Neuroprotective effects of Arctium lappa L. roots against glutamate-induced oxidative stress by inhibiting phosphorylation of p38, JNK and ERK 1/2 MAPKs in PC12 cells

Fasudil-modified macrophages reduce inflammation and regulate the immune response in experimental autoimmune encephalomyelitis

Multiple sclerosis is characterized by demyelination and neuronal loss caused by inflammatory cell activation and infiltration into the central nervous system. Macrophage polarization plays an important role in the pathogenesis of experimental autoimmune encephalomyelitis, a traditional experimental model of multiple sclerosis. This study investigated the effect of Fasudil on macrophages and examined the therapeutic potential of Fasudil-modified macrophages in experimental autoimmune encephalomyelitis. We found that Fasudil induced the conversion of macrophages from the pro-inflammatory M1 type to the anti-inflammatory M2 type, as shown by reduced expression of inducible nitric oxide synthase/nitric oxide, interleukin-12, and CD16/32 and increased expression of arginase-1, interleukin-10, CD14, and CD206, which was linked to inhibition of Rho kinase activity, decreased expression of toll-like receptors, nuclear factor-κB, and components of the mitogen-activated protein kinase signaling pathway, and generation of the pro-inflammatory cytokines tumor necrosis factor-α, interleukin-1β, and interleukin-6. Crucially, Fasudil-modified macrophages effectively decreased the impact of experimental autoimmune encephalomyelitis, resulting in later onset of disease, lower symptom scores, less weight loss, and reduced demyelination compared with unmodified macrophages. In addition, Fasudil-modified macrophages decreased interleukin-17 expression on CD4+ T cells and CD16/32, inducible nitric oxide synthase, and interleukin-12 expression on F4/80+ macrophages, as well as increasing interleukin-10 expression on CD4+ T cells and arginase-1, CD206, and interleukin-10 expression on F4/80+ macrophages, which improved immune regulation and reduced inflammation. These findings suggest that Fasudil-modified macrophages may help treat experimental autoimmune encephalomyelitis by inducing M2 macrophage polarization and inhibiting the inflammatory response, thereby providing new insight into cell immunotherapy for multiple sclerosis.

Neuroprotective neolignan glycosides from the pseudobulbs of Bletilla striata

Four undescribed neolignan glycosides, bletineosides A-D (1-4) were isolated from the pseudobulbs of Bletilla striata. Their structures with absolute configurations were elucidated on the basis of spectroscopic analyses, along with acidic hydrolysis reactions and ECD experiments. All isolates were evaluated for their neuroprotective activities against glutamate-induced PC12 cell injury. Compound 3 and 4 showed significantly neuroprotective effects at the concentration of 10 μM when compared with the model group. Compounds 1-4 represented the first examples of neolignan glycosides from the genus Bletilla. This study disclosed the potency of Bletilla striata as a new source of anti-neurodegenerative agents.

Identification of Fangchinoline as a novel autophagy inhibitor with an adjuvant of chemotherapy against lung cancer

Autophagy is a fundamental recycling pathway that enhances cellular resilience, promoting survival. However, this survival mechanism can impede anti-cancer treatment strategies designed to induce cell death. In this study, we identified a novel autophagy inhibitor, Fangchinoline (Fan) isolated from the traditional Chinese medicine Stephania tetrandra. We speculated that when Fan blocks autophagy, cancer cells lose substantial self-preservation abilities during treatment. Firstly, we examined in detail the mechanism through which Fan inhibits autophagy. Specifically, Fan induced a significant increase in autophagosomes, as indicated by GFP-LC3 labeling, confirmed by the up-regulation of LC3-II. The autophagy receptor protein p62 was also up-regulated, suggesting a potential inhibition of autophagy flux. We further ruled out the possibility of fusion barriers between lysosomes and autophagosomes, as confirmed by their co-localization in double fluorescence staining. However, the lysosomal acid environment might be compromised, as suggested by the diminished fluorescence of acidity-sensitive dyes in the lysosomes and the corresponding decrease in mature forms of lysosomal cathepsin. To test the anti-cancer potential of Fan, we combined it with Cisplatin (Cis) or Paclitaxel (PTX) for lung cancer cell treatment. This combined treatment demonstrated a synergistically enhanced killing effect. These promising anti-tumor results were also replicated in a xenografted tumor model. The significance of this research lies in the identification of Fan as a potent autophagy inhibitor and its potential to enhance the efficacy of existing anti-cancer drugs. By unraveling the mechanisms of Fan's action on autophagy and demonstrating its synergistic effect in combination therapies, our study provides valuable insights for developing novel strategies to overcome autophagy-mediated resistance in cancer treatment.

Urolithin A's Antioxidative, Anti-Inflammatory, and Antiapoptotic Activities Mitigate Doxorubicin-Induced Liver Injury in Wistar Rats

Human colon microbiota produce a metabolite called urolithin A (URO A) from ellagic acid and linked compounds, and this metabolite has been demonstrated to have antioxidant, anti-inflammatory, and antiapoptotic activities. The current work examines the various mechanisms through which URO A protects against doxorubicin (DOX)-induced liver injury in Wistar rats. In this experiment, Wistar rats were administered DOX intraperitoneally (20 mg kg^-1) on day 7 while given URO A intraperitoneally (2.5 or 5 mg kg^-1 d^-1) for 14 days. The serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and gamma glutamyl transferase (GGT) were measured. Hematoxylin and eosin (HE) staining was used to evaluate histopathological characteristics, and then antioxidant and anti-inflammatory properties were evaluated in tissue and serum, respectively. We also looked at how active caspase 3 and cytochrome c oxidase were in the liver. The findings demonstrated that supplementary URO A therapy clearly mitigated DOX-induced liver damage. The antioxidant enzymes SOD and CAT were elevated in the liver, and the levels of inflammatory cytokines, such as TNF-α, NF-kB, and IL-6, in the tissue were significantly attenuated, all of which complemented the beneficial effects of URO A in DOX-induced liver injury. In addition, URO A was able to alter the expression of caspase 3 and cytochrome c oxidase in the livers of rats that were subjected to DOX stress. These results showed that URO A reduced DOX-induced liver injury by reducing oxidative stress, inflammation, and apoptosis.

Arctium lappa (Burdock): Insights from ethnopharmacology potential, chemical constituents, clinical studies, pharmacological utility and nanomedicine

Arctium lappa L. is a medicinal edible homologous plant, commonly known as burdock or bardana, which belongs to the Asteraceae family. It is widely distributed throughout Northern Asia, Europe, and North America and has been utilized for hundreds of years. The roots, fruits, seeds, and leaves of A. lappa have been extensively used in traditional Chinese Medicine (TCM). A. lappa has attracted a great deal of attention due to its possession of highly recognized bioactive metabolites with significant therapeutic potential. Numerous pharmacological effects have been demonstrated in vitro and in vivo by A. lappa and its bioactive metabolites, including antimicrobial, anti-obesity, antioxidant, anticancer, anti-inflammatory, anti-diabetic, anti-allergic, antiviral, gastroprotective, hepatoprotective, and neuroprotective activities. Additionally, A. lappa has demonstrated considerable clinical efficacies and valuable applications in nanomedicine. Collectively, this review covers the properties of A. lappa and its bioactive metabolites, ethnopharmacology aspects, pharmacological effects, clinical trials, and applications in the field of nanomedicine. Hence, a significant attention should be paid to clinical trials and industrial applications of this plant with particular emphasis, on drug discovery and nanotechnology.

TCQA, A Natural Caffeoylquinic Acid Derivative Attenuates H2O2-Induced Neuronal Apoptosis by Suppressing Phosphorylation of MAPKs Signaling Pathway

1,3,5-Tri-O-caffeoyl quinic acid is a caffeoylquinic acid derivative isolated from the roots of Arctium lappa L. Our previous studies have revealed that the ethyl acetate extract of the roots of A. lappa L. and the caffeoylquinic acids contained in it possess antioxidant properties, especially 1,3,5-tri-O-caffeoyl quinic acid. The present study aimed to investigate the protective effects of 1,3,5-tri-O-caffeoyl quinic acid against hydrogen peroxide-induced oxidative stress and explore the underlying mechanism. We found that 1,3,5-tri-O-caffeoyl quinic acid prevented the decline of cell viability and excessive release of lactate dehydrogenase induced by hydrogen peroxide. In addition, Hoechst 33 342 staining and Annexin V-PI double staining showed that 1,3,5-tri-O-caffeoyl quinic acid inhibited hydrogen peroxide-induced neuronal cell apoptosis. 1,3,5-Tri-O-caffeoyl quinic acid reduced the excessive production of intracellular reactive oxygen species, decreased the malondialdehyde content, and improved the activity of superoxide dismutase. Furthermore, 1,3,5-tri-O-caffeoyl quinic acid restored the loss of mitochondrial membrane potential in SH-SY5Y cells induced by hydrogen peroxide. 1,3,5-Tri-O-caffeoyl quinic acid downregulated the overexpression of proapoptotic proteins, including Bax, cytochrome c, cleaved caspase-9, and cleaved caspase-3 as well as promoted the expression of the antiapoptotic protein Bcl-2. Moreover, the phosphorylation of mitogen-activated protein kinases induced by hydrogen peroxide was inhibited by 1,3,5-tri-O-caffeoyl quinic acid. Pretreatment with 1,3,5-tri-O-caffeoyl quinic acid also promoted the activation of phosphorylated Akt. Taken together, these findings suggest that 1,3,5-tri-O-caffeoyl quinic acid exerts protective effects against hydrogen peroxide-induced neuronal apoptosis. In addition, inhibition of the mitogen-activated protein kinase signaling pathway and the activation of Akt are implicated in the antioxidant activity of 1,3,5-tri-O-caffeoyl quinic acid, giving new insight in searching for a compound with antioxidant activity for the treatment of oxidative stress-associated neurological diseases.

HPLC-PDA-Guided isolation of glucosyloxybenzyl 2-isobutylmalates from the pseudobulbs of Bletilla striata with neuroprotective and antimicrobial activities

Twelve undescribed glucosyloxybenzyl 2-isobutylmalates, bletistrosides A-L were obtained from the pseudobulbs of Bletilla striata under the guidance of HPLC-PDA. Their structures and absolute configurations were determined by the spectroscopic analyses, along with acidic hydrolysis and alkaline hydrolysis experiments. The neuroprotective effects and the antimicrobial activities of selective compounds were evaluated. Bletistroside G exhibited potential neuroprotective effect against glutamate-induced PC12 cell injury, with improving cell viabilities by 11.24% compared to the model group at 10 μM. Bletistrosides A, B, G, and L showed weak antimicrobial activities against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, however, bletistroside G showed obviously selective inhibition against P. aeruginosa.

Saccharides from Arctium lappa L. root reduce platelet activation and thrombus formation in a laser injury thrombosis mouse model

Arctium lappa L., also known as burdock, is a popular medicinal plant in traditional Chinese medicine due to its potential therapeutic properties. Saccharides from Arctium lappa L. root (ALR-S) have been extensively studied for their anti-inflammatory and anti-diabetes effects. Platelets play a pivotal role in thrombosis. The present study describes the effects of ALR-S on platelet activation and thrombosis using a laser injury thrombosis in vivo model. The study also measured the effects of ALR-S on platelet activation by analysing aggregation, ATP release, platelet spreading, adhesion and clot retraction in vitro. Specifically, the effects were ALR-S concentration-dependent inhibition of platelet aggregation and ATP release. Activated platelets pretreated with ALR-S showed diminished CD62P expression levels and fibrinogen binding, as measured by flow cytometry. ALR-S inhibited platelet spreading on fibrinogen and adhesion on collagen under shear. ALR-S attenuated platelet activation by decreasing oxidative stress and thrombus formation. These results demonstrated the antiplatelet effects of ALR-S, suggesting the antithrombotic and cardiovascular protective activities of ALR-S as a functional food.

1,3-Dicaffeoylquinic Acid as an Active Compound of Arctium lappa Root Extract Ameliorates Depressive-Like Behavior by Regulating Hippocampal Nitric Oxide Synthesis in Ovariectomized Mice

Menopause is a risk factor for depression. Although 1,3-dicaffeoylquinic acid (1,3-diCQA), a phenolic compound in Arctium lappa (A. lappa) root, has various health benefits, its effects on menopausal depression remain to be determined. Therefore, this study investigates the antidepressant-like effects of 1,3-diCQA from an A. lappa root extract (AE) and the associated molecular mechanisms. Ovariectomized (OVX) mice were orally administered AE for 20 weeks, following which depression-like behaviors were assessed. Although the mice exhibited depression-like behaviors, AE administration mitigated these symptoms by activating the ERK–CREB–BDNF pathway and increasing nNOS levels in the hippocampus. Similarly, a significant increase in nNOS-derived NO production and activation of the ERK–CREB–BDNF pathway was observed in the primary hippocampal neurons. Although this stimulatory effect of 1,3-diCQA was not significantly affected by treatment with estrogen receptor agonist or antagonist, it was inhibited by 7-NI, an nNOS inhibitor. Moreover, mice treated with 1,3-diCQA exhibited a marked improvement in their forced swimming test and tail suspension test immobility, while pretreatment with 7-NI reversed the antidepressant-like effects of 1,3-diCQA. Our results suggest that 1,3-diCQA regulates nNOS in an estrogen recepters-independent manner to increase NO production in OVX mice.

Arctium lappa L. roots ameliorates cerebral ischemia through inhibiting neuronal apoptosis and suppressing AMPK/mTOR-mediated autophagy

BACKGROUND

Arctium lappa L. roots are very popular cultivated vegetables, which possesses various pharmacological activities. Our previous studies have demonstrated that Arctium lappa L. roots exerted protective effects against H₂O₂, glutamate and N-methyl-D-aspartic acid (NMDA)-induced neuronal injury in vitro. However, whether Arctium lappa L. roots could prevent against cerebral ischemia and the underlying mechanism remain unclear.

PURPOSE

The objective of the present study was to investigate the neuroprotective effects of ethyl acetate extract of Arctium lappa L. roots (EAL) and the active ingredient 4,5-O-dicaffeoyl-1-O-[4-malic acid methyl ester]-quinic acid (DCMQA) in EAL against cerebral ischemia and explore the underlying mechanism.

STUDY DESIGN

The neuroprotective effects of EAL and DCMQA were investigated in rats with permanent middle cerebral artery occlusion (MCAO) and in oxygen glucose deprivation/reoxygenation (OGD/R)-stimulated SH-SY5Y cells, respectively.

METHODS

The infarct volume, brain edema and neurological deficits were measured following MCAO. TUNEL and Nissl staining were performed to detect neuronal loss and apoptosis of neurons in rat brains. Cell survival was measured by MTT and LDH assay. In addition, reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) levels were determined by DCFH-DA and JC-1 fluorescent probe, respectively. Hoechst 33342 staining and Annexin V-FITC/PI double staining were performed to evaluate neuronal apoptosis. The expression levels of proteins were evaluated by western blot.

RESULTS

EAL reduced brain infarct volume, ameliorated brain edema and improved neurological deficits in MCAO rats. In addition, EAL inhibited oxidative stress and inflammatory responses following MCAO. Besides, active compound DCMQA alleviated cytotoxicity as well as inhibited over-production of intracellular ROS and loss of MMP induced by OGD/R in SH-SY5Y cells. Moreover, EAL and DCMQA inhibited apoptosis by decreasing the expressions of pro-apoptotic proteins including bax, cytochrome c and cleaved caspase-3 while promoting the bcl-2 expression in MCAO rats and OGD/R-stimulated neurons, respectively. In addition, DCMQA suppressed the production of autophagosomes and down-regulated expression of Beclin 1 and LC3. Furthermore, inhibiting AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) signaling pathway contributed to DCMQA-mediated suppression of autophagy induced by OGD/R.

CONCLUSION

Our findings demonstrate that Arctium lappa L. roots protect against cerebral ischemia through inhibiting apoptosis and AMPK/mTOR-mediated autophagy in vitro and in vivo, providing a theoretical basis for the development of CQAs in Arctium lappa L. roots as neuroprotective drugs for the prevention and treatment of ischemic stroke.

Arctium lappa and Arctium tomentosum, Sources of Arctii radix: Comparison of Anti-Lipoxygenase and Antioxidant Activity as well as the Chemical Composition of Extracts from Aerial Parts and from Roots

Arctium lappa is a weed used in traditional medicine in the treatment of skin inflammation and digestive tract diseases. Arctium tomentosum is used in folk medicine interchangeably with Arctium lappa and, according to European Medicines Agency (EMA) monography, provides an equal source of Arctii radix (Bardanae radix), despite the small amount of research confirming its activity and chemical composition. The aim of the study was the comparison of the anti-lipoxygenase and the antioxidant activity, scavenging of 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide anion (O₂^•−), and hydrogen peroxide (H₂O₂), of 70 % (v/v) ethanolic extracts from the aerial parts and the roots of Arctium lappa and Arctium tomentosum. In the tested extracts, the total polyphenols content and the chemical composition, analyzed with the HPLC–DAD–MSⁿ method, were also compared. The extracts were characterized by strong antioxidant properties, but their ability to inhibit lipoxygenase activity was rather weak. A correlation between the content of polyphenolic compounds and antioxidant activity was observed. The extracts from A. lappa plant materials scavenged reactive oxygen species more strongly than the extracts from A. tomentosum plant materials. Moreover, the extracts from A. lappa plant materials were characterized by the statistically significantly higher content of polyphenolic compounds.

Current Advances in Naturally Occurring Caffeoylquinic Acids: Structure, Bioactivity, and Synthesis

Caffeoylquinic acids (CQAs) are a broad class of secondary metabolites that have been found in edible and medicinal plants from various families. It has been 100 years since the discovery of chlorogenic acid in 1920. In recent years, a number of naturally derived CQAs have been isolated and structurally elucidated. Accumulated evidence demonstrate that CQAs have a wide range of biological activities, such as antioxidation, antibacterial, antiparasitic, neuroprotective, anti-inflammatory, anticancer, antiviral, and antidiabetic effects. Up to date, some meaningful progresses on the biosynthesis and total synthesis of CQAs have also been made. Therefore, it is necessary to comprehensively summarize the structure, biological activity, biosynthesis, and chemical synthesis of CQAs. This review provides extensive coverage of naturally occurring CQAs discovered from 1990 until 2020. Modern isolation techniques, chemical data (including structure, biosynthesis, and total synthesis), and bioactivity are summarized. This would be helpful for further research of CQAs as potential pharmaceutical agents.

Isolation, structure elucidation and neuroprotective effects of caffeoylquinic acid derivatives from the roots of Arctium lappa L

Five undescribed caffeoylquinic acid derivatives (CQAs), along with fifteen known CQAs, were isolated from the roots of Arctium lappa L.(burdock). The chemical structures of compounds were determined using extensive spectroscopic analyses, including UV, IR, NMR and MS. Further in vitro bioactive investigation demonstrated the neuroprotective effects of these compounds against the neurotoxicity of hydrogen peroxide (H₂O₂) and N-methyl-D-aspartate (NMDA). 1,3,5-tri-O-caffeoylquinic acid and 1,4,5-tri-O-caffeoylquinic acid significantly reduced H₂O₂-induced human neuroblastoma SH-SY5Y cell death with concentration for 50% of maximal effect (EC₅₀) values of 17.3 and 19.3 μM. Meanwhile, 3,5-di-O-caffeoyl-1-O-maloylquinic acid displayed protective effect against NMDA-induced cell injury with EC₅₀ values of 18.4 μM. Overall, the more caffeoyl, the better the antioxidant activity, while the maloyl-containing compounds had better anti-NMDA activity.

DCMQA, a caffeoylquinic acid derivative alleviates NMDA-induced neurotoxicity via modulating GluN2A and GluN2B-containing NMDA receptors in vitro

Compound DCMQA (4, 5-O-dicaffeoyl-1-O-[4-malic acid methyl ester]-quinic acid) is a natural caffeoylquinic acid derivative isolated from Arctium lappa L. roots. Caffeoylquinic acid derivatives have been reported to possess neuroprotective effects through inhibiting oxidative stress and apoptosis in vitro. However, whether DCMQA exerts protective effects on N-methyl-D-aspartate (NMDA)-induced neurotoxicity and the underlying mechanism has not been elucidated. In this study, the results indicated that pretreatment of DCMQA prevented the loss of cell viability and attenuated the LDH leakage in SH-SY5Y cells exposed to NMDA. Hoechst 33342 staining and Annexin V-PI double staining illustrated that DCMQA suppressed NMDA-induced morphological damage and neuronal apoptosis. Moreover, DCMQA inhibited NMDA-mediated Ca²⁺ influx, excessive intracellular ROS generation and loss of mitochondrial membrane potential (MMP). Western blot analysis showed that DCMQA attenuated the Bax/Bcl-2 ratio, release of cytochrome c as well as expression of caspase-9 and caspase-3. Besides, DCMQA down-regulated GluN2B-containing NMDA receptors (NMDARs) and up-regulated GluN2A-containing NMDARs, promoted the disruption of nNOS and PSD95 as well as activation of CaMK II-α. Furthermore, computational docking study indicated that DCMQA possessed a good affinity for NMDARs. These results indicated that DCMQA protects SH-SY5Y cells against NMDA-induced neuronal damage. In addition, the underlying mechanisms of DCMQA-mediated neuroprotection are associated with modulating NMDARs and disruption of nNOS-PSD95 as well as the activation of CaMK II-α.

Coniferyl ferulate exerts antidepressant effect via inhibiting the activation of NMDAR-CaMKII-MAPKs and mitochondrial apoptotic pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Xiaoyaosan (XYS), composed of Radix Bupleuri, Radix Angelicae Sinensis, Radix Paeoniae Alba, Rhizoma Atractylodis Macrocephalae, Poria, Herba Menthae, Rhizoma Zingiberis Recens and Radix Glycyrrhizae, is a valuable traditional Chinese medicine (TCM) which is used for the treatment of depression in China. In our previous experiments, we found that coniferyl ferulate (CF) was the main active constituent of Xiaoyaosan based on UPLC-PDA guided isolation technique. However, the antidepressant effect and mechanisms of CF is still unknown.

AIM OF THE STUDY

In the current study, we aim to explore the possible mechanisms involved in the neuroprotective effect of CF in glutamate-injured PC12 cells, and further to confirm the anti-depressant effect of CF on the model of behavioral despair in vivo.

MATERIAL AND METHODS

The model of glutamate-injured PC12 cells was employed to investigate the possible mechanisms involved in the neuroprotective effect of CF. The model of behavioral despair was carried out to examine the in vivo anti-depressant effect of CF.

RESULTS

The results showed that CF significantly attenuated the decrease of cell viability, the release of lactate dehydrogenase (LDH), and the increase of apoptosis rates induced by glutamate. CF could also suppress the influx of Ca²⁺ and the elevation of p-NR2B, p-CaMK II, p-JNK, and p-p38 level induced by glutamate. Besides, CF could also inhibit the generation of reactive oxygen species (ROS), the decrease of SOD activity, the elevation of malondialdehyde (MDA) level, and suppress the loss of mitochondrial membrane potential (MMPs) and the activation Bcl-2/Bax mediated apoptotic pathways induced by glutamate. Furthermore, CF obviously decreased the immobility time in tail suspension test (TST) and forced swimming test (FST).

CONCLUSION

In conclusion, CF exert the indeed anti-depressant effect. The inhibition of NMDAR-CaMKII-MAPKs signaling pathway, oxidative stress, and mitochondrial apoptotic pathways were involved in the anti-depressant effect of CF.

Neuroprotective effects of urolithin A on H2O2-induced oxidative stress-mediated apoptosis in SK-N-MC cells

BACKGROUND/OBJECTIVES

Oxidative stress causes cell damage and death, which contribute to the pathogenesis of neurodegenerative diseases. Urolithin A (UA), a gut microbial-derived metabolite of ellagitannins and ellagic acid, has high bioavailability and various health benefits such as antioxidant and anti-inflammatory effects. However, it is unknown whether it has protective effects against oxidative stress-induced cell death. We investigated whether UA ameliorates H₂O₂-induced neuronal cell death.

MATERIALS/METHODS

We induced oxidative damage with 300 µM H₂O₂ after UA pretreatment at concentrations of 1.25, 2.5, and 5 µM in SK-N-MC cells. Cytotoxicity and cell viability were determined using the CCK-8 assay. The formation of reactive oxygen species (ROS) was measured using a 2,7-dichlorofluorescein diacetate assay. Hoechst 33342 staining was used to characterize morphological changes in apoptotic cells. The expressions of apoptosis proteins were measured using Western blotting.

RESULTS

UA significantly increased cell viability and decreased intracellular ROS production in a dose-dependent manner in SK-N-MC cells. It also decreased the Bax/Bcl-2 ratio and the expressions of cytochrome c, cleaved caspase-9, cleaved caspase-3, and cleaved PARP. In addition, it suppressed the phosphorylation of the p38 mitogen-activated protein kinase (MAPK) pathway.

CONCLUSIONS

UA attenuates oxidative stress-induced apoptosis via inhibiting the mitochondrial-related apoptosis pathway and modulating the p38 MAPK pathway, suggesting that it may be an effective neuroprotective agent.

Phytotoxic activity of crop residues from Burdock and an active substance

Problems related to weed management such as outbreaks of herbicide-resistant weeds have recently increased. An interesting approach to such problems is to use plant materials with phytotoxic activity. Burdock (Arctium lappa L.) is a biennial herb belonging to Asteraceae and is cultivated in several countries. The present study investigated the phytotoxic activity of burdock and its active substances. Extracts of both burdock leaves and roots inhibited the shoot and root growth of cress and barnyard grass, where the level of inhibition increased with increasing extract concentration. The leaf extracts had 2.0-2.5 times higher activity than the root extracts. Bioassay-guided separations of the leaf extracts led to isolation of a phytotoxic substance, onopordopicrin. Onopordopicrin significantly inhibited the shoot and root growth of cress and barnyard grass. The concentrations of the substance required for 50% growth inhibition were 0.27 and 0.26 mM for cress shoots and roots, respectively, and 1.86 and 0.35 mM for barnyard grass shoots and roots, respectively. The present results suggest that burdock leaves have high phytotoxic activity and onopordopicrin may play a major role in the activity. Burdock leaves may be a good resource for weed management.

Arctium lappa contributes to the management of type 2 diabetes mellitus by regulating glucose homeostasis and improving oxidative stress: A critical review of in vitro and in vivo animal-based studies

Diabetes is a metabolic disease highly widespread worldwide, and the most common form is the type 2 diabetes mellitus (T2DM). A large number of synthetic drugs are currently available for the treatment of diabetes; however, they present various side effects and, for this reason, people are increasingly inclined to search natural alternative treatments. Among these, Arctium lappa (A. lappa) has interesting anti-diabetic activities, exerted by improving glucose homeostasis and reducing insulin-resistance. In addition, A. lappa exerts a marked antioxidant activity, an effect known to play a pivotal role in the treatment of T2DM. The purpose of this review is to analyse scientific evidence in order to evaluate the role of A. lappa and its bioactive compounds in management of T2DM. The literature search performed provided only in vitro and animal-based studies. No clinical studies have been conducted in order to investigate the effect of A. lappa on T2DM patients. However, available literature provides evidence for further clinical trials in order to confirm these claimed activities on humans.

Immunomodulatory activity of a fructooligosaccharide isolated from burdock roots

Immunomodulatory activity of burdock fructooligosaccharide (BFO-1) on immune cells in in vitro normal mice, immunosuppressed mice treated with cyclophosphamide and S180 tumor-bearing mice.

Momordica charantia Ethanol Extract Attenuates H₂O₂-Induced Cell Death by Its Antioxidant and Anti-Apoptotic Properties in Human Neuroblastoma SK-N-MC Cells

Oxidative stress, which is induced by reactive oxygen species (ROS), causes cellular damage which contributes to the pathogenesis of neurodegenerative diseases. Momordica charantia (MC), a traditional medicinal plant, is known to have a variety of health benefits, such as antidiabetic, anti-inflammatory, and antioxidant effects. However, it is unknown whether MC has protective effects against oxidative stress-induced neuronal cell death. The aim of this study was to investigate the potential action of MC on oxidative stress induced by H₂O₂. First, we tested whether the pretreatment of Momordica charantia ethanol extract (MCEE) attenuates H₂O₂-induced cell death in human neuroblastoma SK-N-MC cells. MCEE pretreatment significantly improved cell viability and apoptosis that deteriorated by H₂O₂. Further, MCEE ameliorated the imbalance between intracellular ROS production and removal through the enhancement of the intracellular antioxidant system. Intriguingly, the inhibition of apoptosis was followed by the blockage of mitochondria-dependent cell death cascades and suppression of the phosphorylation of the mitogen-activated protein kinase signaling (MAPKs) pathway by MCEE. Taken together, MCEE was shown to be effective in protecting against H₂O₂-induced cell death through its antioxidant and anti-apoptotic properties.

Semi-Preparative Separation of 10 Caffeoylquinic Acid Derivatives Using High Speed Counter-Current Chromatogaphy Combined with Semi-Preparative HPLC from the Roots of Burdock (Arctium lappa L.)

Burdock roots are healthy dietary supplements and a kind of famous traditional Chinese medicine, which contains large amounts of caffeoylquinic acid derivatives. However, little research has been reported on the preparative separation of these compounds from burdock roots. In the present study, a combinative method of HSCCC and semi-preparative HPLC was developed for the semi-preparative separation of caffeoylquinic acid derivatives from the burdock roots. The ethyl acetate extract of burdock roots was first fractionated by MCI macroporous resin chromatography and give three fractions (Fr. 1–3) from the elution of 40% methanol. Then, these three fractions (120 mg) were separately subjected to HSCCC for purification with the solvent system composed of petroleum ether-ethyl acetate-methanol-water at different volume ratios, and the mixtures were further purified by semi-preparative HPLC. As a result, a total of eight known caffeoylquinic acid derivatives including 3-O-caffeoylquinic acid (32.7 mg, 95.7%), 1,5-O- dicaffeoylquinic acid (4.3 mg, 97.2%), 3-O-caffeoylquinic acid methyl ester (12.1 mg, 93.2%), 1,3-O-dicaffeoylquinic acid (42.9 mg, 91.1%), 1,5-O-dicaffeoyl-3-O-(4-maloyl)-quinic acid (4.3 mg, 84.5%), 4,5-O-dicaffeoylquinic acid (5.3 mg, 95.5%), 1,5-O-dicaffeoyl-3-O-succinylquinic acid (8.7 mg, 93.4%), and 1,5-O-dicaffeoyl-4-O-succinylquinic acid (1.7 mg, 91.8%), and two new compounds were obtained. The new compounds were 1,4-O-dicaffeoyl-3-succinyl methyl ester quinic acid (14.6 mg, 96.1%) and 1,5-O-dicaffeoyl-3-O-succinyl methyl ester quinic acid (3.1 mg, 92.6%), respectively. The research indicated that the combination of HSCCC and semi-preparative HPLC is a highly efficient approach for preparative separation of the instability and bioactive caffeoylquinic acid derivatives from natural products.

Mitodepressive, antioxidant, antifungal and anti-inflammatory effects of wild-growing Romanian native Arctium lappa L. (Asteraceae) and Veronica persica Poiret (Plantaginaceae)

The present study aims to evaluate the potential uses of hydroalcoholic extracts obtained from Romanian native wild-growing plants. The hydroalcoholic extracts were obtained from the burdock roots and respectively the aerial parts of birdeye speedwell. The extracts were characterised by HPLC (quantifying 13 compounds in the V. persica extract, 6 compounds in the A. lappa extract and confirming the presence of arctiin and arctigenin in the burdock extract). The antioxidant potential of the crude extracts was evaluated using two methods: the DPPH assay (79.91% for speedwell extract, 76.23% for burdock extract) and the phosphomolybdate method (296.5 mg/g ascorbic acid equivalents for burdock, 324.4 mg/g for speedwell). The crude extracts were found to be active against both fungal lines used (Aspergillus niger and Penicillium hirsutum), inhibition zones - 17.1 mm and 13.1 mm against P. hirsutum, respectively ca. 22 mm for both extracts against A. niger. The cytogenetic effects (assessed using the Allium cepa assay) revealed a series of chromosomal aberrations and nuclear aberrations induced in the meristematic root cells. The anti-inflammatory effect, estimated in two inflammation experimental models, showed a significant effect, especially for the speedwell extract. The results recommend the evaluated extracts as promising sources of biologically-active compounds.

Effect of epigallocatechin-3-gallate on acrylamide-induced oxidative stress and apoptosis in PC12 cells

Acrylamide (ACR) is a chemical intermediate utilized in industry. ACR is also formed during heating of foods containing carbohydrates and amino acids. Therefore, humans are widely exposed to ACR, and ACR neurotoxicity in humans is a significant public health issue attracting wide attention. In this study, we investigated the potential neuroprotective effects of epigallocatechin-3-gallate (EGCG), the most abundant polyphenolic compound in green tea, in PC12 cells treated with ACR. ACR-treated PC12 cells pretreated with various concentrations of EGCG (2.5, 5 and 10 μM) for 24 h had increased viability and acetylcholinesterase activity and reduced apoptosis and necrosis compared to cells exposed to ACR alone. EGCG reduced the expression of bax mRNA, decreased cytochrome c release, reduced intracellular calcium levels, inactivated caspase 3 and increased mitochondrial membrane potential, suggesting that EGCG prevents ACR-induced apoptosis through a mitochondrial-mediated pathway. In addition, EGCG inhibited the formation of reactive oxygen species and lipid peroxidation while enhancing superoxide dismutase activity and glutathione levels, thereby reducing oxidative stress. Our results indicate that pretreatment of PC12 cells with EGCG attenuates ACR-induced apoptosis by reducing oxidative stress. Therefore, drinking green tea may reduce nerve injury induced by ACR.

Caffeoylquinic Acid Derivatives Protect SH-SY5Y Neuroblastoma Cells from Hydrogen Peroxide-Induced Injury Through Modulating Oxidative Status

Oxidative stress has been confirmed as a contribution to the pathogenesis and pathophysiology of many neurological disorders such as Alzheimer's disease and Parkinson's disease. Caffeoylquinic acids (CQAs) are considered to have anti-oxidative stress ability in a previous study, but the structure-activity relationships (SARs) of CQAs in neuroprotective effects are still unclear. In the present study, we primarily expound the SARs of CQAs in counteracting H₂O₂-induced injury in SH-SY5Y cells. We found that CQAs (1-10) represented the protection of SH-SY5Y cells against H₂O₂-induced injury in varying degrees and malonyl groups could obviously increase the anti-oxidative stress ability of CQAs. Intensive studies of 4,5-O-dicaffeoyl-1-O-(malic acid methyl ester)-quinic acid (MDCQA) indicated that the mechanisms could potentially involve activation of endogenous antioxidant enzymes and the regulation of the phosphorylation of MAPKs and AKT. In conclusion, MDCQA could serve as a neuroprotective agent with a potential to attenuate oxidative stress.

Saikosaponin-D Reduces H2O2-Induced PC12 Cell Apoptosis by Removing ROS and Blocking MAPK-Dependent Oxidative Damage

Neuronal oxidative stress (OS) injury has been proven to be associated with many neurodegenerative diseases, and thus, antioxidation treatment is an effective method for treating these diseases. Saikosaponin-D (SSD) is a sapogenin extracted from Bupleurum falcatum and has been shown to have many pharmacological activities. The main purpose of this study was to investigate whether and how SSD protects PC12 cells from H₂O₂-induced apoptosis. The non-toxic level of SSD significantly mitigated the H₂O₂-induced decrease in cell viability, reduced the apoptosis rate, improved the nuclear morphology, and reduced caspase-3 activation and poly ADP-ribose polymerase (PARP) cleavage. Additionally, exogenous H₂O₂-induced apoptosis by damaging the intracellular antioxidation system. SSD significantly slowed the H₂O₂-induced release of malonic dialdehyde (MDA) and lactate dehydrogenase and increased the activity of superoxide dismutase (SOD) and the total antioxidant capacity, thereby reducing apoptosis. More importantly, SSD effectively blocked H₂O₂-induced phosphorylation of extracellular-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (p38MAPK), and specific inhibitors of ERK, JNK, and p38-reduced OS injury and apoptosis, suggesting that SSD reduces OS injury and apoptosis via MAPK signalling pathways. Finally, we confirmed that SSD significantly reduced H₂O₂-induced reactive oxygen species (ROS) accumulation, and the ROS inhibitor blocked the apoptosis caused by MAPK activation and cellular oxidative damage. In short, our study confirmed that SSD reduces H₂O₂-induced PC12 cell apoptosis by removing ROS and blocking MAPK-dependent oxidative damage.

Germinated Brown Rice Alters Aβ(1-42) Aggregation and Modulates Alzheimer's Disease-Related Genes in Differentiated Human SH-SY5Y Cells

The pathogenesis of Alzheimer's disease involves complex etiological factors, of which the deposition of beta-amyloid (Aβ) protein and oxidative stress have been strongly implicated. We explored the effects of H2O2, which is a precursor for highly reactive hydroxyl radicals, on neurotoxicity and genes related to AD on neuronal cells. Candidate bioactive compounds responsible for the effects were quantified using HPLC-DAD. Additionally, the effects of germinated brown rice (GBR) on the morphology of Aβ(1-42) were assessed by Transmission Electron Microscopy and its regulatory effects on gene expressions were explored. The results showed that GBR extract had several phenolic compounds and γ-oryzanol and altered the structure of Aβ(1-42) suggesting an antiamyloidogenic effect. GBR was also able to attenuate the oxidative effects of H2O2 as implied by reduced LDH release and intracellular ROS generation. Furthermore, gene expression analyses showed that the neuroprotective effects of GBR were partly mediated through transcriptional regulation of multiple genes including Presenilins, APP, BACE1, BACE2, ADAM10, Neprilysin, and LRP1. Our findings showed that GBR exhibited neuroprotective properties via transcriptional regulation of APP metabolism with potential impact on Aβ aggregation. These findings can have important implications for the management of neurodegenerative diseases like AD and are worth exploring further.

Neuroprotective effect of Citrus unshiu immature peel and nobiletin inhibiting hydrogen peroxide-induced oxidative stress in HT22 murine hippocampal neuronal cells

BACKGROUND

Oxidative stress-induced cell damage is common in the etiology of several neurobiological disorders, including Alzheimer's disease and Parkinson's disease. In a case study, nobiletin-rich Citrus reticulata peels could prevent the progression of cognitive impairment in donepezil-preadministered Alzheimer's disease patients.

OBJECTIVE

In this study, we investigated the effects and underlying mechanism of nobiletin and Citrus unshiu immature peel (CUIP) water extract, which contains nobiletin as a major compound, on hydrogen peroxide-induced oxidative stress in HT22 cells, a murine hippocampal neuronal model.

MATERIALS AND METHODS

HT22 cells were treated with hydrogen peroxide in the presence or absence of various concentrations of CUIP and nobiletin. Cytotoxicity and apoptotic protein levels were measured by 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and Western blotting.

RESULTS

Pretreatment with CUIP and nobiletin inhibited cell death due to hydrogen peroxide. Hydrogen peroxide-induced the expression of phospho-Jun N-terminal kinases (p-JNK) and p-p38 proteins in HT22 cells; however CUIP and nobiletin suppressed p-JNK and p-p38 without changing JNK or p38. Regarding apoptosis, caspase 3, B-cell lymphoma 2 (Bcl-2), and Bax protein expression was determined. CUIP and nobiletin suppressed caspase 3 and Bax expression, but they induced Bcl-2 expression in HT22 cells.

CONCLUSION

These results show that CUIP and nobiletin can protect against hydrogen peroxide-induced cell death in HT22 neurons via mitogen-activated protein kinases and apoptotic pathways.

SOD2 Mediates Amifostine-Induced Protection against Glutamate in PC12 Cells

Background. Cytoprotectant amifostine attenuates radiation-induced oxidative injury by increasing intracellular manganese superoxide dismutase (SOD2) in peripheral tissue. However, whether amifostine could protect neuronal cells against oxidative injury has not been reported. The purpose of this study is to explore the protection of amifostine in PC12 cells. Methods. PC12 cells exposed to glutamate were used to mimic neuronal oxidative injury. SOD assay kit was taken to evaluate intracellular Cu/Zn SOD (SOD1) and SOD2 activities; western blot analysis and immunofluorescence staining were performed to investigate SOD2 protein expression; MTT, lactate dehydrogenase (LDH), release and cell morphology were used to evaluate cell injury degree, and apoptotic rate and cleaved caspase-3 expression were taken to assess apoptosis; mitochondrial superoxide production, intracellular reactive oxygen species (ROS), and glutathione (GSH) and catalase (CAT) levels were evaluated by reagent kits. Results. Amifostine increased SOD2 activity and expression, decreased cell injury and apoptosis, reduced mitochondrial superoxide production and intracellular ROS generation, and restored intracellular GSH and CAT levels in PC12 cells exposed to glutamate. SOD2-siRNA, however, significantly reversed the amifostine-induced cytoprotective and antioxidative actions. Conclusion. SOD2 mediates amifostine-induced protection in PC12 cells exposed to glutamate.

Neuroprotective effects of Kukoamine B against hydrogen peroxide-induced apoptosis and potential mechanisms in SH-SY5Y cells

Oxidative stress mediates the cell damage in several neurodegenerative diseases, including multiple sclerosis, Alzheimer's disease (AD) and Parkinson's disease (PD). This study aimed at investigating the protective effects of Kukoamine B (KuB) against hydrogen peroxide (H2O2) induced cell injury and potential mechanisms in SH-SY5Y cells. Our results revealed that treatment with KuB prior to H2O2 exposure effectively increased the cell viability, and restored the mitochondria membrane potential (MMP). Furthermore, KuB enhanced the antioxidant enzyme activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) and decreased the malondialdehyde (MDA) content. Moreover, KuB minimized the ROS formation and inhibited mitochondria-apoptotic pathway, MAPKs (p-p38, p-JNK, p-ERK) pathways, but activated PI3K-AKT pathway. In conclusion, we believed that KuB may potentially serve as an agent for prevention of several human neurodegenerative and other disorders caused by oxidative stress.

Neurocytoprotective Effects of Aliphatic Hydroxamates from Lovastatin, a Secondary Metabolite from Monascus-Fermented Red Mold Rice, in 6-Hydroxydopamine (6-OHDA)-Treated Nerve Growth Factor (NGF)-Differentiated PC12 Cells

Lovastatin, a secondary metabolite isolated from Monascus-fermented red rice mold, has neuroprotective activity and permeates the blood-brain barrier. The aim of this study was to enhance the activity of lovastatin for potential use as a treatment for neuronal degeneration in Parkinson's disease. Six lovastatin-derived compounds were semisynthesized and screened for neurocytoprotective activity against 6-hydroxydopamine (6-OHDA)-induced toxicity in human neuroblastoma PC12 cells. Four compounds, designated as 3a, 3d, 3e, and 3f, significantly enhanced cell viability. In particular, compound 3f showed excellent neurocytoprotective activity (97.0 ± 2.7%). Annexin V-FITC and propidium iodide double staining and 4',6-diamidino-2-phenylindole staining indicated that compound 3f reduced 6-OHDA-induced apoptosis in PC12 cells. Compound 3f also reduced caspase-3, -8, and -9 activities, and intracellular calcium concentrations elevated by 6-OHDA in a concentration-dependent manner, without inhibiting reactive oxygen species generation. JC-1 staining indicated that compound 3f also stabilized mitochondrial membrane potential. Thus, compound 3f may be used as a neurocytoprotective agent. Future studies should investigate its potential application as a treatment for Parkinson's disease.