Protective effects of curcumin against oxidative stress parameters and DNA damage in the livers and kidneys of rats with biliary obstruction

Therapeutic approaches for cholestatic liver diseases: the role of nitric oxide pathway

Cholestasis describes bile secretion or flow impairment, which is clinically manifested with fatigue, pruritus, and jaundice. Neutrophils play a crucial role in many diseases such as cholestasis liver diseases through mediating several oxidative and inflammatory pathways. Data have been collected from clinical, in vitro, and in vivo studies published between 2000 and December 2021 in English and obtained from the PubMed, Google Scholar, Scopus, and Cochrane libraries. Although nitric oxide plays an important role in the pathogenesis of cholestatic liver diseases, excessive levels of NO in serum and affected tissues, mainly synthesized by the inducible nitric oxide synthase (iNOS) enzyme, can exacerbate inflammation. NO induces the inflammatory and oxidative processes, which finally leads to cell damage. We found that natural products such as baicalin, curcumin, resveratrol, and lycopene, as well as chemical likes ursodeoxycholic acid, dexamethasone, rosuvastatin, melatonin, and sildenafil, are able to markedly attenuate the NO production and iNOS expression, mainly through inducing the nuclear factor κB (NF-κB), Janus kinase and signal transducer and activator of transcription (JAK/STAT), and toll like receptor-4 (TLR4) signaling pathways. This study summarizes the latest scientific data about the bile acid signaling pathway, the neutrophil chemotaxis recruitment process during cholestasis, and the role of NO in cholestasis liver diseases. Literature review directed us to propose that suppression of NO and its related pathways could be a therapeutic option for preventing or treating cholestatic liver diseases.

Multifunctional nanoparticles encapsulating methotrexate and curcumin for holistic management of rheumatoid arthritis: in-vitro and pre-clinical assessment

PURPOSE

Bovine serum albumin (BSA) nanoparticles (BSA-MTX-CUR-NPs) encapsulating methotrexate (MTX) and curcumin (CUR) was developed with an aim to co-deliver the drugs at the inflamed joint so as to maximize the therapeutic efficacy and alleviate toxic side effects associated with MTX.

METHODS

Nanoparticle albumin-bound technology was used to formulate nanoparticles, followed by characterization for its particle size, polydispersity index, encapsulation efficiency, zeta potential, surface morphology, in-vitro drug release and drug release kinetics. Further, we investigated the pharmacokinetics and pharmacodynamics of the developed nanoparticles in the adjuvant-induced arthritis model.

RESULTS

BSA-MTX-CUR-NPs exhibited particle size of 163.05 ± 1.708 nm, polydispersity index of 0.195 ± 0.0024 and % encapsulation efficiency of 68.23 ± 0.640% for MTX and 75.71 ± 0.216% for CUR with controlled release pattern for both the drugs. The scanning electron microscopy revealed nanoparticles exhibited a spherical shape. DSC study confirmed the absence of incompatibility between the drugs and the excipients. Half-life and area under the curve were significantly higher for MTX in the nanoparticulate form in comparison to free MTX. Pharmacodynamic studies revealed that BSA-MTX-CUR-NPs possessed better disease-modifying effects in comparison to free MTX.

CONCLUSION

Hence, it can be concluded that albumin nanoparticles constitute a viable method for delivering MTX and CUR to inflamed joints simultaneously, because of the strong affinity of albumin and enhanced permeability and retention effect at the inflamed joint. This combinational therapy of MTX & CUR in nanoparticulate form has the potential for the holistic management of rheumatoid arthritis.

Synergetic Effect of Lupeol and Naringin Against Bile Duct Ligation Induced Cardiac Injury in Rats via Modulating Nitrite Level (eNos) and NF-kB /p65 Expression

Cardiac dysfunction such as cirrhotic cardiomyopathy is more common in liver cirrhosis related disorders including primary biliary cholangitis or biliary cirrhosis and primary sclerosing cholangitis. Bile duct ligation (BDL) is an effective model of biliary cholestasis, producing oxidative damage and fibrosis. This research was designed to evaluate the effect of Lupeol and Naringin and its combination on bile duct ligation induced cardiac injury in rats. For pharmacological evaluation, rats were randomly divided into seven groups; intrahepatic cholestasis induced by ligation of the bile duct might lead to cirrhotic cardiomyopathy. The results were analyzed by physical, biochemical and histological examination. The Lupeol (100 mg/kg, p.o.), Naringin (100 mg/kg, p.o.) and its combination (100 mg/kg each) treated group significantly improved physical infarct size, biochemical (Nitrite, SOD, CAT, and GSH) and histological (heart tissue- mitochondrial function/integrity and fibrosis) alterations occurs due to BDL-ligation. This study was concluded that oral administration of Lupeol, Naringin, and its combination has a curative potential against BDL-induced cardiac injury in rats by reducing oxidative stress and inflammatory reactions, resulting in reduced heart necrosis/myocardial infarction and increased myocardial activity. It also inhibits cardiac damage in the rat heart, these effects may be linked to the NO level (eNOS) is increased and the inactivation of the NF-kB-p65 expression pathways.This study also provides new insights into the development of lupeol and Naringin combination that can be used as supportive therapy for cardiovascular diseases.

Dietary Polyphenols Alleviate Autoimmune Liver Disease by Mediating the Intestinal Microenvironment: Challenges and Hopes

Autoimmune liver disease is a chronic liver disease caused by an overactive immune response in the liver that imposes a significant health and economic cost on society. Due to the side effects of existing medicinal medications, there is a trend toward seeking natural bioactive compounds as dietary supplements. Currently, dietary polyphenols have been proven to have the ability to mediate gut-liver immunity and control autoimmune liver disease through modulating the intestinal microenvironment. Based on the preceding, this Review covers the many forms of autoimmune liver illnesses, their pathophysiology, and the modulatory effects of polyphenols on immune disorders. Finally, we focus on how polyphenols interact with the intestinal milieu to improve autoimmune liver disease. In conclusion, we suggest that dietary polyphenols have the potential as gut-targeted modulators for the prevention and treatment of autoimmune liver disease and highlight new perspectives and critical issues for future pharmacological applications.

Protective effect of curcumin on zebrafish liver under ethanol-induced oxidative stress

Oxidative stress has an important role in determining severe damage to the liver, including steatosis. Curcumin (CUR) is a natural polyphenol compound with antioxidant potential but its mechanism is still unclear. In this study, 2% ethanol (ETH) was used to establish a liver injury model in Tg (fabp10: Ps Red) transgenic zebrafish with the fluorescent liver. Ethanol-treated zebrafish had an increased vacuole rate at 144 h post-fertilization (hpf), thus confirming the effectiveness of the proposed model in inducing liver damage. However, when ethanol was submitted to co-exposure with curcumin, fluorescence area and signal intensity, as well as vacuole rate, were similar to the levels found in the control group. RNA-seq results showed that ethanol and CUR affected the regulation of catalytic activity and phenylalanine metabolism, biosynthesis of amino acids, and arginine and proline metabolism signaling pathways. QRT-PCR analysis also showed that treatment with CUR led to the downregulation of genes involved in the Nrf2-Keap1 signaling pathway and altered the expression pattern of genes related to glutathione metabolism (gsr, gpx1a, gstp1, gsto1, and idh1a). CUR also induced an increase in GSH content and recovered decreased GSH caused by ethanol exposure. The findings discussed herein indicate that CUR can promote glutathione synthesis, which aided in the recovery from ethanol-induced liver damage in zebrafish larvae.

Differential neuroprotective effect of curcuminoid formulations in aluminum chloride-induced Alzheimer's disease

Alzheimer's disease (AD) is a slowly progressive brain degenerative disorder which gradually impairs memory, thinking, and ability to perform easy routine tasks. This degenerative disorder mainly targets the elderly people and has imposed an endemic burden on society. Hence, there is a crucial need to investigate the efficacious herbal pharmacotherapies that can effectively mitigate and prevent the pathological hallmarks of AD. The current study aims to explore the potential efficacy of curcuminoid-rich extract (CRE) and its ternary complex (TC). Experimental rodents were administered with AlCl₃ (300 mg/kg) to induce AD and treated with rivastigmine, curcuminoid crude extract, CRE, and TC orally for three consecutive weeks. Neurobehavioral, biochemical, and histopathological studies were performed from the last week of the study period. The mRNA expression of different pathological biomarkers was estimated by RT-qPCR analysis. The results of the study suggested that CRE and TC significantly improved the behavioral, biochemical parameters and acetylcholinesterase inhibitory activity in treatment groups. Histological analysis was also carried out indicating that the neurodegenerative changes and neuronal loss were stabilized by CRE and TC supplementation. CRE and TC supplementation remarkably downregulated the interleukin-1α, tumor necrosis factor-α, interleukin-1β, acetylcholinesterase, and β-secretase pathological gene expression. Hence, it was concluded that CRE and TC may act as promising candidates in the prevention of AD via numerous underlying signaling pathways.

Evaluation of the protective effect of curcumin on encephalopathy caused by intrahepatic and extrahepatic damage in male rats

Objective(s):

Along with increased intracranial pressure (ICP) and brain damage, brain edema is the most common cause of death in patients with hepatic encephalopathy. Curcumin can pass the blood-brain barrier and possesses anti-inflammatory and anti-oxidant properties. This study focuses on the curcumin protective effect on intrahepatic and extrahepatic damage in the brain.

Materials and Methods:

One hundred and forty-four male Albino N-Mary rats were randomly divided into 2 main groups: intrahepatic injury group and extrahepatic cholestasis group. In intra-hepatic injury group intrahepatic damage was induced by intraperitoneal (IP) injection of acetaminophen (500 mg/kg) [19] and included four subgroups: 1. Sham, 2. Acetaminophen (APAP), 3. Normal saline (Veh) which was used as curcumin solvent, and 4. Curcumin (CMN). In extrahepatic cholestasis group intrahepatic damage was caused by common bile duct litigation (BDL) and included four subgroups: 1. Sham, 2. BDL, 3. Vehicle (Veh), and 4. Curcumin (CMN). In both groups, 72 hr after induction of cholestasis, brain water content, blood-brain barrier permeability, serum ammonia, and histopathological indicators were examined and ICP was measured every 24 hr for three days.

Results:

The results showed that curcumin reduced brain edema, ICP, serum ammonia, and blood-brain barrier permeability after extrahepatic and intrahepatic damage. The maximum effect of curcumin on ICP was observed 72 hr after the injection.

Conclusion:

According to our findings, it seems that curcumin is an effective therapeutic intervention for treating encephalopathy caused by extrahepatic and intrahepatic damage.

Iron biodistribution profile changes in the rat spleen after administration of high-fat diet or iron supplementation and the role of curcumin

Curcumin as active metal chelating and antioxidant agent has a potential role in metal reduction and free radicals' neutralization in tissues. Of note, long-term administration of high fat diet (HFD) is considered as a main factor of blood serum iron deficiency. This study aimed to investigate the biodistribution profiles of iron in the spleen after long-term administration of HFD along with iron supplementation. Furthermore, the ameliorative role of curcumin to reduce iron accumulation level and improve the histological abnormalities produced by iron in spleen will be evaluated in the rats. Treated albino rats of this experiment were divided into six groups. Group I was a control group where group II was treated with HFD. Group III and group IV were treated with combination of HFD and curcumin or HFD and iron supplement respectively. Additionally, group V and group VI were treated with combination of HFD, iron supplement and curcumin or curcumin only respectively. Mainly histological analysis was used to investigate iron biodistribution and induced abnormalities in spleen under light microscope. The histochemical specific staining of iron in the spleen showed different biodistribution profiles of iron in the spleen. Administration of the HFD or HFD and iron supplementation increased the iron accumulation in the spleen. Where, curcumin administration with HFD (Group III) or with HFD and iron supplementation (Group V) significantly reduced the iron levels in the spleen. The splenic tissue inflammation, cellular apoptosis and fibrosis produced by higher iron accumulation was ameliorated after administration of curcumin supplementation as shown in the animals treated with HFD/curcumin (Group III) or HFD/iron supplement/curcumin (Group V). This study recommended that, it is preferable to use iron supplementation along with curcumin supplement for less than 4 months to avoid additional iron accumulation in the healthy organs.

El Deib M. Protective Effect of Curcumin against Sodium Salicylate-Induced Oxidative Kidney Damage, Nuclear Factor-Kappa Dysregulation, and Apoptotic Consequences in Rats

This study examined the effect of sodium salicylates (SS), alone and in combination with curcumin (CUR), on kidney function and architecture in rats. Five rat groups were given 1 mL physiological saline/rat orally, 1 mL olive oil/rat orally, 50 mg CUR/kg bwt orally, 300 mg SS/kg bwt intraperitoneally, or CUR+SS for 15 days. The hematological indices, serum protein profile, serum electrolytes balance, oxidative stress, and lipid peroxidation of kidney tissues were assessed. The histopathological examination and immune expression of Caspase-3 and nuclear factor kappa (NF-κB) were conducted. The findings showed that SS injection induced nephrotoxic activity, including increased serum urea, creatinine, and uric acid levels. It also caused apparent pathological alterations with increased Caspase-3 and NF-κB immuno-expression. In addition, thrombocytopenia, leukocytosis, neutrophilia, hyponatremia, hypochloremia, hypocalcemia, and hypomagnesemia but not hyperkalemia and hyperphosphatemia were evident in SS-injected rats. Moreover, SS exposure increased serum α1 globulin, renal tissue malondialdehyde, and Caspase-3 levels but superoxide dismutase, glutathione peroxidase, and Bcl-2 levels declined. Meanwhile, CUR significantly counteracted the SS harmful impacts on kidneys but SS+CUR co-administration induced an anemic condition. Overall, CUR has an evident protective role against SS-induced renal damage, but the disturbed hematological alterations should be carefully taken into consideration in their combined use.

Malondialdehyde (MDA) Production in Atherosclerosis Supplemented with Steamed Tomato

Background and Objective

Malondialdehyde (MDA) may increase influenced by free radicals due to lipid oxidation. Tomato induction considers able to prevent free radical damage and atherosclerosis. Therefore, this study aims to understand the effect of steamed-tomato extracts on MDA and its potential as an early diagnosis of atherosclerosis.

Materials and Methods

A total of 24 healthy 12 weeks-old male-rats were divided into four treatment groups, equally. A normal control group (K₁) was rats with placebo treatment. A negative control group (K₂) was the rats supplemented with 2 mL kg^-1 b.wt. per day of cholesterol until cholesterol. A K₃ group was atherosclerosis rats given with 20 mg kg^-1 b.wt. per day of atorvastatin and a K₄ was atherosclerotic rats supplemented with 16 mg kg^-1 b.wt. per day of tomato extract. All treatments were carried out for 60 consecutive days.

Results

Tomato extract in the K₄ group was succeeded in lowering MDA production. Carotenoid compounds in tomato extract are well known to be prevention agents against lipid oxidation and inhibit free radicals. MDA levels have increased significantly in atherosclerosis conditions, making it potentially noticeable during early atherosclerotic, therefore, potentially developed as biomarkers.

Conclusion

MDA levels increase significantly and simultaneously after high cholesterol diets and in line with lipid parameters and damaged blood vessels. The steamed-tomato extract can reduce MDA, lipids levels and protect endothelial from lipid oxidation. More research should be conducted to breakdown the MDA function in the molecular pathway, including MDA correlation to microRNA expression and cell signaling.

Molecular mechanism of olaquindox-induced hepatotoxicity and the hepatic protective role of curcumin

Olaquindox (OLA) is a chemosynthetic growth promoter, which could promote the treatment of bacterial infections and improve feed energy efficiency. Hepatotoxicity is still a poor feature associated with the adverse effects of OLA. The present study aimed to investigate the molecular mechanism of OLA-induced hepatotoxicity and the protective role of curcumin in mice and HepG2 cells. The result showed that representative biomarkers involved in mitochondrial pathway, p53 pathway, mitogen-activated protein kinase (MAPK) pathway, autophagy and antioxidant pathway were activated. Furthermore, curcumin attenuated OLA-induced serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and liver damage in mice. In addition, cell viability of HepG2 was enhanced by curcumin pretreatment at 5, 10 and 20 μM. Meanwhile, curcumin markedly ameliorated OLA-induced oxidative stress, apoptosis and mitochondrial dysfunction. Moreover, curcumin pretreatment significantly up-regulated the expressions of nuclear factor erythroid-2-related factor 2 (Nrf2) and heme oxygenase-1(HO-1) and down-regulated the expressions of nuclear factor-kappaB (NF-kB) and p53 through reduced the nuclear translocation of NF-kB induced by OLA. In summary, our findings indicated that OLA-induced hepatotoxicity involved in mitochondrial apoptosis, autophagy, p53 pathway, Nrf2/HO-1 pathways, and curcumin regulated OLA-induced liver damage, oxidative stress and apoptosis via activation of Nrf2/HO-1 pathway and suppression of p53 and NF-kB pathway.

Black tea and curcumin synergistically mitigate the hepatotoxicity and nephropathic changes induced by chronic exposure to aflatoxin-B1 in Sprague-Dawley rats

The study aimed to clarify the characteristics of black tea (BTE) and/or curcumin (CMN) against aflatoxin-B1 (AFB1). Forty eight adult male Sprague-Dawley rats were divided into eight groups. G1 was non-treated control. G2, G3, and G4 were olive oil, BTE, and CMN, respectively. G5 was olive oil-dissolved AFB1 (25 µg/kg b.w). G6, G7, and G8 were AFB1 along with BTE (2%), CMN (200 mg/kg b.w.), and BTE plus CMN, respectively. All treatments were orally given for consecutive 90 days. After treatment period, rats were sacrificed. Serobiochemical analysis and histopathology showed hepatorenal dysfunction in response to AFB1. Glutathione-antioxidants were significantly decreased versus increased lipid peroxides (p < .05-.001). AFB1 significantly increased the expression of the antitumor p53, but decreased that of antiapoptotic Bcl2 in liver or kidney tissue, either (p < .05). BTE or CMN ameliorated those changes induced by AFB1 in both liver and kidney with highly pronounced improvement when combined BTE/CMN was used. PRACTICAL APPLICATIONS: Black tea (BTE) and curcumin (CMN) were known for their antioxidant effects, and several studies reported their independent effects against different toxicities including aflatoxicosis. The current study clarifies the ameliorative characteristics of both agents; BTE and/or CMN, against the toxicity resulted from the chronic exposure to aflatoxin-B1 (AFB1) (25 µg/kg b.w. for consecutive 90 days). The dose of either agents, BTE or CMN, was 200 mg/kg b.w. along with AFB1. The pathologic changes, serobiochemical parameters, oxidative stress, histological changes, and the molecular disruption, induced by AFB1 in both liver and kidney were obviously and significantly ameliorated after BTE and/or CMN treatments in variable potencies where both agents showed the most effective antitoxic capacities.

Curcumin Protects Osteoblasts From Oxidative Stress-Induced Dysfunction via GSK3β-Nrf2 Signaling Pathway

Osteoblasts dysfunction, induced by oxidative stress (OS), is one of major pathological mechanisms for osteoporosis. Curcumin (Cur), a bioactive antioxidant compound, isolated from Curcumin longa L, was regarded as a strong reactive oxygen species (ROS) scavenger. However, it remains unveiled whether Cur can prevent osteoblasts from OS-induced dysfunction. To approach this question, we adopted a well-established OS model to investigate the preventive effect of Cur on osteoblasts dysfunction by measuring intracellular ROS production, cell viability, apoptosis rate and osteoblastogenesis markers. We showed that the pretreatment of Cur could significantly antagonize OS so as to suppress endogenous ROS production, maintain osteoblasts viability and promote osteoblastogenesis. Inhibiting Glycogen synthase kinase (GSK3β) and activating nuclear factor erythroid 2 related factor 2 (Nrf2) could significantly antagonize the destructive effects of OS, which indicated the critical role of GSK3β-Nrf2 signaling. Furthermore, Cur also abolished the suppressive effects of OS on GSK3β-Nrf2 signaling pathway. Our findings demonstrated that Cur could protect osteoblasts against OS-induced dysfunction via GSK3β-Nrf2 signaling and provide a promising way for osteoporosis treatment.

Curcumin Attenuates Colistin-Induced Peripheral Neurotoxicity in Mice

Peripheral neurotoxicity often occurs in patients receiving parenteral polymyxin therapy (i.e., colistin methanesulfonate or polymyxin B). The present study aimed to investigate the protective effect of curcumin on colistin-induced peripheral neurotoxicity using a murine model. Female C57BL/6 mice (n = 10 in each group) were randomly divided into the following: (1) control group (saline), (2) curcumin only group (200 mg/kg/day; orally), (3) colistin only group (18 mg/kg/day; i.p.), (4) colistin (18 mg/kg/day) plus curcumin 50 mg/kg/day group, (5) colistin (18 mg/kg/day) plus curcumin 100 mg/kg/day group, (6) colistin (18 mg/kg/day) plus curcumin 200 mg/kg/day group; all mice were treated for 7 days. Orally applied curcumin was detected in the brain, cerebellum, and sciatic nerve. Co-administration of oral curcumin markedly improved colistin-induced impaired sensory and motor dysfunctions in a dose-dependent manner. Curcumin supplementation at 100 and 200 mg/kg significantly decreased lipid peroxidation and upregulated catalase (CAT) and superoxide dismutase (SOD) activities, ATP levels, and Na⁺/K⁺-ATPase activity in sciatic nerve tissue, compared to the colistin alone group. Curcumin supplementation at 200 mg/kg upregulated the levels of AKT, NGF, mTOR, Nrf2, and HO-1 mRNA and concomitantly downregulated Bax, caspases-3, and -9 mRNA; it also decreased caspase-3 and caspase-9 activity. In summary, for the first time, our study reveals that the protective effect of oral curcumin on colistin induced peripheral neurotoxicity is associated with the activation of NGF/Akt and Nrf2/HO-1 pathways and inhibition of oxidative stress. This study highlights the potential clinical application of curcumin as an oral neuroprotective agent coadministered during colistin therapy.

Natural products for the prevention and treatment of cholestasis: A review

Cholestasis is a common manifestation of decreased bile flow in various liver diseases. It results in fibrosis and even cirrhosis without proper treatment. It is believed that a wide range of factors, including transporter dysfunction, oxidative stress, inflammatory damage, and immune disruption, can cause cholestasis. In recent years, natural products have drawn much attention for specific multiple-target activities in diseases. Many attempts have been made to investigate the anticholestatic effects of natural products with advanced technology. This review summarizes recent studies on the biological activities and mechanisms of recognized compounds for cholestasis treatment. Natural products, including various flavonoids, phenols, acids, quinones, saponins, alkaloids, glycosides, and so on, function as comprehensive regulators via ameliorating oxidative stress, inflammation, and apoptosis, restoring bile acid balance with hepatic transporters, and adjusting immune disruption. Moreover, in this progress, nuclear factor erythroid 2-related factor 2, reactive oxygen species production, heme oxygenase-1, NF-κB, cholesterol 7 alpha-hydroxylase, and farnesoid X receptors are thought as main targets for the activity of natural products. Therefore, this review presents the detailed mechanisms that include multiple targets and diverse signalling pathways. Natural products are the valuable when seeking novel therapeutic agents to treat cholestatic liver diseases.

Curcumin as a Therapeutic Strategy in Liver Diseases

Liver diseases are classified as acute and chronic hepatic failures. In particular, chronic pathologies are the most common diseases in the World. Chronic pathologies of liver disease are the most common diseases in the world. There are many causes that induce a progressive and irreversible degeneration of the hepatic parenchyma, but, in general, they lead to the destruction of the normal balance between reactive oxygen stress (ROS) formation and ROS degradation within the liver. The prevalence of disabling diseases, including the hepatic diseases, is increasingly widespread, and it is important to find a safe, inexpensive, accessible and effective way to face this condition. Many recent studies have focused on different natural antioxidants, which could restore the physiological hepatic environment, thereby allowing the normal functioning of this organ. Natural products have been used to discover new leads for treating several diseases; among them, it is important to emphasize curcumin, which is a polyphenol obtained from Curcuma longa Linn, a plant naturally found throughout tropical and subtropical regions of the world.

Inside and Beyond Color: Comparative Overview of Functional Quality of Tomato and Watermelon Fruits

The quali-quantitative evaluation and the improvement of the levels of plant bioactive secondary metabolites are increasingly gaining consideration by growers, breeders and processors, particularly in those fruits and vegetables that, due to their supposed health promoting properties, are considered "functional." Worldwide, tomato and watermelon are among the main grown and consumed crops and represent important sources not only of dietary lycopene but also of other health beneficial bioactives. Tomato and watermelon synthesize and store lycopene as their major ripe fruit carotenoid responsible of their typical red color at full maturity. It is also the precursor of some characteristic aroma volatiles in both fruits playing, thus, an important visual and olfactory impact in consumer choice. While sharing the same main pigment, tomato and watermelon fruits show substantial biochemical and physiological differences during ripening. Tomato is climacteric while watermelon is non-climacteric; unripe tomato fruit is green, mainly contributed by chlorophylls and xanthophylls, while young watermelon fruit mesocarp is white and contains only traces of carotenoids. Various studies comparatively evaluated in vivo pigment development in ripening tomato and watermelon fruits. However, in most cases, other classes of compounds have not been considered. We believe this knowledge is fundamental for targeted breeding aimed at improving the functional quality of elite cultivars. Hence, in this paper, we critically review the recent understanding underlying the biosynthesis, accumulation and regulation of different bioactive compounds (carotenoids, phenolics, aroma volatiles, and vitamin C) during tomato and watermelon fruit ripening. We also highlight some concerns about possible harmful effects of excessive uptake of bioactive compound on human health. We found that a complex interweaving of anabolic, catabolic and recycling reactions, finely regulated at multiple levels and with temporal and spatial precision, ensures a certain homeostasis in the concentrations of carotenoids, phenolics, aroma volatiles and Vitamin C within the fruit tissues. Nevertheless, several exogenous factors including light and temperature conditions, pathogen attack, as well as pre- and post-harvest manipulations can drive their amounts far away from homeostasis. These adaptive responses allow crops to better cope with abiotic and biotic stresses but may severely affect the supposed functional quality of fruits.

Molecular Mechanisms of Neurotoxicity Induced by Polymyxins and Chemoprevention

Neurotoxicity is one major unwanted side-effects associated with polymyxin (i.e., colistin and polymyxin B) therapy. Clinically, colistin neurotoxicity is characterized by neurological symptoms including dizziness, visual disturbances, vertigo, confusion, hallucinations, seizures, ataxia, and facial and peripheral paresthesias. Pathologically, colistin-induced neurotoxicity is characterized by cell injury and death in neuronal cell. This Review covers our current understanding of polymyxin-induced neurotoxicity, its underlying mechanisms, and the discovery of novel neuroprotective agents to limit this neurotoxicity. In recent years, an increasing body of literature supports the notion that polymyxin-induced nerve damage is largely related to oxidative stress and mitochondrial dysfunction. P53, PI3K/Akt, and MAPK pathways are also involved in colistin-induced neuronal cell death. The activation of the redox homeostasis pathways such as Nrf2/HO-1 and autophagy have also been shown to play protective roles against polymyxin-induced neurotoxicity. These pathways have been demonstrated to be upregulated by neuroprotective agents including curcumin, rapamycin and minocycline. Further research is needed toward the development of novel polymyxin formulations in combination with neuroprotective agents to ameliorate this unwanted adverse effect during polymyxins therapy in patients.

Chronic cholestasis is associated with hypogonadism and premature ovarian failure in adult rats (cholestasis causes ovarian hypogonadism)

Hypogonadism is a well-known complication in males with chronic liver diseases. However, the consequences of chronic hepatopathies on female reproductive capacities have received relatively little attention. The present study evaluates the effect of chronic obstructive jaundice on the ovary of adult cycling rats. Estrous cyclicity was monitored to check the functional status of the hypothalamic-pituitary-ovarian axis. Ovarian changes were assessed using histomorphometric, immunohistochemical, and ultrastructural techniques. Chronic cholestasis was associated with estrous cycle irregularities, diminished ovarian weight, primordial follicle loss, atretic follicle prevalence, marked stromal fibrosis, and diminished immunoexpression of proliferation marker and estrogen receptors, in addition to many ultrastructural alterations in theca, granulosa cells, and oocytes of antral follicles. The results establish that chronic cholestasis causes hypogonadism and premature ovarian insufficiency in adult cycling female rats.

Curcumin in Liver Diseases: A Systematic Review of the Cellular Mechanisms of Oxidative Stress and Clinical Perspective

Oxidative stress has been considered a key causing factor of liver damage induced by a variety of agents, including alcohol, drugs, viral infections, environmental pollutants and dietary components, which in turn results in progression of liver injury, non-alcoholic steatohepatitis, non-alcoholic liver disease, liver fibrosis and cirrhosis. During the past 30 years and even after the major progress in the liver disease management, millions of people worldwide still suffer from an acute or chronic liver condition. Curcumin is one of the most commonly used indigenous molecules endowed by various shielding functionalities that protects the liver. The aim of the present study is to comprehensively review pharmacological effects and molecular mechanisms, as well as clinical evidence, of curcumin as a lead compound in the prevention and treatment of oxidative associated liver diseases. For this purpose, electronic databases including “Scopus,” “PubMed,” “Science Direct” and “Cochrane library” were extensively searched with the keywords “curcumin or curcuminoids” and “hepatoprotective or hepatotoxicity or liver” along with “oxidative or oxidant.” Results showed that curcumin exerts remarkable protective and therapeutic effects of oxidative associated liver diseases through various cellular and molecular mechanisms. Those mechanisms include suppressing the proinflammatory cytokines, lipid perodixation products, PI3K/Akt and hepatic stellate cells activation, as well as ameliorating cellular responses to oxidative stress such as the expression of Nrf2, SOD, CAT, GSH, GPx and GR. Taking together, curcumin itself acts as a free radical scavenger over the activity of different kinds of ROS via its phenolic, β-diketone and methoxy group. Further clinical studies are still needed in order to recognize the structure-activity relationships and molecular mechanisms of curcumin in oxidative associated liver diseases.

Epididymal ultrastructural changes associated with chronic cholestasis after bile duct ligation in adult rats

Testicular atrophy and testesterone insufficiency have been commonly reported associated with chronic liver diseases. Though testosterone dependent, the epididymal changes induced by liver disease have never been studied before. Thus, this study aimed to assess the ultrastructural events in the epididymis of rats with chronic obstructive jaundice. Chronic cholestasis induced many epididymal structural alterations manifested by the reduced tubular diameters, thickening of the tubular basement membrane, and regression of the principal cells. This was accompanied with reduction of principal cell organelles, cytoplasmic vacuolations, nuclear alterations, and stereovilli loss. The results establish that chronic cholestasis causes epididymal structural changes due to androgen deficiency.

Curcumin Attenuates on Carbon Tetrachloride-Induced Acute Liver Injury in Mice via Modulation of the Nrf2/HO-1 and TGF-β1/Smad3 Pathway

This study aimed to investigate the protective effect of curcumin against carbon tetrachloride (CCl₄)-induced acute liver injury in a mouse model, and to explain the underlying mechanism. Curcumin at doses of 50, 100 and 200 mg/kg/day were administered orally once daily for seven days prior to CCl₄ exposure. At 24 h, curcumin-attenuated CCl₄ induced elevated serum transaminase activities and histopathological damage in the mouse's liver. Curcumin pre-treatment at 50, 100 and 200 mg/kg significantly ameliorated CCl₄-induced oxidative stress, characterized by decreased malondialdehyde (MDA) formations, and increased superoxide dismutase (SOD), catalase (CAT) activities and glutathione (GSH) content, followed by a decrease in caspase-9 and -3 activities. Curcumin pre-treatment significantly decreased CCl₄-induced inflammation. Furthermore, curcumin pre-treatment significantly down-regulated the expression of TGF-β1 and Smad3 mRNAs (both p < 0.01), and up-regulated the expression of nuclear-factor erythroid 2-related factor 2 (Nrf2) and HO-1 mRNA (both p < 0.01) in the liver. Inhibition of HO-1 attenuated the protective effect of curcumin on CCl₄-induced acute liver injury. Given these outcomes, curcumin could protect against CCl₄-induced acute liver injury by inhibiting oxidative stress and inflammation, which may partly involve the activation of Nrf2/HO-1 and inhibition of TGF-β1/Smad3 pathways.

Curcumin modulation of the activation of PYK2 in peripheral blood mononuclear cells from patients with lupus nephritis

INTRODUCTION

Proline-rich tyrosine kinase 2 (PYK2) provides important signals during the activation of lymphocytes, which is essential in autoimmune diseases. Systemic lupus erythematosus (SLE) is a representative autoimmune disease, and lupus nephritis (LN) is one of its most severe complications. Although glucocorticoid-binding immuno-suppression is the first-line therapy for patients with LN, the common and severe side effects of such treatment call for new strategies to improve long-term prognosis and life quality for these patients. Curcumin has been used to treat autoimmune disease with good curative effect, but little is known about the effect of curcumin on LN patients. Our aim was to investigate the mechanism of curcumin for management of LN, specifically regarding the PYK2 pathways.

MATERIAL AND METHODS

Freshly isolated peripheral blood mononuclear cells (PBMCs) from 20 LN patients and 20 healthy individuals were cultured and stimulated with either PMA, PMA+TyrA9 (PYK2 specific inhibitor), or PMA+Curcumin, and with PBS as control. After 48 hours of incubation, cells were harvested and the expression of PYK2, p-PYK2, CD40L, CTLA-4, and PBMCs proliferation were measured. Then the expression and activation of PYK2 was evaluated using Western blot, the expression of costimulatory molecules CD40L and CTLA-4 protein was evaluated using flow cytometry, and PBMC proliferation was assessed using a [3H]-thymidine incorporation assay.

RESULTS

Curcumin inhibited the expression and activation of PYK2 in PBMCs in patients with LN in vitro. The inhibition rate of curcumin was negatively correlated with the level of serum complement, but positively correlated with 24-h proteinuria. Curcumin also suppressed the expression of costimulatory molecules CD40L and CTLA-4, as well as PBMC proliferation. Interestingly, these effects were not reproduced on PBMC cultures of healthy subjects.

CONCLUSIONS

The inhibition of PYK2 signalling protein may be one of the mechanisms underlying the action of curcumin in LN treatment.

Influence of piperine and quercetin on antidiabetic potential of curcumin

BACKGROUND

Curcumin is a nutraceutical obtained from the rhizomes of Curcuma longa with a significant medicinal value against numerous disorders. However, the potential cannot be completely exploited due to low in vivo bioavailability. Hence, in order to enhance the bioavailability of curcumin, we combined it with the bioavailability enhancers like piperine and quercetin.

METHODS

The present study was targeted to explore the antidiabetic potential of combinatorial extract of curcumin with piperine and quercetin (CPQ) in streptozotocin- and nicotinamide-induced diabetic rats. Diabetes mellitus was induced by single intraperitoneal injection of streptozotocin (55 mg/kg) and nicotinamide (120 mg/kg-1). CPQ was orally administered at 100 mg kg-1 dose/day for a period of 28 days. At the end of 28 days, blood was analyzed for glucose, high density lipoprotein (HDL), low density lipoprotein (LDL) and total cholesterol level. Oral glucose tolerance test (OGTT) was also conducted at the end of 28 days.

RESULTS

Oral administration of CPQ at the dose of 100 mg kg-1 significantly (p<0.01) reduced plasma glucose at the end of 28 days, as compared to the diabetic control group. The reduction in the plasma glucose produced by the CPQ extract was equivalent to that of glibenclamide and significantly more compared to curcumin alone (p<0.01). Furthermore, a significant (p<0.01) reduction in the raised LDL, cholesterol and triglycerides and improvement was observed in the group fed with CPQ compared to diabetic control as well as the alone (p<0.05) curcumin group. There was a significant improvement in the body weight with CPQ compared to diabetes control group. OGTT revealed a significantly high glucose tolerance in CPQ fed rats compared to the diabetic control as well as the rats fed with curcumin alone.

CONCLUSIONS

Treatment with combinatorial extract of curcumin presented a significantly better therapeutic potential when compared with curcumin alone, which reveals that CPQ, with reduced dose of curcumin may serve as a therapeutic agent in the treatment of type 2 diabetes mellitus.

Antigenotoxic properties of Paliurus spina-christi Mill fruits and their active compounds

Background

Paliurus spina-christi Mill. (PS) fruits are widely used for different medical purposes in Turkey. Like in many medicinal herbs the studies concerning their activity, the activities of PS are also not well clarified. The aim of this study is to evaluate the antigenotoxicity of the compounds isolated and identified from the extracts of PS fruits.

Methods

The active compounds were separated, isolated, and determined by chromatographic methods and their structural elucidation was performed by Nuclear Magnetic Resonance (NMR) methods. The compounds were obtained from either ethyl acetate (EA) or n-butanol extracts. The cytotoxicities of the compounds using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and the antigenotoxic activities of the compounds using the alkaline single cell gel electrophoresis techniques (comet assay) were evaluated in Chinese hamster lung fibroblast (V79) cell lines.

Results

The isolated major compounds were identified as (+/−) catechins and gallocatechin from EA fraction and rutin from n-butanol fraction of PS fruits. Their chemical structures were identified by ¹H-NMR, ¹³C-NMR, HMBC, and HMQC techniques. Half-maximal inhibitory concentration of catechins, gallocatechin, and rutin were found to be 734 μg/mL, 220 μg/mL, and 1004 μg/mL, respectively. The methanolic extract of PS (1-100 μg/mL) alone did not induce DNA single-strand breaks while catechins (1-100 μg/mL), gallocatechin (1-50 μg/mL), and rutin (1-50 μg/mL) significantly reduced H₂O₂-induced DNA damage.

Conclusion

It has been suggested that PS fruits and their compounds catechins, gallocatechin and rutin may have beneficial effects in oxidative DNA damage. It seems that PS fruits may be used in protection of the disorders related to DNA damage.

Curcumin prevents mitochondrial dynamics disturbances in early 5/6 nephrectomy: Relation to oxidative stress and mitochondrial bioenergetics

Five-sixths nephrectomy (5/6NX) is a widely used model to study the mechanisms leading to renal damage in chronic kidney disease (CKD). However, early alterations on renal function, mitochondrial dynamics, and oxidative stress have not been explored yet. Curcumin is an antioxidant that has shown nephroprotection in 5/6NX-induced renal damage. The aim of this study was to explore the effect of curcumin on early mitochondrial alterations induced by 5/6NX in rats. In isolated mitochondria, 5/6NX-induced hydrogen peroxide production was associated with decreased activity of complexes I and V, decreased activity of antioxidant enzymes, alterations in oxygen consumption and increased MDA-protein adducts. In addition, it was found that 5/6NX shifted mitochondrial dynamics to fusion, which was evidenced by increased optic atrophy 1 and mitofusin 1 (Mfn1) and decreased fission 1 and dynamin-related protein 1 expressions. These data were confirmed by morphological analysis and immunoelectron microscopy of Mfn-1. All the above-described mechanisms were prevented by curcumin. Also, it was found that curcumin prevented renal dysfunction by improving renal blood flow and the total antioxidant capacity induced by 5/6NX. Moreover, in glomeruli and proximal tubules 5/6NX-induced superoxide anion production by uncoupled nitric oxide synthase (NOS) and nicotinamide adenine dinucleotide phosphate oxidase (NOX) dependent way, this latter was associated with increased phosphorylation of serine 304 of p47phox subunit of NOX. In conclusion, this study shows that curcumin pretreatment decreases early 5/6NX-induced altered mitochondrial dynamics, bioenergetics, and oxidative stress, which may be associated with the preservation of renal function. © 2016 BioFactors, 43(2):293-310, 2017.

Curcumin Attenuates Colistin-Induced Neurotoxicity in N2a Cells via Anti-inflammatory Activity, Suppression of Oxidative Stress, and Apoptosis

Neurotoxicity is an unwanted side-effect seen in patients receiving therapy with the "last-line" polymyxin antibiotics. This is the first study to show that colistin-induced neurotoxicity in neuroblastoma-2a (N2a) cells gives rise to an inflammatory response involving the IL-1β/p-IκB-α/NF-κB pathway. Pretreatment with curcumin at 5, 10, and 20 μM for 2 h prior to colistin (200 μM) exposure for 24 h, produced an anti-inflammatory effect by significantly down-regulating the expression of the pro-inflammatory mediators cyclooxygenase-2 (COX-2), phosphorylation of the inhibitor of nuclear factor-kappa B (NF-κB) (p-IκB)-α, and concomitantly NF-κB levels. Moreover, curcumin significantly decreased intracellular reactive oxygen species (ROS) production and increased the activities of the anti-ROS enzymes superoxide dismutase, catalase, and the intracellular levels of glutathione. Curcumin pretreatment also protected the cells from colistin-induced mitochondrial dysfunction, caspase activation, and subsequent apoptosis. Overall, our findings demonstrate for the first time, a potential role for curcumin for treating polymyxin-induced neurotoxicity through the modulation of NF-κB signaling and its potent anti-oxidative and anti-apoptotic effects.

N-acetyl-l-cysteine Prevents Bile Duct Ligation Induced Renal Injury by Modulating Oxidative Stress

The aim of the present study was to evaluate the effect of N-acetyl-l-cysteine (NAC) on bile duct ligation (BDL) induced oxidative stress in kidneys. Male Wistar rats were randomly segregated into four groups; sham control (SC), SC + NAC, BDL and BDL + NAC group. Liver damage was induced following BDL and renal injury was assessed by kidney function tests along with lipid peroxidation, nitrite levels, thiols and antioxidant enzymes. Three weeks after BDL, rats developed renal dysfunction in terms of elevated serum creatinine levels. BDL animals exhibited an increase in lipid peroxidation, reduction in thiols and redox ratio in liver and kidney tissue along with altered antioxidant enzymes in kidneys. BDL animals that were orally administered NAC at a daily dose 100 mg/kg for duration of two weeks, showed significant reduction in serum creatinine levels. NAC was effective in lowering lipid peroxidation and was able to restore thiol levels along with GSH/GSSG ratio in both liver and kidneys along with the activity of antioxidant enzymes in the kidneys of BDL animals. The results clearly demonstrate the efficacy of NAC in attenuating oxidative stress in kidneys, suggesting a therapeutic role for NAC in individuals with renal dysfunction following BDL.

Evaluation of ameliorative effect of curcumin on imidacloprid-induced male reproductive toxicity in wistar rats

This study was undertaken to investigate the toxic effects of imidacloprid (IM) on male reproductive system and ameliorative effect of curcumin (CMN) in male Wistar rats. For this purpose, IM (45 and 90 mg/kg, body weight) and CMN (100 mg/kg, body weight) were administered orally to the rats either alone or in combinations for a period of 28 days. At the end of experiment, male reproductive toxicity parameters (total sperm count and sperm abnormalities), testosterone level, steroidal enzymatic activity [3β-hydroxysteroid dehydrogenase (3β-HSD) and 17β-HSD], and oxidative stress indicators were estimated in testis and plasma. IM treatments resulted in significant decrease (p < 0.05) in total epididymal sperm count, sperm motility, live sperm count, and increase (p < 0.05) in sperm abnormalities. Activities of gamma-glutamyl transpeptidase, lactate dehydrogenase-x, and sorbitol dehydrogenase were significantly increased (p < 0.05), while, 3β-HSD and 17β-HSD enzymatic activity along with testosterone concentration in testis and plasma were decreased significantly (p < 0.05) in IM-treated rats. IM exposure resulted in significant increase (p < 0.05) in LPO and decrease (p < 0.05) in GSH level along with decreased activities of CAT, SOD, GPx, and GST. IM-treated rats showed histopathological alterations in testis and epididymis. However, the reproductive toxicity parameters, oxidative stress indicators, and histopathological changes were minimized and functional restorations were noticed by co-administration of CMN in IM-treated rats. The results of this study suggest that IM-induced male reproductive toxic effects could be ameliorated by CMN supplementation. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1250-1263, 2016.

Oxidative Stress: A Promising Target for Chemoprevention

Cancer is a leading cause of death worldwide, and treating advanced stages of cancer remains clinically challenging. Epidemiological studies have shown that oxidants and free radicals induced DNA damage is one of the predominant causative factors for cancer pathogenesis. Hence, oxidants are attractive targets for chemoprevention as well as therapy. Dietary agents are known to exert an anti-oxidant property which is one of the most efficient preventive strategy in cancer progression. In this article, we highlight dietary agents can potentially target oxidative stress, in turn delaying, preventing, or treating cancer development. Some of these agents are currently in use in basic research, while some have been launched successfully into clinical trials.

Effects of curcumin on antioxidative activities and cytokine production in Jian carp (Cyprinus carpio var. Jian) with CCl4-induced liver damage

We investigated the protective effects of curcumin on liver-damaged Cyprinus carpio var. Jian (Jian carp). The carp were fed 0.1%, 0.5%, or 1.0% curcumin for 60 days, then injected intraperitoneally with 30% carbon tetrachloride solution. Liver and blood samples were collected to measure the liver index, serum- and liver-associated enzymes, liver histology, nuclear factor-κB (NF-κB)/c-Rel, interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and IL-12 mRNA expression, and the level of NF-κB/c-Rel protein in the liver, and for a comet assay. We found that 0.5% and 1.0% curcumin significantly reduced the CCl(4)-induced increase in the liver index. The comet assay showed that the tail moment, olive tail moment, tail length, and tail DNA% improved in fish pretreated with 0.5 or 1.0% curcumin. CCl(4)-induced histological changes, including extensive hepatocyte degeneration, indistinct cell borders, nuclear condensation, and karyolysis were clearly reduced after treatment with 0.5% and 1.0% curcumin. Moreover, 0.5% and 1.0% curcumin significantly inhibited the CCl(4)-induced increase in serum glutamic oxaloacetic transaminase and promoted the restoration of superoxide dismutase in the liver; 1.0% curcumin significantly reduced serum glutamic pyruvic transaminase and lactate dehydrogenase and hepatic malondialdehyde, but significantly increased the total antioxidant capacity and glutathione levels in the liver. The CCl(4)-induced upregulation of NF-κB/c-Rel, IL-1β, and TNF-α mRNAs and NF-κB/c-Rel protein levels was inhibited by 0.5% and 1.0% curcumin, and IL-12 mRNA was reduced by all three doses of curcumin. The effects of curcumin on the liver index, enzymes, histological changes, and cytokines were dose-dependent. Our results indicate that curcumin reduces CCl(4)-induced liver damage in Jian carp by upregulating antioxidative activities and inhibiting NF-κB, IL-1β, TNF-α, and IL-12 expression.

Anti-fibrotic effect of Holothuria arenicola extract against bile duct ligation in rats

BACKGROUND

Holothuria arenicola is the most important and abundant sea cucumber species in the Mediterranean Sea on the Egyptian coast. The present study aims to assess the anti-oxidative and anticholestatic effects of the sea cucumber Holothuria arenicola extract (HaE) in a model of bile duct ligation in male albino rats.

METHODS

Fifty four male Wistar albino rats were assigned into two main groups, the Sham-operated control and bile duct ligated (BDL) group. After 14 days of surgery, the animals of the group I (Sham control) received distilled water only for 7, 14 and 28 days. Second group (BDL group) was divided into 2 subgroups, animals of these subgroups treated for 7, 14 and 28 consecutive days as follow: subgroup I (BDL), rats of this subgroup administered distilled water orally. Subgroup II (HaE), animals of this subgroup treated orally with HaE (200 mg/kg body weight).

RESULTS

The HaE revealed significant antifibrotic effect as evident by decreasing the levels of total conjugated and unconjugated bilirubin and the activities of serum aminotransferases (ASAT and ALAT) and alkaline phosphatase (ALP) as well as malondialdehyde (MDA) level, and increasing the serum albumin, glutathione reduced (GSH) levels. Treatment with HaE normalized the antioxidant enzyme, glutathione-S-transferase (GST), superoxide dismutase (SOD) and catalase (CAT) activities activities.

CONCLUSION

The present prospective study correlated the antifibrotic effect of HaE to its direct antioxidant effect that can be related to its contents of phenolic compounds specially chlorogenic acid, pyrogallol, rutin and coumaric acid.

The protective role of ferulic acid on sepsis-induced oxidative damage in Wistar albino rats

Oxidative stress has an important role in the development of sepsis-induced multiorgan failure. Ferulic acid (FA), a well-established natural antioxidant, has several pharmacological activities including anti-inflammatory, anticancer and hepatoprotective. This study aimed to investigate the effects of FA on sepsis-induced oxidative damage in Wistar albino rats. Sepsis-induced DNA damage in the lymphocytes, liver and kidney cells of rats were evaluated by comet assay with and without formamidopyrimidine DNA glycosylase (Fpg). The oxidative stress parameters such as superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities and total glutathione (GSH) and malondialdehyde (MDA) levels were also measured. It is found that DNA damage in sepsis+FA-treated group was significantly lower than the sepsis group. FA treatment also decreased the MDA levels and increased the GSH levels and SOD and GSH-Px activities in the sepsis-induced rats. It seems that FA might have ameliorative effects against sepsis-induced oxidative damage.

Beneficial effect of quercetin on cholestatic liver injury

Bile duct obstruction and subsequent cholestasis are associated with hepatocellular injury, cholangiocyte proliferation, stellate cell activation, Kupffer cell activation, oxidative stress, inflammation and fibrosis. Flavonoids have been shown to confer beneficial health effects, including hepatoprotection. However, the molecular mechanism of flavonoid-mediated hepatoprotection is incompletely understood. In this study, we report the protective effect of quercetin on cholestatic liver injury. Cholestasis was produced by bile duct ligation (BDL) in male Sprague-Dawley rats for 3 weeks. Daily oral administration of quercetin was started 1 week before injury and lasted for 4 weeks. In comparison with the control group, the BDL group showed liver injury, as evidenced by histological changes, and elevation in serum biochemicals, ductular reaction, fibrosis, inflammation and oxidative stress. These pathophysiological changes were attenuated by daily quercetin supplementation. Quercetin alleviated BDL-induced transforming growth factor beta-1 (TGF-β1), interleukin-1 beta, connective tissue growth factor and collagen expression. The antifibrotic effect of quercetin was accompanied by reductions in α-smooth muscle actin-positive matrix-producing cells and Smad 2/3 activity critical to the fibrogenic potential of TGF-β1. Quercetin also attenuated BDL-induced oxidative stress, leukocyte accumulation, nuclear factor (NF)-κB activation and proinflammatory cytokine production. Further studies demonstrated an inhibitory effect of quercetin on MyD88 and TGF-β-activated kinase-1 critical for linking toll-like receptor (TLR) and NF-κB. Taken together, the hepatoprotective, anti-inflammatory and antifibrotic effects of quercetin seem to be multifactorial. The beneficial effects of daily quercetin supplementation are associated with antioxidative and anti-inflammatory potential as well as down-regulation of NF-κB and TGF-β/Smad signaling, probably via interference with TLR signaling.

Vitamin A supplementation alleviates extrahepatic cholestasis liver injury through Nrf2 activation

Aim. To investigate the role of vitamin A in liver damage induced by bile duct ligation (BDL) in rats. Methods. Thirty male Wistar rats were randomly divided into three groups: SHAM group, BDL group, and BDL + VitA group . The concentrations of retinol and retinyl palmitate in the liver were analyzed using HPLC, and liver function was evaluated by the level of TBIL, ALT, AST, and ALP in serum. Hepatic oxidative status was estimated by measuring T-SOD, CAT, GSH, MDA, and AOPP. Nrf2 expression was assessed using immunohistochemistry and western blotting, and EMSA was performed to determine Nrf2 DNA-binding activity. The expression of the downstream factors such as Ho1 and Nqo1 was also examined using immunohistochemistry and western blotting assays. Results. Vitamin A treatment restored levels of retinoids in liver, improved liver function, alleviated oxidative stress, and facilitated the translocation of Nrf2 to the nucleus in the experimental obstructive jaundice. Vitamin A was also found to increase the expression of Nrf2 downstream proteins such as Ho1 and Nqo1. Conclusion. Vitamin A was here found to ameliorate cholestatic liver injury. This effect may be related to the activation of Nrf2/ARE pathway in bile duct ligation rats.

Piperine potentiates the hypocholesterolemic effect of curcumin in rats fed on a high fat diet

It has previously been demonstrated that curcumin possesses a hypocholesterolemic effect and potentiates numerous pharmacological effects of curcumin, however, the mechanisms underlying this hypocholesterolemic effect and the interaction between curcumin and piperine remain to be elucidated. In the present study, male Sprague-Dawley rats were fed on a high-fat diet (HFD) to establish a hyperlipidemia (HLP) model. Co-administration of curcumin plus piperine was found to decrease the levels of total cholesterol (TC), triglyceride (TG) and low-density lipoprotein cholesterol in the serum and liver, as well as increase the levels of fecal TC, TG and total bile acid, compared with administration of curcumin alone. Curcumin plus piperine also markedly increased the levels of high-density lipoprotein cholesterol. Furthermore, compared with administration of curcumin alone, administration of curcumin plus piperine resulted in a significant upregulation of the activity and gene expression of apolipoprotein AI (ApoAI), lecithin cholesterol acyltransferase (LCAT), cholesterol 7α-hydroxylase (CYP7A1) and low-density lipoprotein receptor (LDLR). In conclusion, these results indicated that co-administration of curcumin plus piperine potentiates the hypocholesterolemic effects of curcumin by increasing the activity and gene expression of ApoAI, CYP7A1, LCAT and LDLR, providing a promising combination for the treatment of HLP.

Curcumin ameliorates methotrexate-induced nephrotoxicity in rats

Methotrexate is an effective anticancer and immunosuppressive agent. However, nephrotoxicity is one of the complications of its use. On the other hand, curcumin, a naturally occurring polyphenolic compound, is reported to have antioxidant and anti-inflammatory properties. Those two properties are likely to prevent methotrexate-induced nephrotoxicity. The aim of this study is to evaluate the possible protective effect of curcumin against methotrexate-induced nephrotoxicity and delineate various mechanism(s) underlies this effect in rats. Nephrotoxicity was induced in Wistar rats by intraperitoneal administration of methotrexate (7 mg/kg/day) for three consecutive days. Curcumin administration in methotrexate-intoxicated rats resulted in nephroprotective effects as evidenced by the significant decrease in levels of serum creatinine and urea as well as renal malondialdehyde, nitric oxide, and tumor necrosis factor- α with a concurrent increase in renal glutathione peroxidase and superoxide dismutase activities compared to nephrotoxic untreated rats. Additionally, immunohistochemical analysis demonstrated that curcumin treatment markedly reduced cyclooxygenase-2 expression. Histopathological examination confirmed the protective effects of curcumin. In conclusion, curcumin protected rats from methotrexate nephrotoxicity, at least in part, through its antioxidant and anti-inflammatory activities.

Curcumin pretreatment prevents potassium dichromate-induced hepatotoxicity, oxidative stress, decreased respiratory complex I activity, and membrane permeability transition pore opening

Curcumin is a polyphenol derived from turmeric with recognized antioxidant properties. Hexavalent chromium is an environmental toxic and carcinogen compound that induces oxidative stress. The objective of this study was to evaluate the potential protective effect of curcumin on the hepatic damage generated by potassium dichromate (K₂Cr₂O₇) in rats. Animals were pretreated daily by 9-10 days with curcumin (400 mg/kg b.w.) before the injection of a single intraperitoneal of K₂Cr₂O₇ (15 mg/kg b.w.). Groups of animals were sacrificed 24 and 48 h later. K₂Cr₂O₇-induced damage to the liver was evident by histological alterations and increase in the liver weight and in the activity of alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, and alkaline phosphatase in plasma. In addition, K₂Cr₂O₇ induced oxidative damage in liver and isolated mitochondria, which was evident by the increase in the content of malondialdehyde and protein carbonyl and decrease in the glutathione content and in the activity of several antioxidant enzymes. Moreover, K₂Cr₂O₇ induced decrease in mitochondrial oxygen consumption, in the activity of respiratory complex I, and permeability transition pore opening. All the above-mentioned alterations were prevented by curcumin pretreatment. The beneficial effects of curcumin against K₂Cr₂O₇-induced liver oxidative damage were associated with prevention of mitochondrial dysfunction.