Rosmarinic acid attenuates hepatic ischemia and reperfusion injury in rats

Rosmarinic acid prevents post-operative abdominal adhesions in a rat model

This study aims to determine the effects of rosmarinic acid which involved the mechanisms to decrease the postoperative peritoneal adhesion formation in rats. Various incisions and removing a 1 × 1 cm piece of peritoneum was used to induce the peritoneal adhesions. Experimental groups were as follows: 1-Sham group. 2-Control group: Peritoneal adhesions were induced and no treatments were performed. 3-Treatment groups: Following inducing peritoneal adhesions, animals received rosmarinic acid with 50 and 70 mg/kg dosage, respectively. Macroscopic examination of adhesions indicated that adhesion bands were reduced in both treatment groups compared to the control group. Moreover, the adhesion score was decreased in both treatment groups on day 14. Inflammation and fibroblast proliferation were both reduced in the treatment groups on day 14. TGF-β1, TNF-α, and VEGF were all evaluated by western blot and immunohistochemistry on days 3 and 14. Treatment groups reduced inflammatory cytokines on days 3 and 14. The treatment group with a 70 mg/kg dosage decreased TGF-β1 and TNF-α levels more than the other treatment group. The administration of rosmarinic acid significantly reduced MDA and increased CAT levels. In conclusion, the rosmarinic acid was effective to reduce the adhesion bands, inflammatory cytokines, angiogenesis, and oxidative stress.

Effects of iNOS in Hepatic Warm Ischaemia and Reperfusion Models in Mice and Rats: A Systematic Review and Meta-Analysis

Warm ischaemia is usually induced by the Pringle manoeuver (PM) during hepatectomy. Currently, there is no widely accepted standard protocol to minimise ischaemia-related injury, so reducing ischaemia-reperfusion damage is an active area of research. This systematic review and meta-analysis focused on inducible nitric oxide synthase (iNOS) as an early inflammatory response to hepatic ischaemia reperfusion injury (HIRI) in mouse- and rat-liver models. A systematic search of studies was performed within three databases. Studies meeting the inclusion criteria were subjected to qualitative and quantitative synthesis of results. We performed a meta-analysis of studies grouped by different HIRI models and ischaemia times. Additionally, we investigated a possible correlation of endothelial nitric oxide synthase (eNOS) and nitric oxide (NO) regulation with iNOS expression. Of 124 included studies, 49 were eligible for the meta-analysis, revealing that iNOS was upregulated in almost all HIRIs. We were able to show an increase of iNOS regardless of ischemia or reperfusion time. Additionally, we found no direct associations of eNOS or NO with iNOS. A sex gap of primarily male experimental animals used was observed, leading to a higher risk of outcomes not being translatable to humans of all sexes.

Rosmarinic Acid Ameliorates Pulmonary Ischemia/Reperfusion Injury by Activating the PI3K/Akt Signaling Pathway

Pulmonary ischemia/reperfusion (IR) injury is the leading cause of acute lung injury, which is mainly attributed to reactive oxygen species (ROS) induced cell injuries and apoptosis. Since rosmarinic acid (RA) has been identified as an antioxidant natural ester, this natural compound might protect against pulmonary IR injury. In this study, the mice were given RA daily (50, 75, or 100 mg/kg) by gavage for 7 days before the pulmonary IR injury. We found that hypoxemia, pulmonary edema, and serum inflammation cytokines were aggravated in pulmonary IR injury. RA pretreatment (75 and 100 mg/kg) effectively reversed these parameters, while 50 mg/kg RA pretreatment was less pronounced. Our data also indicated RA pretreatment mitigated the upregulation of pro-oxidant NADPH oxidases (NOX2 and NOX4) and the downregulation of anti-oxidant superoxide dismutases (SOD1 and SOD2) upon IR injury. In vitro studies showed RA preserved the viability of anoxia/reoxygenation (AR)-treated A549 cells (a human lung epithelial cell line), and the results showed the protective effect of RA started at 5 μM concentration, reached its maximum at 15 μM, and gradually decreased at 20–25 μM. Besides, RA pretreatment (15 μM) greatly reduced the lactate dehydrogenase release levels subjected to AR treatment. Moreover, the results of our research revealed that RA eliminated ROS production and reduced alveolar epithelial cell apoptosis through activating the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt) signaling pathway, which was supported by using wortmannin, because in the presence of wortmannin, the RA-mediated protection was blocked. Meanwhile, wortmannin also reversed the protective effects of RA in mice. Together, our results demonstrate the beneficial role of RA in pulmonary IR injury via PI3K/Akt-mediated anti-oxidation and anti-apoptosis, which could be a promising therapeutic intervention for pulmonary IR injury.

Cardioprotective effect of rosmarinic acid against myocardial ischaemia/reperfusion injury via suppression of the NF-κB inflammatory signalling pathway and ROS production in mice

CONTEXT

Rosmarinic acid (RosA), a natural poly-phenolic compound isolated from a variety of Labiatae herbs, has been reported to have a range of biological effects.

OBJECTIVE

To investigate the cardioprotective effects of RosA against myocardial ischaemia/reperfusion (I/R) injury.

MATERIALS AND METHODS

Male C57BL/6J mice were given RosA (100 mg/kg) via intragastric administration. After 1 week of administration, the mice were subjected to 30 min/24 h myocardial I/R injury. The mice were randomly subdivided into 4 groups: Vehicle, RosA, Vehicle + I/R, and RosA + I/R. Infarct size (IS), cardiac function (including EF, FS), histopathology, serum enzyme activities, ROS changes, cis aconitase (ACO) activity, and specific mRNA and protein levels were assessed in vivo. HL-1 cells were pre-treated with or without RosA (50 μM), followed by stimulation with 9 h/6 h of oxygen and glucose deprivation/re-oxygenation (OGD/R). The cells were randomly subdivided into 4 groups: Vehicle, RosA, Vehicle + OGD/R, and RosA + OGD/R. Lactate dehydrogenase (LDH) levels, ACO activity, ROS changes and protein levels were measured in vitro.

RESULTS

Treatment with RosA reduced the following indicators in vivo (p < 0.05): (1) IS (14.5%); (2) EF (-23.4%) and FS (-18.4%); (3) the myocardial injury enzymes CK-MB (20.8 ng/mL) and cTnI (7.7 ng/mL); (4) DHE-ROS: (94.1%); (5) ACO activity (-2.1 mU/mg protein); (6) ogdh mRNA level (122.9%); and (7) OGDH protein level (69.9%). Moreover, treatment with RosA attenuated the following indicators in vitro (p < 0.05): (1) LDH level (191 U/L); (2) DHE-ROS: (165.2%); (3) ACO activity (-3.2 mU/mg protein); (4) ogdh mRNA level (70.0%); and (5) OGDH (110.1%), p-IκB-a (56.8%), and p-NF-κB (57.7%) protein levels.

CONCLUSIONS

RosA has the potential to treat myocardial I/R injury with potential application in the clinic.

Effect of silibinin on the expression of MMP2, MMP3, MMP9 and TIMP2 in kidney and lung after hepatic ischemia/reperfusion injury in an experimental rat model

PURPOSE

The protective effect of silibinin on kidney and lung parenchyma during hepatic ischemia/reperfusion injury (IRI) is explored.

METHODS

Sixty-three Wistar rats were separated into three groups: sham; control (45 min IRI); and silibinin (200 μL silibinin administration after 45 min of ischemia and before reperfusion). Immunohistochemistry and real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) were used to evaluate the expression levels of MMP2, MMP3, MMP9, and TIMP2 on kidney and lung.

RESULTS

Comparing sham vs. control groups, confirmed that hepatic IRI increased both renal and lung MMP2, MMP3, MMP9 and TIMP2 expressions starting at 180 min (p<0.001). Comparison of the control vs. silibinin groups showed a statistically significant decrease in the expression levels of MMP2, MMP3, and MMP9 and increase of TIMP2 in kidney and lung parenchyma. The starting point of this decrease was at 120 min after reperfusion, both for kidney and lung parameters, and it was statistically significant at 240 min (p<0.001) for kidney, while silibinin showed a peak of lung protection at 180 min after hepatic reperfusion (p<0.001).

CONCLUSIONS

Hepatic IRI causes distant kidney and lung damage, while a statistically significant protective action, both on kidney and lung parenchyma, is conveyed by the intravenous administration of silibinin.

Thiacloprid Induced Developmental Neurotoxicity via ROS-Oxidative Injury and Inflammation in Chicken Embryo: The Possible Attenuating Role of Chicoric and Rosmarinic Acids

Simple Summary

The current study was designed to evaluate the negative impact of thiacloprid (TH) on the brain tissue of developing chicken embryo models and to evaluate the modulatory effects of chicoric (CA) and rosmarinic (RA) acids. The eggs were injected in ovo with different doses of TH (0.1, 1, 10, and 100 μg/egg). TH significantly increased the oxidative damage in the brain of exposed embryos in a dose-dependent manner (p < 0.001). TH significantly elevated the oxidative stress markers; protein carbonyl, malondialdehyde (MDA) content, and DNA damage (p < 0.001). Myeloperoxidase (MPO) activity and NO significantly increased with overexpression of the pro-inflammatory cytokines (IFN-γ; interferon gamma, TNF-α; tumor necrosis factor alpha, and IL-1β; interleukin-1 beta), stress-related and apoptotic genes (NF-KB, Caspase-3) in the brain tissue on both a biochemical and molecular levels (p < 0.05), while downregulating the expression of antiapoptotic Bcl-2. Co-treatment of CA and RA with TH markedly decreased the insecticide-induced toxicity with a prominent synergistic effect (p < 0.05). In conclusion, TH is suggested to be a possible neurotoxic to embryos of vertebrates and possibly humans. The study also revealed the antioxidant, anti-inflammatory, genoprotective, and antiapoptotic properties of CA and RA against TH toxicity.

Abstract

Insecticides are widely employed in agriculture to control pests and as major factors for enhancing crop productivity. Thiacloprid (TH) is one of the most-used insecticides worldwide. In this study, the negative impact of TH on the brain tissue of developing chicken embryo models and the modulatory effect of chicoric (CA) and rosmarinic (RA) acids were investigated. The eggs were injected in ovo with different doses of TH (0.1, 1, 10, and 100 μg/egg). TH significantly increased the oxidative damage in the brain of exposed embryos in a dose-dependent manner (p < 0.05). TH significantly elevated the oxidative stress markers; protein carbonyl, malondialdehyde content, and DNA damage (p < 0.05). Myeloperoxidase activity and nitric oxide significantly increased with overexpression of the pro-inflammatory cytokines (interferon gamma, tumor necrosis factor alpha, and interleukin-1 beta) and stress-related and apoptotic genes (NF-KB, Caspase-3) in the brain tissue on both biochemical and molecular levels (p < 0.05), while downregulating the expression of antiapoptotic Bcl-2. Co-treatment of CA and RA with TH markedly decreased the insecticide-induced toxicity with a prominent synergistic effect (p < 0.05). In conclusion, TH is suggested to be a possible neurotoxic to embryos of vertebrates including human. The study also revealed the antioxidant, anti-inflammatory, genoprotective, and antiapoptotic property of CA and RA against TH toxicity.

Beneficial effects of natural compounds on experimental liver ischemia-reperfusion injury

Liver ischemia-reperfusion injury (IRI) is a phenomenon inherent to hepatic surgery that severely compromises the organ functionality, whose underlying mechanisms involve cellular and molecular interrelated processes leading to the development of an excessive inflammatory response. Liver resident cells and those recruited in response to injury generate pro-inflammatory signals such as reactive oxygen species, cytokines, chemokines, proteases and lipid mediators that contribute to hepatocellular necrosis and apoptosis. Besides, dying hepatocytes release damage-associated molecular patterns that actívate inflammasomes to further stimulate inflammatory responses leading to massive cell death. Since liver IRI is a complication of hepatic surgery in man, extensive preclinical studies have assessed potential protective strategies, including the supplementation with natural compounds, with the objective to downregulate nuclear factor-κB functioning, the main effector of inflammatory responses. This can be accomplished by either the activation of peroxisome proliferator-activated receptor-α, G protein-coupled receptor 120 or antioxidant signaling pathways, the synthesis of specific pro-resolving mediators, downregulation of Toll-like receptor 4 activity or additional contributory mechanisms that are beginning to be understood. The latter aspect is a crucial issue to be accomplished in preclinical studies, in order to establish adequate conditions for the supplementation with natural products before major liver surgeries in man involving warm IR, such as hepatic trauma or resection of large intrahepatic tumors.

Antihypoxic activity of the dry extract from Nepeta multifida L

The antihypoxic effect of the Nepeta multifida L. dry extract was studied in experiments on white Wistar rats. The life span of animals was determined against the background of acute hypoxias: hypercapnic, hemic, and histotoxic ones. Using the model of acute hypobaric hypoxia/reoxygenation there was evaluated the content of ATP, lactic and pyruvic acids, TBA-active products, reduced glutathione, catalase activity in brain tissue. On the model of acute hypobaric hypoxia/reoxygenation, the content of ATP, lactic and pyruvic acids, reduced glutathione and catalase activity in brain tissue The N. multifida dry extract demonstrated antihypoxic effect at the doses comprised between 100 and 300 mg/kg increasing lifespan of animals in hypercapnic, hemic and histotoxic hypoxias. N. multifida decreases the manifestation of free-radical oxidation processes, increases the activity of the endogenic antioxidant system, and promotes the efficacy of tissue respiration and oxidative phosphorylation coupling in the brain of white rats in hypoxia/reoxygenation.

Changes in Glutathione Content in Liver Diseases: An Update

Glutathione (GSH), a tripeptide particularly concentrated in the liver, is the most important thiol reducing agent involved in the modulation of redox processes. It has also been demonstrated that GSH cannot be considered only as a mere free radical scavenger but that it takes part in the network governing the choice between survival, necrosis and apoptosis as well as in altering the function of signal transduction and transcription factor molecules. The purpose of the present review is to provide an overview on the molecular biology of the GSH system; therefore, GSH synthesis, metabolism and regulation will be reviewed. The multiple GSH functions will be described, as well as the importance of GSH compartmentalization into distinct subcellular pools and inter-organ transfer. Furthermore, we will highlight the close relationship existing between GSH content and the pathogenesis of liver disease, such as non-alcoholic fatty liver disease (NAFLD), alcoholic liver disease (ALD), chronic cholestatic injury, ischemia/reperfusion damage, hepatitis C virus (HCV), hepatitis B virus (HBV) and hepatocellular carcinoma. Finally, the potential therapeutic benefits of GSH and GSH-related medications, will be described for each liver disorder taken into account.

Flavonoid-rich fraction attenuates permethrin-induced toxicity by modulating ROS-mediated hepatic oxidative stress and mitochondrial dysfunction ex vivo and in vivo in rat

The present study explores the antioxidant, anti-microbial, and hepatoprotective potentials of flavonoid-rich fractions from Fumaria officinalis against permethrin-induced liver damage ex vivo/in vivo in rat. However, HPLC-DAD analysis revealed the richness of 6 components in ethyl acetate fraction (EAF) where ferulic acid, rosmarinic acid, and myricetin are the most abundant. The in vitro assays showed that EAFs have impressive antioxidant and anti-microbial properties. Ex vivo, permethrin (PER) (100 μM) induced a decrease of hepatic AST and ALT activities and 25-OH vitamin D and vitamin C levels and an increase of ALP and LDH activities, TBARS, and ϒ-GT levels with a disturbance of oxidative status. The hepatoprotective effect of EAF (1 mg/mL) against PER was confirmed by the amelioration of oxidative stress profile. In vivo, permethrin was found to increase absolute and relative liver weights, plasma transaminase activities, lactate-to-pyruvate ratio, hepatic and mitochondrial lipid peroxidation, and protein oxidation levels. This pesticide triggered a decrease of Ca²⁺ and Mg²⁺-ATPases and mitochondrial enzyme activities. The co-treatment with EAF reestablished the hepatic and mitochondrial function, which could be attributed to its richness in phenolic compounds.

Use of natural anti-oxidants in experimental animal models of hepatic ischemia-reperfusion injury

Background

Ischemia-reperfusion injury (IRI) remains a clinical challenge in liver surgery, trauma and transplantation, contributing to morbidity and mortality worldwide. Thus, its impact, not only on the liver itself but also on remote tissues, has been studied during the last years. Different natural anti-oxidant substances have been researched in animal models, implementing different times of ischemia, aiming to test new therapeutic interventions.

Objective

A literature review has been conducted with two goals: (1) to identify different natural anti-oxidants studied in experimental models; and (2) to summarize the various times of ischemia employed.

Methods

Scientific papers published in PubMed for the period 2000–2020 were searched and reviewed.

Results

More than 30 natural anti-oxidants have been tested. The time of ischemia ranged from 15 to 90 min with 60 min used most frequently, followed by 45 min. No studies were found with time exceeding 90 min.

Conclusions

A significant number of research has been conducted on the use and protective effect of natural anti-oxidants in experimental animal models. Based on the published papers, 45–60 min seems to be the optimal duration of ischemia.

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Liver IRI is a multifactorial and complex process, involving many mechanisms, cells and mediators. Even though, most of these mechanisms have not been completely understood, several substances have been tested in experimental models in order to determine their protective or destructive role.

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Antioxidant therapy is a promising therapeutic pathway that can ameliorate the impact of liver ischemia-reperfusion injury.

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Non-pharmaceutical, natural extracts are increasingly gaining their place into the therapeutic options of physicians, in an attempt to avoid various adverse effects that the chemical drugs can cause.

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New unexplored research areas may include different strains of rats, more studies in larger mammals of comparable anatomy to humans, experiments on different liver diseases, publishing negative results regarding toxic doses of natural antioxidants, and testing different ischemia times.

The effect of rosmarinic acid on deformities occurring in brain tissue by craniectomy method. Histopathological evaluation of IBA-1 and GFAP expressions

PURPOSE

To investigate the role of Rosmarinic acid (RA) in the prevention of traumatic brain injury and the immunohistochemical analysis of IBA-1 and GFAP expressions.

METHODS

Healthy male rats were randomly divided into 3 groups consisting of 10 rats. Groups were as follows; control group, traumatic brain injury (TBI) group, and TBI+RA group. After traumatic brain injury, blood samples were taken from the animals and analyzed with various biochemical markers. And then IBA-1 and GFAP expressions were evaluated immunohistochemically.

RESULTS

Significant results were obtained in all biochemical parameters between groups. Immunohistochemical sections showed IBA-1 not only in microglia and macrophage activity but also in degenerative neurons in blood vessel endothelial cells. However, GFAP reaction and post-traumatic rosmarinic acid administration showed positive expression in astrocytes with regular structure around the blood vessel.

CONCLUSION

Rosmarinic acid in blood vessel endothelial cells showed that preserving the integrity of astrocytic structure in the blood brain barrier may be an important antioxidant.

Investigation of the role of rosmarinic acid treatment in regulating inflammation, cell damage, and angiogenesis in rat ovarian torsion and detorsion models

PURPOSE

To investigate the protective effect of rosmarinic acid (RA) in ovarian ischemia/reperfusion injury using biochemical, histopathological, and immunohistochemical methods.

METHODS

Wistar female rats (n = 32) were randomly divided into four groups: control, ischemia, ischemia-reperfusion, and ischemia-reperfusion with RA. Rosmarinic acid was given at a dose of 50 mg/kg by oral gavage three hours after reperfusion. Malondialdehyde (MDA) levels and glutathione peroxidase (GSH-Px) activities were determined in the ovary tissue homogenates for each rat.

RESULTS

In the ischemia-reperfusion with RA group, the epithelial cells are regularly regulated at the periphery, and the degenerative changes in preantral and antral follicle cells are reduced. Follicle cells and cells in the corpus luteum showed a decrease in vascular endothelial growth factor (VEGF) expression, while VEGF demonstrated a positive reaction in vascular endothelial cells and stromal cells. The TNF-α expression due to the decreased degenerative effect and inflammation was positive in the macrophage cells. The expression of caspase-3 as an apoptosis change was negative in antral follicle cells and granular cells around the antral follicle.

CONCLUSION

Different doses of RA may be useful in preventing ischemic damage after vascularization, inflammation, and apoptotic development after ischemia/reperfusion.

Nephroprotective effect of green tea, rosmarinic acid and rosemary on N-diethylnitrosamine initiated and ferric nitrilotriacetate promoted acute renal toxicity in Wistar rats

The present study was designed to investigate the chemoprotective effect of green tea extract (GTE), rosmarinic acid (RA) and rosemary extract (RE) against diethylnitrosamine (DEN) initiated and ferric nitrilotriacetate (Fe-NTA) promoted nephrotoxicity in rats. Forty male rats were categorized into five: Group I included healthy rats, group II received DEN+Fe-NTA, group III received 200 mg/kg b.wt. of RE+DEN+Fe-NTA, group IV received 1 g/kg b.wt. of GTE+DEN+Fe-NTA and group V received 50 mg/kg b.wt. of RA+DEN+Fe-NTA. RE, GTE, RA were given orally for 14 days before single intraperitoneal administration of DEN (160 mg/kg) till the end of the experiment. Eighteen days after DEN, a single intraperitoneal dose of Fe-NTA (5 mg Fe/kg) was administrated to rats to promote nephrotoxicity. The biochemical parameters were analyzed in serum at time intervals while the malondialdehyde (MDA) and tumor necrosis factor-alpha (TNF-α) were assessed in both serum and renal tissues. Kidney from each group was histopathologically examined at time intervals. The administration of Fe-NTA after DEN dose to albino rats resulted in acute nephrotoxicity which was characterized by a highly significant elevation of serum urea, creatinine, uric acid (p=0.000), serum and renal MDA and TNF-α (p=0.000) with vacuolation of epithelial lining renal tubules. The administration of RE, GTE and RA prior to DEN+Fe-NTA treatment significantly ameliorated the observed increased levels of the above mentioned parameters. GTE, RA & RE exerted a protective effect against renal toxicity with GTE showing a more pronounced effect on renal function parameters while RA showed the best antioxidant impact.

Therapeutic Potential of Rosmarinic Acid: A Comprehensive Review

Naturally occurring food-derived active ingredients have received huge attention for their chemopreventive and chemotherapy capabilities in several diseases. Rosmarinic acid (RA) is a caffeic acid ester and a naturally-occurring phenolic compound in a number of plants belonging to the Lamiaceae family, such as Rosmarinus officinalis (rosemary) from which it was formerly isolated. RA intervenes in carcinogenesis through different ways, including in tumor cell proliferation, apoptosis, metastasis, and inflammation. On the other hand, it also exerts powerful antimicrobial, anti-inflammatory, antioxidant and even antidepressant, anti-aging effects. The present review aims to provide an overview on anticancer activities of RA and to deliberate its therapeutic potential against a wide variety of diseases. Given the current evidence, RA may be considered as part of the daily diet in the treatment of several diseases, with pre-determined doses avoiding cytotoxicity.

Antisteatotic and antioxidant activities of Thymbra spicata L. extracts in hepatic and endothelial cells as in vitro models of non-alcoholic fatty liver disease

ETHNOPHARMACOLOGICAL RELEVANCE

Thymbra spicata, a member of the Lamiaceae family, is native to eastern Mediterranean area. Leaves of this plant are rich in phenolic compounds and are a popular remedy of traditional medicine in Lebanon to prevent and/or counteract hyperlipidemia and hyperglycemia.

AIM OF THE STUDY

To evaluate the antisteatotic and antioxidant activities of extracts from leaves of Thymbra spicata L. using in vitro models of non-alcoholic fatty liver disease (NAFLD), a leading cause of liver-related morbidity and mortality worldwide, for whom no effective treatments are still available.

MATERIALS AND METHODS

Two different extracts from Thymbra spicata L. aerial parts were prepared using water (TW) or ethanol (TE) as solvent. Their chemical composition was characterized by gas and liquid chromatography coupled with mass spectrometry. Both extracts were tested on cultured hepatic and endothelial cells treated to mimic in vitro a multisistemic pathology such as NAFLD. We assayed the effects on lipid accumulation, free radical production, lipid peroxidation, cell migration.

RESULTS

Both the total phenolic and the total flavonoid contents were higher in the ethanolic extract. Rosmarinic acid was the most abundant polyphenol in TW, while TE was richer in carvacrol. Our findings demonstrated that both extracts ameliorated lipid accumulation, oxidative stress and inflammation in the NAFLD cellular models. However, the aqueous extract was more effective to reduce hepatic steatosis, and the ethanolic extract had higheranti-oxidant potential and wound healing activity.

CONCLUSIONS

T. spicata extracts could be promising bioactive products to develop natural therapeutic agents or dietary supplements to treat NAFLD and obesity-related metabolic disease. Our findings suggest that while the ethanolic extract might be used in preventing endothelium dysfunction, the aqueous extract would act better as lipid-lowering agent.

Hepatoprotective effects of rosmarinic acid: Insight into its mechanisms of action

Liver diseases such as hepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma are one of the major health challenges in the world and many conditions such as inadequate nutrition, viral infection, ethanol and drug abuse, xenobiotic exposure, and metabolic diseases have been implicated in the development and progression of liver diseases. Several factors including lipid peroxidation, production of reactive oxygen species (ROS), peroxynitrite formation, complement factors and proinflammatory mediators, such as cytokines and chemokines, are involved in hepatic diseases. Rosmarinic acid (RA) is a natural phenolic compound found mainly in the family Lamiaceae consisting of several medicinal plants, herbs and spices. Several biological activities have been reported for RA and these include antioxidant properties as a ROS scavenger and lipid peroxidation inhibitor, anti-inflammatory, neuroprotective and antiangiogenic among others. This review is aimed at discussing the effects of RA on the liver, highlighting its hepatoprotective potential and the underlying mechanisms.

Rosmarinic acid attenuates hepatic steatosis by modulating ER stress and autophagy in oleic acid-induced HepG2 cells

Non-alcoholic fatty acid disease (NAFLD) has become an emerging entity of liver disorders worldwide. Oxidative stress and deranged autophagy-induced endoplasmic reticulum (ER) stress has recently been recognized as one of the prime factors involved in the pathological mechanism underlying NAFLD and progressive non-alcoholic steato-hepatitis (NASH). Epidemiological and experimental data reveal the potency of dietary polyphenols in averting NAFLD. In this line, to analyse and address the underlying pathogenic mechanisms, in the present study, oleic acid-induced HepG2 cells were treated with rosmarinic acid (RA), a dietary polyphenol with well-established cytoprotective properties. Treatment with rosmarinic acid (20 μg) was found to potently counter the elevated levels of total cholesterol (TC) and triglycerides (TG). Additionally, exposure of oleic acid-induced HepG2 cells to rosmarinic acid showed reduced levels of ROS and increased activity of enzymic and non-enzymic antioxidants. The steatotic HepG2 cells presented a pronounced increase in the expression of key ER stress markers such as p-PERK, p-IRE-1, ATF-6, p-eIF-α and CHOP, which was considerably reduced upon treatment with rosmarinic acid. Moreover, exposure to rosmarinic acid altered the deranged autophagic mechanism in oleic acid-induced HepG2 cells, which was observed via the protein expression of Beclin 1, LC31, ATG5 and ATG7. This study demonstrates that rosmarinic acid abrogates NAFLD via diminishing ER stress by nullifying oxidative stress and restoring deranged autophagy and can be used as a potent adjunct in the treatment of NAFLD, thus illustrating the valuable application of polyphenols in combating NAFLD.

Non-alcoholic fatty acid disease (NAFLD) has become an emerging entity of liver disorders worldwide.

Beneficial effects of rosmarinic acid against alcohol-induced hepatotoxicity in rats

Alcohol is a severe hepatotoxicant that causes a variety of liver disorders. Rosmarinic acid (RA), a natural phenol, shows some biological activities, including antioxidant and anti-inflammatory effects. We investigated the effects of RA (10 mg/kg) against ethanol-induced oxidative damage and hepatotoxicity in rats. Animals received ethanol (4 g/kg, i.g.) and (or) RA (10 mg/kg, i.g.) daily for 4 weeks. At the end of the treatment period, rats were weighed and use for biochemical, molecular, and histopathological examinations. Ethanol increased hepatic lipid peroxidation (P < 0.001) and decreased hepatic levels of reduced glutathione (P < 0.01), catalase (P < 0.05), and superoxide dismutase (P < 0.001) compared with control group. RA prevented the prooxidant and antioxidant imbalance induced by ethanol in liver. Furthermore, RA ameliorated the increased liver mass, serum levels of ALT, AST, LDH, TNF-α, and IL-6 in ethanol group. Necrosis and infiltration of inflammatory cells in liver parenchyma were attenuated by RA treatment. Our findings showed that RA prevents ethanol-induced oxidant/antioxidant imbalance and liver injury in an experimental model of ethanol-induced hepatotoxicity. Therefore, RA may be a good candidate to protect against ethanol-induced hepatotoxicity; this deserves consideration and further examination.

Effects of rosmarinic acid on acetaminophen-induced hepatotoxicity in male Wistar rats

CONTEXT

Drug-induced liver injury is a significant worldwide clinical problem. Rosmarinic acid (RA), a natural phenol, has antioxidant effects.

OBJECTIVE

The effects of RA against acetaminophen (N-acetyl-p-amino-phenol (APAP))-induced oxidative damage and hepatotoxicity in rats were investigated.

MATERIALS AND METHODS

Male Wistar rats were pretreated with RA (10, 50 and 100 mg/kg, i.g.) for one week. On day 7, rats received APAP (500 mg/kg, i.p.). Then aspartate aminotransferase (AST), alanine aminotransferase (ALT), albumin, total protein, malondialdehyde (MDA), glutathione (GSH), total antioxidant capacity (TAC), glutathione S-transferase (GST), cytochrome CYP450 and histopathological changes were determined.

RESULTS

APAP-induced oxidative stress in liver by a significant increase in the level of MDA (7.6 ± 0.21 nmol/mg) as well as a decrease in the contents of TAC (1.75 ± 0.14 μmol/g), GSH (1.9 ± 0.22 μmol/g) and GST) 3.2 ± 0.28 U/mg). RA treatment decreased MDA (4.32 ± 0.35 nmol/mg) but increased the contents of TAC (3.51 ± 0.34 μmol/g), GSH (3.42 ± 0.16 μmol/g) and GST (5.71 ± 0.71 μmol/g) in APAP group. RA 100 mg/kg decreased ALT (91.5 ± 1.5 U/L), AST (169 ± 8.8 U/L) and CYP450 (3 ± 0.2 nmol/min/mg) in APAP group. Histologically RA attenuated hepatic damage by decreasing necrosis, inflammation, and haemorrhage in liver sections of APAP group.

DISCUSSION AND CONCLUSIONS

This is the first report that oral administration of RA dose-dependently elicited significant hepatoprotective effects in rats through inhibition of hepatic CYP2E1 activity and lipid peroxidation. RA-protected hepatic GSH and GST reserves and total tissue antioxidant capacity.

Hepatoprotective activities of rosmarinic acid against extrahepatic cholestasis in rats

Though rosmarinic acid possesses nutritional, pharmaceutical, and toxic properties and shows therapeutic potential on liver diseases, its therapeutic effects against cholestatic liver diseases have not been proven. Using an extrahepatic cholestasis rat model by bile-duct ligation (BDL), daily oral administration of rosmarinic acid showed improvement effects on liver histology, serum biochemicals, ductular reaction, oxidative stress, inflammation, and fibrosis. Rosmarinic acid alleviated BDL-induced transforming growth factor beta-1 (TGF-β1) production and hepatic collagen deposition, and the anti-fibrotic effects were accompanied by reductions in matrix-producing cells and Smad2/3. BDL rats showed increased hepatic NF-κB/AP-1 activities, inflammatory cell infiltration/accumulation, and cytokine production, and these signs of hepatic inflammation were ameliorated by rosmarinic acid. Mechanistic study revealed an inhibitory effect of rosmarinic acid on the axis of the high mobility group box-1 (HMGB1)/toll-like receptor-4 (TLR4) in BDL rats. Results of cultured hepatic stellate cells further showed the impacts of rosmarinic acid which attenuated TGF-β1-induced stellate cell mitogenic and fibrogenic activation. Our findings support the concept that rosmarinic acid could serve as a hepatoprotective agent, and dietary rosmarinic acid supplementation may be beneficial in terms of improving cholestasis-related liver injury via mechanisms involving resolution of oxidative burden and down-regulation of HMGB1/TLR4, NF-κB, AP-1, and TGF-β1/Smad signaling.

New progress in roles of nitric oxide during hepatic ischemia reperfusion injury

Hepatic ischemia reperfusion injury (HIRI) is a clinical condition which may lead to cellular injury and organ dysfunction. The role of nitric oxide (NO) in HIRI is complicated and inconclusive. NO produced by endothelial nitric oxide synthase (eNOS) activation plays a protective role during early HIRI. But eNOS overexpression and the resulting excessive NO bioavailability can aggravate liver injury. NO induced by inducible nitric oxide synthase (iNOS) may have either a protective or a deleterious effect during the early phase of HIRI, but it may protect the liver during late HIRI. Here, we reviewed the latest findings on the role of NO during HIRI: (1) NO exerts a protective effect against HIRI by increasing NO bioavailability, downregulating p53 gene expression, decreasing inflammatory chemokines, reducing ROS via inhibiting the mitochondrial respiratory chain, activating sGC-GTP-cGMP signal pathway to reduce liver cell apoptosis, and regulating hepatic immune functions; (2) eNOS protects against HIRI by increasing NO levels, several eNOS/NO signal pathways (such as Akt-eNOS/NO, AMPK-eNOS/NO and HIF-1α-eNOS/NO) participating in the anti-HIRI process, and inhibiting over-expression of eNOS also protects against HIRI; and (3) the inhibition of iNOS prevents HIRI. Thus, the adverse effects of NO should be avoided, but its positive effect in the clinical treatment of diseases associated with HIRI should be recognized.

Rosmarinic acid protects rat hippocampal neurons from cerebral ischemia/reperfusion injury via the Akt/JNK3/caspase-3 signaling pathway

Cerebral ischemia/reperfusion injury can result in neuronal death, which further results in brain damage and can even lead to death. Although recent studies showed that rosmarinic acid (RA) exerts neuroprotective effects and attenuates ischemia-induced brain injury and neuronal cell death, little is known about the precise mechanisms that occur during cerebral ischemia/reperfusion (I/R). Therefore, the aim of this study was to examine the underlying mechanism of the neuroprotective effects of RA against ischemic brain injury induced by cerebral I/R. Transient global brain ischemia was induced by 4-vessel occlusion in adult male Sprague-Dawley rats. We randomly divided rats into five groups: sham, I/R, I/R+RA, I/R+Vehicle and I/R+RA+LY. Open-field, closed-field and Morris water maze tests were carried our separately to examine the anxiety and cognitive behavior of each group. Cresyl violet staining was used to examine the survival of hippocampal CA1 pyramidal neurons. The levels of p-Akt, p-JNK3 and cleaved caspase-3 in the hippocampus were also examined by Western blotting. Our results showed that administration of RA protected locomotive ability, relieved anxiety behavior and protected cognitive ability in cerebral I/R-injured rats. Additionally, RA significantly protected neurons in the hippocampal CA1 region against cerebral I/R-induced damage. Furthermore, RA increased the phosphorylation of Akt1, downregulated the phosphorylation of JNK3 and reduced the expression of cleaved caspase-3. Finally, the Akt inhibitor LY294002 reversed all the protective effects of RA, indicating that RA protects neurons in the hippocampal CA1 region from ischemic damage through the Akt/JNK3/caspase-3 signaling pathway.

Preconditioning methods in the management of hepatic ischemia reperfusion- induced injury: Update on molecular and future perspectives

Hepatic IR (ischemia reperfusion) injury is a commonly encountered obstacle in the post-operative management of hepatic surgery. Hepatic IR occurs during 'Pringle maneuver' for reduction of blood loss or during a brief period of cold storage followed by reperfusion of liver grafts. The stress induced during hepatic IR, triggers a spectrum of cellular responses leading to the varying degrees of hepatic complications which in turn affect the post operative care. Different preconditioning methods either activate or subdue different sets of molecular signals, resulting in varied levels of protection against hepatic IR injury. Yet, there is a serious lacuna in the knowledge regarding the choice of preconditioning methods and the resulting molecular changes in order to assess the efficiency and choice of these methods correctly. This review provides an update on the various preconditioning approaches such as surgical/ischemic, antioxidant, pharmaceutical and genetic preconditioning strategies published during last six years (2009-2015). Further, we discuss the attenuation or inhibition of specific inflammatory, apoptotic and necrotic markers in the various experimental models of liver IR subjected to different preconditioning strategies. While enlisting the controversies in the ischemic preconditioning strategy, we bring out the uncertainties in the existing molecular targets and their reliability in the attenuation of hepatic IR injury. Future research studies would include the novel preconditioning strategies employ i) the targeted gene silencing of key molecular targets inducing IR, ii) hyper expression of beneficial molecular signals against IR via gene transfer techniques. The above studies would see the combination of these latest techniques with the established preconditioning strategies for better post-operative hepatic management.

Mixed results with mixed disulfides

A period of research with Helmut Sies in the 1980s is recalled. Our experiments aimed at an in-depth understanding of metabolic changes due to oxidative challenges under near-physiological conditions, i.e. perfused organs. A major focus were alterations of the glutathione and the NADPH/NADP(+) system by different kinds of oxidants, in particular formation of glutathione mixed disulfides with proteins. To analyze mixed disulfides, a test was adapted which is widely used until today. The observations in perfused rat livers let us believe that glutathione-6-phosphate dehydrogenase (G6PDH), i.a. might be activated by glutathionylation. Although we did not succeed to verify this hypothesis for the special case of G6PDH, the regulation of enzyme/protein activities by glutathionylation today is an accepted posttranslational mechanism in redox biology in general. Our early experimental approaches are discussed in the context of present knowledge.

Molecular mechanisms of rosmarinic acid from Salvia miltiorrhiza in acute lymphoblastic leukemia cells

ETHNOPHARMACOLOGICAL RELEVANCE

Rosmarinic acid (RA), a major hydrosoluble bioactive compound found in the Chinese medicinal herb, Salvia miltiorrhiza Bunge, which has been used in traditional Chinese medicine to treat various diseases, including cancer. However, the mechanisms have not been fully elucidated.

AIM OF THE STUDY

Guided by microarray hybridization and Ingenuity Pathway Analysis, we identified modes of action of rosmarinic acid (RA) isolated from S. miltiorrhiza on acute lymphoblastic leukemia cells.

MATERIALS AND METHODS

Microarray data were verified by independent methods: Real-time RT-PCR (mRNA expression), resazurin assay (cytotoxicity of RA towards parental CCRF-CEM, multidrug-resistant CEM/ADR5000 cells and normal lymphocytes), flow cytometry (cell cycle arrest, apoptosis, necroptosis, generation of reactive oxygen species (ROS), disruption of mitochondrial membrane potential (MMP)), single cell gel electrophoresis (DNA damage), molecular docking and gene promoter binding motif analysis (NFκB), Western blotting (nuclear NFκB translocation, PARP cleavage, caspase 3/7/9 expression), and fibronectin-based cell adhesion assay.

RESULTS

RA dose-dependently inhibited CCRF-CEM and CEM/ADR5000 cells, but caused less cytotoxicity towards normal lymphocytes. RA simultaneously induced apoptosis and necrosis, as shown by cell morphology and annexin V-PI assay. DNA damage was dose-dependently induced without ROS generation, which subsequently led to cell cycle arrest. RA-stimulated MMP dysfunction activated PARP-cleavage and caspase-independent apoptosis. In accordance with molecular docking and gene promoter binding motif analyses, p65 translocation from the cytosol to the nucleus was blocked by RA, indicating a mechanistic role of the NFκB pathway to explain RA's action. RA affected cellular movement as evaluated by ameliorating cell adhesion to fibronectin.

CONCLUSIONS

RA induced apoptosis and necrosis in a ROS-independent DNA damage and caspase-independent manner. These results may contribute to the rationale use of S. miltiorrhiza and RA in traditional medicine of leukemia.

Molecular pathways in protecting the liver from ischaemia/reperfusion injury: a 2015 update

Ischaemia/reperfusion injury is an important cause of liver damage during surgical procedures such as hepatic resection and liver transplantation, and represents the main cause of graft dysfunction post-transplantation. Molecular processes occurring during hepatic ischaemia/reperfusion are diverse, and continuously include new and complex mechanisms. The present review aims to summarize the newest concepts and hypotheses regarding the pathophysiology of liver ischaemia/reperfusion, making clear distinction between situations of cold and warm ischaemia. Moreover, the most updated therapeutic strategies including pharmacological, genetic and surgical interventions, as well as some of the scientific controversies in the field are described.