The recent recognition of male reproductive system dysfunction in conditions of suboptimal reproductive outcomes makes it crucial to investigate the contributions of toxicant exposures to infertility and sub-fertility. We aimed to identify toxicity in the male reproductive system at the mitochondrial level in response to co-exposure to bisphenol A and acetaminophen, and we investigated whether melatonin ameliorated this toxicity.

METHODS

Male Wistar rats were divided into six groups (n=10 each): a control group and groups that received melatonin, bisphenol A, acetaminophen, bisphenol A and acetaminophen, and bisphenol A and acetaminophen with melatonin treatment.

RESULTS

Significantly higher lipid peroxidation was observed in the testicular mitochondria and sperm in the treatment groups than in the control group. Levels of glutathione and the activities of catalase, glutathione peroxidase, glutathione reductase, and manganese superoxide dismutase decreased significantly in response to the toxicant treatments. Likewise, the toxicant treatments significantly decreased the sperm count and motility, while significantly increasing sperm mortality. Melatonin mitigated the adverse effects of bisphenol A and acetaminophen.

CONCLUSION

Co-exposure to bisphenol A and acetaminophen elevated oxidative stress in the testicular mitochondria, and this effect was alleviated by melatonin.

Comparison of antithyroid effects and hepatic complications of methimazole with catechin and its nanoencapsulation form in adult male rats

OBJECTIVES

Methimazole is an antithyroid drug and is used clinically in hyperthyroidism. Liver dysfunction is one of the side effects of methimazole. Catechins are natural flavonoids and have antioxidant, antithyroid, and liver protection effects. Despite the wide range of biological properties of catechins, their effective use is limited due to poor water solubility, low stability, and low bioavailability. Catechin niosomal nanoencapsulation improves the properties of catechin and increases its antioxidant activities.

METHODS

Niosomal vesicles were synthesized by the Thin Film Hydration method and their physicochemical characteristics, morphology, and percentage of trapped catechin in them were determined by dynamic light scattering (DLS), transmission electron microscopy (TEM), and spectrophotometry, respectively. In this study, 32 adult male rats were divided into 4 groups: control, 50 mg/kg methimazole, 100 mg/kg catechin, and 100 mg/kg nanocapsule niosomal form of catechin. The drugs were administered orally and the duration of treatment was 8 weeks. Then, the serum concentration of thyroid hormones and thyroid stimulating hormone (TSH) by enzyme-linked immunosorbent assay (ELISA) method, and serum liver function tests were performed using an autoanalyzer. The activities of hepatic oxidative enzymes were measured spectrophotometrically.

RESULTS

Our study showed that the percentage of catechin encapsulation in the niosome was calculated to be 51%. A significant difference was observed in the catechin and encapsulated catechin treatment groups compared to the methimazole group (p <0.0001). In all three treatment groups of methimazole, catechin, and niosomal nanocapsule catechin, serum levels of TT3, TT4, FT3, FT4, body weight and daily consumption of water and food were significantly reduced compared to the control group (p <0.0001).

CONCLUSIONS

The antithyroid effects of catechin and its encapsulated form were comparable to methimazole. Also, the encapsulation improved the hepatoprotective effects of catechin.

Ameliorative effects of chickpea flavonoids on redox imbalance and mitochondrial complex I dysfunction in type 2 diabetic rats

Chickpeas are an important source of flavonoids in the human diet, and researchers have demonstrated that flavonoids have antidiabetic compositions in chickpeas. Because the NAD⁺/NADH redox balance is heavily perturbed in diabetes and complex I is the only site for NADH oxidation and NAD⁺ regeneration, in the present study, mitochondrial complex I was used as a target for anti-diabetes. The objective of this study was to investigate the effects of a crude chickpea flavonoid extract (CCFE) on NAD⁺/NADH redox imbalance and mitochondrial complex I dysfunction in the pancreas as well as oxidative stress in type 2 diabetes mellitus (T2DM) rats. Our results demonstrated that the degree of NAD⁺/NADH redox imbalance in the pancreas of T2DM rats was alleviated by CCFE, which is likely attributed to the inhibition of the polyol pathway and the decrease in poly ADP ribose polymerase (PARP) and sirtuin 3 (Sirt3) activities. Moreover, mitochondrial complex I dysfunction in the pancreas of T2DM rats was ameliorated by CCFE through the suppression of the activity of complex I. Furthermore, CCFE treatment could attenuate oxidative stress in T2DM rats, which was proven by the reduction in hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) as well as the upregulation of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) in serum. CCFE treatment significantly improved dyslipidemia in T2DM rats.

Antioxidant compounds from Annona crassiflora fruit peel reduce lipid levels and oxidative damage and maintain the glutathione defense in hepatic tissue of Triton WR-1339-induced hyperlipidemic mice

Dyslipidemia is a risk factor for the pathogenesis of several diseases, such as obesity, hypertension, atherosclerosis and cardiovascular diseases. In addition to interfering with serum concentrations of cholesterol and triglycerides, hyperlipidemia is involved in oxidative stress increase and reduction of the endogenous antioxidant defenses. The fruit peel of Annona crassiflora crude extract (CEAc) and its polyphenols-rich fraction (PFAc) were investigated against hypertriglyceridemia, hypercholesterolemia and hepatic oxidative stress in Triton WR-1339-induced hyperlipidemic mice. Lipid parameters in serum, feces and liver, as well as hepatic oxidative status, and enzymatic and non-enzymatic antioxidant defense systems were analyzed. Pre-treatment with CEAc for 12 days decreased hepatic triglycerides and total cholesterol, and similar to PFAc, increased the high-density lipoprotein level. There were reductions in lipid peroxidation and protein carbonylation, as well as restoration of the glutathione defense system and total thiol content in the liver of the hyperlipidemic mice treated with PFAc. The fruit peel of A. crassiflora, a promising natural source of bioactive molecules, showed a potential lipid-lowering action and hepatoprotective activities triggered by reduction of oxidative damage and maintenance of the enzymatic and non-enzymatic antioxidant systems impaired by the hyperlipidemic state.

Laccase and Its Mutant Displayed on the Bacillus subtilis Spore Coat for Oxidation of Phenolic Compounds in Organic Solvents

Enzymes displayed on the Bacillus subtilis spore coat have several features that are useful for biocatalysis. The enzyme is preimmobilized on an inert surface of the spore coat, which is due to the natural sporulation process. As a result, protein stability can be increased, and they are resistant to environmental changes. Next, they would not lyse under extreme conditions, such as in organic solvents. Furthermore, they can be easily removed from the reaction solution and reused. The laboratory evolved CotA laccase variant T480A-CotA was used to oxidize the following phenolic substrates: (+)-catechin, (−)-epicatechin, and sinapic acid. The kinetic parameters were determined and T480A-CotA had a greater Vmax/Km than wt-CotA for all substrates. The Vmax/Km for T480A-CotA was 4.1, 5.6, and 1.4-fold greater than wt-CotA for (+)-catechin, (−)-epicatechin, and sinapic acid, respectively. The activity of wt-CotA and T480A-CotA was measured at different concentrations from 0–70% in organic solvents (dimethyl sulfoxide, ethanol, methanol, and acetonitrile). The Vmax for T480A-CotA was observed to be greater than the wt-CotA in all organic solvents. Finally, the T480A-CotA was recycled 7 times over a 23-h period and up to 60% activity for (+)-catechin remained. The product yield was up to 3.1-fold greater than the wild-type.

Chitosan coated synergistically engineered nanoemulsion of Ropinirole and nigella oil in the management of Parkinson's disease: Formulation perspective and In vitro and In vivo assessment

The research presented aims at developing Ropinirole hydrochloride (RHCl) nanoemulsion (NE) with nigella oil for Parkinson's disease (PD). In silico study was done to explore interactions of ropinirole and thymoquinone at receptor site (TNF-α and NFK-β). Ropinirole and Thymoquinone forms a hydrogen bond with residue Arginine 201 and residue Arginine 253 with a bond length of 1.89 Å and 2.30 Å at the NF-κβ receptor. NE was optimized using Central Composite Rotatable Design (CCRD). The globule size of chitosan coated NE, Polydispersity index (PDI) and zeta potential were 183.7 ± 5.2 nm, 0.263 ± 0.005, and 24.9 mV respectively. NE exhibited 85.28% transmittance showing the formulation was clear and transparent. TEM showed that NE had spherical globules with no aggregation. The formulation had a stable pH value of 5.8 ± 0.18. In vitro release and permeation studies exhibited 2 folds and 3.4 folds enhancement when compared with the drug suspension. Neurobehavioral activity and biochemical parameters corroborated well with the pharmacokinetic results. Histopathological study and immunohistochemical analysis were performed to get better picture of 6-OHDA induced toxicity and reversal of PD symptoms. Thus, the NE tailored is a promising synergistic approach yielding enticing outcomes for better management of PD related symptoms.

Catechin supplementation prevents kidney damage in rats repeatedly exposed to cadmium through mitochondrial protection

Nephrotoxicity is recognized as a serious disorder affected by chronic cadmium exposure. Imbalance between radical generation and elimination is considered a critical factor involved in the initiation and progression of renal injury caused by this heavy metal. The present study investigated the possible protection by catechin, a natural phenolic antioxidant, against cadmium nephrotoxicity and elucidated its potential mechanism. Male Wistar rats were assigned to receive vehicle, cadmium (CdCl₂ 2 mg/kg, i.p.) and cadmium plus catechin (25, 50, and 100 mg/kg, orally, respectively). After 4 weeks of treatment, rats exposed to cadmium demonstrated a marked rise in blood urea nitrogen and creatinine, a fall in creatinine clearance, and renal pathologies like severe tubular damage, apoptosis, and abnormal mitochondrial structure. Significant increases in malondialdehyde, nitric oxide, and tumor necrosis factor-alpha, while reductions in antioxidant thiols, superoxide dismutase, and catalase, were also detected in the kidney tissues of cadmium-intoxicated rats. These alterations were associated with mitochondrial dysfunction as supported by an increase in mitochondrial reactive oxygen species production and a decline in mitochondrial membrane potential. Treatment with catechin significantly attenuated all the changes caused by cadmium. These findings suggest that catechin effectively protects the kidney against toxic effect of cadmium, presumably through its antioxidant, anti-inflammation, and mitochondrial protection. The study outcomes not only add evidence to reinforce the medical benefits of catechin but also, most importantly, give rise to a prospect of developing renal preventive strategy for individuals who are at risk of cadmium contamination by means of catechin supplementation.

Hepatoprotective potential of Phyllanthus muellarianus leaf extract: studies on hepatic, oxidative stress and inflammatory biomarkers

CONTEXT

Leaves of Phyllanthus muellarianus (Kuntze) Exell. (Euphorbiacea) are widely used in the management of liver disorders in Nigeria. However, no there is no scientific validation to support this use.

OBJECTIVE

Hepatoprotective effect of Phyllanthus muellarianus aqueous leaf extract was investigated in acetaminophen-induced liver injury mice.

MATERIALS AND METHODS

Hepatoprotective effect of Phyllanthus muellarianus aqueous leaf extract was evaluated in acetaminophen-induced hepatic damage in Swiss albino mice using biomarkers of hepatocellular indices, oxidative stress, proinflammatory factors and lipid peroxidation. Mice received distilled water, 100, 200, or 400 mg/kg b.w of Phyllanthus muellarianus aqueous leaf extract, respectively, for seven days. Treatment groups were challenged with 300 mg/kg b.w of acetaminophen on the sixth day.

RESULTS

Oral administration of Phyllanthus muellarianus aqueous leaf extract significantly (p < 0.05) attenuates acetaminophen-mediated alterations in serum alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, albumin and total bilirubin by 76.56, 85.41, 89.39, 82.77 and 78.38%. Similarly, acetaminophen-mediated decrease in activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glucose 6-phosphate dehydrogenase were significantly attenuated in the liver of mice by 85.10, 80.81, 80.45, 76.23 and 95.22%, respectively. Increased levels of conjugated dienes, lipid hydroperoxides, malondialdehyde, protein carbonyl, fragmented DNA, tumor necrosis factor-α, interleukin-6 and -8 were significantly lowered by Phyllanthus muellarianus aqueous leaf extract.

CONCLUSION

Overall, results of this study show that Phyllanthus muellarianus halted acetaminophen-mediated hepatotoxicity due to its capability to enhance antioxidant enzymes.

Mitochondria As the Target for the Modulatory Effect of Curcumin in Oxaliplatin-induced Toxicity in Isolated Rat Liver Mitochondria

BACKGROUND AND AIMS

To explore hepatoprotective action of curcumin (CMN, a bioflavonoid) on oxaliplatin (Oxa)-triggered mitochondrial oxidative stress and respiratory chain complexes in liver of rats. Oxa is a ubiquitously utilized platinum-based chemotherapeutic agent commonly used for the treatment of colorectal cancer. Mitochondria have recently emerged as targets for anticancer drugs in several kinds of toxicity including hepatotoxicity that can lead to neoplastic disease. There is a dearth of evidence involving the role of mitochondria in mediating Oxa-evoked hepatotoxicity and its underlying mechanism is still debatable.

METHODS

The study was performed in mitochondria isolated from liver of Wistar rats. Oxa (200 μg/mL) and CMN (5 μmol) were incubated under in vitro conditions.

RESULTS

Oxa evoked a significant increase in the membrane lipid peroxidation (LPO) levels, protein carbonyl (PC) contents, decrease in reduced glutathione (GSH) and nonprotein thiol (NP-SH) levels. Oxa also caused a marked decline in the activities of enzymatic antioxidants and respiratory chain enzymes (I, II, III and V) in liver mitochondria. CMN pre-treatment significantly prevented the activities of enzymatic antioxidants and mitochondrial respiratory chain enzymes. CMN also restored the LPO and PC contents, GSH and NP-SH levels in liver mitochondria.

CONCLUSION

CMN intake might be effective in regulation of Oxa-evoked mitotoxicity during chemotherapy. Moreover, it is included in the armamentarium for anticancer agent-induced oxidative stress.

Hepatoprotective Properties of a Polyphenol-Enriched Fraction from Annona crassiflora Mart. Fruit Peel against Diabetes-Induced Oxidative and Nitrosative Stress

A polyphenol-enriched fraction from Annona crassiflora fruit peel (Ac-Pef) containing chlorogenic acid, (epi)catechin, procyanidin B2, and caffeoyl-glucoside was investigated against hepatic oxidative and nitrosative stress in streptozotocin-induced diabetic rats. Serum biochemical parameters, hepatic oxidative and nitrosative status, glutathione defense system analysis, and in silico assessment of absorption, distribution, metabolism, excretion, and toxicity (ADMET) of the main compounds of Ac-Pef were carried out. Ac-Pef treatment during 30 days decreased serum alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase activities, as well as hepatic lipid peroxidation, protein carbonylation and nitration, inducible nitric oxide synthase level, and activities and expressions of glutathione peroxidase, superoxide dismutase, and catalase. There were increases in antioxidant capacity, glutathione reductase activity, and reduced glutathione level. ADMET predictions of Ac-Pef compounds showed favorable absorption and distribution, with no hepatotoxicity. A. crassiflora fruit peel showed hepatoprotective properties, indicating a promising natural source of bioactive molecules for prevention and therapy of diabetes complications.

(+)-Catechin prevents methylglyoxal-induced mitochondrial dysfunction and apoptosis in EA.hy926 cells

OBJECTIVE

To investigate whether (+)-catechin, a strong antioxidant, can prevent methylglyoxal (MGO)-induced cytotoxicity and its mechanism.

METHODS

Cytotoxicity, apoptosis, reactive oxygen species (ROS) generation, hydrogen peroxide (H₂O₂) formation, mitochondrial membrane potential (MMP) and mitochondrial morphology were measured in EA.hy926 cells.

RESULT

MGO (4 mM)-induced cytotoxicity was markedly inhibited by (+)-catechin (0.1-4 mM) in 24 h. 1 mM MGO-induced apoptotic cell death (44.7%) was significantly inhibited by 4 mM (+)-catechin (to 24.4%), 1 mM aminoguanidine (AG) (to 28.8%) or 4 mM N-acetylcysteine (NAC) (to 24.3%). (+)-Catechin (4 mM) or AG (4 mM) can inhibit the decrease of MMP induced by MGO (2-8 mM) in 3 h. (+)-Catechin (4 mM) or AG (4 mM) can inhibit MGO (4 mM)-induced mitochondrial swelling in 3 h. However, MGO (4 mM)-induced ROS and H₂O₂ generation was not prevented by (+)-catechin (4 mM).

CONCLUSIONS

(+)-Catechin prevents MGO-induced cytotoxicity in EA.Hy926 cells through inhibiting apoptosis and mitochondrial damage.

Role of melatonin in mitigating nonylphenol-induced toxicity in frontal cortex and hippocampus of rat brain

Nonylphenol (NP), an environmental endocrine disruptor mimics estrogen and is a potential toxicant both under in vitro and in vivo conditions. In this study, the effect of melatonin on NP- induced neurotoxicity and cognitive alteration was investigated in adult male Wistar rats. Melatonin supplementation has been known to protect cells from neurotoxic injury. The animals were divided into three groups namely, control (vehicle) which received olive oil orally and treated rats received NP (25 mg/kg, per os) thrice a week for 45 days while the third group i.e., NP + melatonin, animals were co-administered melatonin (10 mg/kg, i.p.) along with NP. On the 46th day, rats were assessed for anxiety, motor co-ordination, grip strength and cognitive performance using Morris water maze test and then sacrificed for biochemical and histopathological assays in brain tissues. Melatonin improved the behavioral performance in NP exposed group. The results showed that NP significantly decreased the activity of acetylcholine esterase (AchE), monoamine oxidase (MAO) and Na⁺/K⁺-ATPase, in rat brain tissue along with other enzymes of antioxidant milieu. The outcome of the study shows that NP, like other persistent endocrine disrupting pollutants, creates a potential risk of cognitive, neurochemical and histopathological perturbations as a result of environmental exposure. Taken together, our study demonstrates that melatonin is protective against NP-induced neurotoxicity.

Mitochondrial dysfunction induced by Bisphenol A is a factor of its hepatotoxicity in rats

Bisphenol A (BPA), an estrogenic and endocrine disrupting agent, is widely used in manufacturing of polycarbonate plastics and epoxy resins. BPA and other endocrine disrupting chemicals (EDCs) act via multiple mechanisms including interference with mitochondrial functions. Mitochondria are the hub of cellular energy pool and hence are the target of many EDCs. We studied perturbation of activities of mitochondrial enzymes by BPA and its possible role in hepatotoxicity in Wistar rats. Rats were exposed to BPA (150 mg/kg, 250 mg/kg, 500 mg/kg per os, for 14 days) and activities of enzymes of mitochondrial electron transport chain (ETC) were measured. Besides, other biochemical parameters such as superoxide generation, protein oxidation, and lipid peroxidation (LPO) were also measured. Our results indicated a significant decrease in the activities of enzymes of mitochondrial ETC complexes, i.e., complex I, II, III, IV, and V along with significant increase in LPO and protein oxidation. Additionally, a significant increase in mitochondrial superoxide generation was also observed. All these findings could be attributed to enhanced oxidative stress, decrease in reduced glutathione level, and decrease in the activity of superoxide dismutase in rat liver mitochondria isolated from BPA-treated rats. BPA treatment also caused a significant increase in serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and lactate dehydrogenase indicating its potential hepatotoxicity. Furthermore, histopathological findings revealed marked edema formation, hepatocellular degeneration, and necrosis of liver tissue in BPA-exposed rats. In conclusion, this study provides an evidence of impaired mitochondrial bioenergetics and liver toxicity after high-dose BPA exposure in rats. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1922-1934, 2016.

Neuroprotective effects of melatonin as evidenced by abrogation of oxaliplatin induced behavioral alterations, mitochondrial dysfunction and neurotoxicity in rat brain

Neurotoxicity is a burdensome consequence of platinum-based chemotherapy that neutralizes the administration of effective dosage and often prompts treatment withdrawal. Oxaliplatin (Oxa), a third-era platinum analogue that is active against both early-organize and progressed colorectal growth, produces critical neurotoxicity. It has been reported that the Melatonin (Mel) is a pineal hormone its metabolites display important antioxidant properties in nervous system. There is dearth of literature involving the role of mitochondria and cytosolic compartments mediated Oxa-induced neurotoxicity and its underlying mechanisms are still debatable. Rats were pre-treated with Mel (10mg/kg b.wt., i.p.) and treated with Oxa (4mg/kg b.wt. i.p.) for 5 consecutive days. For neurobehavioral performances, decreased locomotor activity and muscular strength were observed in rats. Treatment with Mel in Oxa treated rats could protect the Oxa induced alterations in motor activity and muscular strength. For painful neuropathy, thermal hyperalgesia/nociceptive tests were evaluated. In addition, pre-treatment of Mel could block or alter the inactivation of Bcl-2, caspase 3 apoptotic protein and alterations Cytochrome c (Cyt c) release in an Oxa rich environment. Pre-treatment of Mel have shown an alteration in hyperalgesia behaviour in Oxa treated rats. Oxidative stress biomarkers, levels of non-enzymatic antioxidants and mitochondrial complexes were evaluated against neurotoxicity induced by Oxa. Mel pre-treatment replenished the mitochondrial lipid peroxidation levels and protein carbonyl content induced by Oxa. Mel also modulated altered non-enzymatic, enzymatic antioxidants and complex enzymes of mitochondria. Futures studies are also required to identify other molecular markers involved in neurotoxicity induced by Oxa and possible action of Mel in its modulation.

Targeted delivery of quercetin loaded mesoporous silica nanoparticles to the breast cancer cells

BACKGROUND

Mesoporous silica nanoparticles (MSNs) have been promising vehicles for drug delivery. Quercetin (Q), a natural flavonoid, has been reported to have many useful effects. However, poor water solubility as well as less bioavailability has confined its use as a suitable anti-cancer drug. Therefore, profound approach is required to overcome these drawbacks.

METHODS

We have synthesized folic acid (FA) armed mesoporous silica nanoparticles (MSN-FA-Q) loaded with quercetin and then characterized it by DLS, SEM, TEM and FTIR. MTT, confocal microscopy, flow cytometry, scratch assay and immunoblotting were employed to assess the cell viability, cellular uptake, cell cycle arrest, apoptosis, wound healing and the expression levels of different signalling molecules in breast adenocarcinoma cells. Nanoparticle distribution was investigated by using ex vivo optical imaging and CAM assay was employed to assess tumor regression.

RESULTS

MSN-FA-Q facilitates higher cellular uptake and allows more drug bioavailability to the breast cancer cells with over-expressed folate receptors. Our experimental results suggest that the newly synthesized MSN-FA-Q nanostructure caused cell cycle arrest and apoptosis in breast cancer cells through the regulation of Akt & Bax signalling pathways. Besides, we also observed that MSN-FA-Q has a concurrent anti-migratory role as well.

CONCLUSION

This uniquely engineered quercetin loaded mesoporous silica nanoparticle ensures a targeted delivery with enhanced bioavailability.

GENERAL SIGNIFICANCE

Effective targeted therapeutic strategy against breast cancer cells.

Neuroprotective activities of curcumin and quercetin with potential relevance to mitochondrial dysfunction induced by oxaliplatin

Peripheral neurotoxicity is one of the serious dose-limiting side effects of oxaliplatin (Oxa) when used in the treatment of malignant conditions. It is documented that it elicits major side effects specifically neurotoxicity due to oxidative stress forcing the patients to limit its clinical use in long-term treatment. Oxidative stress has been proven to be involved in Oxa-induced toxicity including neurotoxicity. The mitochondria have recently emerged as targets for anticancer drugs in various kinds of toxicity including neurotoxicity that can lead to neoplastic disease. However, there is paucity of literature involving the role of the mitochondria in mediating Oxa-induced neurotoxicity and its underlying mechanism is still debatable. The purpose of this study was to investigate the dose-dependent damage caused by Oxa on isolated brain mitochondria under in vitro conditions. The study was also designed to investigate the neuroprotective effects of nutraceuticals, curcumin (CMN), and quercetin (QR) on Oxa-induced mitochondrial oxidative stress and respiratory chain complexes in the brain of rats. Oxidative stress biomarkers, levels of nonenzymatic antioxidants, activities of enzymatic antioxidants, and mitochondrial complexes were evaluated against the neurotoxicity induced by Oxa. Pretreatment with CMN and QR significantly replenished the mitochondrial lipid peroxidation levels and protein carbonyl content induced by Oxa. CMN and QR ameliorated altered nonenzymatic and enzymatic antioxidants and complex enzymes of mitochondria. We conclude that CMN and QR, by attenuating oxidative stress as evident by mitochondrial dysfunction, hold promise as agents that can potentially reduce Oxa-induced adverse effects in the brain.

The Role of Oxidative Stress and Antioxidants in Liver Diseases

A complex antioxidant system has been developed in mammals to relieve oxidative stress. However, excessive reactive species derived from oxygen and nitrogen may still lead to oxidative damage to tissue and organs. Oxidative stress has been considered as a conjoint pathological mechanism, and it contributes to initiation and progression of liver injury. A lot of risk factors, including alcohol, drugs, environmental pollutants and irradiation, may induce oxidative stress in liver, which in turn results in severe liver diseases, such as alcoholic liver disease and non-alcoholic steatohepatitis. Application of antioxidants signifies a rational curative strategy to prevent and cure liver diseases involving oxidative stress. Although conclusions drawn from clinical studies remain uncertain, animal studies have revealed the promising in vivo therapeutic effect of antioxidants on liver diseases. Natural antioxidants contained in edible or medicinal plants often possess strong antioxidant and free radical scavenging abilities as well as anti-inflammatory action, which are also supposed to be the basis of other bioactivities and health benefits. In this review, PubMed was extensively searched for literature research. The keywords for searching oxidative stress were free radicals, reactive oxygen, nitrogen species, anti-oxidative therapy, Chinese medicines, natural products, antioxidants and liver diseases. The literature, including ours, with studies on oxidative stress and anti-oxidative therapy in liver diseases were the focus. Various factors that cause oxidative stress in liver and effects of antioxidants in the prevention and treatment of liver diseases were summarized, questioned, and discussed.

Role of dietary pro-oxidants in the maintenance of health and resilience to oxidative stress

The average length of human life is increasing, but so does the incidence of age- and lifestyle-related diseases. Improving diet and lifestyle is a key strategy for lifelong health and underlying mechanisms may well include increasing resilience pathways. The purpose of this review is to highlight and evaluate novel mechanisms by which dietary pro-oxidants, including bioactive phytochemicals and fatty acids, increase reactive oxygen species (ROS) concentrations just enough to activate transcription factor activation of nuclear factor erythroid 2 related factor 2 (Nrf-2) and heat shock factor (HSF), leading to an increase in levels of antioxidant enzymes and heat shock proteins that protect against the damaging effects of ROS. An increasing number of in vivo studies have now shown that dietary pro-oxidant compounds can increase the production of such resilience products. In most studies, dietary pro-oxidants normalized levels of antioxidant enzymes that were decreased by a range of different challenges, rather than raising levels of resilience products per se. Also, it is important to consider that the antioxidant response can be different for different organs. For future studies, however, the measurement of resilience markers may significantly improve our ability to prove the efficacy by which dietary bioactives with pro-oxidant capacities improve lifelong health.

The effects of bioactive compounds from plant foods on mitochondrial function: a focus on apoptotic mechanisms

Mitochondria are essential organelles for cellular integrity and functionality maintenance and their imparement is implicated in the development of a wide range of diseases, including metabolic, cardiovascular, degenerative and hyperproliferative pathologies. The identification of different compounds able to interact with mitochondria for therapeutic purposes is currently becoming of primary importance. Indeed, it is well known that foods, particularly those of vegetable origin, present several constituents with beneficial effects on health. This review summarizes and updates the most recent findings concerning the mechanisms through which different dietary compounds from plant foods affect mitochondria functionality in healthy and pathological in vitro and in vivo models, paying particular attention to the pathways involved in mitochondrial biogenesis and apoptosis.

Solidified self-nanoemulsifying formulation for oral delivery of combinatorial therapeutic regimen: part II in vivo pharmacokinetics, antitumor efficacy and hepatotoxicity

PURPOSE

The present work focuses on the in vivo evaluation of tamoxifen and quercetin combination loaded into solid self-nanoemulsifying drug delivery system (s-Tmx-QT-SNEDDS).

METHODS

Lyophilization was employed to prepare s-Tmx-QT-SNEDDS using Aerosil 200 as carrier. The developed formulation was evaluated for in vitro cell cytotoxicity, in vivo pharmacokinetics, antitumor efficacy and toxicity studies.

RESULTS

In vivo pharmacokinetics revealed ~8-fold and ~4-fold increase in oral bioavailability of tamoxifen and quercetin, respectively as compared to free counterparts. s-Tmx-QT-SNEDDS exhibited significantly higher cell cytotoxicity, as compared to free drug combination revealing ~32-fold and ~22-fold higher dose reduction index for tamoxifen and quercetin, respectively estimated using median effect dose analysis. s-Tmx-QT-SNEDDS could suppress tumor growth in DMBA induced tumor bearing animals by ~80% in contrast to ~35% observed with tamoxifen citrate. The significant appreciation in antitumor efficacy was further supported by normalized levels of tumor angiogenesis markers (MMP-2 and MMP-9). Finally, complete obliteration in tamoxifen induced hepatotoxicity was observed upon administration of developed formulation in contrast to that of clinically available tamoxifen citrate when measured as function of hepatotoxicity markers and histopathological changes.

CONCLUSIONS

In nutshell, co-encapsulation of quercetin with tamoxifen in solid SNEDDS poses great potential in improving the therapeutic efficacy and safety of tamoxifen.

The relationship between the structure and biological actions of green tea catechins

Catechins and their gallate esters are a class of polyphenolic compounds. The catechin subclass known as flavan-3-ols have recently attracted much attention with regards to their beneficial effect on human health. Their biological actions are dependent on the structure of the compounds and vary according to cell type. They are best known as powerful antioxidants; however depending on the doses they also exhibit prooxidant effects. The anti- or prooxidant effects of green tea catechins have been implicated in the modulation of several cellular functions often associated with strong chemoprotective properties. This review summarises the benefit catechins to human health, the main molecular pathways modulated by catechins. The relationship between the structure and activity of the catechins needs to be studied further. In the future, the structure of catechins could be modified so as to synthesise novel compounds with more specific beneficial properties and higher bioavailability.

Comparison of taurine, GABA, Glu, and Asp as scavengers of malondialdehyde in vitro and in vivo

The purpose of this study is to determine if amino acid neurotransmitters such as gamma-aminobutyric acid (GABA), taurine, glutamate (Glu), and aspartate (Asp) can scavenge activated carbonyl toxicants. In vitro, direct reaction between malondialdehyde (MDA) and amino acids was researched using different analytical methods. The results indicated that scavenging activated carbonyl function of taurine and GABA is very strong and that of Glu and Asp is very weak in pathophysiological situations. The results provided perspective into the reaction mechanism of taurine and GABA as targets of activated carbonyl such as MDA in protecting nerve terminals. In vivo, we studied the effect of taurine and GABA as antioxidants by detecting MDA concentration and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities. It was shown that MDA concentration was decreased significantly, and the activities of SOD and GSH-Px were increased significantly in the cerebral cortex and hippocampus of acute epileptic state rats, after the administration of taurine and GABA. The results indicated that the peripherally administered taurine and GABA can scavenge free radicals and protect the tissue against activated carbonyl in vivo and in vitro.

Thioredoxin-mediated redox regulation of resistance to endocrine therapy in breast cancer

Resistance to endocrine therapy in breast carcinogenesis due to the redox regulation of the signal transduction system by reactive oxygen species (ROS) is the subject of this review article. Both antiestrogens and aromatase inhibitors are thought to prevent cancer through modulating the estrogen receptor function, but other mechanisms cannot be ruled out as these compounds also block metabolism and redox cycling of estrogen and are free radical scavengers. Endocrine therapeutic agents, such as, tamoxifen and other antiestrogens, and the aromatase inhibitor, exemestane, are capable of producing ROS. Aggressive breast cancer cells have high oxidative stress and chronic treatment with exemestane, fulvestrant or tamoxifen may add additional ROS stress. Breast cancer cells receiving long-term antiestrogen treatment appear to adapt to this increased persistent level of ROS. This, in turn, may lead to the disruption of reversible redox signaling that involves redox-sensitive phosphatases, protein kinases, such as, ERK and AKT, and transcription factors, such as, AP-1, NRF-1 and NF-κB. Thioredoxin modulates the expression of estrogen responsive genes through modulating the production of H2O2 in breast cancer cells. Overexpressing thioredoxine reductase 2 and reducing oxidized thioredoxin restores tamoxifen sensitivity to previously resistant breast cancer cells. In summary, it appears that resistance to endocrine therapy may be mediated, in part, by ROS-mediated dysregulation of both estrogen-dependent and estrogen-independent redox-sensitive signaling pathways. Further studies are needed to define the mechanism of action of thioredoxin modifiers, and their effect on the redox regulation that contributes to restoring the antiestrogen-mediated signal transduction system and growth inhibitory action.

Mitochondria-mediated mitigatory role of curcumin in cisplatin-induced nephrotoxicity

Cisplatin (CP) is one of the most potent chemotherapeutic anti-tumour drugs, and it has been implicated in renal toxicity. Oxidative stress has been proven to be involved in CP-induced toxicity including nephrotoxicity. However, there is paucity of literature involving role of mitochondria in mediating CP-induced renal toxicity, and its underlying mechanism remains unclear. Therefore, the present study was undertaken to examine the antioxidant potential of curcumin (CMN; a natural polyphenolic compound) against the mitochondrial toxicity of CP in kidneys of male rats. Acute toxicity was induced by a single intra-peritoneal injection of CP (6 mg kg(-1) ). We studied the ameliorative effect of CMN pre-treatment (200 mg kg(-1) ) on the toxicity of CP in rat kidney mitochondria. CP caused a significant elevation in the mitochondrial lipid peroxidation (LPO) levels and protein carbonyl (PC) content. Pre-treatment of rat with CMN significantly replenished the mitochondrial LPO levels and PC content. It also restored the CP-induced modulatory effects on altered enzymatic and non-enzymatic antioxidants in kidney mitochondria. We hypothesize that the reno-protective effects of CMN may be related to its predisposition to scavenge free radicals, and upregulate antioxidant machinery in kidney mitochondria.

Letrozole induces hepatotoxicity without causing oxidative stress: the protective effect of melatonin

AIM

The aim of this study was to determine the effects of letrozole (LTZ), an aromatase inhibitor (AI), and melatonin (MLT) on hepatic function and oxidative stress in female rats.

MATERIAL AND METHODS

A total of 32 female rats were divided equally into four groups (n = 8). Control group received saline (0.5 ml/day, oral gavage). LTZ was administered to rats by daily oral gavage at 1 mg/kg dose. LTZ + MLT group was given LTZ (1 mg/kg, oral gavage) plus MLT (0.5 mg/kg/day, s.c.). MLT group was given MLT (0.5 mg/kg/day) by s.c. injection. The activities of superoxide dismutase (SOD) and catalase (CAT) and malondialdehyde (MDA) levels were measured in liver tissue. Total antioxidant capacity (TAC), total oxidant status (TOS), ALT, AST, GGT, ALP, LDH, bilirubin, BUN, creatinine, total cholesterol (TC), high-density lipoprotein (HDL) and triglyceride (TG) were assayed in serum samples.

RESULTS

The oxidative stress parameters did not differ between groups. LTZ administration increased hepatic function parameters such as AST, LDH, ALP, bilirubin and MLT improved the disturbances of hepatic function. LTZ caused minimal histological changes in liver tissue and MLT treatment reversed those dejenerations.

DISCUSSION

LTZ may cause hepatotoxicity without inducing oxidative stress and MLT restores hepatic activity.

Should Red Wine Be Considered a Functional Food?

  Functional foods may be regarded as foods that have nutritional value, but in particular, they also have beneficial effects on one or more body functions. Thus, functional foods may improve health and/or reduce the risk of developing certain diseases when taken in amounts that can be consumed in a normal diet. Based on nearly 2 decades of research since the term "French paradox" was first coined in 1992, wine would appear to fit this definition. Yet there seems to be reluctance to consider wine as a functional food. In this review, we present an overview of the accumulated evidence for the health benefits of wine-and its key phenolic components such as resveratrol, quercetin, catechin-and show that these alone are not enough to firmly establish wine as a functional food. What is required is to create clearly defined products based on wine that are targeted to consumers' needs and expectations when it comes to purchasing functional foods. Moreover, the crucial question of alcohol and health also needs to be addressed by the functional food industry. Suggestions are presented for working through this issue, but in many regards, wine is like any other food-it should be consumed sensibly and in amounts that are beneficial to health. Overindulgence of any kind does not promote good health.

Effects of (-) -epigallocatechin gallate in liver of an animal model of combined (physical and mental) fatigue

OBJECTIVE

Fatigue can be classified as physical and mental depending on the cause. However, in our daily lives, combined fatigue, which is the combination of physical and mental fatigue, is most often experienced. In this study, the effects of (-)-epigallocatechin gallate (EGCg) on combined fatigue were assessed.

METHODS

To produce an animal model of combined fatigue, rats were kept in a cage filled with water to a height of 1.5 cm for 5 d. To evaluate the extent of fatigue, the rats swam with a load of steel rings that weighed approximately 8% of their body weight and were attached to their tails.

RESULTS

Fatigued rats treated with EGCg (50 or 100 mg/kg intraperitoneally [not for 25 mg/kg]) for 5 d could swim longer than fatigued animals given saline. Although levels of thiobarbituric acid-reactive substances in the plasma, brain, and skeletal muscle were not different between control and fatigued rats, thiobarbituric acid-reactive substance levels were higher in livers of fatigued animals than in livers of control animals. Oral intake of EGCg (50 or 100 mg/kg) for 5 d significantly decreased thiobarbituric acid-reactive substance levels in livers of fatigued animals.

CONCLUSION

These results suggest that EGCg (50 or 100 mg/kg) is effective for attenuating fatigue. EGCg given orally appears to have an antioxidant effect on the oxidatively damaged liver of fatigued animals.