1, 5-Dicaffeoylquinic acid-mediated glutathione synthesis through activation of Nrf2 protects against OGD/reperfusion-induced oxidative stress in astrocytes

Di-caffeoylquinic acid: a potential inhibitor for amyloid-beta aggregation

Alzheimer's disease (AD) remains a challenging neurodegenerative disorder with limited therapeutic success. Traditional Chinese Medicine (TCM), as a promising new source for AD, still requires further exploration to understand its complex components and mechanisms. Here, focused on addressing Aβ (1-40) aggregation, a hallmark of AD pathology, we employed a Thioflavin T fluorescence labeling method for screening the active molecular library of TCM which we established. Among the eight identified, 1,3-di-caffeoylquinic acid emerged as the most promising, exhibiting a robust binding affinity with a KD value of 26.7 nM. This study delves into the molecular intricacies by utilizing advanced techniques, including two-dimensional (2D) 15N-1H heteronuclear single quantum coherence nuclear magnetic resonance (NMR) and molecular docking simulations. These analyses revealed that 1,3-di-caffeoylquinic acid disrupts Aβ (1-40) self-aggregation by interacting with specific phenolic hydroxyl and amino acid residues, particularly at Met-35 in Aβ (1-40). Furthermore, at the cellular level, the identified compounds, especially 1,3-di-caffeoylquinic acid, demonstrated low toxicity and exhibited therapeutic potential by regulating mitochondrial membrane potential, reducing cell apoptosis, and mitigating Aβ (1-40)-induced cellular damage. This study presents a targeted exploration of catechol compounds with implications for effective interventions in AD and sheds light on the intricate molecular mechanisms underlying Aβ (1-40) aggregation disruption.

Armeniacae semen amarum: a review on its botany, phytochemistry, pharmacology, clinical application, toxicology and pharmacokinetics

Armeniacae semen amarum-seeds of Prunus armeniaca L. (Rosaceae) (ASA), also known as Kuxingren in Chinese, is a traditional Chinese herbal drug commonly used for lung disease and intestinal disorders. It has long been used to treat coughs and asthma, as well as to lubricate the colon and reduce constipation. ASA refers to the dried ripe seed of diverse species of Rosaceae and contains a variety of phytochemical components, including glycosides, organic acids, amino acids, flavonoids, terpenes, phytosterols, phenylpropanoids, and other components. Extensive data shows that ASA exhibits various pharmacological activities, such as anticancer activity, anti-oxidation, antimicrobial activity, anti-inflammation, protection of cardiovascular, neural, respiratory and digestive systems, antidiabetic effects, and protection of the liver and kidney, and other activities. In clinical practice, ASA can be used as a single drug or in combination with other traditional Chinese medicines, forming ASA-containing formulas, to treat various afflictions. However, it is important to consider the potential adverse reactions and pharmacokinetic properties of ASA during its clinical use. Overall, with various bioactive components, diversified pharmacological actions and potent efficacies, ASA is a promising drug that merits in-depth study on its functional mechanisms to facilitate its clinical application.

Curcumin inhibits the activity and induces apoptosis of activated hepatic stellate cell by suppressing autophagy

Curcumin, a kind of natural compound, has been previously proven to inhibit the autophagy in hepatic stellate cells (HSCs) and induce their apoptosis. However, it is not clear whether the enhanced apoptosis of activated HSCs (aHSCs) caused by curcumin depends on autophagy inhibition. We aim to verify this hypothesis and explore the potential mechanisms in this study. Immortalized human HSC line LX-2 was used as an experimental specimen and pretreated with transforming growth factor β1(TGF-β1) for 24 h to activate it before drug application. The levels of autophagy, apoptosis, cell activity, lipid metabolism, and the activity of the PI3K/Akt/mTOR signal pathway were evaluated by multiple methods, such as Western blotting, mcherry-EGFP-LC3B adenoviruses transfection, immunofluorescence, Nile Red staining, flow cytometry among others. Our results showed that rapamycin, an autophagy activator, could partly offset the effects of curcumin on autophagy and apoptosis of LX-2 cells, while 3-Methyladenine (3-MA), an autophagy inhibitor, could enhance these effects. Furthermore, curcumin could promote the activity of the PI3K/Akt/mTOR signal pathway in LX-2 cells, while PI3K inhibitor could partly offset this effect and increase the autophagy level. Overall, we demonstrated that curcumin could inhibit the activity and promote LX-2 cells apoptosis by suppressing autophagy by activating the PI3K/Akt/mTOR signal pathway. In addition, lipid recovery and energy deprivation due to autophagy inhibition may be the exact mechanism by which curcumin attenuates the pro-fibrotic activity of LX-2.

The Role of the NRF2 Pathway in Maintaining and Improving Cognitive Function

Nuclear factor (erythroid-derived 2)-like 2 (NRF2) is a redox-sensitive transcription factor that binds to the antioxidant response element consensus sequence, decreasing reactive oxygen species and regulating the transcription of a wide array of genes, including antioxidant and detoxifying enzymes, regulating genes involved in mitochondrial function and biogenesis. Moreover, NRF2 has been shown to directly regulate the expression of anti-inflammatory mediators reducing the expression of pro-inflammatory cytokines. In recent years, attention has turned to the role NRF2 plays in the brain in different diseases such Alzheimer’s disease, Parkinson’s disease, Huntington’s disease and others. This review focused on the evidence, derived in vitro, in vivo and from clinical trials, supporting a role for NRF2 activation in maintaining and improving cognitive function and how its activation can be used to elicit neuroprotection and lead to cognitive enhancement. The review also brings a critical discussion concerning the possible prophylactic and/or therapeutic use of NRF2 activators in treating cognitive impairment-related conditions.

The Age-Related Macular Degeneration (AMD)-Preventing Mechanism of Natural Products

Age-related macular degeneration (AMD) is related to central visual loss in elderly people and, based on the increment in the percentage of the aging population, the number of people suffering from AMD could increase. AMD is initiated by retinal pigment epithelium (RPE) cell death, finally leading to neovascularization in the macula lutea. AMD is an uncurable disease, but the symptom can be suppressed. The current therapy of AMD can be classified into four types: device-based treatment, anti-inflammatory drug treatment, anti-vascular endothelial growth factor treatment, and natural product treatment. All these therapies have adverse effects, however early AMD therapy used with products has several advantages, as it can prevent RPE cell apoptosis in safe doses. Cell death (apoptosis) is caused by various factors, such as oxidative stress, inflammation, carbonyl stress, and a deficiency in essential components for cells, and RPE cell death is related to oxidative stress, inflammation, and carbonyl stress. Some natural products have anti-oxidative effects, anti-inflammation effects, and/or anti-carbonylation effects. The AMD preventive mechanism of natural products varies, with some natural products activating one or more anti-apoptotic pathways, such as the Nrf2/HO-1 anti-oxidative pathway, the anti-inflammasome pathway, and the anti-carbonyl pathway. As AMD drug candidates from natural products effectively inhibit RPE cell death, they have the potential to be developed as drugs for preventing early (dry) AMD.

Anti-inflammatory effect of Ailanthus altissima (Mill.) Swingle leaves in lipopolysaccharide-stimulated astrocytes

ETHNOPHARMACOLOGICAL RELEVANCE

Activated astrocytes are involved in the progression of neurodegenerative diseases. Traditionally, Ailanthus altissima (Mill.) Swingle, widely distributed in East Asia, has been used as a medicine for the treatment of fever, gastric diseases, and inflammation. Although A. altissima has been reported to play an anti-inflammatory role in peripheral tissues or cells, its role in the central nervous system (CNS) remains unclear.

AIM OF THE STUDY

In the present study, we investigated the anti-inflammatory effects and mechanism of action of A. altissima in primary astrocytes stimulated by lipopolysaccharide (LPS).

MATERIALS AND METHODS

A nitrite assay was used to measure nitric oxide (NO) production, and the tetrazolium salt 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay was performed to determine cytotoxicity. The expression levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and mitogen-activated protein kinase (MAPK) were determined with western blotting. Reverse-transcription PCR was used to assess the expression of inflammatory cytokines. The levels of reactive oxygen species were measured using 2,7-dichlorodihydrofluorescein diacetate. Luciferase assay and immunocytochemistry were used for assessing nuclear factor-kappa B (NF-κB) transcription and p65 localization, respectively. Memory and social interaction were analyzed using the Y-maze and three-chamber tests, respectively.

RESULTS

The ethanol extract of A. altissima leaves (AAE) inhibited iNOS and COX-2 expression in LPS-stimulated astrocytes. Moreover, AAE reduced the transcription of various proinflammatory mediators, hindered NF-κB activation, and suppressed extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) activation without p38 activation. Ultra-high performance liquid chromatography with mass spectrometry analysis revealed that AAE comprised ethyl gallate, quercetin, and kaempferol, along with luteolin, which has anti-inflammatory properties, and repressed LPS-induced nitrite levels and the nuclear translocation of p65. Finally, oral administration of AAE attenuated LPS-induced memory and social impairment in mice and repressed LPS-induced ERK and JNK activation in the cortices of mice.

CONCLUSION

AAE could have therapeutic uses in the treatment of neuroinflammatory diseases via suppression of astrocyte activation.

Plant-Derived Compounds as Promising Therapeutics for Vitiligo

Vitiligo is the most common depigmenting disorder characterized by white patches in the skin. The pathogenetic origin of vitiligo revolves around autoimmune destruction of melanocytes in which, for instance, oxidative stress is responsible for melanocyte molecular, organelle dysfunction and melanocyte specific antigen exposure as well as melanocyte cell death and thus serves as an important contributor for vitiligo progression. In recent years, natural products have shown a wide range of pharmacological bioactivities against many skin diseases, and this review focuses on the effects and mechanisms of natural compounds against vitiligo models. It is showed that some natural compounds such as flavonoids, phenols, glycosides and coumarins have a protective role in melanocytes and thereby arrest the depigmentation, and, additionally, Nrf2/HO-1, MAPK, JAK/STAT, cAMP/PKA, and Wnt/β-catenin signaling pathways were reported to be implicated in these protective effects. This review discusses the great potential of plant derived natural products as anti-vitiligo agents, as well as the future directions to explore.

Impact of Antioxidant Natural Compounds on the Thyroid Gland and Implication of the Keap1/Nrf2 Signaling Pathway

BACKGROUND

Natural compounds with potential antioxidant properties have been used in the form of food supplements or extracts with the intent to prevent or treat various diseases. Many of these compounds can activate the cytoprotective Nrf2 pathway. Besides, some of them are known to impact the thyroid gland, often with potential side-effects, but in other instances, with potential utility in the treatment of thyroid disorders.

OBJECTIVE

In view of recent data regarding the multiple roles of Nrf2 in the thyroid, this review summarizes the current bibliography on natural compounds that can have an effect on thyroid gland physiology and pathophysiology, and it discusses the potential implication of the Nrf2 system in the respective mechanisms.

METHODS & RESULTS

Literature searches for articles from 1950 to 2018 were performed in PubMed and Google Scholar using relevant keywords about phytochemicals, Nrf2 and thyroid. Natural substances were categorized into phenolic compounds, sulfur-containing compounds, quinones, terpenoids, or under the general category of plant extracts. For individual compounds in each category, respective data were summarized, as derived from in vitro (cell lines), preclinical (animal models) and clinical studies. The main emerging themes were as follows: phenolic compounds often showed potential to affect the production of thyroid hormones; sulfur-containing compounds impacted the pathogenesis of goiter and the proliferation of thyroid cancer cells; while quinones and terpenoids modified Nrf2 signaling in thyroid cell lines.

CONCLUSION

Natural compounds that modify the activity of the Nrf2 pathway should be evaluated carefully, not only for their potential to be used as therapeutic agents for thyroid disorders, but also for their thyroidal safety when used for the prevention and treatment of non-thyroidal diseases.

Caffeoylquinic Acids with Potential Biological Activity from Plant In vitro Cultures as Alternative Sources of Valuable Natural Products

BACKGROUND

For a long time, the researchers have been looking for new efficient methods to enhance production and obtain valuable plant secondary metabolites, which would contribute to the protection of the natural environment through the preservation of various plant species, often rare and endangered. These possibilities offer plant in vitro cultures which can be performed under strictly-controlled conditions, regardless of the season or climate and environmental factors. Biotechnological methods are promising strategies for obtaining the valuable plant secondary metabolites with various classes of chemical compounds including caffeoylquinic acids (CQAs) and their derivatives. CQAs have been found in many plant species which are components in the daily diet and exhibit a wide spectrum of biological activities, including antioxidant, immunomodulatory, antihypertensive, analgesic, anti-inflammatory, hepato- and neuroprotective, anti-hyperglycemic, anticancer, antiviral and antimicrobial activities. They have also been found to offer protection against Alzheimer's disease, and play a role in weight reduction and lipid metabolism control, as well as modulating the activity of glucose-6-phosphatase involved in glucose metabolism.

METHODS

This work presents the review of the recent advances in use in vitro cultures of various plant species for the alternative system to the production of CQAs and their derivatives. Production of the secondary metabolites in in vitro culture is usually performed with cell suspension or organ cultures, such as shoots and adventitious or transformed roots. To achieve high production of valuable secondary metabolites in in vitro cultures, the optimization of the culture condition is necessary with respect to both biomass accumulation and metabolite content. The optimization of the culture conditions can be achieved by choosing the type of medium, growth regulators or growth conditions, selection of high-productivity lines or culture period, supplementation of the culture medium with precursors or elicitor treatments. Cultivation for large-scale in bioreactors and genetic engineering: Agrobacterium rhizogenes transformation and expression improvement of transcriptional factor or genes involved in the secondary metabolite production pathway are also efficient strategies for enhancement of the valuable secondary metabolites.

RESULTS

Many studies have been reported to obtain highly productive plant in vitro cultures with respect to CQAs. Among these valuable secondary metabolites, the most abundant compound accumulated in in vitro cultures was 5-CQA (chlorogenic acid). Highly productive cultures with respect to this phenolic acid were Leonurus sibiricus AtPAP1 transgenic roots, Lonicera macranthoides and Eucomia ulmoides cell suspension cultures which accumulated above 20 mg g-1 DW 5-CQA. It is known that di- and triCQAs are less common in plants than monoCQAs, but it was also possible to obtain them by biotechnological methods.

CONCLUSION

The results indicate that the various in vitro cultures of different plant species can be a profitable approach for the production of CQAs. In particular, an efficient production of these valuable compounds is possible by Lonicera macranthoides and Eucomia ulmoides cell suspension cultures, Leonurus sibiricus transformed roots and AtPAP1 transgenic roots, Echinacea angustifolia adventitious shoots, Rhaponticum carthamoides transformed plants, Lavandula viridis shoots, Sausera involucrata cell suspension and Cichorium intybus transformed roots.

Centella Asiatica Improves Memory and Promotes Antioxidative Signaling in 5XFAD Mice

Centella asiatica (CA) herb is a traditional medicine, long reputed to provide cognitive benefits. We have reported that CA water extract (CAW) treatment improves cognitive function of aged Alzheimer’s disease (AD) model Tg2576 and wild-type (WT) mice, and induces an NRF2-regulated antioxidant response in aged WT mice. Here, CAW was administered to AD model 5XFAD female and male mice and WT littermates (age: 7.6 +/− 0.6 months), and object recall and contextual fear memory were tested after three weeks treatment. CAW’s impact on amyloid-β plaque burden, and markers of neuronal oxidative stress and synaptic density, was assessed after five weeks treatment. CAW antioxidant activity was evaluated via nuclear transcription factor (erythroid-derived 2)-like 2 (NRF2) and NRF2-regulated antioxidant response element gene expression. Memory improvement in both genders and genotypes was associated with dose-dependent CAW treatment without affecting plaque burden, and marginally increased synaptic density markers in the hippocampus and prefrontal cortex. CAW treatment increased Nrf2 in hippocampus and other NRF2 targets (heme oxygenase-1, NAD(P)H quinone dehydrogenase 1, glutamate-cysteine ligase catalytic subunit). Reduced plaque-associated SOD1, an indicator of oxidative stress, was observed in the hippocampi and cortices of CAW-treated 5XFAD mice. We postulate that CAW treatment leads to reduced oxidative stress, contributing to improved neuronal health and cognition.

Neuromodulatory Activity of Dietary Phenolics Derived from Corchorus olitorius L

Dietary phenolics are known for their potent antioxidant and anti-inflammatory activities, making them promising candidates for protection against neuroinflammation and neurodegeneration. Hydroalcohol extract of Egyptian species of Corchorus olitorius L. (Co) leaves was investigated for its neuroprotective effects in a lipopolysaccharide-induced neuroinflammatory mouse model. Twenty five metabolites were characterized from the bioactive extract using high-performance liquid chromatography HPLC/PDA/HRESI/MSⁿ , revealing 1,5-dicaffeoylquinic acid (Co11) as one of the major constituents (5.7%), which was isolated and its identity was confirmed by spectral data as first report. Co significantly protected microglia against H₂ O₂ -induced cytotoxicity and immunohistochemistry showed reduced expression of the astrocytic marker, glial fibrillary acidic protein, and the inflammatory marker, cyclooxygenase-2. These findings correlated with significant improvement of cognitive functions and reduction of LPS-induced neurodegeneration in Co-treated mice as revealed by histopathology. The current study shows promising effects of Co in limiting neurodegeneration and cognitive impairment caused by neuroinflammation and glial cell activation. PRACTICAL APPLICATION: Information presented here shed light on the promising effects of Corchorus olitorius (Co) for the modulation of neuroinflammatory pathways improving the neuroinflammation-related neurodegeneration and cognitive decline. This makes Co a promising candidate as a nutraceutical supplement to be used against neuroinflammation-related disorders.

Potential anti-vitiligo properties of cynarine extracted from Vernonia anthelmintica (L.) Willd

Vitiligo is a depigmentation disorder of the skin. It is primarily caused by the destruction of melanocytes or obstruction of the melanin synthesis pathway. Melanin is a type of skin pigment that determines skin color. The seeds of Vernonia anthelmintica (L.) Willd (Kaliziri) are used for treating skin diseases including vitiligo in traditional Uyghur medicine. 1,5‑Dicaffeoylquinic acid (1,5‑diCQA) is a natural polyphenolic compound widely distributed in plants and extracted from Kaliziri seeds. Therefore, in the present study, the effect of 1,5‑diCQA on melanin synthesis in B16 cell was evaluated, and its molecular mechanism was explored. The results indicated that 1,5‑diCQA treatment of B16 cells stimulated an increase of intracellular melanin level and tyrosinase (TYR) activity without cytotoxicity. Reverse transcription quantitative polymerase chain reaction results also indicated that 1,5‑diCQA may markedly improve the protein expression and RNA transcription of microphthalmia‑associated transcription factor (MITF), melanogenic enzyme Tyr, tyrosinase‑related protein 1 (TRP 1) and tyrosinase‑related protein 2 (TRP 2). Additional results identified that 1,5‑diCQA may promote the phosphorylation of p38 mitogen‑activated protein kinase (p38 MAPK) and extracellular signal‑regulated kinase (ERK) MAPK. Notably, the increased levels of intracellular melanin synthesis and tyrosinase expression induced by 1,5‑diCQA treatment were significantly attenuated by the protein kinase A (PKA) inhibitor H‑89. Intracellular cyclic adenosine monophosphate (cAMP) concentration and phosphorylation of cAMP‑response element binding protein was increased following 1,5‑diCQA treatment. These results indicated that 1,5‑diCQA stimulated melanogenesis via the MAPK and cAMP/PKA signaling pathways in B16 cells, which has potential therapeutic implications for vitiligo.

Comparing the role of Ginkgolide B and Ginkgolide K on cultured astrocytes exposed to oxygen‑glucose deprivation

Ginkgolide B (GB) and ginkgolide K (GK) are two main active monomers of ginkgolides that present a unique group of diterpenes found naturally in the leaves of the Ginkgo biloba tree. Astrocytes are the most abundant cell type within the central nervous system (CNS) and serve essential roles in maintaining healthy brain function. The present study compared the biological effects of GB and GK on astrocytes exposed to oxygen-glucose deprivation (OGD). The results demonstrated that GB and GK exhibit many different actions. The level of the platelet-activating factor (PAF) was elevated on astrocytes exposed to OGD, and inhibited by GB and GK treatment. Although GB and GK inhibited the expression of p-NF-κB/p65, GK exerted stronger anti-inflammatory and antioxidant effects on astrocytes exposed to OGD than GB by inhibiting interleukin (IL)-6 and tumor necrosis factor-α, and inducing IL-10 and the nuclear factor-erythroid 2-related factor 2/HO-1 signaling pathway. When compared with GB treatment, GK treatment maintained high levels of phosphoinositide 3-kinase/phosphorylated-protein kinase B expression, and induced a marked upregulation of Wnt family member 1 and brain derived neurotrophic factor, indicating that GK, as a natural plant compound, may have more attractive prospects for clinical application in the treatment of neurological disorders than GB.

Centella asiatica increases hippocampal synaptic density and improves memory and executive function in aged mice

INTRODUCTION

Centella asiatica is a plant used for centuries to enhance memory. We have previously shown that a water extract of Centella asiatica (CAW) attenuates age-related spatial memory deficits in mice and improves neuronal health. Yet the effect of CAW on other cognitive domains remains unexplored as does its mechanism of improving age-related cognitive impairment. This study investigates the effects of CAW on a variety of cognitive tasks as well as on synaptic density and mitochondrial and antioxidant pathways.

METHODS

Twenty-month-old CB6F1 mice were treated with CAW (2 mg/ml) in their drinking water for 2 weeks prior to behavioral testing. Learning, memory, and executive function were assessed using the novel object recognition task (NORT), object location memory task (OLM), and odor discrimination reversal learning (ODRL) test. Tissue was collected for Golgi analysis of spine density as well as assessment of mitochondrial, antioxidant, and synaptic proteins.

RESULTS

CAW improved performance in all behavioral tests suggesting effects on hippocampal and cortical dependent memory as well as on prefrontal cortex mediated executive function. There was also an increase in synaptic density in the treated animals, which was accompanied by increased expression of the antioxidant response gene NRF2 as well as the mitochondrial marker porin.

CONCLUSIONS

These data show that CAW can increase synaptic density as well as antioxidant and mitochondrial proteins and improve multiple facets of age-related cognitive impairment. Because mitochondrial dysfunction and oxidative stress also accompany cognitive impairment in many pathological conditions this suggests a broad therapeutic utility of CAW.

Centella asiatica - Phytochemistry and mechanisms of neuroprotection and cognitive enhancement

This review describes in detail the phytochemistry and neurological effects of the medicinal herb Centella asiatica (L.) Urban. C. asiatica is a small perennial plant that grows in moist, tropical and sub-tropical regions throughout the world. Phytochemicals identified from C. asiatica to date include isoprenoids (sesquiterpenes, plant sterols, pentacyclic triterpenoids and saponins) and phenylpropanoid derivatives (eugenol derivatives, caffeoylquinic acids, and flavonoids). Contemporary methods for fingerprinting and characterization of compounds in C. asiatica extracts include liquid chromatography and/or ion mobility spectrometry in conjunction with high-resolution mass spectrometry. Multiple studies in rodent models, and a limited number of human studies support C. asiatica's traditional reputation as a cognitive enhancer, as well as its anxiolytic and anticonvulsant effects. Neuroprotective effects of C.asiatica are seen in several in vitro models, for example against beta amyloid toxicity, and appear to be associated with increased mitochondrial activity, improved antioxidant status, and/or inhibition of the pro-inflammatory enzyme, phospholipase A2. Neurotropic effects of C. asiatica include increased dendritic arborization and synaptogenesis, and may be due to modulations of signal transduction pathways such as ERK1/2 and Akt. Many of these neurotropic and neuroprotective properties of C.asiatica have been associated with the triterpene compounds asiatic acid, asiaticoside and madecassoside. More recently, caffeoylquinic acids are emerging as a second important group of active compounds in C. asiatica, with the potential of enhancing the Nrf2-antioxidant response pathway. The absorption, distribution, metabolism and excretion of the triterpenes, caffeoylquinic acids and flavonoids found in C. asiatica have been studied in humans and animal models, and the compounds or their metabolites found in the brain. This review highlights the remarkable potential for C. asiatica extracts and derivatives to be used in the treatment of neurological conditions, and considers the further research needed to actualize this possibility.

The novel contributors of anti-diabetic potential in mulberry polyphenols revealed by UHPLC-HR-ESI-TOF-MS/MS

To explore the comprehensive phenolic profile of mulberry (Morus alba L.) fruit and reveal the novel anti-diabetic constituents, mulberry polyphenols (MP) were fractionated through gradient ethanol elution and subjected to composition and bioactivity analysis. Forty-seven phenolic compounds were identified and quantified through UHPLC-HR-ESI-TOF-MS/MS, including twenty-one newly identified compounds such as delphinidin 3-rutinoside-5-glucoside and cyanidin 3-rutinoside dimer. The antioxidant activity and anti-diabetic potential of fractionated MP were analyzed in vitro and ex vivo with HepG2 and pancreatic β-cell RIN-m5F. Hierarchical cluster analysis and Pearson correlation coefficients revealed compounds such as syringic acid and galloylcyanidin-glycoside contributed most to inhibit α-glucosidase activity. Quercetin and cyanidin-glycosides were essential for cellular antioxidant activity. Dihydroquercetin and 1,5-dicaffeoylquinic acid were newly identified and validated as the main contributors after rutin to protect RIN-m5F cells against glucotoxicity. Such findings suggest the promising role of MP for type II diabetics and lay the foundation of further utilization and investigation.

Quantification of Antioxidant Phenolic Compounds in a New Chrysanthemum Cultivar by High-Performance Liquid Chromatography with Diode Array Detection and Electrospray Ionization Mass Spectrometry

The flowers of Chrysanthemum morifolium Ramat. have been used as an herbal tea and in traditional medicine, and the plant has been developed to produce horticultural cultivars of various colors and shapes. In this study, a new chrysanthemum cultivar with dark purple petals (C. morifolium cv. ARTI-Dark Chocolate; ADC) was developed by radiation-induced mutation breeding of its original cultivar with purple striped white petals (C. morifolium cv. Noble Wine, NW). The phenolic profile and antioxidant property of ADC were investigated and compared with NW and the commercially available medicinal herb, C. morifolium with yellow petals (CM), in order to find a scientific support to produce a new source of natural antioxidant. Flavonoid and phenolic acid profiles of the ethanol extracts of the three flowers were analyzed by high-performance liquid chromatography-diode array detector-electrospray ionization mass spectrometry (HPLC-DAD-ESIMS), while antioxidant properties were evaluated using the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging assay. Among the tested flowers, ADC possessed the strongest antioxidant capacity and the highest phenolic contents. Flavonoids (acacetin, apigenin, luteolin, acacetin-7-O-β-glucoside, apigenin-7-O-β-glucoside, luteolin-7-O-β-glucoside, and linarin) and phenolic acids (chlorogenic acid and mixture of 1,4-, 1,5-, and 3,5-dicaffeoylquinic acids) were identified and quantified.

Brazilian green propolis water extract up-regulates the early expression level of HO-1 and accelerates Nrf2 after UVA irradiation

Background

Exposure to ultraviolet A (UVA) irradiation is the major cause of human skin aging. Suppression of UVA irradiation-induced skin fibroblast cell damage protects the skin against aging. An oxidative stress response transcription factor nuclear factor-(erythroid-derived 2)-related factor 2 (Nrf2) has an important role as a cytoprotective system against oxidative stress in the human skin and other organs. Propolis has been commonly used as a traditional medicine since ancient times. The water extract of propolis (WEP) mainly contains caffeoylquinic acids. In our previous study, we reported that WEP and its major constituents protected immortalized human skin fibroblast cells (NB1-RGB) against UVA irradiation-induced cell death. In this study, we examined the mechanism of WEP-mediated skin protection and the possible involvement of Nrf2/antioxidant response element (ARE) pathways.

Methods

Brazilian green propolis was used in the present study (Minas Gerais State, Brazil), Baccharis dracunculifolia is its main source. The Baccharis propolis was extracted with water at 50 °C to yield water extract. The NB1-RGB cell cultures were incubated for 23 h. After replenishing the medium, WEP or its constituents were added to the cell cultures. After 1 h, the cells were exposed to 10 J/cm² of UVA light (365 nm UVA light source, CL-1000 L UV Closslinkers, Ultraviolet Products Ltd., Cambridge, UK). Heme oxygenase-1 (HO-1) expression levels in NB1-RGB cells were evaluated using western blotting. Nrf2 nuclear translocation changes in NB1-RGB cells were indicated using immunostaining.

Results

We demonstrated that WEP pretreatment up-regulated HO-1 expression level after UVA irradiation at earlier time points than vehicle pretreatment did, and three main constituents of WEP showed similar effects. Furthermore, WEP pretreatment also accelerated Nrf2 nuclear translocation after UVA irradiation.

Conclusions

Our findings indicated that WEP acts as an early inducer of HO-1 and rapid activator of Nrf2 to protect against UVA-induced oxidative stress.

Low expression of lncRNA-GAS5 is implicated in human primary varicose great saphenous veins

The cellular mechanisms of primary varicose great saphenous veins (GSVs) involve inflammation, apoptosis, and proliferation of local cells and extracellular matrix degradation. Long non-coding RNAs (lncRNAs) play important roles in these cellular processes; however, which and how lncRNAs related to these mechanisms take effect on GSVs remain unclear. By screening lncRNAs that might experience changes in GSV varicosities, we selected the lower expressed lncRNA-GAS5 (growth arrest specific transcript 5) for functional assessments. Silencing of lncRNA-GAS5 promoted cell proliferation and migration, and cell cycle of the human saphenous vein smooth muscle cells (HSVSMCs), whereas overexpressing it inhibited these cellular behaviors and reduced apoptosis of HSVSMCs. RNA pull-down experiment revealed a direct bind of lncRNA-GAS5 to a Ca²⁺-dependent RNA-binding protein, Annexin A2. Further experiments showed that silencing of Annexin A2 reduced the HSVSMCs proliferation and vice versa. In the context of lncRNA-GAS5 knockdown, silencing of Annexin A2 reduced the proliferation of HSVSMCs while overexpression of Annexin A2 increased the proliferation. Thus, the low expression of lncRNA-GAS5 may facilitate HSVSMCs proliferation and migration through Annexin A2 and thereby the pathogenesis of GSV varicosities.

Lipoxin A4 Activates Nrf2 Pathway and Ameliorates Cell Damage in Cultured Cortical Astrocytes Exposed to Oxygen-Glucose Deprivation/Reperfusion Insults

Lipoxin A4 (LXA4), a potent antioxidant and anti-inflammation mediator, protects brains against cerebral ischemia/reperfusion (I/R) injury in vivo. However, few reports concern its function on astrocytes during cerebral I/R injury. The pathogenesis of cerebral I/R injury involves oxidative stress caused by reactive oxygen species (ROS). Upregulation of nuclear factor erythroid 2-related factor 2 (Nrf2) is generally considered to reduce oxidative stress. Nrf2 can induce heme oxygenase-1 (HO-1) expression and glutathione (GSH) release to combat increased oxidative stress. We investigated the effects of LXA4 on astrocytic cell damage, the production of ROS, and Nrf2 pathway, especially on HO-1 expression and GSH release in cultured cortical astrocytes exposed to oxygen-glucose deprivation (OGD)/recovery (OGDR) insults. Primary astrocytes were subjected to a 4-h OGD, followed by 8-h recovery. Cell viability, the production of ROS, and GSH release were measured. Furthermore, Nrf2, HO-1, and p62 expression levels were determined by Western blot. Moreover, Nrf2 location was studied by immunofluorescence staining. Treatment of LXA4 attenuates OGDR-induced cell damage and the production of ROS in a concentration-related manner. LXA4 induced Nrf2 expression and its nuclear translocation, as well as HO-1 expression and GSH release. Moreover, LXA4 induced the excess p62 accumulation. These results indicate that LXA4 can effectively protect against OGDR-induced cell damage in astrocytes, and activation of Nrf2 pathway to reduce oxidative stress may be involved in its protective effects. p62 accumulation induced by LXA4 may be closely related to Nrf2 activation.

The rolC gene increases caffeoylquinic acid production in transformed artichoke cells

Caffeoylquinic acids are found in artichokes, and they are currently considered important therapeutic or preventive agents for treating Alzheimer's disease and diabetes. We transformed artichoke [the cultivated cardoon or Cynara cardunculus var. altilis DC (Asteraceae)] with the rolC gene, which is a known inducer of secondary metabolism. High-performance liquid chromatography with UV and high-resolution mass spectrometry (HPLC-UV-HRMS) revealed that the predominant metabolites synthesized in the transgenic calli were 1,5-dicaffeoylquinic acid, 3,4-dicaffeoylquinic acid, and chlorogenic acid. The rolC-transformed calli contained 1.5% caffeoylquinic acids by dry weight. The overall production of these metabolites was three times higher than that of the corresponding control calli. The enhancing effect of rolC remained stable over long-term cultivation.

Isoliquiritigenin-induced effects on Nrf2 mediated antioxidant defence in the HL-60 cell monocytic differentiation

To evaluate the role of redox homeostasis in differentiation in human promyelocytic leukemia cells (HL-60) induced by isoliquiritigenin (ISL) through modulation of the nuclear erythroid-related factor 2/antioxidant responsive element (Nrf2/ARE) pathway. Morphological changes, cell surface markers CD11b/CD14, and nitroblue tetrazolium (NBT)-reducing ability were used to determine the differentiation of HL-60, and 2,7-dichlorofluorescein was used to detect the level of intracellular reactive oxygen species (ROS). Thiobarbituric acid test was utilised to determine the levels of malondialdehyde production in ISL-treated HL-60. The study determines and presents the redox state of the ratio of reduced/oxidised glutathione as a consequence of progression from differentiation in HL-60. Expression levels of the Nrf2/ARE downstream target genes were determined by quantitative polymerase chain reaction. Nicotinamide adenine dinucleotide phosphate-oxidase (NADPH oxidase) inhibitors, apocynin (APO), and diphenyleneiodonium (DPI) were used for the preliminary study to determine the potential downstream targets regulated by NADPH oxidase in ISL-induced HL-60 differentiation. The data showed a strong dose-response relationship between ISL exposure and the characteristics of HL-60 differentiation, namely, morphology changes, NBT reductive activities, and expression levels of surface antigens CD11b/CD14. Intercellular redox homeostasis changes toward oxidation during drug exposure are necessary to support ISL-induced differentiation. The unique expression levels of the Nrf2/ARE downstream target genes in the differentiation of HL-60 recorded a statistically significant and dose-dependent increase (P < 0.05), which were suppressed by NADPH oxidase inhibitor, APO, and DPI. ISL as a differentiation-inducing agent with mechanisms involved in the Nrf2/ARE pathway to modulate intercellular redox homeostasis, and thus, facilitate differentiation.

Inulae Flos and Its Compounds Inhibit TNF-α- and IFN-γ-Induced Chemokine Production in HaCaT Human Keratinocytes

The present study is to investigate which kinds of solvent extracts of Inulae Flos inhibit the chemokine productions in HaCaT cell and whether the inhibitory capacity of Inulae Flos is related with constitutional compounds. The 70% methanol extract showed comparatively higher inhibition of thymus and activation-regulated chemokine (TARC/CCL17) in HaCaT cells, therefore this extract was further partitioned with n-hexane, chloroform, ethyl acetate, butanol, and water. The ethyl acetate fraction inhibited TARC, macrophage-derived chemokine (MDC/CCL22), and regulated on activation of normal T-cell-expressed and -secreted (RANTES/CCL5) production in HaCaT cells better than the other fractions. The compounds of Inulae Flos, such as 1,5-dicaffeoylquinic acid and luteolin, inhibited TARC, MDC, and RANTES production in HaCaT cells. 1,5-Dicaffeoylquinic acid was contained at the highest concentrations both in the 70% methanol extract and ethyl acetate fraction and inhibited the secretion of chemokines dose-dependently more than the other compounds. Luteolin also represented dose-dependent inhibition on chemokine productions although it was contained at lower levels in 70% methanol extract and solvent fractions. These results suggest that the inhibitory effects of Inulae Flos on chemokine production in HaCaT cell could be related with constituent compounds contained, especially 1,5-dicaffeoylquinic acid and luteolin.

Natural products as potential anticonvulsants: caffeoylquinic acids

Current anticonvulsant therapies are generally directed at symptomatic treatment by suppressing excitability within the brain. Consequently, they have adverse effects such as cognitive impairment, dependence, and abuse. The need for more effective and less toxic anticonvulsants has generated renewed interest in natural products for the treatment of convulsions. Caffeoylquinic acids (CQs) are naturally occurring phenolic acids that are distributed widely in plants. There has been increasing interest in the biological activities of CQs in diseases of the central nervous system. In this issue, Nugroho et al. give evidence for the anticonvulsive effect of a CQ-rich extract from Aster glehni Franchet et Sckmidt. They optimized the extract solvent conditions, resulting in high levels of CQs and peroxynitrite-scavenging activity. Then, they investigated the sedative and anticonvulsive effects in pentobarbital- and pentylenetetrazole-induced models in mice. The CQ-rich extract significantly inhibited tonic convulsions as assessed by onset time, tonic extent, and mortality. They suggested that the CQ-rich extract from A. glehni has potential for treating convulsions. This report provides preclinical data which may be used for the development of anticonvulsants from natural products.

Fumarates promote cytoprotection of central nervous system cells against oxidative stress via the nuclear factor (erythroid-derived 2)-like 2 pathway

Oxidative stress is central to the pathology of several neurodegenerative diseases, including multiple sclerosis, and therapeutics designed to enhance antioxidant potential could have clinical value. The objective of this study was to characterize the potential direct neuroprotective effects of dimethyl fumarate (DMF) and its primary metabolite monomethyl fumarate (MMF) on cellular resistance to oxidative damage in primary cultures of central nervous system (CNS) cells and further explore the dependence and function of the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) pathway in this process. Treatment of animals or primary cultures of CNS cells with DMF or MMF resulted in increased nuclear levels of active Nrf2, with subsequent up-regulation of canonical antioxidant target genes. DMF-dependent up-regulation of antioxidant genes in vivo was lost in mice lacking Nrf2 [Nrf2(-/-)]. DMF or MMF treatment increased cellular redox potential, glutathione, ATP levels, and mitochondrial membrane potential in a concentration-dependent manner. Treating astrocytes or neurons with DMF or MMF also significantly improved cell viability after toxic oxidative challenge in a concentration-dependent manner. This effect on viability was lost in cells that had eliminated or reduced Nrf2. These data suggest that DMF and MMF are cytoprotective for neurons and astrocytes against oxidative stress-induced cellular injury and loss, potentially via up-regulation of an Nrf2-dependent antioxidant response. These data also suggest DMF and MMF may function through improving mitochondrial function. The clinical utility of DMF in multiple sclerosis is being explored through phase III trials with BG-12, which is an oral therapeutic containing DMF as the active ingredient.

NF-kappaB p65 modulates the telomerase reverse transcriptase in the HepG₂ hepatoma cell line

Nuclear factor-kappa B (NF-kappaB) regulates the expression of various genes, several genes involved in inflammation and tumorigenesis, including those of the liver. A role for NF-kappaB has been implicated in the pathogenesis of hepatocellular carcinoma. This transcription factor can regulate hTERT gene transcription. Expression of hTERT was found to be at high levels in hepatocellular carcinoma. However, positive effects of NF-kappaB on hTERT protein synthesis in HepG(2) cells are unknown. In this study, we show that LPS (specific binding to TLR4 to activate NF-kappaB) was positive for NF-kappaB p65 mRNA expression and activation, and also up-regulated hTERT mRNA and protein expressions at 36h in a dose-dependent manner. In contrast, MG-132 (blocking the activity of 26S proteasome and thereby preventing nuclear translocation of NF-kappaB) significantly inhibited activation of NF-kappaB and mRNA expression. And also reduced the expression of hTERT at both mRNA and protein levels at 36h in a dose-dependent manner. Furthermore, dexamethasone inhibited LPS-induced activation of NF-kappaB and expression of the hTERT in HepG(2) cells. These findings suggest that NF-kappaB may modulate hTERT mRNA level, importantly, in protein level in HepG(2) cells and dexamethasone inhibits LPS-induced hTERT via blocking NF-kappaB.

Multiple oxygen tension environments reveal diverse patterns of transcriptional regulation in primary astrocytes

The central nervous system normally functions at O₂ levels which would be regarded as hypoxic by most other tissues. However, most in vitro studies of neurons and astrocytes are conducted under hyperoxic conditions without consideration of O₂-dependent cellular adaptation. We analyzed the reactivity of astrocytes to 1, 4 and 9% O₂ tensions compared to the cell culture standard of 20% O₂, to investigate their ability to sense and translate this O₂ information to transcriptional activity. Variance of ambient O₂ tension for rat astrocytes resulted in profound changes in ribosomal activity, cytoskeletal and energy-regulatory mechanisms and cytokine-related signaling. Clustering of transcriptional regulation patterns revealed four distinct response pattern groups that directionally pivoted around the 4% O₂ tension, or demonstrated coherent ascending/decreasing gene expression patterns in response to diverse oxygen tensions. Immune response and cell cycle/cancer-related signaling pathway transcriptomic subsets were significantly activated with increasing hypoxia, whilst hemostatic and cardiovascular signaling mechanisms were attenuated with increasing hypoxia. Our data indicate that variant O₂ tensions induce specific and physiologically-focused transcript regulation patterns that may underpin important physiological mechanisms that connect higher neurological activity to astrocytic function and ambient oxygen environments. These strongly defined patterns demonstrate a strong bias for physiological transcript programs to pivot around the 4% O₂ tension, while uni-modal programs that do not, appear more related to pathological actions. The functional interaction of these transcriptional ‘programs’ may serve to regulate the dynamic vascular responsivity of the central nervous system during periods of stress or heightened activity.