Trans-cinnamaldehyde protects C2C12 myoblasts from DNA damage, mitochondrial dysfunction and apoptosis caused by oxidative stress through inhibiting ROS production

Tenuazonic acid-induced mycotoxicosis in an immunosuppressed mouse model and its prophylaxis with cinnamaldehyde

Patients with impaired immune systems are particularly vulnerable to infections. With the increasing number of immunocompromised patients, it becomes necessary to design studies that evaluate the effects of toxic contaminants that are a part of our daily lives. Simultaneously, the management of these toxic components also becomes essential. Therefore, the present study evaluated the possible protective role of cinnamaldehyde (Cin) against tenuazonic acid-induced mycotoxicosis in the immunosuppressed murine model. Tenuazonic acid (TeA), a toxin usually produced by Alternaria species, is a common contaminant in tomato and tomato-based products. Evaluating the potential toxicity of a hazardous chemical necessitates the use of in vitro, in vivo, and in silico methods. Here, the immunomodulatory effect of TeA was assessed in vitro using mouse splenocytes. In silico docking was carried out for the tumour markers of eight organs and TeA. The haematological, histopathological, and biochemical aspects were analysed in vivo. The sub-chronic intoxication of mice with TeA showed elevated malondialdehyde, reduced catalase, and superoxide dismutase production, along with abnormal levels of aspartate aminotransferase and alanine transaminase. The treatment with Cin prevented TeA-induced alterations of antioxidant defense enzyme activities and significantly forbade TeA-induced organ damage, showing therapeutic effects and toxicity reduction in TeA-induced mycotoxicosis.

Cinnamaldehyde attenuates TNF-α induced skeletal muscle loss in C2C12 myotubes via regulation of protein synthesis, proteolysis, oxidative stress and inflammation

Inflammation is the primary driver of skeletal muscle wasting, with oxidative stress serving as both a major consequence and a contributor to its deleterious effects. In this regard, regulation of both can efficiently prevent atrophy and thus will increase the rate of survival [1]. With this idea, we hypothesize that preincubation of Cinnamaldehyde (CNA), a known compound with anti-oxidative and anti-inflammatory properties, may be able to prevent skeletal muscle loss. To examine the same, C2C12 post-differentiated myotubes were treated with 25 ng/ml Tumor necrosis factor-alpha (TNF-α) in the presence or absence of 50 μM CNA. The data showed that TNF-α mediated myotube thinning and a lower fusion index were prevented by CNA supplementation 4 h before TNF-α treatment. Moreover, a lower level of ROS and thus maintained antioxidant defense system further underlines the antioxidative function of CNA in atrophic conditions. CNA preincubation also inhibited an increase in the level of inflammatory cytokines and thus led to a lower level of inflammation even in the presence of TNF-α. With decreased oxidative stress and inflammation by CNA, it was able to maintain the intracellular level of injury markers (CK, LDH) and SDH activity of mitochondria. In addition, CNA modulates all five proteolytic systems [cathepsin-L, UPS (atrogin-1), calpain, LC3, beclin] simultaneously with an upregulation of Akt/mTOR pathway, in turn, preserves the muscle-specific proteins (MHCf) from degradation by TNF-α. Altogether, our study exhibits attenuation of muscle loss and provides insight into the possible mechanism of action of CNA in curbing TNF-α induced muscle loss, specifically its effect on proteolysis and protein synthesis.

Pathogenesis of Neurodegenerative Diseases and the Protective Role of Natural Bioactive Components

Neurodegenerative diseases are a serious problem throughout the world. There are several causes of neurodegenerative diseases; these include genetic predisposition, accumulation of misfolded proteins, oxidative stress, neuroinflammation, and excitotoxicity. Oxidative stress increases the production of reactive oxygen species (ROS) that advance lipid peroxidation, DNA damage, and neuroinflammation. The cellular antioxidant system (superoxide dismutase, catalase, peroxidase, and reduced glutathione) plays a crucial role in scavenging free radicals. An imbalance in the defensive actions of antioxidants and overproduction of ROS intensify neurodegeneration. The formation of misfolded proteins, glutamate toxicity, oxidative stress, and cytokine imbalance promote the pathogenesis of Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. Antioxidants are now attractive molecules to fight against neurodegeneration. Certain vitamins (A, E, C) and polyphenolic compounds (flavonoids) show excellent antioxidant properties. Diet is the major source of antioxidants. However, diet medicinal herbs are also rich sources of numerous flavonoids. Antioxidants prevent ROS-mediated neuronal degeneration in post-oxidative stress conditions. The present review is focused on the pathogenesis of neurodegenerative diseases and the protective role of antioxidants. KEY TEACHING POINTSThis review shows that multiple factors are directly or indirectly associated with the pathogenesis of neurodegenerative diseases.Failure to cellular antioxidant capacity increases oxidative stress that intensifies neuroinflammation and disease progression.Different vitamins, carotenoids, and flavonoids, having antioxidant capacity, can be considered protective agents.

Cinnamaldehyde Alleviates Bone Loss by Targeting Oxidative Stress and Mitochondrial Damage via the Nrf2/HO-1 Pathway in BMSCs and Ovariectomized Mice

Osteoporosis (OP) is typically brought on by disruption of bone homeostasis. Excessive oxidative stress and mitochondrial dysfunction are believed to be the primary mechanisms underlying this disorder. Therefore, in order to restore bone homeostasis effectively, targeted treatment of oxidative stress and mitochondrial dysfunction is necessary. Cinnamaldehyde (CIN), a small molecule that acts as an agonist for the nuclear factor erythroid 2-related factor (Nrf2), has been found to possess antiapoptotic, anti-inflammatory, and antioxidant properties. We found that CIN, while rescuing apoptosis, can also reduce the accumulation of reactive oxygen species (ROS) to improve mitochondrial dysfunction and thus restore the osteogenic differentiation potential of BMSCs disrupted by hydrogen peroxide (H2O2) exposure. The role of CIN was preliminarily considered to be a consequence of Nrf2/HO-1 axis activation. The ovariectomized mice model further demonstrated that CIN treatment ameliorated oxidative stress in vivo, partially reversing OVX-induced bone loss. This improvement was seen in the trabecular microarchitecture and bone biochemical indices. However, when ML385 was concurrently injected with CIN, the positive effects of CIN were largely blocked. In conclusion, this study sheds light on the intrinsic mechanisms by which CIN regulates BMSCs and highlights the potential therapeutic applications of these findings in the treatment of osteoporosis.

Activation of Nrf2/HO-1 antioxidant signaling correlates with the preventive effect of loganin on oxidative injury in ARPE-19 human retinal pigment epithelial cells

BACKGROUND

Loganin, a type of iridoid glycoside derived from Corni Fructus, is known to have beneficial effects various chronic diseases. However, studies on mechanisms related to antioxidant efficacy in human retinal pigment epithelial (RPE) cells have not yet been conducted.

OBJECTIVES

This study was to investigate whether loganin could inhibit oxidative stress-mediated cellular damage caused by hydrogen peroxide (H₂O₂) in human RPE ARPE-19 cells.

METHODS

The preventive effect of loganin on H₂O₂-induced cytotoxicity, reactive oxygen species (ROS) generation, DNA damage and apoptosis was investigated. In addition, immunofluorescence staining and immunoblotting analysis were applied to evaluate the related mechanisms.

RESULTS

The loss of cell viability and increased ROS accumulation in H₂O₂-treated ARPE-19 cells were significantly abrogated by loganin pretreatment, which was associated with activation of nuclear factor erythroid 2-related factor 2 (Nrf2) and increased expression of heme oxygenase-1 (HO-1). Loganin also markedly attenuated H₂O₂-induced DNA damage, ultimately ameliorating apoptosis. In addition, H₂O₂-induced mitochondrial dysfunction was reversed in the presence of loganin as indicated by preservation of mitochondrial integrity, decrease of Bax/Bcl-2 expression ratio, reduction of caspase-3 activity and suppression of cytochrome c release into the cytoplasm. However, zinc protoporphyrin, a selective inhibitor of HO-1, remarkably alleviated the preventive effect offered by loganin against H₂O₂-mediated ARPE-19 cell injury, suggesting a critical role of Nrf2-mediated activation of HO-1 in the antioxidant activity of loganin.

CONCLUSION

The results of this study suggest that loganin-induced activation of the Nrf2/HO-1 axis is at least involved in protecting at least ARPE-19 cells from oxidative injury.

Phloroglucinol Inhibits Oxidative-Stress-Induced Cytotoxicity in C2C12 Murine Myoblasts through Nrf-2-Mediated Activation of HO-1

Phloroglucinol is a class of polyphenolic compounds containing aromatic phenyl rings and is known to have various pharmacological activities. Recently, we reported that this compound isolated from Ecklonia cava, a brown alga belonging to the family Laminariaceae, has potent antioxidant activity in human dermal keratinocytes. In this study, we evaluated whether phloroglucinol could protect against hydrogen peroxide (H2O2)-induced oxidative damage in murine-derived C2C12 myoblasts. Our results revealed that phloroglucinol suppressed H2O2-induced cytotoxicity and DNA damage while blocking the production of reactive oxygen species. We also found that phloroglucinol protected cells from the induction of apoptosis associated with mitochondrial impairment caused by H2O2 treatment. Furthermore, phloroglucinol enhanced the phosphorylation of nuclear factor-erythroid-2 related factor 2 (Nrf2) as well as the expression and activity of heme oxygenase-1 (HO-1). However, such anti-apoptotic and cytoprotective effects of phloroglucinol were greatly abolished by the HO-1 inhibitor, suggesting that phloroglucinol could increase the Nrf2-mediated activity of HO-1 to protect C2C12 myoblasts from oxidative stress. Taken together, our results indicate that phloroglucinol has a strong antioxidant activity as an Nrf2 activator and may have therapeutic benefits for oxidative-stress-mediated muscle disease.

Phloroglucinol Attenuates DNA Damage and Apoptosis Induced by Oxidative Stress in Human Retinal Pigment Epithelium ARPE-19 Cells by Blocking the Production of Mitochondrial ROS

Phloroglucinol, a phenolic compound, is known to possess a potent antioxidant ability. However, its role in retinal cells susceptible to oxidative stress has not been well elucidated yet. Thus, the objective of this study was to evaluate whether phloroglucinol could protect against oxidative damage in cultured human retinal pigment epithelium ARPE-19 cells. For this purpose, ARPE-19 cells were stimula ted with hydrogen peroxide (H₂O₂) to mimic oxidative stress. Cell viability, cytotoxicity, apoptosis, reactive oxygen species (ROS) generation, mitochondrial function, DNA damage, and autophagy were then assessed. Our results revealed that phloroglucinol ameliorated cell viability, cytotoxicity, and DNA damage in H₂O₂-exposued ARPE-19 cells and blocked production of ROS. Phloroglucinol also counteracted H₂O₂-induced apoptosis by reducing Bax/Bcl-2 ratio, blocking activation of caspase-3, and inhibiting degradation of poly (ADP-ribose) polymerase. H₂O₂ caused mitochondrial impairment and increased expression levels of mitophagy markers such as PINK1and PARKIN known to be associated with mitochondrial ROS (mtROS) generation and cytosolic release of cytochrome c. However, these changes were significantly attenuated by phloroglucinol. Mito-TEMPO, a selective mitochondrial antioxidant, further enhanced the protective effect of phloroglucinol against dysfunctional mitochondria. Furthermore, H₂O₂ induced autophagy, but not when ARPE-19 cells were pretreated with phloroglucinol, meaning that autophagy by H₂O₂ contributed to the pro-survival mechanism and that phloroglucinol protected ARPE-19 cells from apoptosis by blocking autophagy. Taken together, these results suggest that phloroglucinol can inhibit oxidative stress-induced ARPE-19 cell damage and dysfunction by protecting DNA damage, autophagy, and subsequent apoptosis through mitigation of mtROS generation. Thus, phloroglucinol might have therapeutic potential to prevent oxidative stress-mediated damage in RPE cells.

Cinnamaldehyde Regulates Insulin and Caspase-3 Signaling Pathways in the Sporadic Alzheimer's Disease Model: Involvement of Hippocampal Function via IRS-1, Akt, and GSK-3β Phosphorylation

Insulin signaling disruption and caspase-3 cleavage play a pathologic role in Alzheimer's disease (AD). Evidence suggested that cinnamaldehyde (Cin), the major component of cinnamon, has the ability to act as a neuroprotective agent. However, little evidence is available to demonstrate its effectiveness in regulating the insulin and caspase-3 signaling pathways and underlying molecular mechanisms. Therefore, the present study was conducted to correlate the molecular mechanisms of these signaling pathways and Cin treatment on animal behavioral performance in an intracerebroventricular (ICV)-streptozotocin (STZ, 3 mg/kg) model. The sporadic AD rat model was treated with Cin (10 and 100 mg/kg; intraperitoneal, i.p) daily for 2 weeks. Novel object recognition (NOR), Morris water maze (MWM), and elevated plus maze (EPM) tests were performed to assess recognition/spatial memory and anxiety-like behavior, respectively. Hippocampal Aβ aggregation was assessed using Congo red staining. The activity of hippocampal caspase-3 and IRS-1/Akt/GSK-3β signaling pathways were analyzed using the Western blot technique. The results revealed that Cin (100 mg/kg, effective dose) improved recognition/spatial memory deficits and anxiety-like behavior. In addition, Cin negated the effects of STZ on Aβ aggregation and caspase-3 cleavage in the hippocampus. Furthermore, the Western blot method showed that hippocampal IRS-1/AKT/GSK-3β phosphorylation was altered in ICV-STZ animal model, while Cin modulated this signaling pathway through decreasing Phospho.IRS-1_Ser307/Total.IRS-1 ratio and also increasing Phospho.Akt_Ser473/Total.Akt and Phospho.GSK-3β_Ser9/Total.GSK-3β ratios. These findings suggest that Cin is involved in the regulation of hippocampal IRS-1/AKT/GSK-3β and caspase-3 pathways in a sporadic AD model, and modulation of these signaling pathways also influences the animal behavioral performance.

Cinnamaldehyde regulates mitochondrial quality against hydrogen peroxide induced apoptosis in mouse lung mesenchymal stem cells via the PINK1/Parkin signaling pathway

Background

Idiopathic pulmonary fibrosis (IPF) is a fatal respiratory disease without effective treatments. Mitochondrial dysfunction weakens the ability of mesenchymal stem cells (MSCs) to repair the distal lung epithelium, which is a probable pathogenesis of IPF. In previous research, we found that cinnamaldehyde (CA) can maintain the mitochondrial morphology of MSCs.

Methods

This present study evaluated the effect and mechanism of CA on murine lung MSCs using the hydrogen peroxide model. Antioxidant effects and mitochondrial function were determined using flow cytometry. The mRNA levels of mitochondrial dynamics and the expressions of autophagy-related proteins were also detected.

Results

CA can increase the levels of SOD, MMP and ATP, decrease the rate of ROS and apoptosis, and restore the mitochondrial structure. CA can also improve the mRNA expression of MFN1, MFN2, FIS1, DRP1, OPA1, and PGC-1α, increase the expression of LC3 II and p62 and promote the PINK1/Parkin signaling pathway. Our results demonstrated that CA can control mitochondrial quality and avoid apoptosis, which may be associated with the regulation of the PINK1/Parkin signaling pathway.

Antitumor Activities of Aqueous Cinnamon Extract on 5637 Cell Line of Bladder Cancer through Glycolytic Pathway

Background

Pharmacotherapy with medicinal plants is a promising approach to treat cancer. Cinnamon is a medicinal plant whose properties have been proven in various fields of medical sciences. Among its biological activities, its antioxidant and antiviral effects can be mentioned. In this study, the antitumor effects of Cinnamon with a focus on glucose metabolism in bladder cancer carcinoma cell-line 5637 were investigated.

Methods

Aqueous extract of Cinnamon was prepared from Cinnamon bark. Bladder cancer 5637cell line were treated with different concentrations of aqueous extract of Cinnamon. MTT was used to evaluate cell viability at 24, 48, and 72 h. The concentration of 1.25, 2.50, and 5 mg/ml was used. Apoptosis was assessed with Hochest33258 staining. For evaluating of aqueous extract of Cinnamon effect on glycolysis, the gene expression of epidermal growth factor receptor 2 (ErbB2), heat shock protein transcription factor1 (HSF1), and lactate dehydrogenase A (LDHA), as well as protein levels of HSF1 and LDHA, LDH activity, glucose consumption, and lactate production, were measured.

Results

Aqueous extract of Cinnamon significantly decreased ErbB2, HSF1, and LDHA gene expression and also decreased the protein level of HSF1 and LDHA, LDH activity, glucose consumption, and lactate production dose-dependently (p < 0.05).

Conclusion

Our finding showed that the aqueous extract of Cinnamon can inhibit proliferation in 5637 cells by inhibition of glycolysis and induction of apoptosis.

Aqueous extracts of Corni Fructus protect C2C12 myoblasts from DNA damage and apoptosis caused by oxidative stress

BACKGROUND

Although the various pharmacological effects of Corni Fructus are highly correlated with its antioxidant activity, the blocking effect against oxidative stress in muscle cells is not clear. The purpose of this study was to investigate the effect of aqueous extracts of Corni Fructus (CFE) against oxidative stress caused by hydrogen peroxide (H₂O₂) in murine skeletal C2C12 myoblasts.

METHODS AND RESULTS

MTT assay for cell viability, DCF-DA staining for reactive oxygen species (ROS) production, Comet assay for DNA damage, annexin V-FITC and PI double staining for apoptosis, JC-1 staining and caspase assay for monitor mitochondrial integrity, and western blotting for related protein levels were conducted in H₂O₂ oxidative stressed C2C12 cells. Our results showed that CFE pretreatment significantly ameliorated the loss of cell viability and inhibited apoptosis in H₂O₂-treated C2C12 cells in a concentration-dependent manner. DNA damage induced by H₂O₂ was also markedly attenuated in the presence of CFE, which was associated with suppression of ROS generation. In addition, H₂O₂ reduced mitochondrial membrane potential and caused downregulation of Bcl-2 and upregulation of Bax expression, although these were abrogated by CFE pretreatment. Moreover, CFE blocked H₂O₂-induced cytosolic release of cytochrome c, activation of caspase-9 and caspase-3, and degradation of poly (ADP-ribose) polymerase.

CONCLUSION

Taken together, the present results demonstrate that CFE could protect C2C12 cells from H₂O₂-induced damage by eliminating ROS generation, thereby blocking mitochondria-mediated apoptosis pathway. These results indicate that CFE has therapeutic potential for the prevention and treatment of oxidative stress-mediated myoblast injury.

Epitalon protects against post-ovulatory aging-related damage of mouse oocytes in vitro

The developmental potential of oocytes decreases with time after ovulation in vivo or in vitro. Epitalon is a synthetic short peptide made of four amino acids (alanine, glutamic acid, aspartic acid, and glycine), based on a natural peptide called epithalamion extracted from the pineal gland. It is a potent antioxidant, comparable to melatonin, that may confer longevity benefits. The current study aims to test the protective effects of Epitalon on the quality of post-ovulatory aging oocytes. Epitalon at 0.1mM was added to the culture medium, and the quality of oocytes was evaluated at 6h, 12h, and 24h of culture. We found that 0.1mM Epitalon reduced intracellular reactive oxygen species. Epitalon treatment significantly decreased frequency of spindle defects and abnormal distribution of cortical granules during aging for 12h and 24h, while increased mitochondrial membrane potential and DNA copy number of mitochondria, thus decreasing apoptosis of oocytes by 24h of in vitro aging. Our results suggest that Epitalon can delay the aging process of oocytes in vitro via modulating mitochondrial activity and ROS levels.

Induction of apoptotic cell death in human bladder cancer cells by ethanol extract of Zanthoxylum schinifolium leaf, through ROS-dependent inactivation of the PI3K/Akt signaling pathway

BACKGROUND/OBJECTIVES

Zanthoxylum schinifolium is traditionally used as a spice for cooking in East Asian countries. This study was undertaken to evaluate the anti-proliferative potential of ethanol extracts of Z. schinifolium leaves (EEZS) against human bladder cancer T24 cells.

MATERIALS/METHODS

Subsequent to measuring the cytotoxicity of EEZS, the anti-cancer activity was measured by assessing apoptosis induction, reactive oxygen species (ROS) generation, and mitochondrial membrane potential (MMP). In addition, we determined the underlying mechanism of EEZS-induced apoptosis through various assays, including Western blot analysis.

RESULTS

EEZS treatment concentration-dependently inhibited T24 cell survival, which is associated with apoptosis induction. Exposure to EEZS induced the expression of Fas and Fas-ligand, activated caspases, and subsequently resulted to cleavage of poly (ADP-ribose) polymerase. EEZS also enhanced the expression of cytochrome c in the cytoplasm by suppressing MMP, following increase in the ratio of Bax:Bcl-2 expression and truncation of Bid. However, EEZS-mediated growth inhibition and apoptosis were significantly diminished by a pan-caspase inhibitor. Moreover, EEZS inhibited activation of the phosphoinositide 3-kinase (PI3K)/Akt pathway, and the apoptosis-inducing potential of EEZS was promoted in the presence of PI3K/Akt inhibitor. In addition, EEZS enhanced the production of ROS, whereas N-acetyl cysteine (NAC), a ROS scavenger, markedly suppressed growth inhibition and inactivation of the PI3K/Akt signaling pathway induced by EEZS. Furthermore, NAC significantly attenuated the EEZS-induced apoptosis and reduction of cell viability.

CONCLUSIONS

Taken together, our results indicate that exposure to EEZS exhibits anti-cancer activity in T24 bladder cancer cells through ROS-dependent induction of apoptosis and inactivation of the PI3K/Akt signaling pathway.

Schisandrae Fructus ethanol extract attenuates particulate matter 2.5-induced inflammatory and oxidative responses by blocking the activation of the ROS-dependent NF-κB signaling pathway

BACKGROUND/OBJECTIVES

Schisandrae Fructus, the fruit of Schisandra chinensis Baill., has traditionally been used as a medicinal herb for the treatment of various diseases, and has proven its various pharmacological effects, including anti-inflammatory and antioxidant activities. In this study, we investigated the inhibitory effect of Schisandrae Fructus ethanol extract (SF) on inflammatory and oxidative stress in particulate matter 2.5 (PM2.5)-treated RAW 264.7 macrophages.

MATERIALS/METHODS

To investigate the anti-inflammatory and antioxidant effects of SF in PM2.5-stimulated RAW 264.7 cells, the levels of pro-inflammatory mediator such as nitric oxide (NO) and prostaglandin E₂ (PGE₂), cytokines including interleukin (IL)-6 and IL-1β, and reactive oxygen species (ROS) were measured. To elucidate the mechanism underlying the effect of SF, the expression of genes involved in the generation of inflammatory factors was also investigated. We further evaluated the anti-inflammatory and antioxidant efficacy of SF against PM2.5 in the zebrafish model.

RESULTS

The results indicated that SF treatment significantly inhibited the PM2.5-induced release of NO and PGE₂, which was associated with decreased inducible NO synthase and cyclooxygenase-2 expression. SF also attenuated the PM2.5-induced expression of IL-6 and IL-1β, reducing their extracellular secretion. Moreover, SF suppressed the PM2.5-mediated translocation of nuclear factor-kappa B (NF-κB) from the cytosol into nuclei and the degradation of inhibitor IκB-α, indicating that SF exhibited anti-inflammatory effects by inhibiting the NF-κB signaling pathway. In addition, SF abolished PM2.5-induced generation of ROS, similar to the pretreatment of a ROS scavenger, but not by an inhibitor of NF-κB activity. Furthermore, SF showed strong protective effects against NO and ROS production in PM2.5-treated zebrafish larvae.

CONCLUSIONS

Our findings suggest that SF exerts anti-inflammatory and antioxidant effects against PM2.5 through ROS-dependent down-regulating the NF-κB signaling pathway, and that SF can be a potential functional substance to prevent PM2.5-mediated inflammatory and oxidative damage.

Protection against Oxidative Stress-Induced Apoptosis by Fermented Sea Tangle (Laminaria japonica Aresch) in Osteoblastic MC3T3-E1 Cells through Activation of Nrf2 Signaling Pathway

The purpose of the present study was to explore the efficacy of fermented extract of sea tangle (Laminaria japonica Aresch, FST) with Lactobacillus brevis on DNA damage and apoptosis in hydrogen peroxide (H₂O₂)-stimulated osteoblastic MC3T3-E1 cells and clarify related signaling pathways. Our results showed that exposure to FST significantly improved cell viability, inhibited apoptosis, and suppressed the generation of reactive oxygen species (ROS) in H₂O₂-stimulated cells. In addition, H₂O₂ triggered DNA damage in MC3T3-E1 cells was markedly attenuated by FST pretreatment. Moreover, H₂O₂-induced mitochondrial dysfunctions associated with apoptotic events, including loss of mitochondrial membrane potential (MMP), decreased Bcl-2/Bcl-2 associated x-protein (Bax) ratio, and cytosolic release of cytochrome c, were reduced in the presence of FST. FST also diminished H₂O₂-induced activation of caspase-3, which was associated with the ability of FST to protect the degradation of poly (ADP-ribose) polymerase. Furthermore, FST notably enhanced nuclear translocation and phosphorylation of nuclear factor erythroid 2-related factor 2 (Nrf2) in the presence of H₂O₂ with concomitant upregulation of heme oxygenase-1 (HO-1) expression. However, artificial blockade of this pathway by the HO-1 inhibitor, zinc protoporphyrin IX, greatly abolished the protective effect of FST against H₂O₂-induced MC3T3-E1 cell injury. Taken together, these results demonstrate that FST could protect MC3T3-E1 cells from H₂O₂-induced damage by maintaining mitochondrial function while eliminating ROS along with activation of the Nrf2/HO-1 antioxidant pathway.

Mori Ramulus Suppresses Hydrogen Peroxide-Induced Oxidative Damage in Murine Myoblast C2C12 Cells through Activation of AMPK

Mori Ramulus, the dried twigs of Morus alba L., has been attracting attention for its potent antioxidant activity, but its role in muscle cells has not yet been elucidated. The purpose of this study was to evaluate the protective effect of aqueous extracts of Mori Ramulus (AEMR) against oxidative stress caused by hydrogen peroxide (H₂O₂) in C2C12 mouse myoblasts, and in dexamethasone (DEX)-induced muscle atrophied models. Our results showed that AEMR rescued H₂O₂-induced cell viability loss and the collapse of the mitochondria membrane potential. AEMR was also able to activate AMP-activated protein kinase (AMPK) in H₂O₂-treated C2C12 cells, whereas compound C, a pharmacological inhibitor of AMPK, blocked the protective effects of AEMR. In addition, H₂O₂-triggered DNA damage was markedly attenuated in the presence of AEMR, which was associated with the inhibition of reactive oxygen species (ROS) generation. Further studies showed that AEMR inhibited cytochrome c release from mitochondria into the cytoplasm, and Bcl-2 suppression and Bax activation induced by H₂O₂. Furthermore, AEMR diminished H₂O₂-induced activation of caspase-3, which was associated with the ability of AEMR to block the degradation of poly (ADP-ribose) polymerase, thereby attenuating H₂O₂-induced apoptosis. However, compound C greatly abolished the protective effect of AEMR against H₂O₂-induced C2C12 cell apoptosis, including the restoration of mitochondrial dysfunction. Taken together, these results demonstrate that AEMR could protect C2C12 myoblasts from oxidative damage by maintaining mitochondrial function while eliminating ROS, at least with activation of the AMPK signaling pathway. In addition, oral administration of AEMR alleviated gastrocnemius and soleus muscle loss in DEX-induced muscle atrophied rats. Our findings support that AEMR might be a promising therapeutic candidate for treating oxidative stress-mediated myoblast injury and muscle atrophy.

Induction of Apoptosis by Isoalantolactone in Human Hepatocellular Carcinoma Hep3B Cells through Activation of the ROS-Dependent JNK Signaling Pathway

Isoalantolactone (IALT) is one of the isomeric sesquiterpene lactones isolated from the roots of Inula helenium L. IALT is known to possess various biological and pharmacological activities, but its anti-cancer mechanisms are not well understood. The aim of the present study was to investigate the anti-proliferative effects of IALT in human hepatocellular carcinoma (HCC) cells and to evaluate the potential anti-cancer mechanisms. Our results demonstrated that IALT treatment concentration-dependently suppressed the cell survival of HCC Hep3B cells, which was associated with the induction of apoptosis. IALT increased the expression of death-receptor-related proteins, activated caspases, and induced Bid truncation, subsequently leading to cleavage of poly (ADP-ribose) polymerase. In addition, IALT contributed to the cytosolic release of cytochrome c by destroying mitochondrial integrity, following an increase in the Bax/Bcl-2 expression ratio. However, IALT-mediated growth inhibition and apoptosis were significantly attenuated in the presence of a pan-caspase inhibitor, suggesting that IALT induced caspase-dependent apoptosis in Hep3B cells. Moreover, IALT activated the mitogen-activated protein kinases signaling pathway, and the anti-cancer effect of IALT was significantly diminished in the presence of a potent c-Jun N-terminal kinase (JNK) inhibitor. IALT also improved the generation of intracellular reactive oxygen species (ROS), whereas the ROS inhibitor significantly abrogated IALT-induced growth reduction, apoptosis, and JNK activation. Furthermore, ROS-dependent apoptosis was revealed as a mechanism involved in the anti-cancer activity of IALT in a 3D multicellular tumor spheroid model of Hep3B cells. Taken together, our findings indicate that IALT exhibited anti-cancer activity in HCC Hep3B cells by inducing ROS-dependent activation of the JNK signaling pathway.

Loganin Inhibits Lipopolysaccharide-Induced Inflammation and Oxidative Response through the Activation of the Nrf2/HO-1 Signaling Pathway in RAW264.7 Macrophages

Inflammation caused by the excessive secretion of inflammatory mediators in abnormally activated macrophages promotes many diseases along with oxidative stress. Loganin, a major iridoid glycoside isolated from Cornus officinalis, has recently been reported to exhibit anti-inflammatory and antioxidant effects, whereas the underlying mechanism has not yet been fully clarified. Therefore, the aim of the present study is to investigate the effect of loganin on inflammation and oxidative stress in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. Our results indicated that loganin treatment markedly attenuated the LPS-mediated phagocytic activity and release of nitric oxide (NO) and prostaglandin E₂, which was associated with decreased the expression of inducible NO synthase and cyclooxygenase-2. In addition, loganin suppressed the expression and their extracellular secretion of LPS-induced pro-inflammatory cytokines, such as tumor necrosis factor-α and interleukin-1β. Furthermore, loganin abolished reactive oxygen species (ROS) generation, and promoted the activation of nuclear factor-E2-related factor 2 (Nrf2) and the expression of heme oxygenase-1 (HO-1) in LPS-stimulated macrophages. However, zinc protoporphyrin, a selective HO-1 inhibitor, reversed the loganin-mediated suppression of pro-inflammatory cytokines in LPS-treated macrophages. In conclusion, our findings suggest that the upregulation of the Nrf2/HO-1 signaling pathway is concerned at least in the protective effect of loganin against LPS-mediated inflammatory and oxidative stress, and that loganin can be a potential functional agent to prevent inflammatory and oxidative damage.

Anti-Inflammatory Effect of Auranofin on Palmitic Acid and LPS-Induced Inflammatory Response by Modulating TLR4 and NOX4-Mediated NF-κB Signaling Pathway in RAW264.7 Macrophages

Chronic inflammation, which is promoted by the production and secretion of inflammatory mediators and cytokines in activated macrophages, is responsible for the development of many diseases. Auranofin is a Food and Drug Administration-approved gold-based compound for the treatment of rheumatoid arthritis, and evidence suggests that auranofin could be a potential therapeutic agent for inflammation. In this study, to demonstrate the inhibitory effect of auranofin on chronic inflammation, a saturated fatty acid, palmitic acid (PA), and a low concentration of lipopolysaccharide (LPS) were used to activate RAW264.7 macrophages. The results show that PA amplified LPS signals to produce nitric oxide (NO) and various cytokines. However, auranofin significantly inhibited the levels of NO, monocyte chemoattractant protein-1, and pro-inflammatory cytokines, such as interleukin (IL)-1β, tumor necrosis factor-α, and IL-6, which had been increased by co-treatment with PA and LPS. Moreover, the expression of inducible NO synthase, IL-1β, and IL-6 mRNA and protein levels increased by PA and LPS were reduced by auranofin. In particular, the upregulation of NADPH oxidase (NOX) 4 and the translocation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) induced by PA and LPS were suppressed by auranofin. The binding between the toll-like receptor (TLR) 4 and auranofin was also predicted, and the release of NO and cytokines was reduced more by simultaneous treatment with auranofin and TLR4 inhibitor than by auranofin alone. In conclusion, all these findings suggested that auranofin had anti-inflammatory effects in PA and LPS-induced macrophages by interacting with TLR4 and downregulating the NOX4-mediated NF-κB signaling pathway.

Nargenicin A1 attenuates lipopolysaccharide-induced inflammatory and oxidative response by blocking the NF-κB signaling pathway

Inflammation caused by the excessive production of pro-inflammatory mediators and cytokines in abnormally activated macrophages promotes the initiation and progression of many diseases along with oxidative stress. Previous studies have suggested that nargenicin A1, an antibacterial macrolide isolated from Nocardia sp. may be a potential treatment for inflammatory responses and oxidative stress, but the detailed mechanisms are still not well studied. In this study, we investigated the inhibitory effect of nargenicin A1 on inflammatory and oxidative stress in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and zebrafish (Danio rerio) models. Our results indicated that nargenicin A1 treatment significantly inhibited LPS-induced release of pro-inflammatory mediators including nitric oxide (NO) and prostaglandin E₂, which was associated with decreased inducible NO synthase and cyclooxygenase-2 expression. In addition, nargenicin A1 attenuated the LPS-induced expression of pro-inflammatory cytokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and monocyte chemotactic protein-1, reducing their extracellular secretion. Nargenicin A1 also suppressed LPS-induced generation of reactive oxygen species. Moreover, nargenicin A1 abolished the LPS-mediated nuclear translocation of nuclear factor-kappa B (NF-κB) and the degradation of inhibitor IκB-α, indicating that nargenicin A1 exhibited anti-inflammatory effects by inhibiting the NF-κB signaling pathway. Furthermore, nargenicin A1 showed strong protective effects against NO and ROS production in LPS-injected zebrafish larvae. In conclusion, our findings suggest that nargenicin A1 ameliorates LPS-induced anti-inflammatory and antioxidant effects by downregulating the NF-κB signaling pathway, and that nargenicin A1 can be a potential functional agent to prevent inflammatory- and oxidative-mediated damage.

The regulation of the TLR4/NF-κB and Nrf2/HO-1 signaling pathways is involved in the inhibition of lipopolysaccharide-induced inflammation and oxidative reactions by morroniside in RAW 264.7 macrophages

Morroniside, a major iridoid glycoside isolated from Cornus officinalis, has a variety of beneficial pharmacological properties. Although morroniside has recently been reported to exhibit anti-inflammatory and antioxidant effects, the detailed mechanism has not yet been fully elucidated. In this study, we investigated the inhibitory effect of morroniside on inflammatory and oxidative stress activated by lipopolysaccharide (LPS) in RAW 264.7 macrophages. Our results indicated that morroniside pretreatment significantly inhibited the LPS-induced phagocytic activity and release of pro-inflammatory factors, which was associated with blocking the expression of their regulatory genes. Morroniside also markedly suppressed the expression of myeloid differentiation factor 88 as well as Toll-like receptor 4 (TLR4), and attenuated the translocation of nuclear factor-κB (NF-κB) to the nucleus in LPS-treated RAW 264.7 macrophages. Furthermore, morroniside prevented the binding of LPS to the TLR4 on the cell surface. In addition, morroniside abolished reactive oxygen species (ROS) generation, and enhanced the expression of heme oxygenase-1 (HO-1) following activation of nuclear factor-E2-related factor 2 (Nrf2) in LPS-stimulated RAW 264.7 macrophages. However, zinc protoporphyrin, a specific inhibitor of HO-1, reversed the morroniside-mediated inhibition of inflammatory response in LPS-treated RAW 264.7 macrophages. In conclusion, our findings suggest that morroniside exerts LPS-induced anti-inflammatory and antioxidant effects by targeting the TLR4/NF-κB and Nrf2/HO-1 signaling pathways in RAW 264.7 macrophages. Taken together, our findings suggest that morroniside interacted structurally and electrochemically with TLR4/MD2 complex, consequently can be a potential functional agent to prevent inflammatory and oxidative damage.

ROS-Mediated Anti-Tumor Effect of Coptidis Rhizoma against Human Hepatocellular Carcinoma Hep3B Cells and Xenografts

Coptidis Rhizoma is the dried rhizome from the Coptis chinensis Franch. that has been shown to have a number of beneficial pharmacological properties including antioxidant, anti-inflammatory, and anti-cancer effects. However, the anti-cancer effects of Coptidis Rhizoma on hepatocellular carcinoma (HCC) remain unclear. In this study, we investigated the anti-cancer properties of Coptidis Rhizoma ethanol extract (CR) in HCC Hep3B cells and in a xenograft mouse model. Our results showed that the CR significantly inhibited cell growth and induced apoptosis in Hep3B cells through increased expression of Bcl-2 associated x-protein (Bax) and cleavage of poly-ADP ribose polymerase (PARP), reduced expression of Bcl-2, and activated caspases. CR also increased the generation of intracellular reactive oxygen species (ROS), which caused a loss of mitochondrial membrane potential (MMP, ΔΨm) and activation of the mitochondria-mediated intrinsic apoptosis pathway. Moreover, N-acetylcysteine (NAC), a ROS inhibitor, markedly blocked the effects of CR on apoptotic pathways. CR also induced the expression of light chain 3 (LC3)-I/II, a key autophagy regulator, whereas CR-mediated autophagy was significantly suppressed by NAC. In addition, pre-treatment with NAC perfectly attenuated the inhibition of cell invasion and migration of CR-stimulated Hep3B cells. Furthermore, oral administration of CR suppressed Hep3B tumor growth in xenograft mice without toxicity, alterations to body weight, or changes in hematological and biochemical profiles. Taken together, our findings suggest that CR has anti-tumor effects that result from ROS generation, and may be a potential pharmacological intervention for HCC.

The anti-cancer effect of betulinic acid in u937 human leukemia cells is mediated through ROS-dependent cell cycle arrest and apoptosis

Although previous studies have shown anti-cancer activity of betulinic acid (BA), a pentacyclic triterpenoid, against various cancer lines, the underlying molecular mechanisms are not well elucidated. In this study, we evaluated the mechanisms involved in the anti-cancer efficacy of BA in U937 human myeloid leukemia cells. BA exerted a significant cytotoxic effect on U937 cells through blocking cell cycle arrest at the G2/M phase and inducing apoptosis, and that the intracellular reactive oxygen species (ROS) levels increased after treatment with BA. The down-regulation of cyclin A and cyclin B1, and up-regulation of cyclin-dependent kinase inhibitor p21WAF1/CIP1 revealed the G2/M phase arrest mechanism of BA. In addition, BA induced the cytosolic release of cytochrome c by reducing the mitochondrial membrane potential with an increasing Bax/Bcl-2 expression ratio. BA also increased the activity of caspase-9 and -3, and subsequent degradation of the poly (ADP-ribose) polymerase. However, quenching of ROS by N-acetyl-cysteine, an ROS scavenger, markedly abolished BA-induced G2/M arrest and apoptosis, indicating that the generation of ROS plays a key role in inhibiting the proliferation of U937 cells by BA treatment. Taken together, our results provide a mechanistic rationale that BA exhibits anti-cancer properties in U937 leukemia cells through ROS-dependent induction of cell cycle arrest at G2/M phase and apoptosis.

Suppression of Lipopolysaccharide-Induced Inflammatory and Oxidative Response by 5-Aminolevulinic Acid in RAW 264.7 Macrophages and Zebrafish Larvae

In this study, we investigated the inhibitory effect of 5-aminolevulinic acid (ALA), a heme precursor, on inflammatory and oxidative stress activated by lipopolysaccharide (LPS) in RAW 264.7 macrophages by estimating nitric oxide (NO), prostaglandin E2 (PGE2), cytokines, and reactive oxygen species (ROS). We also evaluated the molecular mechanisms through analysis of the expression of their regulatory genes, and further evaluated the anti-inflammatory and antioxidant efficacy of ALA against LPS in the zebrafish model. Our results indicated that ALA treatment significantly attenuated the LPS-induced release of pro-inflammatory mediators including NO and PGE2, which was associated with decreased inducible NO synthase and cyclooxygenase-2 expression. ALA also inhibited the LPS-induced expression of pro-inflammatory cytokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6, reducing their extracellular secretion. Additionally, ALA abolished ROS generation, improved the mitochondrial mass, and enhanced the expression of heme oxygenase-1 (HO-1) and the activation of nuclear translocation of nuclear factor-E2-related factor 2 (Nrf2) in LPS-stimulated RAW 264.7 macrophages. However, zinc protoporphyrin, a specific inhibitor of HO-1, reversed the ALA-mediated inhibition of pro-inflammatory cytokines production and activation of mitochondrial function in LPS-treated RAW 264.7 macrophages. Furthermore, ALA significantly abolished the expression of LPS-induced pro-inflammatory mediators and cytokines, and showed strong protective effects against NO and ROS production in zebrafish larvae. In conclusion, our findings suggest that ALA exerts LPS-induced anti-inflammatory and antioxidant effects by upregulating the Nrf2/HO-1 signaling pathway, and that ALA can be a potential functional agent to prevent inflammatory and oxidative damage.

Betulinic Acid Restricts Human Bladder Cancer Cell Proliferation In Vitro by Inducing Caspase-Dependent Cell Death and Cell Cycle Arrest, and Decreasing Metastatic Potential

Betulinic acid (BA) is a naturally occurring pentacyclic triterpenoid and generally found in the bark of birch trees (Betula sp.). Although several studies have been reported that BA has diverse biological activities, including anti-tumor effects, the underlying anti-cancer mechanism in bladder cancer cells is still lacking. Therefore, this study aims to investigate the anti-proliferative effect of BA in human bladder cancer cell lines T-24, UMUC-3, and 5637, and identify the underlying mechanism. Our results showed that BA induced cell death in bladder cancer cells and that are accompanied by apoptosis, necrosis, and cell cycle arrest. Furthermore, BA decreased the expression of cell cycle regulators, such as cyclin B1, cyclin A, cyclin-dependent kinase (Cdk) 2, cell division cycle (Cdc) 2, and Cdc25c. In addition, BA-induced apoptosis was associated with mitochondrial dysfunction that is caused by loss of mitochondrial membrane potential, which led to the activation of mitochondrial-mediated intrinsic pathway. BA up-regulated the expression of Bcl-2-accociated X protein (Bax) and cleaved poly-ADP ribose polymerase (PARP), and subsequently activated caspase-3, -8, and -9. However, pre-treatment of pan-caspase inhibitor markedly suppressed BA-induced apoptosis. Meanwhile, BA did not affect the levels of intracellular reactive oxygen species (ROS), indicating BA-mediated apoptosis was ROS-independent. Furthermore, we found that BA suppressed the wound healing and invasion ability, and decreased the expression of Snail and Slug in T24 and 5637 cells, and matrix metalloproteinase (MMP)-9 in UMUC-3 cells. Taken together, this is the first study showing that BA suppresses the proliferation of human bladder cancer cells, which is due to induction of apoptosis, necrosis, and cell cycle arrest, and decrease of migration and invasion. Furthermore, BA-induced apoptosis is regulated by caspase-dependent and ROS-independent pathways, and these results provide the underlying anti-proliferative molecular mechanism of BA in human bladder cancer cells.

Urban Aerosol Particulate Matter Promotes Necrosis and Autophagy via Reactive Oxygen Species-Mediated Cellular Disorders that are Accompanied by Cell Cycle Arrest in Retinal Pigment Epithelial Cells

Urban particulate matter (UPM) is recognized as a grave public health problem worldwide. Although a few studies have linked UPM to ocular surface diseases, few studies have reported on retinal dysfunction. Thus, the aim of the present study was to evaluate the influence of UPM on the retina and identify the main mechanism of UPM toxicity. In this study, we found that UPM significantly induced cytotoxicity with morphological changes in ARPE-19 human retinal pigment epithelial (RPE) cells and increased necrosis and autophagy but not apoptosis. Furthermore, UPM significantly increased G2/M arrest and simultaneously induced alterations in cell cycle regulators. In addition, DNA damage and mitochondrial dysfunction were remarkably enhanced by UPM. However, the pretreatment with the potent reactive oxygen species (ROS) scavenger N-acetyl-L-cysteine (NAC) effectively suppressed UPM-mediated cytotoxicity, necrosis, autophagy, and cell cycle arrest. Moreover, NAC markedly restored UPM-induced DNA damage and mitochondrial dysfunction. Meanwhile, UPM increased the expression of mitophagy-regulated proteins, but NAC had no effect on mitophagy. Taken together, although further studies are needed to identify the role of mitophagy in UPM-induced RPE injury, the present study provides the first evidence that ROS-mediated cellular damage through necrosis and autophagy is one of the mechanisms of UPM-induced retinal disorders.

Atorvastatin Attenuates Isoflurane-Induced Activation of ROS-p38MAPK/ATF2 Pathway, Neuronal Degeneration, and Cognitive Impairment of the Aged Mice

Isoflurane, a widely used volatile anesthetic, induces neuronal apoptosis and memory impairments in various animal models. However, the potential mechanisms and effective pharmacologic agents are still not fully understood. The p38MAPK/ATF-2 pathway has been proved to regulate neuronal cell survival and inflammation. Besides, atorvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, exerts neuroprotective effects. Thus, this study aimed to explore the influence of atorvastatin on isoflurane-induced neurodegeneration and underlying mechanisms. Aged C57BL/6 mice (20 months old) were exposed to isoflurane (1.5%) anesthesia for 6 h. Atorvastatin (5, 10, or 20 mg/kg body weight) was administered to the mice for 7 days. Atorvastatin attenuated the isoflurane-induced generation of ROS and apoptosis. Western blotting revealed a decrease in cleaved caspase-9 and caspase-3 expression in line with ROS levels. Furthermore, atorvastatin ameliorated the isoflurane-induced activation of p38MAPK/ATF-2 signaling. In a cellular study, we proved that isoflurane could induce oxidative stress and inflammation by activating the p38MAPK/ATF-2 pathway in BV-2 microglia cells. In addition, SB203580, a selected p38MAPK inhibitor, inhibited the isoflurane-induced inflammation, oxidative stress, and apoptosis. The results implied that p38MAPK/ATF-2 was a potential target for the treatment of postoperative cognitive dysfunction.

Inhibition of Lipopolysaccharide-Induced Inflammatory and Oxidative Responses by Trans-cinnamaldehyde in C2C12 Myoblasts

Background: Trans-cinnamaldehyde (tCA), a bioactive component found in Cinnamomum cassia, has been reported to exhibit anti-inflammatory and antioxidant effects, but its efficacy in muscle cells has yet to be found. In this study, we investigated the inhibitory effect of tCA on inflammatory and oxidative stress induced by lipopolysaccharide (LPS) in C2C12 mouse skeletal myoblasts. Methods: To investigate the anti-inflammatory and antioxidant effects of tCA in LPS-treated C2C12 cells, we measured the levels of pro-inflammatory mediator, cytokines, and reactive oxygen species (ROS). To elucidate the mechanism underlying the effect of tCA, the expression of genes involved in the expression of inflammatory and oxidative regulators was also investigated. We further evaluated the anti-inflammatory and antioxidant efficacy of tCA against LPS in the zebrafish model. Results: tCA significantly inhibited the LPS-induced release of pro-inflammatory mediators and cytokines, which was associated with decreased expression of their regulatory genes. tCA also suppressed the expression of Toll-like receptor 4 (TLR4) and myeloid differentiation factor, and attenuated the nuclear translocation of nuclear factor-kappa B (NF-κB) and the binding of LPS to TLR4 on the cell surface in LPS-treated C2C12 cells. Furthermore, tCA abolished LPS-induced generation of ROS and expression levels of ROS producing enzymes, NADPH oxidase 1 (NOX1) and NOX2. However, tCA enhanced the activation of nuclear translocation of nuclear factor-E2-related factor 2 (Nrf2) and the expression of heme oxygenase-1 (HO-1) in LPS-stimulated C2C12 myoblasts. In addition, tCA showed strong protective effects against NO and ROS production in LPS-injected zebrafish larvae. Conclusions: Our findings suggest that tCA exerts its inhibitory ability against LPS-induced inflammatory and antioxidant stress in C2C12 myoblasts by targeting the TLR4/NF-κB, which might be mediated by the NOXs and Nrf2/HO-1 pathways.

Inhibition of oxidative stress induced-cytotoxicity by coptisine in V79-4 Chinese hamster lung fibroblasts through the induction of Nrf-2 mediated HO-1 expression

BACKGROUND

Coptisine is a natural alkaloid compound and is known to have multiple beneficial effects including antioxidant activity. However, whether it can protect lung fibroblasts from oxidative damage has not been studied yet.

OBJECTIVES

To investigate the potential inhibitory effect of coptisine against oxidative stress in V79-4 lung fibroblast cells.

METHODS

V79-4 cells were treated with H₂O₂ (1 mM) in the presence or absence of coptisine (50 µg/ml), N-acetyl cysteine (NAC, 10 mM) or zinc protoporphyrin IX (ZnPP, 10 µM) for the indicated times. The alleviating effects of coptisine on cytotoxicity, cell cycle arrest, apoptosis, reactive oxygen species (ROS) production, DNA damage, mitochondrial dynamics, and inhibition of ATP production against H₂O₂ were investigated. Western blot analysis was used to analyze the expression levels of specific proteins.

RESULTS

Coptisine inhibited H₂O₂-induced cytotoxicity and DNA damage by blocking abnormal ROS generation. H₂O₂ treatment caused cell cycle arrest at the G2/M phase accompanied by increased expression of cyclin-dependent kinase (Cdk) inhibitor p21^WAF1/CIP1 and decreased expression of cyclin B1 and cyclin A. However, these effects were attenuated in the presence of coptisine or NAC. Coptisine also prevented apoptosis by decreasing the rate of Bax/Bcl-2 expression in H₂O₂-stimulated cells and suppressing the loss of mitochondrial membrane potential and the cytosolic release of cytochrome c. In addition, the activation of nuclear factor-erythroid-2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) was markedly promoted by coptisine in the presence of H₂O₂. However, zinc protoporphyrin IX, a potent inhibitor of HO-1, attenuated the ROS scavenging and anti-apoptotic effects of coptisine.

CONCLUSIONS

Based on current data, we suggest that coptisine can be used as a potential treatment for oxidative stress-related lung disease.

Natural Cinnamaldehyde and Its Derivatives Ameliorate Neuroinflammatory Pathways in Neurodegenerative Diseases

Neurodegenerative diseases are devastating and incurable disorders characterized by neuronal dysfunction. The major focus of experimental and clinical studies are conducted on the effects of natural products and their active components on neurodegenerative diseases. This review will discuss an herbal constituent known as cinnamaldehyde (CA) with the neuroprotective potential to treat neurodegenerative disorders, such as Alzheimer's disease (AD) and Parkinson's disease (PD). Accumulating evidence supports the notion that CA displays neuroprotective effects in AD and PD animal models by modulating neuroinflammation, suppressing oxidative stress, and improving the synaptic connection. CA exerts these effects through its action on multiple signaling pathways, including TLR4/NF-κB, NLRP3, ERK1/2-MEK, NO, and Nrf2 pathways. To summarize, CA and its derivatives have been shown to improve pathological changes in AD and PD animal models, which may provide a new therapeutic option for neurodegenerative interventions. To this end, further experimental and clinical studies are required to prove the neuroprotective effects of CA and its derivatives.