Protective Effects Of Carnosic Acid Research Articles

Induction of Phosphorylated Tau Accumulation and Memory Impairment by Bisphenol A and the Protective Effects of Carnosic Acid in In Vitro and In Vivo.

Bisphenol A (BPA) is a component of polycarbonate plastics that has been implicated in memory impairment. The present study investigated the effect of carnosic acid (CA) on memory deficit induced by BPA and the role of Akt in this mechanism. First, SH-SY5Y cells were treated with 20nM BPA and 1μM CA for 12h. The results showed that treatment of CA with BPA improved the alternation of IRS-1/Akt/GSK-3β as well as the induction of ApoE and Ser396p-tau. Moreover, treatment of CA with BPA restored the signaling involved in long-term potentiation (LTP) effect, leading to induction of synaptic-related proteins, such as PSD-95, synapsin1a, and pro-BDNF. Wortmannin treatment alleviated the reversal by CA. Then, C57BL/6J male mice were orally administered with CA to test the memory function in BPA treatment. The results showed that CA and RE can improve BPA-induced impairment of motor, recognition, and spatial memory by using open-field test (OFT), novel objective recognition test (NOR), and Y-maze test, respectively. Moreover, CA and RE improved the phosphorylation of tau and the reduction of PSD-95, synapsin1a, and pro-BDNF proteins induced by BPA. Therefore, the results indicated that CA decreased the phosphorylated tau and memory impairment induced by BPA through Akt pathway.

The protective effect of carnosic acid on dextran sulfate sodium-induced colitis based on metabolomics and gut microbiota analysis

Accumulating evidence suggests that the gut microbiota plays an important role in the pathogenesis of inflammatory bowel disease (IBD). Carnosic acid (CA) is a major antioxidant component of rosemary and sage. Herein, we investigated the protective effects of dietary CA on dextran sodium sulfate (DSS)-induced colitis mouse model with an emphasis on its impact on the composition and metabolic function of gut microbiota. We found that CA effectively attenuated DSS-stimulated colitis in mice, as evidenced by reduced disease activity index (DAI), and systemic and colonic inflammation. Additionally, CA restored microbial diversity and improved the composition of gut microbiota in DSS-treated mice. Moreover, Spearman’s correlation coefficient showed a significant correlation between the fecal metabolites and the gut microbiota species. Changes in gut microbiota and the correlated metabolites might partially explain CA’s anti-inflammatory effects against colitis. Future clinical trials are needed to determine the therapeutic effects and mechanisms of CA on IBD in humans.

Protective Effects of Carnosic Acid on Lipopolysaccharide-Induced Acute Kidney Injury in Mice.

Septic acute kidney injury (AKI) is an important medical problem worldwide, but current treatments are limited. During sepsis, lipopolysaccharide (LPS) activates various signaling pathways involved in multiorgan failure. Carnosic acid is a natural phenolic diterpene and has multiple bioactivities, such as anti-tumor, anti-inflammatory, and anti-oxidative effects. However, the effect of carnosic acid on septic AKI has not been explored. Therefore, this study aimed to determine whether carnosic acid has a therapeutic effect on LPS-induced kidney injury. Administration of carnosic acid after LPS injection ameliorated histological abnormalities and renal dysfunction. Cytokine production, immune cell infiltration, and nuclear factor-κB activation after LPS injection were also alleviated by carnosic acid. The compound suppressed oxidative stress with the modulation of pro-oxidant and antioxidant enzymes. Tubular cell apoptosis and caspase-3 activation were also inhibited by carnosic acid. These data suggest that carnosic acid ameliorates LPS-induced AKI via inhibition of inflammation, oxidative stress, and apoptosis and could serve as a useful treatment agent for septic AKI.

Carnosic acid protects against ferroptosis in PC12 cells exposed to erastin through activation of Nrf2 pathway

AimsFerroptosis is involved in the pathogenesis of spinal cord injury (SCI). Carnosic acid (CA) is a natural phenolic diterpene, which possesses diversiform activities. However, whether the protective effect of CA on SCI is partly due to inhibition of ferroptosis was seldom investigated. Therefore, the objective of this study aimed to investigate the role of CA on ferroptosis in PC12 cells and the underlying mechanisms. Main methodsCell viability, malondialdehyde (MDA) contents, glutathione (GSH) levels, and iron levels were detected to identify the construction of ferroptosis model in PC12 cell induced by erastin. The safe concentrations of CA on PC12 cells were measured via cell counting kit-8 (CCK-8) assays. Then, cellular MDA contents, GSH levels, iron levels, reactive species (RS) generation, and mitochondrial morphology were tested to determine the influence of CA on ferroptosis in erastin-treated PC12 cells. In addition, Western blot and RT-qPCR were utilized to detecteddetect the ferroptosis-related genes and proteins expression levels. Key findingsOur study indicated that treatment with CA could reversed the increased MDA, iron, and RS levels, as well as the decreased GSH levels in erastin-treated PC12 cells. The protective effect of CA could be blocked by ML385. The inhibitory effect of CA on ferroptosis probably was partially governed by activation of Nrf2 to regulate the GSH synthesis and metabolism and cellular iron homeostasis. SignificanceCA can inhibit ferroptosis in PC12 cells induced by erastin via activating Nrf2 pathway, indicating that CA could lead to neuroprotective effect by restraining the occurrence of ferroptosis.

Effect of carnosic acid on acrylamide induced neurotoxicity: in vivo and in vitro experiments

Acrylamide (ACR), one of the most toxic chemical agents in humans and animals has several uses in different industries. Carnosic acid is an important biological antioxidant extracted from rosemary. In this study, the protective effect of carnosic acid on ACR-induced neurotoxicity in rat and PC12 cells has been investigated. Male Wistar rats were randomly divided into eight groups including (1) control group, (2) ACR (50 mg/kg, i.p.), (3–6) ACR plus carnosic acid (5, 10, 20, and 40 mg/kg, i.p.), (7) ACR plus vitamin E (200 mg/kg i.p., every other day), and (8) carnosic acid (40 mg/kg i.p.). After 11 days, behavioral tests were evaluated. Malondialdehyde (MDA), glutathione (GSH) and Bax, Bcl-2, and caspase 3 protein levels in brain tissue were measured. In in vitro study, the protective effects of carnosic acid on ACR toxicity were assessed by MTT assay. ACR caused severe motor impairment compared to control, increased MDA, and decreased GSH level. ACR increased Bax/Bcl-2 ratio and cleaved caspase-3. Carnosic acid (40 mg/kg) significantly recovered locomotor disorders. Additionally, carnosic acid increased GSH content, reduced MDA, and decreased Bax/Bcl-2 ratio, and caspase 3 protein levels. Carnosic acid increased cell viability compared to ACR at concentrations of 2.5–10 μM. Carnosic acid is the most abundant antioxidant compound found in the rosemary leaves. Recently, natural compounds have been suggested as potential treatment interventions for various diseases through their antioxidant properties. In this study, carnosic acid reduced ACR-induced toxicity through inhibition of oxidative stress and apoptosis.

Protective effect of carnosic acid on acrylamide-induced liver toxicity in rats: Mechanistic approach over Nrf2-Keap1 pathway.

Acrylamide is a food contaminant with a range of toxic effects. Carnosic acid (C20 H28 O4 ) is a phenolic compound found in plants and has many beneficial effects. In this study, we aimed at investigating the effect of carnosic acid on acrylamide-induced liver damage. Rats (n = 7) were allotted to control, carnosic acid, acrylamide, acrylamide + carnosic acid groups. Animals were euthanized. Their blood was taken for biochemical analysis, and liver tissue was excised for morphological, immunohistochemical, and immunoblotting analyses. As a result, acrylamide reduced bodyweight, liver weight, catalase, and total antioxidant capacity levels but increased alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, malondialdehyde, total oxidant status, oxidative stress index levels, Nrf2, and Keap1 protein levels. In addition, acrylamide disrupted liver histology leading to vascular congestion, cellular infiltration, necrotic cells, and so forth. Carnosic acid cotreatment ameliorated the altered biochemical parameters, liver histology, Nrf2, and Keap1 enzyme levels. In conclusion, carnosic acid has the potential to be used as a protective agent against acrylamide-induced liver damage.

Protective effects of carnosic acid on retinal ganglion cells in acute ocular hypertension rats.

To observe the protective effects of carnosic acid on rat retinal ganglion cells (RGCs) among acute ocular hypertension rats. Sixty male SPF (specific-pathogen-free) SD rats (10weeks) were randomly assigned to untreated group, carnosic-acid-treated group and hypertensive group with 20 rats for each. The acute ocular hypertension animal model was induced by the perfusion of normal saline solution into anterior chamber of eyes to elevate the intraocular pressure (IOP) to 110mmHg for 60min in the rats of the carnosic-acid-treated group and hypertensive group. Then, the carnosic acid dissolving in dimethyl sulfoxide (DMSO) was intraperitoneally injected for consecutive 7days in the carnosic-acid-treated group, and only DMSO was used in the same way in the hypertensive group. The rats were killed 2weeks after experiment, and retinal sections were prepared for histopathological and apoptotic retinal ganglion cells (RGCs) examination by hemotoxylin and eosin staining and TUNEL staining. Use immunofluorescence employed to examine the survival of RGCs. This study protocol was approved by the Ethic Committee for Experimental Animal of Three Gorges University. The retinal morphology and structure were clear in the untreated group. The edema of retinal tissue, loosely arranged RGCs and swollen nucleus were seen in the hypertensive group. In the carnosic-acid-treated group, the retinal morphology and structure were regular. The retinal nerve fiber layer (RNFL) thickness was (32.96 ± 1.63), (58.96 ± 1.57) and (50.11 ± 2.37) μm, and the apoptotic cell number was (6.92 ± 2.96), (29.85 ± 6.40) and (14.69 ± 2.98)/field, and the survived cell number was (2363.17 ± 148.45), (1308.67 ± 106.02) and (1614.17 ± 96.39)/0.235mm2 in the untreated group, hypertensive group and carnosic-acid-treated group, respectively, showing significant differences among groups (F = 339.284, 81.583, 122.68, all at P < 0.01). Compared with the untreated group, the RNFL thickness was thickened, the number of apoptotic RGCs was much more, and the number of survived RGCs was decreased in the hypertensive group. In the carnosic-acid-treated group, the RNFL thickness was thinner, the number of apoptotic RGCs was reduced, and the number of survived RGCs was increased in comparison with the untreated group (all at P < 0.01). Carnosic acid plays a protective effect on RGCs by inhibiting the cell apoptosis in acute ocular hypertension rats.

PINK1/parkin-mediated mitophagy pathway is related to neuroprotection by carnosic acid in SH-SY5Y cells

Impairment in mitophagy contributes to the pathology of Parkinson's disease. This study investigated whether Phosphatase and tensin homologue (PTEN)-induced kinase 1 (PINK1)/parkin-mediated mitophagy is linked to the protective effect of carnosic acid (CA) from rosemary. Treatment of SH-SY5Y cells with 6-hydroxydopamine (6-OHDA) disrupted the mitochondrial membrane potential, inhibited voltage-dependent anion channel 1 (VDAC1) protein, and induced cytosolic cytochrome c, but CA pretreatment reversed these findings. By immunofluorescence, CA pretreatment was shown to increase the co-localization of red fluorescence (parkin) and MitoTracker green FM fluorescence (mitochondria), indicating that CA promoted the translocation of parkin into mitochondria. Immunoprecipitation with VDAC1 antibody showed that 6-OHDA treatment decreased the interaction of ubiquitinated protein with VDAC1. However, CA pretreatment reversed this reduction in the interaction of ubiquitinated protein with VDAC1. Silencing of PINK1 and parkin by use of small interfering RNA (siRNA) attenuated the ability of CA to reverse 6-OHDA-inhibited autophagic vacuoles. Moreover, in PINK1 siRNA-transfected cells, CA no longer reversed these actions of 6-OHDA on the inhibition of mitophagy-related proteins (PINK1, parkin, VDAC1, and LC3-II) and anti-apoptotic Bcl-2 protein, as well as the induction of apoptotic-related proteins, and nuclear condensation. In conclusion, CA appears to counteract the neurotoxicity of 6-OHDA by activating PINK1/parkin-mediated mitophagy.

Carvedilol (CAR) combined with carnosic acid (CAA) attenuates doxorubicin-induced cardiotoxicity by suppressing excessive oxidative stress, inflammation, apoptosis and autophagy

Doxorubicin (DOX) is a wide spectrum antitumor drug. However, its clinical application is limited due to the cardiotoxicity. Carvedilol (CAR) is a β-blocker used to treat high blood pressure and heart failure. Accordingly, supplementation with natural antioxidants or plant extracts exerts protective effects against various injury in vivo. Carnosic acid (CAA), the principal constituent of rosemary, has various biological activities, including antioxidant, antitumor, and anti-inflammatory. Here, heart injury mouse model was established using DOX (20 mg/kg) in vivo. And cardiac muscle cell line of H9C2 was subjected to 0.5 μM of DOX for 24 h in vitro. Then, the protective effects of CAA and CAR alone, or the two in combination on DOX-induced cardiotoxicity in vivo and in vitro were explored. The results indicated that both CAA and CAR, when used alone, were moderately effective in attenuating DOX-induced cardiotoxicity. The combination of two drugs functioned synergistically to ameliorate cardiac injury caused by DOX, as evidenced by the significantly reduced collagen accumulation and improved dysfunction of heart. CAA and CAR exhibited stronger anti-oxidative role in DOX-treated mice partly by augmenting the expression and activities of the anti-oxidative enzymes. In addition, inflammatory response was significantly suppressed by the two in combination, proved by the decreased pro-inflammatory cytokines (COX2, TNF-α, IL-6, IL-1β and IL-18), which was associated with the inactivation of nuclear factor κB (NF-κB). Furthermore, DOX-stirred apoptosis and autophagy were dramatically attenuated by the co-treatments of CAA and CAR through down-regulating cleaved Caspase-3 and LC3B signaling pathways. The effects of CAA and CAR combination against cardiotoxicity were observed in H9C2 cells with DOX stimulation. Our findings above suggested that the use of CAR and CAA in combination could be expected to have synergistic efficacy and significant potential against cardiotoxicity induced by DOX.

Protective effect of carnosic acid and its semisynthetic derivatives against H2O2-induced neurotoxicity

Carnosic acid and its new derivatives (17 in total) were tested for their protective effects on hippocampal neuron against H2O2-induced damage using cell counting kit-8. Carnosic acid and its derivatives showed significant neuroprotective activity. Moreover, ester 4 and amides 5k, 5 l, 5 m had higher activity than that of carnosic acid. The catechol hydroxyl groups and carboxyl groups might not be truly necessary for the neuroprotective activity of CA. Choosing suitable substituents helps to further improve the activity and physicochemical properties of the compounds. We expect that our research results will provide some new ideas for the development of novel neuroprotection agents using derivatives of carnosic acid.

Protective effects of carnosic acid against mitochondria-mediated injury in H9c2 cardiomyocytes induced by hypoxia/reoxygenation.

Myocardial ischemia and reperfusion occurs in myocardial infarction. Timely reperfusion will exacerbate the injury through the mitochondria-mediated apoptosis in cardiomyocytes due to the accumulation of excessive reactive oxygen species (ROS). In order to identify novel therapeutic approaches, the cardioprotective effects of carnosic acid and the underlying mechanisms were investigated in the present study in H9c2 cardiomyocytes injured by hypoxia/reoxygenation in vitro. The viability of H9c2 cardiomyocytes was detected by MTT assay and further confirmed by the detection of intracellular lactate dehydrogenase (LDH) release. The mitochondrial function in H9c2 cardiomyocytes was evaluated using fluorescence methods. The proteins related to apoptosis, including caspase-3, B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax) were analyzed by western blot analysis, and the activity of caspase-3 was determined using a colorimetric method. As a result, carnosic acid was demonstrated to improve the viability of H9c2 cardiomyocytes and suppress the leakage of cytosolic lactate dehydrogenase under hypoxia/reoxygenation. In addition, the overproduction of intracellular ROS and intracellular calcium overload were ameliorated in the presence of carnosic acid. The dysfunction of mitochondria in H9c2 cardiomyocytes was also attenuated by carnosic acid through blocking the collapse of mitochondrial membrane potential (MMP) and mitochondrial permeability transition pore (mPTP) opening. Furthermore, the apoptosis of H9c2 cardiomyocytes resulted from hypoxia/reoxygenation was inhibited by carnosic acid through the upregulation of Bcl-2 and the downregulation of Bax and caspase-3 levels. These results provided evidence for further investigation that would assist in the development of novel therapeutic approaches for myocardial infarction.

Protective effect of carnosic acid against acrylamide-induced toxicity in RPE cells

Acrylamide is a substance that can be neurotoxic in humans and experimental animals. It is formed at different rates in starchy foods cooked at temperatures above 120 °C as a result of interaction between monosaccharides and the amino acid asparagine. Carnosic acid accounts for over 90% of the antioxidant properties of rosemary extract and is a powerful inhibitor of lipid peroxidation in microsomal and liposomal systems. Carnosic acid has been shown to protect against oxidative and inflammatory effects. In order to investigate the protective properties of carnosic acid against acrylamide-induced toxicity in human retinal pigment epithelium (RPE) cells, ARPE-19 cells were pre-treated with 10 μM carnosic acid for 24 h followed by treatment with acrylamide (0.7 or 1 mM) for 24 h. ARPE-19 cells pre-treated with 10 μM carnosic acid showed significantly increased cell viability and decreased cell death rate when compared to ARPE-19 cells treated with acrylamide alone. Activities of SOD and catalase and the level of GSH and expression of NRF2 and a number of anti-oxidant genes were significantly decreased in ARPE-19 cells, while there were significant increases in ROS and MDA; pre-treatment with carnosic acid significantly counteracted these changes. Our results suggest that carnosic acid protected RPE cells from acrylamide-induced toxicity.

Carnosic acid protects against acetaminophen-induced hepatotoxicity by potentiating Nrf2-mediated antioxidant capacity in mice.

Acetaminophen (APAP) overdose is one of the most common causes of acute liver failure. The study aimed to investigate the protective effect of carnosic acid (CA) on APAP-induced acute hepatotoxicity and its underlying mechanism in mice. To induce hepatotoxicity, APAP solution (400 mg/kg) was administered into mice by intraperitoneal injection. Histological analysis revealed that CA treatment significantly ameliorated APAP-induced hepatic necrosis. The levels of both alanine aminotransferase (ALT) and aspartate transaminase (AST) in serum were reduced by CA treatment. Moreover, CA treatment significantly inhibited APAP-induced hepatocytes necrosis and lactate dehydrogenase (LDH) releasing. Western blot analysis showed that CA abrogated APAP-induced cleaved caspase-3, Bax and phosphorylated JNK protein expression. Further results showed that CA treatment markedly inhibited APAP-induced pro-inflammatory cytokines TNF-α, IL-1β, IL-6 and MCP-1 mRNA expression and the levels of phosphorylated IκBα and p65 protein in the liver. In addition, CA treatment reduced APAP- induced hepatic malondialdehyde (MDA) contents and reactive oxygen species (ROS) accumulation. Conversely, hepatic glutathione (GSH) level was increased by administration of CA in APAP-treated mice. Mechanistically, CA facilitated Nrf2 translocation into nuclear through blocking the interaction between Nrf2 and Keap1, which, in turn, upregulated anti-oxidant genes mRNA expression. Taken together, our results indicate that CA facilitates Nrf2 nuclear translocation, causing induction of Nrf2-dependent genes, which contributes to protection from acetaminophen hepatotoxicity.

Protective effect of carnosic acid against paraquat-induced redox impairment and mitochondrial dysfunction in SH-SY5Y cells: Role for PI3K/Akt/Nrf2 pathway

Carnosic acid (CA) is a phenolic diterpene isolated from Rosmarinus officinalis and exerts anti-inflammatory, antioxidant, and anticarcinogenic activities in different cell types. It has been reported that CA is able to cause protective effects on experimental models of neurodegeneration. However, the exact mechanism by which CA prevents neuronal degeneration remains to be better studied. We investigated here whether there is a role for CA as a neuroprotective agent in a paraquat (PQ) model of Parkinson's disease (PD) regarding cellular and mitochondrial-related redox parameters. SH-SY5Y cells were treated with CA for 12h and were exposed to 100μM PQ for 24h. It was found that CA at different concentrations prevented the effects of PQ on cell viability and redox parameters. CA alleviated reactive oxygen and nitrogen species production elicited by PQ, as well as decreased the toxic effect on mitochondrial function. Inhibition of Pi3K/Akt pathway with LY294002 or silencing of Nrf2 expression partially blocked the reversal of redox impairment induced by CA. Therefore, CA activated Nrf2 through modulation of PI3K/Akt pathway resulting in increased levels of antioxidant enzymes and consequent neuroprotection. Thus, CA may be viewed as a potential neuroprotective agent to be used in cases of Parkinson's disease (PD).

Role for the PI3K/Akt/Nrf2 signaling pathway in the protective effects of carnosic acid against methylglyoxal-induced neurotoxicity in SH-SY5Y neuroblastoma cells

Glycation, a process that occurs endogenously and generates advanced glycation end products (AGEs), presents an important role in cases of neurodegeneration, as for instance Alzheimer's disease (AD). Methylglyoxal (MG), a dicarbonyl compound, is the most potent inducer of AGEs, whose levels have been found increased in samples obtained from subjects suffering from AD. Moreover, MG induces protein cross-linking and redox impairment in vitro and in vivo. Carnosic acid (CA), a phenolic diterpene isolated from Rosmarinus officinalis, exerts protective effects in neuronal cells by increasing antioxidant defenses and detoxification systems. In the present work, we aimed to investigate whether there is a role for CA against MG-induced neurotoxicity. Data obtained here clearly demonstrate that CA pretreatment (1 μM for 12 h) caused cytoprotective effects and counteracted the damage elicited by MG in SH-SY5Y cells. CA inhibited loss of mitochondrial membrane polarity (MMP) and cytochrome c release from mitochondria, consequently blocking activation of pro-apoptotic caspase enzymes. Furthermore, CA alleviated MG-induced oxidative and nitrosative damage. CA prevented MG-dependent neurotoxicity by activating the PI3K/Akt/Nrf2 signaling pathway and the antioxidant enzymes modulated by Nrf2 transcription factor. Overall, the data presented here show the protective role of CA by its ability to counteract MG negative effects.

Protective efficacy of carnosic acid against hydrogen peroxide induced oxidative injury in HepG2 cells through the SIRT1 pathway.

Carnosic acid (CA), found in rosemary, has been reported to have antioxidant and antiadipogenic properties. Here, we investigate the molecular mechanism by which CA inhibits hydrogen peroxide (H2O2)-induced injury in HepG2 cells. Cells were pretreated with 2.5-10 μmol/L CA for 2 h and then exposed to 3 mmol/L H2O2 for an additional 4 h. CA dose-dependently increased cell viability and decreased lactate dehydrogenase activities. Pretreatment with CA completely attenuated the inhibited expression of manganese superoxide dismutase (MnSOD) and the B-cell lymphoma-extra large (Bcl-xL), and reduced glutathione activity caused by H2O2, whereas it reversed reactive oxygen species accumulation and the increase in cleaved caspase-3. Importantly, sirtuin 1 (SIRT1), a NAD(+)-dependent deacetylase, was significantly increased by CA. Considering the above results, we hypothesized that SIRT1 may play important roles in the protective effects of CA in injury induced by H2O2. As expected, SIRT1 suppression by Ex527 (6-chloro-2,3,4,9-tetrahydro-1H-carbazole-1-carboxamide) and siRNA-mediated SIRT1 silencing (si-SIRT1) significantly aggravated the H2O2-induced increased level of cleaved caspase-3 but greatly reduced the decreased expression of MnSOD and Bcl-xL. Furthermore, the positive regulatory effect of CA was inhibited by si-SIRT1. Collectively, the present study indicated that CA can alleviate H2O2-induced hepatocyte damage through the SIRT1 pathway.

Protection from cyanide-induced brain injury by the Nrf2 transcriptional activator carnosic acid.

Cyanide is a life-threatening, bioterrorist agent, preventing cellular respiration by inhibiting cytochrome c oxidase, resulting in cardiopulmonary failure, hypoxic brain injury, and death within minutes. However, even after treatment with various antidotes to protect cytochrome oxidase, cyanide intoxication in humans can induce a delayed-onset neurological syndrome that includes symptoms of Parkinsonism. Additional mechanisms are thought to underlie cyanide-induced neuronal damage, including generation of reactive oxygen species. This may account for the fact that antioxidants prevent some aspects of cyanide-induced neuronal damage. Here, as a potential preemptive countermeasure against a bioterrorist attack with cyanide, we tested the CNS protective effect of carnosic acid (CA), a pro-electrophilic compound found in the herb rosemary. CA crosses the blood-brain barrier to up-regulate endogenous antioxidant enzymes via activation of the Nrf2 transcriptional pathway. We demonstrate that CA exerts neuroprotective effects on cyanide-induced brain damage in cultured rodent and human-induced pluripotent stem cell-derived neurons in vitro, and in vivo in various brain areas of a non-Swiss albino mouse model of cyanide poisoning that simulates damage observed in the human brain. Cyanide, a potential bioterrorist agent, can produce a chronic delayed-onset neurological syndrome that includes symptoms of Parkinsonism. Here, cyanide poisoning treated with the proelectrophillic compound carnosic acid, results in reduced neuronal cell death in both in vitro and in vivo models through activation of the Nrf2/ARE transcriptional pathway. Carnosic acid is therefore a potential treatment for the toxic central nervous system (CNS) effects of cyanide poisoning. ARE, antioxidant responsive element; Nrf2 (NFE2L2, Nuclear factor (erythroid-derived 2)-like 2).

Sirtuin 1-Mediated Inhibition of p66shc Expression Alleviates Liver Ischemia/Reperfusion Injury

Ischemia/reperfusion is a leading cause of liver damage after surgical intervention, trauma, and transplantation. It has been reported that the nicotinamide adenine dinucleotide-dependent deacetylase sirtuin 1 attenuates myocardial, cerebral, and renal ischemia/reperfusion damage. This study aimed to investigate the involvement of sirtuin 1-mediated p66shc inhibition in liver ischemia/reperfusion and explore the effect of carnosic acid and ischemic preconditioning on liver ischemia/reperfusion-induced damage. Laboratory investigation. University laboratory. Male Sprague-Dawley rats and HepG2 cells. The rats were subjected to 45 minutes of ischemia to 70% of the liver, followed by 3-hour reperfusion. The HepG2 cells were subjected to hypoxia/reoxygenation-induced injury. In the rats with liver ischemia/reperfusion injury, carnosic acid pretreatment and ischemic preconditioning dramatically reduced the serum aminotransferase activity and proinflammatory chemokine levels and improved the liver histological evaluations. Carnosic acid and ischemic preconditioning also increased manganese superoxide dismutase and Bcl-xL, but down-regulated cleaved caspase-3. Interestingly, the protective effect of carnosic acid and ischemic preconditioning was positively associated with sirtuin 1 activation. By contrast, p66shc, a kinase that promotes oxidative injury and apoptosis, was inhibited by carnosic acid and ischemic preconditioning. Sirtuin 1 small interfering RNA knockdown experiments confirmed that carnosic acid increased sirtuin 1-mediated repression of p66shc in HepG2 cells and that the protective effect of carnosic acid against hypoxia/reoxygenation injury was inhibited by the sirtuin 1 inhibitor nicotinamide. These results suggest that carnosic acid protects hepatocytes from hypoxia/reoxygenation damage through sirtuin 1-mediated p66shc suppression. To support this notion, we further demonstrated that the sirtuin 1 activator resveratrol achieved a protective effect similar to that of carnosic acid against hypoxia/reoxygenation injury, whereas sirtuin 1 small interfering RNA and nicotinamide had the opposite effect. Carnosic acid and ischemic preconditioning protect against ischemia/reperfusion-induced liver injury. Mechanistically, the protective effect involves the sirtuin 1-mediated inhibition of p66shc, suggesting that this pathway is a novel potential therapeutic target for protecting the liver from ischemia/reperfusion injury.

Protective effect of carnosic acid in neural cell models

Protective effect of carnosic acid in neural cell models

Carnosic acid protects biomolecules from free radical-mediated oxidative damage in vitro

The protective effects of carnosic acid (CA), a naturally occurring catechol-type poly-phenolic diterpene, against free radical-induced oxidative damage to lipids, proteins, and DNA were evaluated in this study. The oxidation of human serum albumin and rat liver homogenate were induced by Cu2+/H2O2. Fe2+/VitC and 2,2′-azobis(2,4-dimethylvaleronitrile) were used to initiate linoleic acid (LA) peroxidation. Oxidative damage of DNA was carried out using 2,2′-azobis(2-amidinopropane) dihydrochloride (AAPH). The results showed that CA significantly inhibited the oxidative damages to proteins, LA and DNA caused by various types of free radicals. Moreover, in the Fe2+/VitC induced-LA peroxidation reaction system, the addition of CA also inhibited the cytotoxic effects of oxidized linoleic acid on RAW 264.7 cells. These results suggest that it might be possible to use CA to prevent or treat the oxidative stress-related disorders and diseases.