Curcuma longa Linn. extract and curcumin protect CYP 2E1 enzymatic activity against mercuric chloride-induced hepatotoxicity and oxidative stress: A protective approach

Curcumin and analogues in mitigating liver injury and disease consequences: From molecular mechanisms to clinical perspectives

BACKGROUND

Liver injury is a prevalent global health concern, impacting a substantial number of individuals and leading to elevated mortality rates and socioeconomic burdens. Traditional primary treatment options encounter resource constraints and high costs, prompting exploration of alternative adjunct therapies, such as phytotherapy. Curcumin demonstrates significant therapeutic potential across various medical conditions, particularly emerging as a promising candidate for liver injury treatment.

PURPOSE

This study aims to provide current evidence maps of curcumin and its analogs in the context of liver injury, covering aspects of biosafety, toxicology, and clinical trials. Importantly, it seeks to summarize the intricate mechanisms modulated by curcumin.

METHODS

We conducted a comprehensive search of MEDLINE, Web of Science, and Embase up to July 2023. Titles and abstracts were reviewed to identify studies that met our eligibility criteria. The screening process involved three authors independently assessing the potential of curcumin mitigating liver injury and its disease consequences by reviewing titles, abstracts, and full texts.

RESULTS

Curcumin and its analogs have demonstrated low toxicity in vitro and in vivo. However, the limited bioavailability has hindered their advanced use in liver injury. This limitation can potentially be addressed by nano-curcumin and emerging drug delivery systems. Curcumin plays a role in alleviating liver injury by modulating the antioxidant system, as well as cellular and molecular pathways. The specific mechanisms involve multiple pathways, such as NF-κB, p38/MAPK, and JAK2/STAT3, and the pro-apoptosis Bcl-2/Bax/caspase-3 axis in damaged cells. Additionally, curcumin targets nutritional metabolism, regulating the substance in liver cells and tissues. The microenvironment associated with liver injury, like extracellular matrix and immune cells and factors, is also regulated by curcumin. Initial evaluation of curcumin and its analogs through 12 clinical trials demonstrates their potential application in liver injury.

CONCLUSION

Curcumin emerges as a promising phytomedicine for liver injury owing to its effectiveness in hepatoprotection and low toxicity profile. Nevertheless, in-depth investigations are warranted to unravel the complex mechanisms through which curcumin influences liver tissues and overall physiological milieu. Moreover, extensive clinical trials are essential to determine optimal curcumin dosage forms, maximizing its benefits and achieving favorable clinical outcomes.

Coenzyme Q10-Loaded Albumin Nanoparticles Protect against Redox Imbalance and Inflammatory, Apoptotic, and Histopathological Alterations in Mercuric Chloride-Induced Hepatorenal Toxicity in Rats

Exposure to mercuric chloride (HgCl2), either accidental or occupational, induces substantial liver and kidney damage. Coenzyme Q10 (CoQ10) is a natural antioxidant that also has anti-inflammatory and anti-apoptotic activities. Herein, our study aimed to investigate the possible protective effects of CoQ10 alone or loaded with albumin nanoparticles (CoQ10NPs) against HgCl2-induced hepatorenal toxicity in rats. Experimental animals received CoQ10 (10 mg/kg/oral) or CoQ10NPs (10 mg/kg/oral) and were injected intraperitoneally with HgCl2 (5 mg/kg; three times/week) for two weeks. The results indicated that CoQ10NP pretreatment caused a significant decrease in serum liver and kidney function markers. Moreover, lowered MDA and NO levels were associated with an increase in antioxidant enzyme activities (SOD, GPx, GR, and CAT), along with higher GSH contents, in both the liver and kidneys of intoxicated rats treated with CoQ10NPs. Moreover, HgCl2-intoxicated rats that received CoQ10NPs revealed a significant reduction in the hepatorenal levels of TNF-α, IL-1β, NF-κB, and TGF-β, as well as an increase in the hepatic level of the fibrotic marker (α-SMA). Notably, CoQ10NPs counteracted hepatorenal apoptosis by diminishing the levels of Bax and caspase-3 and boosting the level of Bcl-2. The hepatic and renal histopathological findings supported the abovementioned changes. In conclusion, these data suggest that CoQ10, alone or loaded with albumin nanoparticles, has great power in reversing the hepatic and renal tissue impairment induced by HgCl2 via the modulation of hepatorenal oxidative damage, inflammation, and apoptosis. Therefore, this study provides a valuable therapeutic agent (CoQ10NPs) for preventing and treating several HgCl2-induced hepatorenal disorders.

Mercury chloride alters heterochromatin domain organization and nucleolar activity in mouse liver

Mercury is a highly toxic element that induces severe alterations and a broad range of adverse effects on health. Its exposure is a global concern because it is widespread in the environment due to its multiple industrial, domestic, agricultural and medical usages. Among its various chemical forms, both humans and animals are mainly exposed to mercury chloride (HgCl₂), methylmercury and elemental mercury. HgCl₂ is metabolized primarily in the liver. We analysed the effects on the nuclear architecture of an increasing dosage of HgCl₂ in mouse hepatocytes cell culture and in mouse liver, focusing specifically on the organization, on some epigenetic features of the heterochromatin domains and on the nucleolar morphology and activity. Through the combination of molecular and imaging approaches both at optical and electron microscopy, we show that mercury chloride induces modifications of the heterochromatin domains and a decrease of some histones post-translational modifications associated to heterochromatin. This is accompanied by an increase in nucleolar activity which is reflected by bigger nucleoli. We hypothesized that heterochromatin decondensation and nucleolar activation following mercury chloride exposure could be functional to express proteins necessary to counteract the harmful stimulus and reach a new equilibrium.

Amelioration of mercuric chloride-induced physiologic and histopathologic alterations in rats using vitamin E and zinc chloride supplement

The drastic effects of mercuric chloride and the protective efficiency of vitamin E and zinc chloride co-supplementation were clearly investigated in this study. Male rats were divided into four groups. The first was the control. The second received vitamin E (100 mg/kg) and zinc chloride (30 mg/kg) daily. In comparison, the third received mercuric chloride (1 mg/kg) daily, and the fourth received the same mercuric chloride dose supplemented with the same vitamin E and zinc chloride doses. Mercury promotes a significant decline in body weight. It causes a considerable reduction in total red blood cells (RBCs) count and hemoglobin concentration; however, white blood cells (WBCs) increased significantly. Significant mercury-induced elevations in hepatic and renal functions were observed. Mercury induced substantial reductions in catalase (CAT) and superoxide dismutase (SOD). Mercury caused apoptotic DNA fragmentation. It induced degeneration and necrosis in the liver and kidney. It induced necrosis, leukocyte infiltration and blood vessel congestion in the cerebral cortex. Shrinkage and deterioration of Purkinje cells of the cerebellum were observed in response to mercuric chloride toxicity. Mercuric chloride enhanced shrinking in seminiferous tubules and Leydig cells. It reduced sperm count, sperm motility, and testosterone concentration; however, it promoted abnormal sperm morphology. Administration of vitamin E and zinc chloride showed marked improvement in different parameters under investigation, however, further research is needed to determine fate of mercury.

Comprehensive Review Regarding Mercury Poisoning and Its Complex Involvement in Alzheimer's Disease

Mercury (Hg) is considered one of the most widespread toxic environmental pollutants, which seems to have multiple effects on organisms even at low concentrations. It has a critical role in many health problems with harmful consequences, with Hg primarily targeting the brain and its components, such as the central nervous system (CNS). Hg exposure was associated with numerous CNS disorders that frequently trigger Alzheimer's disease (AD). Patients with AD have higher concentrations of Hg in blood and brain tissue. This paper aims to emphasize a correlation between Hg and AD based on the known literature in the occupational field. The outcome shows that all these concerning elements could get attributed to Hg. However, recent studies did not investigate the molecular level of Hg exposure in AD. The present review highlights the interactions between Hg and AD in neuronal degenerations, apoptosis, autophagy, oxidative stress (OS), mitochondrial malfunctions, gastrointestinal (GI) microflora, infertility and altering gene expression.

Unravelling the antifungal mode of action of curcumin by potential inhibition of CYP51B: A computational study validated in vitro on mucormycosis agent, Rhizopus oryzae

Like human, fungi too are known to share lot of structural similarities amongst their CYPs (Cytochrome P450 super family of enzymes) which allows antifungal 'azole' compounds to interact with CYPs of human. Clotrimazole, an 'azole' antifungal drug, is a known inhibitor of fungal CYP named CYP51B. Curcumin, a phytochemical obtained from Curcuma longa has the ability to interact with several different human CYPs to induce inhibition. The sequence and the structural similarities amongst both human and fungal CYPs suggest a strong possibility for curcumin to interact with fungal CYP51B to behave like an antifungal agent. To test this hypothesis a study was designed involving mucormycosis agent, Rhizopus oryzae. The ability of curcumin to interact with fungal CYP51B was analysed computationally through molecular docking, MM-GBSA and Molecular Dynamics (MD) simulation assessment. Further, interaction profile for fungal CYP51B-curcumin was compared with human CYP3A4-curcumin, as there are published evidence describing curcumin as an inhibitor of human CYPs. Additionally, to validate in silico findings, an in vitro assay was performed to examine the antifungal potentials of curcumin on the R. oryzae. Conclusive results allow us to determine a plausible mode of action of curcumin to act as an antifungal against a mucormycosis agent.

The Antioxidant Efficacy of Wheatgrass (Triticum Aestivum) on Mercuric Chloride (HgCl2) - Induced Oxidative Stress in Rat Model

Mercury is a harmful toxic pollutant, which has hepato-nephrotoxic, hematotoxic, genotoxic and neurotoxic, effects. The aim of the study was to evaluate the protective efficacy of wheatgrass on mercuric chloride (HgCl2) induced oxidative stress and associated complications in rat model. Albino rats were divided into four groups (three rats per group). Group I normal control group. Group II oxidative stressed group received mercuric chloride (0.5 mg/kg/day). Group III only received wheatgrass extract (100 mg/kg/day), whereas Group IV received wheatgrass (100 mg/kg/day) after one hour, followed by mercuric chloride (0.5 mg/kg/day) for 30 days. The results of the study showed that wheatgrass supplementation significantly decreased the HgCl2 induced elevated oxidative stress parameters Plasma Malondialdehyde (MDA) content, Plasma membrane redox system (PMRS), Advanced oxidation protein products (AOPP), simultaneously elevated lipid profile (Total Cholesterol, Triglycerides, Low-density lipoprotein (LDL), liver enzymes as, Plasma Alkaline phosphatase (ALP), Aspartate aminotransferase (AST), and Alanine aminotransferase (ALT), Serum Urea, and Creatinine levels in rats. In addition, wheatgrass treatment improved the antioxidant status in terms of intracellular Reduced Glutathione (GSH), Ferric reducing antioxidant power (FRAP) and 2, 2- diphenyl -1- picrylhydrazyl (DPPH). Therefore it can be concluded that wheatgrass has great potential to diminish the stress-mediated complications and improve the antioxidant status.

Hepatoprotective Plants from Bangladesh: A Biophytochemical Review and Future Prospect

Liver diseases are quite prevalant in many densely populated countries, including Bangladesh. The liver and its hepatocytes are targeted by virus and microbes, as well as by chemical environmental toxicants, causing wide-spread disruption of metabolic fuctions of the human body, leading to death from end-stage liver diseases. The aim of this review is to systematically explore and record the potential of Bangladeshi ethnopharmacological plants to treat liver diseases with focus on their sources, constituents, and therapeutic uses, including mechanisms of actions (MoA). A literature survey was carried out using Pubmed, Google Scholar, ScienceDirect, and Scopus databases with articles reported until July, 2020. A total of 88 Bangladeshi hepatoprotective plants (BHPs) belonging to 47 families were listed in this review, including Euphorbiaceae, Cucurbitaceae, and Compositae families contained 20% of plants, while herbs were the most cited (51%) and leaves were the most consumed parts (23%) as surveyed. The effect of BHPs against different hepatotoxins was observed via upregulation of antioxidant systems and inhibition of lipid peroxidation which subsequently reduced the elevated liver biomarkers. Different active constituents, including phenolics, curcuminoids, cucurbitanes, terpenoids, fatty acids, carotenoids, and polysaccharides, have been reported from these plants. The hepatoameliorative effect of these constituents was mainly involved in the reduction of hepatic oxidative stress and inflammation through activation of Nrf2/HO-1 and inhibition of NF-κB signaling pathways. In summary, BHPs represent a valuable resource for hepatoprotective lead therapeutics which may offer new alternatives to treat liver diseases.

Quantitative protein profiling of phenobarbital-induced drug metabolizing enzymes in rat liver by liquid chromatography mass spectrometry using formalin-fixed paraffin-embedded samples

Administration of a compound can induce drug-metabolizing enzymes (DMEs) in the liver. DME induction can affect various parameters in toxicology studies. Therefore, evaluation of DME induction is important for interpreting test compound-induced biological responses. Several methods such as measurement of hepatic microsomal DME activity using substrates, electron microscopy, or immunohistochemistry have been used; however, these methods are limited in throughput and specificity or are not quantitative. Liquid chromatography mass spectrometry (LC/MS)-based protein analysis can detect and quantify multiple proteins simultaneously per assay. Studies have shown that formalin-fixed paraffin-embedded (FFPE) samples, which are routinely collected in toxicology studies, can be used for LC/MS-based protein analysis. To validate the utility of LC/MS using FFPE samples for quantitative evaluation of DME induction, we treated rats with a DME inducer, phenobarbital, and compared the protein expression levels of 13 phase-I and 11 phase-II DMEs between FFPE and fresh frozen hepatic samples using LC/MS. A good correlation between data from FFPE and frozen samples was obtained after analysis. In FFPE and frozen samples, the expression of 6 phase-I and 8 phase-II DMEs showed a similar significant increase and a prominent rise in Cyp2b2 and Cyp3a1 levels. In addition, LC/MS data were consistent with the measurement of microsomal DME activities. These results suggest that LC/MS-based protein expression analysis using FFPE samples is as effective as that using frozen samples for detecting DME induction.

Zuotai (β-HgS)-containing 70 Wei Zhen-Zhu-Wan differs from mercury chloride and methylmercury on hepatic cytochrome P450 in mice

Background: Zuotai (mainly β-HgS)-containing 70 Wei-Zhen-Zhu-Wan (70W, Rannasangpei) is a famous Tibetan medicine for treating cardiovascular and gastrointestinal diseases.  We have shown that 70W protected against CCl 4 hepatotoxicity.  CCl 4 is metabolized via cytochrome P450 (CYP) to produce reactive metabolites. Whether 70W has any effect on CYPs is unknown and such effects should be compared with mercury compounds for safety evaluation.   Methods: Mice were given clinical doses of 70W (0.15-1.5 g/kg, po), Zuotai (30 mg/kg, po), and compared to HgCl 2 (33.6 mg/kg, po) and MeHg (3.1 mg/kg, po) for seven days. Liver RNA and protein were isolated for qPCR and Western-blot analysis. Results: 70W and Zuotai had no effects on hepatic mRNA expression of Cyp1a2, Cyp2b10, Cyp3a11, Cyp4a10 and Cyp7a1, and corresponding nuclear receptors [aryl hydrocarbon receptor (AhR), constitutive androstane receptor (CAR), pregnane X receptor (PXR), peroxisome proliferator-activated receptor-α (PPARα); farnesoid X receptor (FXR)]. In comparison, HgCl 2 and MeHg increased mRNA expression of Cyp1a2, Cyp2b10, Cyp4a10 and Cyp7a1 except for Cyp3a11, and corresponding nuclear receptors except for PXR. Western-blot confirmed mRNA results, showing increases in CYP1A2, CYP2B1, CYP2E1, CYP4A and CYP7A1 by HgCl 2 and MeHg only, and all treatments had no effects on CYP3A. Conclusions: Zuotai and Zuotai-containing 70W at clinical doses had minimal influence on hepatic CYPs and corresponding nuclear receptors, while HgCl 2 and MeHg produced significant effects.  Thus, the use of total Hg content to evaluate the safety of HgS-containing 70W is inappropriate.

Zuotai (β-HgS)-containing 70 Wei Zhen-Zhu-Wan differs from mercury chloride and methylmercury on hepatic cytochrome P450 in mice

Background: Zuotai (mainly β-HgS)-containing 70 Wei-Zhen-Zhu-Wan (70W, Rannasangpei) is a famous Tibetan medicine for treating cardiovascular and gastrointestinal diseases.  We have shown that 70W protected against CCl 4 hepatotoxicity.  CCl 4 is metabolized via cytochrome P450 (CYP) to produce reactive metabolites. Whether 70W has any effect on CYPs is unknown and such effects should be compared with mercury compounds for safety evaluation.   Methods: Mice were given clinical doses of 70W (0.15-1.5 g/kg, po), Zuotai (30 mg/kg, po), and compared to HgCl 2 (33.6 mg/kg, po) and MeHg (3.1 mg/kg, po) for seven days. Liver RNA and protein were isolated for qPCR and Western-blot analysis. Results: 70W and Zuotai had no effects on hepatic mRNA expression of Cyp1a2, Cyp2b10, Cyp3a11, Cyp4a10 and Cyp7a1, and corresponding nuclear receptors [aryl hydrocarbon receptor (AhR), constitutive androstane receptor (CAR), pregnane X receptor (PXR), peroxisome proliferator-activated receptor-α (PPARα); farnesoid X receptor (FXR)]. In comparison, HgCl 2 and MeHg increased mRNA expression of Cyp1a2, Cyp2b10, Cyp4a10 and Cyp7a1 except for Cyp3a11, and corresponding nuclear receptors except for PXR. Western-blot confirmed mRNA results, showing increases in CYP1A2, CYP2B1, CYP2E1, CYP4A and CYP7A1 by HgCl 2 and MeHg only, and all treatments had no effects on CYP3A. Conclusions: Zuotai and Zuotai-containing 70W at clinical doses had minimal influence on hepatic CYPs and corresponding nuclear receptors, while HgCl 2 and MeHg produced significant effects.  Thus, the use of total Hg content to evaluate the safety of HgS-containing 70W is inappropriate.

Antioxidant and Protective Effects of Artemisia campestris Essential Oil Against Chlorpyrifos-Induced Kidney and Liver Injuries in Rats

This study is aimed to elucidate the possible antioxidant and protective effects of Artemisia campestris essential oil (ACEO) against the deleterious effects of chlorpyrifos (CPF) in rats. The in vivo study revealed increases in aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), and alkaline phosphatase (ALP) activities and the serum contents of creatinine, urea, uric acid, cholesterol, triglycerides, low density lipoproteins (LDL), and glucose in rats treated with CPF as compared to controls. Meanwhile, hepatic and renal activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) in liver and kidney decreased and the content of malondialdehyde (MDA) increased. Some histopathologic features were noticed in liver and kidney of the CPF group. Interestingly, ACEO alleviated the biochemical disruptions and reduced these hepato-renal morphologic changes.

Preclinical Evidence of Curcuma longa and Its Noncurcuminoid Constituents against Hepatobiliary Diseases: A Review

Hepatobiliary disease currently serves as an important public health issue due to the fact that it is one of the major causes of death among economically active individuals and can easily progress to chronic diseases. Despite the development of vaccines and numerous drugs, a definite treatment remains lacking owing to different stages of the disease itself, its intricate pathogenesis, an effect uncertainty for long-term use, resistance, and side effects. Curcuma longa (C. longa), which belongs to the family Zingiberaceae and the genus Curcuma, has long been used not only as spice for curry or dye but also as a constituent of herbal formula for the treatment of different diseases due to its bioactive activities. Recently, many studies on the experimental results of C. longa have been published relative to hepatobiliary diseases such as fatty liver, hepatitis, cirrhosis, and tumors. Therefore, in this review, we aimed to summarize the pharmacological effects and underlying molecular mechanisms of C. longa and its four compounds, β-elemene, germacrone, ar-turmerone, and bisacurone, against hepatobiliary diseases. C. longa exhibited antioxidant, hepatoprotective, antisteatotic, anti-inflammatory, antifibrotic, antitumor, and cholagogic effects by regulating apoptosis, CYP2E1, Nrf, lipid metabolism-related factors, TGF-β, NF-κB, CYP7A1, and so on. In particular, β-elemene could be an attractive compound owing to its remarkable hepatoprotective, anti-inflammatory, antifibrotic, and antitumor activities. Altogether, the present review provides a preclinical basis for the efficacy of C. longa as an effective therapeutic agent for the prevention and treatment of hepatobiliary diseases, despite the need for further studies to establish the extraction conditions and separation of active constituents with high bioavailability, and warrants further evaluation in clinical trials.

Protective Effect of DPPD on Mercury Chloride-Induced Hepatorenal Toxicity in Rats

Mercury is a global environmental pollutant, accumulating mainly in the kidney and liver inducing hepatorenal toxicity, oxidative stress, and tissue damage. Oxidative stress is caused by an imbalance between free radicals' production and cellular antioxidant defense systems. In the present study, we investigated the effect of N N′-diphenyl-1, 4-phenylenediamine (DPPD) antioxidant activity against mercury chloride- (HgCl₂-) induced renal and hepatic toxicity. Thirty adult female Sprague Dawley rats were divided into three equal groups: the first group was injected with saline only and served as a control, the second group was injected with HgCl₂, and the third group received DPPD + HgCl₂ rats injected with HgCl₂ without treatment showing a significant increase in alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), urea, creatinine, and uric acids compared to control. Moreover, the second group showed a significant reduction in the activity of the antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH)) in addition to a marked increase in the malondialdehyde (MDA) content, histopathological alterations, collagen deposition, CD8%, CD4%, and TGF-β% in kidney and liver tissues compared with the control group. Treatment with DPPD showed significant recovery (p ≤ 0.001) in all previous parameters and histopathological examination. In conclusion, we suggested that DPPD may have a promising antioxidant capacity, gives it the applicability to be used as a prophylactic agent against mercury-induced hepatorenal cytotoxicity in the future.

Medicinal plants and natural products can play a significant role in mitigation of mercury toxicity

Mercury is a heavy metal of considerable toxicity. Scientific literature reveals various plants and plant derived natural products, i.e., phytochemicals, which can alleviate experimentally induced mercury toxicity in animals. The present review attempts to collate those experimental studies on medicinal plants and phytochemicals with ameliorative effects on mercury toxicity. A literature survey was carried out by using Google, Scholar Google, Scopus and Pub-Med. Only the scientific journal articles found in the internet for the last two decades (1998–2018) were considered. Minerals and semi-synthetic or synthetic analogs of natural products were excluded. The literature survey revealed that in pre-clinical studies 27 medicinal plants and 27 natural products exhibited significant mitigation from mercury toxicity in experimental animals. Clinical investigations were not found in the literature. Admissible research in this area could lead to development of a potentially effective agent from the plant kingdom for clinical management of mercury toxicity in humans.

Rutin protects mercuric chloride-induced nephrotoxicity via targeting of aquaporin 1 level, oxidative stress, apoptosis and inflammation in rats

OBJECTIVE

Mercury is a dangerous industrial and environmental pollutant which induces severe damage in diverse organs in animal and humans. The aim of this study was to investigate the protective effect of rutin (50 and 100 mg/kg body weight) against mercuric chloride (HgCl₂) (1.23 mg/kg b.w.) toxicity in rats.

METHODS

The experiment was carried out in male Sprague Dawley rats (n = 35) which was divided into five groups as follow: control, rutin-100, HgCl₂, HgCl₂ + rutin-50 and HgCl₂ + rutin-100.

RESULTS

The results showed that HgCl₂ caused a marked increase in the malondialdehyde (MDA) level and significantly decreased antioxidant enzyme activities (p < 0.05). HgCl₂ also provoked inflammatory responses by elevating the levels of tumor necrosis factor-α (TNF-α), B-cell lymphoma-3 (Bcl-3), interleukin-1β (IL-1β), nuclear factor kappa B (NF-κB), interleukin-33 (IL-33), and activities of mitogen-activated protein kinase 14 (MAPK 14) and myeloperoxidase (MPO) (p < 0.05). HgCl₂ also prompted the apoptotic pathway by increasing the levels of Bcl-2 associated X protein (Bax) and p53, expression of terminal deoxynucleotidyl transferase dUNT nick end labeling (TUNEL) and cysteine aspartate specific protease-3 (caspase-3). HgCl₂ changed histological integrity of kidney and expression of 8-hydroxy-2'-deoxyguanosine (8-OHdG) while caused a decrease in aquaporin 1 (AQP1) water channel protein level. In contrast to this, rutin significantly decreased oxidative stress, apoptosis, inflammation and histopathological alterations while increased AQP1 levels in kidney tissues (p < 0.05).

CONCLUSION

The present study indicated that rutin has a nephroprotective effect due to its anti-inflammatory, antioxidant and antiapoptotic properties.

Protective effects of phenolic acids on mercury-induced DNA damage in precision-cut kidney slices

Objective(s):

Precision-cut tissue slices are considered an organotypic 3D model widely used in biomedical research. The comet assay is an important screening test for early genotoxicity risk assessment that is mainly applied on in vitro models. The aim of the present study was to provide a 3D organ system for determination of genotoxicity using a modified method of the comet assay since the stromal components from the original tissue make this technique complicated.

Materials and Methods:

A modified comet assay technique was validated using precision-cut hamster kidney slices to analyze the antigenotoxic effect of the phenolic compounds caffeic acid, chlorogenic acid, and rosmarinic acid in tissue slices incubated with 15 µM HgCl₂. Cytotoxicity of the phenolic compounds was studied in Vero cells, and by morphologic analysis in tissue slices co-incubated with HgCl₂ and phenolic compounds.

Results:

A modification of the comet assay allows obtaining better and clear comet profiles for analysis. Non-cytotoxic concentrations of phenolic acids protected kidney tissue slices against mercury-induced DNA damage, and at the same time, were not nephrotoxic. The highest protection was provided by 3 µg/ml caffeic acid, although 6 µg/ml rosmarinic and 9 µg/ml chlorogenic acids also exhibited protective effects.

Conclusion:

This is the first time that a modification of the comet assay technique is reported as a tool to visualize the comets from kidney tissue slices in a clear and simple way. The phenolic compounds tested in this study provided protection against mercury-induced genotoxic damage in precision-cut kidney slices.

L-α-Phosphatidylcholine attenuates mercury-induced hepato-renal damage through suppressing oxidative stress and inflammation

The potential ameliorative effects of L-α-phosphatidylcholine (PC) against mercuric chloride (HgCl₂)-induced hematological and hepato-renal damage were investigated. Rats were randomly allocated into four groups (n = 12): control, PC (100 mg/kg bwt, intragastrically every other day for 30 consecutive days), HgCl₂ (5 mg/kg bwt, intragastrically daily), and PC plus HgCl₂. Hematological and hepato-renal dysfunctions were evaluated biochemically and histopathologically. Hepatic and renal oxidative/antioxidative indices were evaluated. The expression of proinflammatory cytokines (tumor necrosis factor-α and interleukin-6) was also detected by ELISA. HgCl₂ significantly increased serum aminotransferases (ALT, AST), urea, and creatinine levels that are indicative of hepato-renal damage. HgCl₂ also induced a significant accumulation of malondialdehyde (+ 195%) with depletion of glutathione (- 43%) levels in the liver and renal tissues. The apparent hepato-renal oxidative damage was associated with obvious organ dysfunction that was confirmed by impairments in the liver and kidney histoarchitecture. Furthermore, HgCl₂ significantly attenuated the expression of proinflammatory cytokines named tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Conversely, PC treatment attenuated these effects, which improved the hematological and serum biochemical alternations, reduced the oxidative stress and proinflammatory cytokine levels, and ameliorated the intensity of the histopathological alterations in livers and kidneys of HgCl₂-treated rats. It could be concluded that PC displayed potential anti-inflammatory and antioxidant activities against HgCl₂-induced hepato-renal damage via suppression of proinflammatory cytokines and declining oxidative stress.

Protective Effect of Curcuma Against Chromium Hepatotoxicity in Rats

This study was carried out to investigate the antioxidant effects of curcuma against chromium-induced alterations in hepatic indices and dysfunctions in the antioxidant system. Forty male Wistar rats were randomly divided into four groups and were treated for 30 consecutive days. The control group (0-0) received per os mineral water and normal diet. The second group (0-Cur) received mineral water and an experimental diet containing 2% of curcuma powder, whereas the third group (Cr-0) was orally fed (per os) with 15 mg/kg body weight/day of potassium dichromate and normal diet. The last group (Cr-Cur) received per os 15 mg/kg of potassium dichromate and a diet with 2% of curcuma. The treatment by chromium was found to elicit a perturbation in biochemical parameters producing a significant increase in glycemia, triglycerides, cholesterol, ALP, ALT, AST, and LDH levels. On the contrary, a significant reduction was observed in the oxidative stress-related parameters (GSH, GPx, CAT, and GST). Moreover, we noticed that liver sections of rats intoxicated with chromium showed a disrupted architecture. However, the administration of curcuma revealed an intense reduction in the oxidative stress induced by chromium, ameliorating the levels of the majority of the previous parameters. The data of this study revealed the potent antioxidant effects of curcuma in reducing oxidative stress damage induced by the hexavalent chromium.

Curcumin Alleviates β Amyloid-Induced Neurotoxicity in HT22 Cells via Upregulating SOD2

Curcumin protects neuronal cells exposed to β amyloid (Aβ); the mechanism, however, is still obscure. The aim of this study is to determine whether the type 2 superoxide dismutase (SOD2) mediates curcumin-induced protective effects in Aβ-treated neuronal cells. In this study, the HT22 neuronal cells were exposed to Aβ to imitate neuronal injury in Alzheimer's disease (AD). After 24-h treatment, 10 μM Aβ decreased cell viability and mitochondrial functions, including mitochondrial complex activities and mitochondrial membrane potential (MMP), and also downregulated anti-oxidants SOD2, glutathione (GSH), and catalase (CAT) levels (P < 0.05), meanwhile, increased lactic dehydrogenase (LDH) release, apoptosis level, intracellular reactive oxygen species (ROS) and mitochondrial superoxide accumulation (P < 0.05). And, co-administration of 1 μM curcumin significantly reduced the Aβ-induced cell injury and oxidative damage above (P < 0.05). Downregulating SOD2 by using small interfering RNA (siRNA), however, significantly abolished the curcumin-induced protective and anti-oxidative effects in HT22 cells (P < 0.05); the scramble (SC)-siRNA did not cause marked effects on the curcumin-induced protective effects (P > 0.05). These findings showed that curcumin can alleviate Aβ-induced injury in neuronal cells, and SOD2 protein may mediate the neuroprotective effects.

Yangyin Qingre Huoxue Method in Traditional Chinese Medicine Ameliorates Atherosclerosis in ApoE-/- Mice Suffering from High-Fat Diet and HSP65 Aggression

Atherosclerosis (AS) is a complicated arterial disease resulting from abnormal lipid deposition and inflammatory injury, which is attributed to Yin deficiency, accumulation of heat materials, and stasis of blood flow in Traditional Chinese Medicine (TCM) theory. Thus, according to TCM theory, the method of nourishing Yin (Yangyin), clearing away heat (Qingre), and promoting blood circulation (Huoxue) is a reasonable strategy, which has achieved remarkable clinical efficacy in the treatment of AS, but the mechanisms remain to be known. In this study, we evaluated the effects of Yangyin Qingre Huoxue Prescription (YQHP) on AS in ApoE^-/- mice suffering from a high-fat diet and heat shock protein (HSP65) attack. YQHP regulated levels of blood lipids and inflammation-linked cytokines as well as Th17/Treg ratio in peripheral blood. Suppressed IL-6-p-STAT3 signaling and restored IL-2-p-STAT5 signaling in the presence of YQHP may partake in the regulation of Th17 and Treg differentiation. Moreover, YQHP modulated transcriptional levels of costimulator CD80 in aortas as well corresponding to the downregulation of GM-CSF in serum and CD3 expression in CD4⁺ T cells, which might indicate the potential of YQHP to regulate antigen presenting cells. All these effects eventually promoted the improvement of atherosclerotic lesions. In addition, YQHP promoted less monocyte infiltration in the liver and lower levels of AST, ALT, and AKP production than simvastatin. Conclusively, lipid-regulating and anti-inflammatory functions mediated by YQHP with lower hepatotoxicity than simvastatin hindered the progression of HSP65 aggravated AS in ApoE^-/- mice, indicating the effectiveness of Yangyin Qingre Huoxue Method in the treatment of AS.

Bioactivity, Health Benefits, and Related Molecular Mechanisms of Curcumin: Current Progress, Challenges, and Perspectives

Curcumin is a principal curcuminoid of turmeric (Curcuma longa), which is commonly used as a spice in cooking and a yellow pigment in the food processing industry. Recent studies have demonstrated that curcumin has a variety of biological activities and pharmacological performances, providing protection and promotion of human health. In addition to presenting an overview of the gut metabolism of curcumin, this paper reviews the current research progress on its versatile bioactivity, such as antioxidant, anti-inflammatory, and immune-regulatory activities, and also intensively discusses its health benefits, including the protective or preventive effects on cancers and diabetes, as well as the liver, nervous system, and cardiovascular systems, highlighting the potential molecular mechanisms. Besides, the beneficial effects of curcumin on human are further stated based on clinical trials. Considering that there is still a debate on the beneficial effects of curcumin, we also discuss related challenges and prospects. Overall, curcumin is a promising ingredient of novel functional foods, with protective efficacy in preventing certain diseases. We hope this comprehensive and updated review will be helpful for promoting human-based studies to facilitate its use in human health and diseases in the future.