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

Contribution of phenolamides to the quality evaluation in Lycium spp

ETHNOPHARMACOLOGICAL RELEVANCE

Goji berry is a general term for various plant species in the genus Lycium. Goji has long been historically used in traditional Chinese medicines. Goji is a representative tonic medicine that has the effects of nourishing the liver and kidney and benefiting the essence and eyesight. It has been widely used in the treatment of various diseases, including tinnitus, impotence, spermatorrhea and blood deficiency, since ancient times.

AIM OF THE REVIEW

This study aims to comprehensively summarize the quality evaluation methods of the main compounds in goji, as well as the current research status of the phenolamides in goji and their pharmacological effects, to explore the feasibility of using phenolamides as quality control markers and thus improve the quality and efficacy in goji.

MATERIALS AND METHODS

Relevant literature from PubMed, Web of Science, Science Direct, CNKI and other databases was comprehensively collected, screened and summarized.

RESULTS

According to the collected literature, the quality evaluation markers of goji in the Pharmacopoeia of the People's Republic of China are Lycium barbarum polysaccharide (LBP) and betaine. As a result of its structure complexity, only the total level of LBP can be determined, while betaine is not prominent in the pharmacological action of goji and lacks species distinctiveness. Neither of them can well explain the quality of goji. KuA and KuB are commonly used as quality evaluation markers of the Lycii cortex because of their high levels and suitable pharmacological activity. Goji is rich in polyphenols, carotenoids and alkaloids. Many studies have used the above compounds to establish quality evaluation methods but the results have not been satisfactory. Phenolamides have often been neglected in previous studies because of their low single compound levels and high separation difficulty. However, in recent years, the favorable pharmacological activities of phenolamides have been gradually recognized, and studies on goji phenolamides are greatly increasing. In addition, phenolamides have higher species distinctiveness than other compounds and can be combined with other compounds to better evaluate the quality of goji to improve its average quality.

CONCLUSIONS

The phenolamides in the goji are rich and play a key role in antioxidation, anti-inflammation, neuroprotection and immunomodulation. As a result of their characteristics, it is suitable to evaluate the quality by quantitative analysis of multi-components by single-marker and fingerprint. This method can be combined with other techniques to improve the quality evaluation system of goji, which lays a foundation for their effectiveness and provides a reference for new quality evaluation methods of similar herbal medicines.

Discovery of palmatine derivatives as potent neuroprotective agents

Alzheimer's disease is a neurodegenerative disorder characterized by the presence of neurodegenerative lesions and cognitive impairment. In this study, a series of novel palmatine derivatives were designed and synthesized through the introduction of a heteroatom using carbodiimide-mediated condensation. The synthesized compounds were then screened for toxicity and potency, leading to the identification of compound 2q, which exhibited low toxicity and high potency. Our findings demonstrated that compound 2q displayed significant neuroprotective activity in vitro, emerging as a promising candidate for Alzheimer's disease treatment.

New neuroprotective derivatives of cinnamic acid by biotransformation

Microbial transformation is extensively utilized to generate new metabolites in bulk amounts with more specificity and improved activity. As cinnamic acid was reported to exhibit several important pharmacological properties, microbial transformation was used to obtain its new derivatives with enhanced biological activities. By manipulating the 2-stage fermentation protocol of biotransformation, five metabolites were produced from cinnamic acid. Two of them were new derivatives; N-propyl cinnamamide 2̲ and 2-methyl heptyl benzoate 3̲ produced by Alternaria alternata. The other 3 metabolites, p-hydroxy benzoic acid 4̲, cinnamyl alcohol 5̲ and methyl cinnamate 6̲, were produced by Rhodotorula rubra, Rhizopus species and Penicillium chrysogeneum, respectively. Cinnamic acid and its metabolites were evaluated for their cyclooxygenase (COX) and acetylcholinesterase (AChE) inhibitory activities. Protection against H2O2 and Aβ1-42 induced-neurotoxicity in human neuroblastoma (SH-SY5Y) cells was also monitored. Metabolite 4̲ was more potent as a COX-2 inhibitor than the parent compound with an IC50 value of 1.85 ± 0.07 μM. Out of the tested compounds, only metabolite 2̲ showed AChE inhibitory activity with an IC50 value of 8.27 μM. These results were further correlated with an in silico study of the binding interactions of the active metabolites with the active sites of the studied enzymes. Metabolite 3̲ was more potent as a neuroprotective agent against H2O2 and Aβ1-42 induced-neurotoxicity than catechin and epigallocatechin-3-gallate as positive controls. This study suggested the two new metabolites 2̲ and 3̲ along with metabolite 4̲ as potential leads for neurodegenerative diseases associated with cholinergic deficiency, neurotoxicity or neuroinflammation.

Soy yogurt using Lactobacillus plantarum 200655 and fructooligosaccharides: neuroprotective effects against oxidative stress

This study aimed to evaluate the effect of Lactobacillus plantarum 200655 and fructooligosaccharides (FOS) on soymilk fermentation and the neuroprotective effects of fermented soymilk (FS). The addition of FOS did not affect the physicochemical properties during fermentation. It helped that L. plantarum 200655 survive for 21 days of storage at 4 °C. FOS increased the β-glucosidase activity of L. plantarum 200655, total phenolic content, and antioxidant activities, such as radical scavenging and reducing power of FS. In addition, FS with FOS exerted neuroprotective effects in SH-SY5Y cells against H2O2-induced oxidative stress. FS with 3% and 5% FOS (FS3 and FS5) significantly increased cell viability and gene expression of neuronal markers, such as brain-derived neurotrophic factor and tyrosine hydroxylase. Moreover, FS3 and FS5 significantly reduced lactate dehydrogenase release and the gene expression of Bax/Bcl-2 ratio, caspase-9, and caspase-3. These results indicated that FS3 and FS5, with enhanced antioxidant properties, could protect SH-SY5Y cells against H2O2-induced damage. Therefore, soymilk fermented with L. plantarum 200655 and FOS can be used as a prophylactic functional food with neuroprotective effects against oxidative stress.

Kukoamine A Improves Mycoplasma pneumoniae Pneumonia by Regulating miR-222-3p/Superoxide Dismutase 2

Mycoplasma pneumoniae pneumonia (MPP) represents a common respiratory disease in children patients. Kukoamine A (KuA) is a spermine alkaloid found in the Chinese herb Cortex Lycii radices, which has a variety of pharmacological properties. However, no study has been reported on the role of KuA in MPP. Exosomes, a type of lipid bilayer-enclosed extracellular vesicles, can be delivered to the target cells, where they regulate function and physiology. With the use of human alveolar basal epithelial cells (HABECs) as an in vitro model, in this study, we sought to characterize the changes in levels of superoxide dismutase 2 (SOD2) and proinflammatory cytokines including IL-6 and TNF-α in HABECs in response to exosomes, which were isolated from peripheral blood serum of MPP patients. We found that, compared to normal, MPP patients exhibited a significant up-regulated miR-222-3p. Further, exosomal miR-222-3p downregulated SOD2 activity but promoted nuclear NF-κB activity and expression of IL-6 and TNF-α in HABECs, ultimately leading to an oxidative stress condition. Interestingly, such stimulating effects were attenuated by the pretreatment of KuA. This study suggests a critical role possessed by KuA in MPP by regulating the miR-222-3p/SOD2 axis, which represents a promising strategy for the treatment of MPP.

Brazilian sunberry (Solanum oocarpum Sendtn): Alkaloid composition and improvement of mitochondrial functionality and insulin secretion of INS-1E cells

Chronic high-glucose levels induce the generation of reactive oxygen species leading to mitochondrial dysfunction, which is one of the pathological triggers in the development of diabetes. This study investigated the alkaloid composition of two fruits of the genus Solanum, fruta-do-lobo (Solanum lycocarpum) and juá-açu (Solanum oocarpum), and their capacity to protect against oxidative damage and defective insulin secretion induced by chronic high-glucose levels. LC-MS and molecular network of fruit crude extracts reveals that juá-açu and fruta-do-lobo contain kukoamines and glycoalkaloids, respectively. Two purification processes were used to enrich those alkaloids. Fruta-do-lobo extract rich in glycoalkaloids showed a strong cytotoxicity effect, however the juá-açu enriched extract was able to protect mitochondrial functionality against glucotoxicity and stimulate insulin secretion even under conditions of hyperglycemia. These results are promising and suggest that juá-açu is a potential source of bioactive compounds for adjuvant/co-adjuvant therapy for diabetes.

Neuroprotective Effects of Heat-Killed Lactobacillus plantarum 200655 Isolated from Kimchi Against Oxidative Stress

Oxidative stress plays an important role in exacerbating neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and Huntington's disease. In a previous study, Lactobacillus plantarum 200655 was shown to possess probiotic and antioxidant potential. The current study aimed to evaluate the neuroprotective effects of heat-killed L. plantarum 200655. We incubated intestinal cells (HT-29) with heat-killed L. plantarum 200655 in a conditioned medium (CM) and found that the brain-derived neurotrophic factor (BDNF) mRNA level was elevated in the HT-29 cells and the CM contained high concentrations of BDNF. The CM protected neuroblastoma cells (SH-SY5Y) from hydrogen peroxide (H₂O₂)-induced toxicity. Moreover, the CM increased BDNF and tyrosine hydroxylase (TH) mRNA expression and significantly reduced the apoptosis-related Bax/Bcl-2 ratio in H₂O₂-treated SH-SY5Y cells. At the protein level, the CM resulted in downregulation of caspase-3. These results indicate that L. plantarum 200655 might be used as a prophylactic functional ingredient to prevent neurodegenerative disease.

An optically active isochroman-2H-chromene conjugate potently suppresses neuronal oxidative injuries associated with the PI3K/Akt and MAPK signaling pathways

Increasing evidence suggests that the use of potent neuroprotective agents featured with novel pharmacological mechanism would offer a promising strategy to delay or prevent the progression of neurodegeneration. Here, we provide the first demonstration that the chiral nonracemic isochroman-2H-chromene conjugate JE-133, a novel synthetic 1,3-disubstituted isochroman derivative, possesses superior neuroprotective effect against oxidative injuries. Pretreatment with JE-133 (1-10 μM) concentration-dependently prevented H2O2-induced cell death in SH-SY5Y neuroblastoma cells and rat primary cortical neurons. Pretreatment with JE-133 significantly alleviated H2O2-induced apoptotic changes. These protective effects could not be simply attributed to the direct free radical scavenging as JE-133 had moderate activity in reducing DPPH free radical. Further study revealed that pretreatment with JE-133 (10 μM) significantly decreased the phosphorylation of MAPK pathway proteins, especially ERK and P38, in the neuronal cells. In addition, blocking PI3K/Akt pathway using LY294002 partially counteracted the cell viability-enhancing effect of JE-133. We conclude that JE-133 exerts neuroprotection associated with dual regulative mechanisms and consequently activating cell survival and inhibiting apoptotic changes, which may provide important clues for the development of effective neuroprotective drug lead/candidate.

Complementary Chinese Herbal Medicine Therapy Improves Survival in Patients With Pemphigus: A Retrospective Study From a Taiwan-Based Registry

Pemphigus is a life-threatening and skin-specific inflammatory autoimmune disease, characterized by intraepidermal blistering between the mucous membranes and skin. Chinese herbal medicine (CHM) has been used as an adjunct therapy for treating many diseases, including pemphigus. However, there are still limited studies in effects of CHM treatment in pemphigus, especially in Taiwan. To more comprehensively explore the effect of long-term CHM treatment on the overall mortality of pemphigus patients, we performed a retrospective analysis of 1,037 pemphigus patients identified from the Registry for Catastrophic Illness Patients database in Taiwan. Among them, 229 and 177 patients were defined as CHM users and non-users, respectively. CHM users were young, predominantly female, and had a lesser Charlson comorbidity index (CCI) than non-CHM users. After adjusting for age, sex, prednisolone use, and CCI, CHM users had a lower overall mortality risk than non-CHM users (multivariate model: hazard ratio (HR): 0.422, 95% confidence interval (CI): 0.242–0.735, p = 0.0023). The cumulative incidence of overall survival was significantly higher in CHM users than in non-users (p = 0.0025, log rank test). Association rule mining and network analysis showed that there was one main CHM cluster with Qi–Ju–Di–Huang–Wan (QJDHW), Dan–Shen (DanS; Radix Salviae miltiorrhizae; Salvia miltiorrhiza Bunge), Jia–Wei–Xiao–Yao-–San (JWXYS), Huang–Lian (HL; Rhizoma coptidis; Coptis chinensis Franch.), and Di–Gu–Pi (DGP; Cortex lycii; Lycium barbarum L.), while the second CHM cluster included Jin–Yin–Hua (JYH; Flos lonicerae; Lonicera hypoglauca Miq.) and Lian–Qiao (LQ; Fructus forsythiae; Forsythia suspensa (Thunb.) Vahl). In Taiwan, CHMs used as an adjunctive therapy reduced the overall mortality to approximately 20% among pemphigus patients after a follow-up of more than 6 years. A comprehensive CHM list may be useful in future clinical trials and further scientific investigations to improve the overall survival in these patients.

Neuroprotective effects of natural compounds on neurotoxin-induced oxidative stress and cell apoptosis

OBJECTIVES

Overproduction of reactive species, notably reactive oxygen (ROS) and nitrogen (RNS) species, along with the failure of balancing effects of endogenous antioxidant defenses result in destruction of cellular structures, lipids, proteins, and genetic material, which lead to oxidative stress. Oxidative stress-induced neuronal apoptosis plays a pivotal role in pathogenesis of neurodegeneration. Antioxidants represent one of the medical choice strategies for protecting against this unbalanced oxidation-antioxidation status. Recently, natural compounds with neuroprotective potential that can scavenge free radicals and protect cells from oxidative damage have received extensive attention.

METHODS

In this review, we summarized the detailed research progress on the medicinal plants-derived natural compounds with potential anti-oxidation effects and their molecular mechanisms on modulating the neurotoxin (6-OHDA, H₂O₂, glutamate, Aβ)-induced oxidative stress and cell apoptosis.

RESULTS

The natural compounds that efficacious in modulating reactive species production and mitochondrial function include flavonoids, glucosides, alkaloids, polyphenols, lignans, coumarins, terpenoids, quinones and others. They decreased the neurotoxin-induced oxidative damage and apoptosis by (1) decreasing ROS/RNS generation, lipid peroxidation, caspase-3 and caspase-9 activities, LDH release, the ratio of Bax/Bcl-2, Ca²⁺ influx and cytochrome c release, (2) elevating MMP, and (3) restoring endogenous antioxidant enzymatic activities (CAT, GSH-Px, GSR, SOD). And they exerted neuroprotective effects against cell damages and apoptosis by modulating the oxidative cascades of different signaling pathways (Nrf2/HO-1, NF-κB, MAPKs, PI3K/Akt, GSK-3β) and preventing mitochondria-dependent apoptosis pathways.

DISCUSSION

The present work reviews the role of oxidative stress in neurodegeneration, highlighting the potential anti-oxidation effects of natural compounds as a promising approach to develop innovative neuroprotective strategy.

Meta-Analysis on the Chinese Herbal Formula Xiaoer-Feike Granules as a Complementary Therapy for Children With Acute Lower Respiratory Infections

Background

Over the past five years the Chinese herbal formula (CHF) medicine, Xiaoer-Feike granules (XFG), has become a widely used adjuvant therapy for acute lower respiratory infections (ALRI). Considering the rapid popularization and application of XFG, and the lack of systematic evidence evaluating its effectiveness and safety in treating ALRI, it is necessary to conduct a meta-analysis to determine its benefits for patients.

Methods

This study systematically identified randomized controlled trials (RCTs) of XFG treatments for ALRI through July 2019 using four English-databases (PubMed, Cochrane Library, Ovid, and Web of Science) and four Chinese-databases (Sino-med database, China National Knowledge Infrastructure (CNKI), VIP database, and the WANFANG database). We then performed a quality assessment and data analysis with Review Manager 5.3.5 and Stata 15.1.

Results

Twenty-one RCTs involving 3425 patients were randomly divided into an XFG group and a conventional medicine (CM) group. The results showed that the clinical efficacy rate (CER) of the XFG group was significantly higher than that of the CM group (RR=1.17, 95% CI =1.13-1.22, P< 0.00001). In comparison with the CM group, the XFG group had strikingly shortened: resolution time of cough (RTC) (MD = -1.92; 95% CI =-2.33, -1.51, P<0.00001); resolution time of rale (RTR) (MD = -1.68; 95% CI =-2.27, -1.10, P<0.00001); resolution time of fever (RTF) (MD = -1.46; 95% CI =-1.92, -1.00, P<0.00001); resolution time of inflammatory lesions (RTIL) (MD = -2.43, 95% CI =-2.94, -1.93, P< 0.00001); and hospital stays (HS) (MD = -2.26, 95% CI =-3.03, -1.49, P< 0.00001). At the cellular and molecular level, the CD4, CD8, CD4/CD8, IL-6, TNF-α, and CRP levels were significantly improved when CM was complemented with XFG. In addition, no significant difference was observed between the XFG and CM groups in terms of the adverse events (AE) (RR =0.97, 95% CI= 0.61-1.54, P= 0.89).

Conclusions

The findings of this meta-analysis support the use of XFG in the treatment of ALRI. However, these results should be treated with caution due to the significant heterogeneity and publication bias of existing data. Further well-designed and high-quality RCTs are needed to interrogate the efficacy and safety of XFG.

The Chemistry and Health Benefits of Dietary Phenolamides

Phenolamides, also known as hydroxycinnamic acid amides or phenylamides, have been reported throughout the plant kingdom, while a few of these amine-conjugated hydroxycinnamic acids are unique in foods. The current knowledge of their specific functions in plant development and defense is readily available as is their biosynthesis; however, their functionality in humans is still largely unknown. Of the currently known phenolamides, the most common are avenanthramides, which are unique in oats and similar to the well-known drug Tranilast, which possess anti-inflammatory, antioxidant, anti-itch, and antiatherogenic activities. While recent data have brought to light more information regarding the other known phenolamides, such as hordatines, dimers of agmatine conjugated to hydroxycinnamic acid, and kukoamines, spermine-derived phenolamides, the information is still severely limited, leaving their potential health benefits to speculation. Herein, to highlight the importance of dietary phenolamides to human health, we review and summarize the four major subgroups of phenolamides, including their chemical structures, dietary sources, and reported health benefits. We believe that the studies on phenolamides are still in the infancy stage and additional health benefits of these phenolamides may yet be identified.

Neuroprotective Effects of Lindleyin on Hydrogen Peroxide-Induced Cell Injury and MPTP-Induced Parkinson's Disease in C57BL/6 Mice

Oxidative stress (OS) is a crucial factor influencing the development of Parkinson's disease (PD). Here we first reported that Lindleyin (Lin), one of the major components of rhubarb, possessed neuroprotective effects against H₂O₂-induced SH-SY5Y cell injury and MPTP-induced PD of C57BL/6 mice. The results showed that Lin can decrease cell death and apoptotic rate induced by H₂O₂ through inhibiting mitochondrial apoptotic pathway and increasing the activities of SOD, GSH-Px, and CAT as well as decreasing the level of MDA. In addition, in vivo studies showed that oral administration of Lin (5 or 20 mg/kg) showed significant change in motor function deficits, antioxidant enzyme activities, apoptotic pathway, and tyrosine hydroxylase expression. Our results reveal that Lin might be a promising anti-PD agent by reducing OS and apoptosis.

Dihydroagarofuran sesquiterpenoid derivatives from the leaves of Tripterygium wilfordii with potential neuroprotective effects against H2O2-induced SH-SY5Y cell injuries

In this study, eight undescribed sesquiterpenoid esters and four known analogues were isolated and their absolute configurations were determined by ECD calculations and single-crystal X-ray diffraction analysis.

N6-(2-hydroxyethyl)-adenosine from Cordyceps cicadae attenuates hydrogen peroxide induced oxidative toxicity in PC12 cells

N⁶-(2-hydroxyethyl)-adenosine (HEA), is one of the active molecule found in Cordyceps cicadae. The protective effect of HEA against H₂O₂ induced oxidative damage in PC12 cells and the mechanism of action was investigated. The cells were exposed to varying concentrations of HEA (5-40 μM) for a period of 24 h and further incubated with 100 μM of H₂O₂ for an another 12 h. Cell viability, LDH release, MMP collapse, Ca²⁺ overload, antioxidant parameters (reactive oxygen species generation (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), inflammatory mediators (interleukins 6 and 1β (IL-6 and IL-1β), tumor necrosis factor alpha (TNF-α) and NF-kB were evaluated. The results obtained showed that cells exposed to H₂O₂ toxicity showed reduced cell viability, increased LDH, ROS and Ca²⁺ overload. However, prior treatment of PC12 cells with HEA increased cell viability, reduced LDH release, MMP collapse, Ca²⁺ overload and ROS generation induced by H₂O₂ toxicity. Furthermore, HEA also increased the activities of antioxidant enzymes and inhibited lipid peroxidation as well as reduced IL-6, IL-1β, TNF-α and NF-kB. Thus, our results provided insight into the attenuative effect of HEA against H₂O₂ induced cell death through its antioxidant action by reducing ROS generation, oxidative stress and protecting mitochondrial function.

Metal Chelation Therapy and Parkinson's Disease: A Critical Review on the Thermodynamics of Complex Formation between Relevant Metal Ions and Promising or Established Drugs

The present review reports a list of approximately 800 compounds which have been used, tested or proposed for Parkinson's disease (PD) therapy in the year range 2014-2019 (April): name(s), chemical structure and references are given. Among these compounds, approximately 250 have possible or established metal-chelating properties towards Cu(II), Cu(I), Fe(III), Fe(II), Mn(II), and Zn(II), which are considered to be involved in metal dyshomeostasis during PD. Speciation information regarding the complexes formed by these ions and the 250 compounds has been collected or, if not experimentally available, has been estimated from similar molecules. Stoichiometries and stability constants of the complexes have been reported; values of the cologarithm of the concentration of free metal ion at equilibrium (pM), and of the dissociation constant Kd (both computed at pH = 7.4 and at total metal and ligand concentrations of 10-6 and 10-5 mol/L, respectively), charge and stoichiometry of the most abundant metal-ligand complexes existing at physiological conditions, have been obtained. A rigorous definition of the reported amounts is given, the possible usefulness of this data is described, and the need to characterize the metal-ligand speciation of PD drugs is underlined.

A network pharmacology study on the triterpene saponins from Medicago sativa L. for the treatment of Neurodegenerative diseases

Neurodegenerative diseases (NDDs) are characterized by progressive and irreversible, is a kind of complex illnesses, and the long-term therapy which is frequently associated with adverse side effects. Medicago sativa L., widely consumed as a vegetable, has the effects of improving memory and relieving central nervous system diseases. However, there are less studies on its specific mechanism for NDDs. In this investigation, we applied a method of network pharmacology, which combined molecular docking and network analysis to decipher the mechanisms of M. sativa in NDDs. The pharmacological system generated 55 triterpene saponins from M. sativa, and predicted 27 potential targets with 100 pathways in the treatment of NDDs. As a result, 13 compounds, 10 target proteins, and 6 signaling pathways were found to play important roles in the treatment of NDDs. In addition, in vitro experiments of isolates confirmed activities for NDDs, which were consistent with the results of network pharmacology prediction. PRACTICAL APPLICATIONS: Medicago sativa L. has been widely consumed as a vegetable, which possesses many nutritional components. As a functional food stuff, M. sativa can improve human health, such as memory improving activities, relieving central nervous system diseases, immunomodulatory, antioxidant, anticancer, and anti-inflammatory. In this article, the mechanism of triterpene saponins from M. sativa against NDDs was successfully predicted by network pharmacology method. The results will serve as a reference of M. sativa against NDDs.

Comparative analysis of in vitro neurotoxicity of methylmercury, mercury, cadmium, and hydrogen peroxide on SH-SY5Y cells

Mercury (Hg) and cadmium (Cd) are the major toxic heavy metals and are known to induce neurotoxicity. Although many studies have shown that several heavy metals have neurotoxic effects, the cellular and molecular mechanisms thereof are still not clear. Oxidative stress is reported to be a common and important mechanism in cytotoxicity induced by heavy metals. However, the assays for identifying toxic mechanisms were not performed under the same experimental conditions, making it difficult to compare toxic properties of the heavy metals. In this study, we investigated the mechanisms underlying neurotoxicity induced by heavy metals and H₂O₂, focusing on cell death, cell proliferation, and oxidative stress under the same experimental condition. Our results showed that MeHg caused lactate dehydrogenase (LDH) release, caspase activation and cell-cycle alteration, and ROS generation in accordance with decreased cell viability. HgCl₂ caused LDH release and cell-cycle alteration, but not caspase activation. CdCl₂ had a remarkable effect on the cell cycle profiles without induction of LDH release, caspase activation, or ROS generation. Pretreatment with N-acetyl-l-cysteine (NAC) prevented the decrease in cell viability induced by MeHg and HgCl₂, but not CdCl₂. Our results demonstrate a clear difference in neurotoxic mechanisms induced by MeHg, HgCl₂, CdCl₂ or H₂O₂ in SH-SY5Y cells. Elucidating the characteristics and mechanisms of each heavy metal under the same experimental conditions will be helpful to understand the effect of heavy metals on health and to develop a more effective therapy for heavy metal poisoning.

The influence of alkaloids on oxidative stress and related signaling pathways

Alkaloids have always attracted scientific interest due to either their positive or negative effects on human beings. This review aims to summarize their antioxidant effects by both classical in vitro scavenging assay and at the cellular level. Since most in vitro studies used the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging assay, the results from those studies are summed up in the first part of the article. In the second part, available data on the effect of alkaloids on NADPH-oxidase, the key enzyme for reactive oxygen species production, at the cellular level, are summarized. More than 130 alkaloids were tested by DPPH assay. However, due to methodological differences, a direct comparison is hardly possible. It can be at least concluded that some of them were either similar to or even more active than standard antioxidants and the number of aromatic hydroxyl groups seems to be the major determinant for the activity. The data on inhibition of NADPH-oxidase activity by alkaloids demonstrated that there is little relationship to the DPPH assay. The mechanism seems to be based on inhibition of synthesis, activation or translocation of NADPH-oxidase subunits. In some alkaloids, activation of the nuclear factor Nrf2 pathway was documented to be the grounds for inhibition of NADPH-oxidase. Interestingly, many alkaloids can behave both as anti-oxidants and pro-oxidants depending on conditions and pro-oxidation might be the reason for activation of Nrf2. Available data on other "antioxidant" transcription factors FOXOs and PPARs are also mentioned.

Orexin-A protects SH-SY5Y cells against H2O2-induced oxidative damage via the PI3K/MEK1/2/ERK1/2 signaling pathway

Orexin-A elicits multiple potent effects on a variety of tumor cells via different signaling pathways. However, it is unknown whether it has a neuroprotective effect on SH-SY5Y human neuroblastoma cells. This study investigated the neuroprotective effect of Orexin-A against hydrogen peroxide (H₂O₂)-induced oxidative damage in SH-SY5Y cells and the underlying mechanism. H₂O₂ treatment decreased the viability of SH-SY5Y cells, induced apoptosis, and decreased superoxide dismutase activity. Orexin-A attenuated these effects, indicating that it protects SH-SY5Y cells against H₂O₂-induced oxidative damage. Pre-treatment with Orexin-A also attenuated H₂O₂-induced increases in phosphorylation of MEK_1/2 and ERK_1/2. Moreover, these effects of Orexin-A were reduced in the presence of the PI3K inhibitor LY294002. Finally, pre-treatment with LY294002 abrogated attenuation of the H₂O₂-induced decrease in cell viability and increase in caspase-3/7 activity by Orexin-A. These results show that the PI3K/MEK_1/2/ERK_1/2 signaling pathway is involved in the neuroprotective effects of Orexin-A against H₂O₂-induced oxidative damage in SH-SY5Y cells. Our findings provide insight into the neuroprotective effects of Orexin-A and the underlying mechanism, which will be useful for the treatment of nervous system diseases.

Comparative evaluation of four triterpenoid glycoside saponins of bacoside A in alleviating sub-cellular oxidative stress of N2a neuroblastoma cells

OBJECTIVES

To examine the neuroprotective property of triterpenoid glycoside saponins of Bacopa monnieri (L.) Wettst. bacoside A and its components against H₂ O₂ -induced oxidative stress on neuronal (N2a) cells.

METHODS

The cytoprotective effects of individual bacoside A components were evaluated towards oxidative stressed neuronal cells. Bacoside A was screened for neuronal cell viability (MTT assay) and change in intracellular reactive oxygen species (ROS), anti-apoptotic properties and mitochondrial membrane potential (MMP) using fluorescence microscopy.

KEY FINDINGS

Different bacoside A components showed decrease in N2a cell viability below 100 (%) after bacoside A concentration of 0.4 mg/ml. Further, cytoprotective effect of optimized dose of bacoside A was analysed for alleviating oxidative stressed, apoptosis and MMP in H₂ O₂ stressed neuronal cells. Results showed increase in MMP, and decrease in apoptotic induction, without much change in nuclear integrity in stressed neuronal cells. Results showed bacoside A3 and bacopaside II have comparatively higher cytoprotective ability whilst isomer of bacopasponin C, bacopasaponin C and mixture showed comparatively less response.

CONCLUSIONS

Amongst four different bacoside A components, bacoside A3 and bacopaside II showed comparatively higher neuroprotective response analysed as higher cell viability and decreased intracellular ROS, suggesting better regulation of cyto-(neuronal) protection of N2a cells.

Acer okamotoanum protects SH-SY5Y neuronal cells against hydrogen peroxide-induced oxidative stress

Oxidative stress by over-production of reactive oxygen species (ROS) in brain is widely known as a cause of neurodegenerative disease. We investigated protective effects of Acer okamotoanum against oxidative stress by hydrogen peroxide (H₂O₂) in SH-SY5Y neuronal cells. Acer okamotoanum reduced ROS production and lactate dehydrogenase release in H₂O₂-induced SH-SY5Y cells, resulting in elevation of cell viability. To elucidate protective mechanisms, we measured inflammation and apoptosis-associated protein expressions. Treatment with A. okamotoanum dose-dependently decreased pro-inflammatory proteins such as inducible nitric oxide synthase and cyclooxygenase-2. Treatment with A. okamotoanum showed down-regulation of pro-apoptosis genes such as cleaved caspase-3, cleaved caspase-9, and Bax, and up-regulation of anti-apoptosis protein including Bcl-2, in H₂O₂-induced SH-SY5Y cells. We demonstrated potential anti-inflammatory and anti-apoptotic effect of A. okamotoanum in H₂O₂-induced SH-SY5Y cells. These results suggest that A. okamotoanum may possess neuroprotective potential, but further study is necessary to elucidate its pharmacological effects in neurodegenerative diseases.

Alkaloids with neuroprotective effects from the leaves of Isatis indigotica collected in the Anhui Province, China

Six undescribed alkaloids, indiforine A-F, together with four known ones, were isolated from the leaves of Isatis indigotica Fortune. Their structures were elucidated on the basis of extensive spectroscopic analyses. The absolute configurations of indiforine A and B were determined by comparison of the experimental and calculated electronic circular dichroism spectra, as well as experimental and calculated optical rotations. The isolated alkaloids were evaluated for their neuroprotective activities against H₂O₂-induced cell injury in human neuroblastoma SH-SY5Y cells. The results showed that in H₂O₂-induced SH-SY5Y cell injury models, indiforine A and B exhibited potent neuroprotective activities. Further investigation of the most potent indiforine A by Hoechst 33258 staining and Annexin V/PI analysis demonstrated that it could protect SH-SY5Y cells from oxidative damage through inhibiting cell apoptosis.

Antioxidant and Cytoprotective Effects of Kukoamines A and B: Comparison and Positional Isomeric Effect

In this study, two natural phenolic polyamines, kukoamine A and B, were comparatively investigated for their antioxidant and cytoprotective effects in Fenton-damaged bone marrow-derived mesenchymal stem cells (bmMSCs). When compared with kukoamine B, kukoamine A consistently demonstrated higher IC50 values in PTIO•-scavenging (pH 7.4), Cu2+-reducing, DPPH•-scavenging, •O₂−-scavenging, and •OH-scavenging assays. However, in the PTIO•-scavenging assay, the IC50 values of each kukoamine varied with pH value. In the Fe2+-chelating assay, kukoamine B presented greater UV-Vis absorption and darker color than kukoamine A. In the HPLC⁻ESI⁻MS/MS analysis, kukoamine A with DPPH• produced radical-adduct-formation (RAF) peaks (m/z 922 and 713). The 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl (MTT) assay suggested that both kukoamines concentration-dependently increased the viabilities of Fenton-damaged bmMSCs at 56.5⁻188.4 μM. However, kukoamine A showed lower viability percentages than kukoamine B. In conclusion, the two isomers kukoamine A and B can protect bmMSCs from Fenton-induced damage, possibly through direct or indirect antioxidant pathways, including electron-transfer, proton-transfer, hydrogen atom transfer, RAF, and Fe2+-chelating. Since kukoamine B possesses higher potentials than kukoamine A in these pathways, kukoamine B is thus superior to kukoamine A in terms of cytoprotection. These differences can ultimately be attributed to positional isomeric effects.

Protective effects of perilla oil and alpha linolenic acid on SH-SY5Y neuronal cell death induced by hydrogen peroxide

BACKGROUND/OBJECTIVE

Oxidative stress plays a key role in neuronal cell damage, which is associated with neurodegenerative disease. The aim of present study was to investigate the neuroprotective effects of perilla oil (PO) and its active component, alpha-linolenic acid (ALA), against hydrogen peroxide (H₂O₂)-induced oxidative stress in SH-SY5Y neuronal cells.

MATERIALS/METHODS

The SH-SY5Y human neuroblastoma cells exposed to 250 µM H₂O₂ for 24 h were treated with different concentrations of PO (25, 125, 250 and 500 µg/mL) and its major fatty acid, ALA (1, 2.5, 5 and 25 µ/mL). We examined the effects of PO and ALA on H₂O₂-induced cell viability, lactate dehydrogenase (LDH) release, and nuclear condensation. Moreover, we determined whether PO and ALA regulated the apoptosis-related protein expressions, such as cleaved-poly ADP ribose polymerase (PARP), cleaved caspase-9 and -3, BCL-2 and BAX.

RESULTS

Treatment of H₂O₂ resulted in decreased cell viability, increased LDH release, and increase in the nuclei condensation as indicated by Hoechst 33342 staining. However, PO and ALA treatment significantly attenuated the neuronal cell death, indicating that PO and ALA potently blocked the H₂O₂-induced neuronal apoptosis. Furthermore, cleaved-PARP, cleaved caspase-9 and -3 activations were significantly decreased in the presence of PO and ALA, and the H₂O₂-mediated up-regulated BAX/BCL-2 ratio was blocked after treatment with PO and ALA.

CONCLUSIONS

PO and its main fatty acid, ALA, exerted the protective activity from neuronal oxidative stress induced by H₂O₂. They regulated apoptotic pathway in neuronal cell death by alleviation of BAX/BCL-2 ratio, and down-regulation of cleaved-PARP and cleaved caspase-9 and -3. Although further studies are required to verify the protective mechanisms of PO and ALA from neuronal damage, PO and ALA are the promising agent against oxidative stress-induced apoptotic neuronal cell death.

Synergistic protective effect of paeoniflorin and β-ecdysterone against rotenone-induced neurotoxicity in PC12 cells

There are several factors, like oxidative stress and neurons loss, involving neurodegenerative diseases such as Parkinson's disease (PD). The combination of antioxidant and anti-apoptotic agent is becoming a promising approach to fight against PD. This study evaluates the hypothesis that paeoniflorin (PF) and β-ecdysterone (β-Ecd) synergize to protect PC12 cells against toxicity induced by PD-related neurotoxin rotenone. The combination of PF and β-Ecd, hereafter referred to as the PF/β-Ecd, at suboptimal concentrations increased the viability of rotenone-exposed PC12 cells in a synergistic manner. PF and β-Ecd cooperate to attenuate the rotenone-induced apoptosis by decrease in Bax expression, caspase-9 activity, and caspase-3 activity. PF or PF/β-Ecd, but not β-Ecd, inhibited rotenone-triggered protein kinase C-δkinase C-δ (PKCδ) upregulation and nuclear factor κB (NF-κB) activation. β-Ecd or PF/β-Ecd, but not PF, enhanced serine/threonine protein kinase (Akt) activation, promoted nuclear factor E2-related factor 2 (Nrf2) nuclear accumulation, suppressed reactive oxygen species (ROS) production. Neuroprotection of PF/β-Ecd could be completely blocked by PKCδ inhibitor rottlerin plus Akt specific inhibitor LY294002. Dual blockade of the PKCδ/NF-κB pathway by PF and activation of Akt/Nrf2 pathway by β-Ecd results in a synergistic neuroprotective effect against rotenone-induced neurotoxicity in vitro. These findings provide the rationale for determining the in vivo activity of combined therapy with PF and β-Ecd against PD.

The neuroprotective and antioxidant profiles of selenium-containing polysaccharides from the fruit of Rosa laevigata

A rapid and effective approach for the extraction and separation of polysaccharides from the title fruit was developed using microwave-assisted aqueous two-phase extraction with a PEG/ammonium sulfate system.

Extraction and isolation of polyhydroxy triterpenoids from Rosa laevigata Michx. fruit with anti-acetylcholinesterase and neuroprotection properties

Rosa laevigata fruit, at present, is becoming increasingly popular as a functional foodstuff with several nutritional and medicinal properties.

Vitamin E (α‑tocopherol) ameliorates aristolochic acid‑induced renal tubular epithelial cell death by attenuating oxidative stress and caspase‑3 activation

Aristolochic acid (AA) is a component identified in traditional Chinese remedies for the treatment of arthritic pain, coughs and gastrointestinal symptoms. However, previous studies have indicated that AA can induce oxidative stress in renal cells leading to nephropathy. α-tocopherol exists in numerous types of food, such as nuts, and belongs to the vitamin E isoform family. It possesses antioxidant activities and has been used previously for clinical applications. Therefore, the aim of the present study was to determine whether α-tocopherol could reduce AA-induced oxidative stress and renal cell cytotoxicity, determined by cell survival rate, reactive oxygen species detection and apoptotic features. The results indicated that AA markedly induced H₂O₂ levels and caspase-3 activity in renal tubular epithelial cells. Notably, the presence of α-tocopherol inhibited AA-induced H₂O₂ and caspase-3 activity. The present study demonstrated that antioxidant mechanisms of α-tocopherol may be involved in the increased survival rates from AA-induced cell injury.

Astragaloside IV attenuates the H2O2-induced apoptosis of neuronal cells by inhibiting α-synuclein expression via the p38 MAPK pathway

An oxidative stress insult is one of the principal causes of Parkinson's disease. Astragaloside IV (AS-IV), a constituent extracted from Astragalus membranaceus, has been demonstrated to exert antioxidant effects. However, the mechanisms responsible for the antioxidant properties and neuro-protective effects of AS-IV remain unclear. In this study, we examined the protective effects of AS-IV against the apoptosis of human neuronal cells (SH-SY5Y cells) induced by hydrogen peroxide (H₂O₂). The results revealed that AS-IV pre-treatment attenuated the H₂O₂-induced loss of SH-SY5Y cells in a dose-dependent manner; AS-IV exerted significant protecitve effects by decreasing the apoptotic ratio and attenuating reactive oxygen species overproduction in H₂O₂-exposed SH-SY5Y cells. By means of immunofluorescence staining, AS-IV was found to decrease the expression of α-synuclein and to increase the expression of tyrosine hydroxylase (TH) in the cells, which had been increased and decreased, respectively by H₂O₂. As shown by western blot analysis, the protective effects of AS-IV against SH-SY5Y cell injury induced by H₂O₂ were also mediated via the downregulation of the ratio of Bax/Bcl-2. We found that the neuroprotective effects of AS-IV were associated with the inhibition of the expression of the α-synuclein via the p38 mitogen-activated protein kinase (MAPK) signalling pathway. On the whole, our results suggest that AS-IV exerts protective effects against neurodegenerative diseases by targeting α-synuclein or TH.

[Salidroside protects PC12 cells from H2O2-induced apoptosis via suppressing NOX2-ROS-MAPKs signaling pathway]

OBJECTIVE

To investigate the molecular mechanism by which salidroside protects PC12 cells from H₂O₂-induced apoptosis.

METHODS

PC12 cells cultured in DMEM supplemented with 10% horse serum and 5% fetal bovine serum were pretreated with different doses of salidroside for 2 h and then stimulated with H₂O₂ for different lengths of time. The expression levels of PARP and caspase 3 and the phosphorylation of p38, ERK and JNK were determined with Western blotting. The cell nuclear morphology was observed after DAPI staining. The production of ROS was detected using a ROS detection kit, and the levels of gp91^phox and p47^phox in the membrane and cytoplasm were detected by membrane-cytoplasm separation experiment; the binding between gp91^phox and p47^phox was assayed by coimmunoprecipitation experiment.

RESULTS

Salidroside dose-dependently suppressed cell apoptosis, lowered phosphorylation levels of p38, ERK and JNK, inhibited the production of ROS, reduced the binding between gp91^phox and p47^phox, and inhibited the activity of NOX2 in PC12 cells exposed to H₂O₂.

CONCLUSION

Salidroside protects PC12 cells from H₂O₂-induced apoptosis at least partly by suppressing NOX2-ROS-MAPKs signaling pathway.

Individual and combined use of ginsenoside F2 and cyanidin-3-O-glucoside attenuates H2O2-induced apoptosis in HEK-293 cells via the NF-κB pathway

Ginsenoside F2 and cyanidin-3-O-glucoside synergistically inhibited H₂O₂-induced apoptosis in HEK-293 cells through mitochondria-mediated apoptotic and NF-κB pathways.

Lactucopicrin ameliorates oxidative stress mediated by scopolamine-induced neurotoxicity through activation of the NRF2 pathway

Cholinergic activity plays a vital role in cognitive function, and is reduced in individuals with neurodegenerative diseases. Scopolamine, a muscarinic cholinergic antagonist, has been employed in many studies to understand, identify, and characterize therapeutic targets for Alzheimer's disease (AD). Scopolamine-induced dementia is associated with impairments in memory and cognitive function, as seen in patients with AD. The current study aimed to investigate the molecular mechanisms underlying scopolamine-induced cholinergic neuronal dysfunction and the neuroprotective effect of lactucopicrin, an inhibitor of acetylcholine esterase (AChE). We investigated apoptotic cell death, caspase activation, generation of reactive oxygen species (ROS), mitochondrial dysfunction, and the expression levels of anti- and pro-apoptotic proteins in scopolamine-treated C6 cells. We also analyzed the expression levels of antioxidant enzymes and nuclear factor (erythroid-derived 2)-like 2 (NRF2) in C6 cells and neurite outgrowth in N2a neuroblastoma cells. Our results revealed that 1 h scopolamine pre-treatment induced cytotoxicity by increasing apoptotic cell death via oxidative stress-mediated caspase 3 activation and mitochondrial dysfunction. Scopolamine also downregulated the expression the antioxidant enzymes superoxide dismutase, glutathione peroxidase, and catalase, and the transcription factor NRF2. Lactucopicrin treatment protected C6 cells from scopolamine-induced toxicity by reversing the effects of scopolamine on those markers of toxicity. In addition, scopolamine attenuated the secretion of neurotrophic nerve growth factor (NGF) in C6 cells and neurite outgrowth in N2a cells. As expected, lactucopicrin treatment enhanced NGF secretion and neurite outgrowth. Our study is the first to show that lactucopicrin, a potential neuroprotective agent, ameliorates scopolamine-induced cholinergic dysfunction via NRF2 activation and subsequent expression of antioxidant enzymes.

Neuroprotective oleanane triterpenes from the roots of Bupleurum chinense

The discovery of new natural compounds with pharmacological properties is an increasingly important field, and a continuous phytochemical investigation of the roots of Bupleurum chinense D.C. has led to the isolation of 17 triterpenoids, including three new oleanane triterpenes (1-3) together with 14 known ones. Their structures were determined on the basis of 1D and 2D NMR spectra as well as HR-ESI-MS data. The cytotoxicities of all compounds against five selected human cancer cell lines were assayed. Only compounds 9 and 14 exhibited moderate activities. Recently, a number of investigations have focused on the neuroprotective properties of triterpenoids in B. chinense. In order to expand our knowledge about this herb, the neuroprotective effects of compounds 1-17 against hydrogen peroxide (H2O2)-induced neuronal cell damage in human neuroblastoma SH-SY5Y cells were evaluated. Compounds 1-3, 6-7 showed significant neuroprotective effects against H2O2-induced SH-SY5Y cell death. Preliminary structure-activity relationships (SARs) between neuroprotective effects and the isolates were also discussed.

Insight into the inhibition mechanism of kukoamine B against CpG DNA via binding and molecular docking analysis

The binding and inhibition mechanism of kukoamine B against CpG DNA is proposed.