Antioxidant Compound, Oxyresveratrol, Inhibits APP Production through the AMPK/ULK1/mTOR-Mediated Autophagy Pathway in Mouse Cortical Astrocytes

Oxyresveratrol (OxyR), a well-known polyphenolic phytoalexin, possesses a wide range of pharmacological and biological properties, comprising antioxidant, anti-inflammatory, free radical scavenging, anti-cancer, and neuroprotective activities. Autophagy is a cellular self-degradation system that removes aggregated or misfolded intracellular components via the autophagosome-lysosomal pathway. Astrocyte accumulation is one of the earliest neuropathological changes in Alzheimer’s disease (AD), and amyloid precursor protein (APP) is the hallmark of AD. OxyR could affect APP modulation via the autophagy pathway. Here, we have reported that OxyR promotes autophagy signaling and attenuates APP production in primary cortical astrocytes based on immunofluorescence and immunoblotting assay results. Co-treatment with the late-stage autophagy inhibitor chloroquine (CQ) and OxyR caused significantly higher microtubule-associated protein light chain 3 (LC3)-II protein levels and LC3 puncta counts, demonstrating that OxyR stimulated autophagic flux. We also found that OxyR significantly reduced the levels of the autophagy substrate p62/SQSTM1, and p62 levels were significantly augmented by co-treatment with OxyR and CQ, because of the impaired deficiency of p62 in autolysosome. Likewise, pretreatment with the autophagy inhibitor, 3-methyladenine (3-MA), resulted in significantly fewer OxyR-induced LC3 puncta and lower LC3-II expression, suggesting that OxyR-mediated autophagy was dependent on the class III PI3-kinase pathway. In contrast, OxyR caused significantly lower LC3-II protein expression when pretreated with compound C, an AMP-activated protein kinase (AMPK) inhibitor, indicating that AMPK signaling regulated the OxyR-induced autophagic pathway. Additionally, co-treatment with OxyR with rapamycin intended to inhibit the mammalian target of rapamycin (mTOR) caused significantly lower levels of phospho-S6 ribosomal protein (pS6) and higher LC3-II expression, implying that OxyR-mediated autophagy was dependent on the mTOR pathway. Conversely, OxyR treatment significantly upregulated unc-51-like autophagy activating kinase 1 (ULK1) expression, and ULK1 small interfering RNAs (siRNA) caused significantly lower OxyR-induced LC3 puncta counts and LC3-II expression, indicating that ULK1 was essential for initiating OxyR-induced autophagy. However, we found that OxyR treatment astrocytes significantly increased the expression of lysosome-associated membrane protein 1 (LAMP1). Finally, we established a stress-induced APP production model using corticosterone (CORT) in cortical astrocytes, which produced significantly more APP than the equivalent using dexamethasone (DEX). In our experiment we found that CORT-induced APP production was significantly attenuated by OxyR through the autophagy pathway. Therefore, our study reveals that OxyR regulates AMPK/ULK1/mTOR-dependent autophagy induction and APP reduction in mouse cortical astrocytes.

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Modulation of O-GlcNAcylation Regulates Autophagy in Cortical Astrocytes

Oxidative Medicine and Cellular Longevity ◽

10.1155/2019/6279313 ◽

2019 ◽

Vol 2019 ◽

pp. 1-13 ◽

Cited By ~ 6

Author(s):

Md. Ataur Rahman ◽

Hongik Hwang ◽

Yoonjeong Cho ◽

Hyewhon Rhim

Keyword(s):

Posttranslational Modification ◽

Autophagic Flux ◽

Single Pair ◽

Cortical Astrocytes ◽

Intracellular Proteins ◽

Protein Functions ◽

Nutrient Signaling ◽

Autophagic Degradation ◽

Recycling Pathway ◽

Lc3 Puncta

The addition of O-linked β-N-acetylglucosamine (O-GlcNAcylation) to serine and threonine residues is a common posttranslational modification of intracellular proteins which modulates protein functions and neurodegenerative diseases, controlled by a single pair of enzymes, O-GlcNAcase (OGA), and O-GlcNAcylation transferase (OGT). Autophagy is a cellular recycling pathway activated by stress and nutrient signaling; however, the mechanism by which O-GlcNAcylation modification regulates autophagy in cortical astrocytes is poorly understood. Here, we report that increased O-GlcNAcylation by the suppression of OGA activity using thiamet-G and OGA siRNA did not affect autophagy, whereas decreased O-GlcNAcylation caused by OGT inhibition by alloxan and OGT siRNA increased autophagy. OGT inhibitor and siRNA accumulated LC3 puncta, and cotreatment with chloroquine (CQ), an autophagy inhibitor, significantly increased LC3 puncta and LC3-II protein, confirming that decreased O-GlcNAcylation promotes autophagic flux. In particular, we found that OGT knockdown increases the fusion between autophagosomes as well as lysosomes and stimulates autophagy to promote lysosomal-associated membrane protein 1 (LAMP-1). Additionally, decreasing O-GlcNAcylation by treatment with alloxan, OGT siRNA, and OGA overexpression significantly decreased the level of autophagy substrate SQSTM1/p62, indicating that autophagic degradation was activated. Together, our study reveals a mechanism by which the modulation of O-GlcNAcylation modification regulates autophagy in mouse cortical astrocytes.

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Essential role for autophagy protein VMP1 in maintaining neuronal homeostasis and preventing axonal degeneration

Cell Death and Disease ◽

10.1038/s41419-021-03412-5 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Panpan Wang ◽

Xi Chen ◽

Yuanyuan Wang ◽

Congcong Jia ◽

Xinyao Liu ◽

...

Keyword(s):

Mammalian Cells ◽

Substantia Nigra Pars Compacta ◽

Motor Deficits ◽

Autophagic Flux ◽

Sequestosome 1 ◽

Neuronal Homeostasis ◽

Autophagy Pathway ◽

Lc3 Puncta ◽

The Impact

AbstractVacuole membrane protein 1 (VMP1), the endoplasmic reticulum (ER)-localized autophagy protein, plays a key role during the autophagy process in mammalian cells. To study the impact of VMP1-deficiency on midbrain dopaminergic (mDAergic) neurons, we selectively deleted VMP1 in the mDAergic neurons of VMP1fl/fl/DATCreERT2 bigenic mice using a tamoxifen-inducible CreERT2/loxp gene targeting system. The VMP1fl/fl/DATCreERT2 mice developed progressive motor deficits, concomitant with a profound loss of mDAergic neurons in the substantia nigra pars compacta (SNc) and a high presynaptic accumulation of α-synuclein (α-syn) in the enlarged terminals. Mechanistic studies showed that VMP1 deficiency in the mDAergic neurons led to the increased number of microtubule-associated protein 1 light chain 3-labeled (LC3) puncta and the accumulation of sequestosome 1/p62 aggregates in the SNc neurons, suggesting the impairment of autophagic flux in these neurons. Furthermore, VMP1 deficiency resulted in multiple cellular abnormalities, including large vacuolar-like structures (LVSs), damaged mitochondria, swollen ER, and the accumulation of ubiquitin+ aggregates. Together, our studies reveal a previously unknown role of VMP1 in modulating neuronal survival and maintaining axonal homeostasis, which suggests that VMP1 deficiency might contribute to mDAergic neurodegeneration via the autophagy pathway.

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Evaluation of antioxidant enzyme content, phenolic content, and antibacterial activity of Commiphora gileadensis grown in Saudi Arabia

Main Group Chemistry ◽

10.3233/mgc-200969 ◽

2021 ◽

Vol 19 (4) ◽

pp. 329-343

Author(s):

Yaaser Q. Almulaiky ◽

Ammar AL-Farga

Keyword(s):

Antibacterial Activity ◽

Saudi Arabia ◽

Oral Hygiene ◽

Leaf Extract ◽

Radical Scavenging Activity ◽

Radical Scavenging ◽

Scavenging Activity ◽

Reference Drug ◽

Wide Range ◽

Peel Extract

Commiphora gileadensis is commonly used in Saudi Arabia for oral hygiene. A lack of data about its biological activity encouraged us to evaluate the antioxidant and antibacterial activities of its leaf and stem extracts. Ethanol, methanol, acetone and deionized water were tested as extraction solvents. 80% methanol gave the highest extracted concentrations of phenolic and flavonoid substances. The leaf and stem extracts were respectively evaluated for their radical scavenging activity with DPPH (EC50 = 3.39, and 1.06), ABTS (EC50 = 0.690, and 0.55), and peroxide scavenging activity (EC50 = 2.43, and 1.28). GC-MS identified a wide range of compounds that may be responsible for these activities of the results observed. The highest levels of chlorophyll, carotenoids, and lycopene were found in the leaf extract while level of proanthocyanidins was found in the stem peels extract. The peroxidase and catalase activities of stem peel extract were higher than those of the leaf extract. The findings showed that the leaf and stem peel extracts of C. gileadensis exhibited significant antibacterial activity against the test organisms. The minimum inhibitory concentrations for the plant extracts were compared with the standard reference drug Augmentin but the time–kill curves for the C. gileadensis extracts showed that they were less effective than Augmentin. Moreover, the stem peel extract exhibited stronger antibacterial activity than the leaf extract. In conclusion, C. gileadensis can be an important source of natural antioxidants, used as a healthy chewing stick for teeth brushing and oral hygiene purposes.

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Antimicrobial and antioxidant potentials of non-cytotoxic extracts of corticolous lichens sampled in Armenia

AMB Express ◽

10.1186/s13568-021-01271-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Razmik Sargsyan ◽

Arsen Gasparyan ◽

Gohar Tadevosyan ◽

Hovik Panosyan

Keyword(s):

Antifungal Activity ◽

Methanol Extract ◽

Radical Scavenging Activity ◽

Radical Scavenging ◽

Cytotoxic Activities ◽

Bacterial Strains ◽

Evernia Prunastri ◽

Wide Range ◽

Antibacterial And Antifungal ◽

Acetone Extracts

AbstractDue to wide range of secondary metabolites, lichens were used from antiquity as sources of colorants, perfumes and medicaments. This research focuses on exploring the antioxidant, antimicrobial and cytotoxic activities of methanol, ethanol, acetone extracts and aqueous infusions of corticolous lichens sampled from Armenia. Methanol, ethanol and acetone extracts from all tested lichens were active against Gram-positive bacterial strains. The most effective solvent to retrieve antimicrobial compounds was methanol. Aqueous infusions of tested lichens didn’t show any significant antibacterial and antifungal activity. The highest antimicrobial activity was observed for methanol extract of Ramalina sinensis. The minimum inhibitory concentration of methanol extract of Ramalina sinensis were 0.9–1.8 mg mL− 1. Pseudevernia furfuracea demonstrated antifungal activity (Ø 12 mm). Methanol extract of Parmelia sulcata demonstrated largest 1,1-diphenyl-2-picryl-hydrazil (DPPH) radical scavenging activity (71 %). The cytotoxicity was measured on human HeLa (cervical carcinoma) cell lines using microculture tetrazolium test assay. The IC50 values estimated for methanol extracts of Peltigera praetextata, Evernia prunastri, Ramalina sinensis and Ramalina farinacea species in HeLa cell line were within 1.8–2.8 mg mL− 1 and considered as non-cytotoxic. Obtained results suggest that studied lichens can be prospective in biotechnologies as alternative sources of antimicrobial and antioxidant substances.

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Synthesis, Antiproliferative Activity and Radical Scavenging Ability of 5-O-Acyl Derivatives of Quercetin

Molecules ◽

10.3390/molecules26061608 ◽

2021 ◽

Vol 26 (6) ◽

pp. 1608

Author(s):

Stephen Lo ◽

Euphemia Leung ◽

Bruno Fedrizzi ◽

David Barker

Keyword(s):

Antiproliferative Activity ◽

Biological Activities ◽

Radical Scavenging Activity ◽

Radical Scavenging ◽

Breast Cancer Cell Lines ◽

Scavenging Activity ◽

Plant Materials ◽

Wide Range ◽

Derivatives Of ◽

Acyl Derivatives

Quercetin is a flavonoid that is found in many plant materials, including commonly eaten fruits and vegetables. The compound is well known for its wide range of biological activities. In this study, 5-O-acyl derivatives of quercetin were synthesised and assessed for their antiproliferative activity against the HCT116 colon cancer and MDA-MB-231 breast cancer cell lines; and their radical scavenging activity against the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical species. Four derivatives were found to have improved the antiproliferative activity compared to quercetin whilst retaining radical scavenging activity.

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Low Dose of Fluoride in the Culture Medium of Cordyceps militaris Promotes Its Growth and Enhances Bioactives with Antioxidant and Anticancer Properties

Journal of Fungi ◽

10.3390/jof7050342 ◽

2021 ◽

Vol 7 (5) ◽

pp. 342

Author(s):

Xiaoshuai Li ◽

Jia Wang ◽

Huayue Zhang ◽

Long Xiao ◽

Zhongfang Lei ◽

...

Keyword(s):

Low Dose ◽

Radical Scavenging ◽

Potassium Fluoride ◽

Cordyceps Militaris ◽

Carotenoid Content ◽

Market Demand ◽

Fruiting Bodies ◽

Human Osteosarcoma Cells ◽

Wide Range ◽

Bioactive Ingredients

Cordyceps militaris possesses several compounds with medicinal properties, and is commonly used in traditional Chinese functional food and medicine for a variety of health benefits. Because of its rare occurrence in nature, the market demand for artificial C. militaris is on the rise. Furthermore, efforts to increase its bioactive ingredients have also been considered in research. In this study, we aimed to investigate the effect of fluoride on the growth and enrichment of bioactive compounds in C. militaris. A wide range of potassium fluoride concentrations (0, 0.001, 0.01, 0.1, and 1 mM) were added to the culture media as a source of fluoride during the cultivation of C. militaris fruiting bodies. The contents of fluorine and bioactive substances of the fruiting bodies in normal (NM) and fluorine-supplemented (FM) media were measured and compared. C. militaris raised in the growth medium supplemented with 0.01 mM potassium fluoride led to a 44.86% (1.55 ± 0.14 g/bottle) increase in biomass and a 23.43% (3161.38 ± 35.71 µg/g) increase in total carotenoid content in the fruiting bodies. Furthermore, a remarkable increase in superoxide dismutase-like activity (84.75 U/mg) and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (IC50 = 2.59 mg/mL) was recorded. In human cancer cell-based assays, C. militaris raised in FM caused stronger cytotoxicity, apoptosis, and cell cycle arrest in human osteosarcoma cells. These results demonstrated that a low dose of fluoride could stimulate the growth of C. militaris fruiting bodies and enhance the production of bioactive ingredients that possess useful antioxidant and anticancer activities.

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Tenovin-6 impairs autophagy by inhibiting autophagic flux

Cell Death and Disease ◽

10.1038/cddis.2017.25 ◽

2017 ◽

Vol 8 (2) ◽

pp. e2608-e2608 ◽

Cited By ~ 12

Author(s):

Hongfeng Yuan ◽

Brandon Tan ◽

Shou-Jiang Gao

Keyword(s):

Cell Types ◽

Inhibitory Effect ◽

Lymphocytic Leukemia ◽

Autophagic Flux ◽

Dependent Manner ◽

Autophagy Pathway ◽

Sarcoma Cells ◽

Regulatory Functions

Abstract Tenovin-6 has attracted significant interest because it activates p53 and inhibits sirtuins. It has anti-neoplastic effects on multiple hematopoietic malignancies and solid tumors in both in vitro and in vivo studies. Tenovin-6 was recently shown to impair the autophagy pathway in chronic lymphocytic leukemia cells and pediatric soft tissue sarcoma cells. However, whether tenovin-6 has a general inhibitory effect on autophagy and whether there is any involvement with SIRT1 and p53, both of which are regulators of the autophagy pathway, remain unclear. In this study, we have demonstrated that tenovin-6 increases microtubule-associated protein 1 light chain 3 (LC3-II) level in diverse cell types in a time- and dose-dependent manner. Mechanistically, the increase of LC3-II by tenovin-6 is caused by inhibition of the classical autophagy pathway via impairing lysosomal function without affecting the fusion between autophagosomes and lysosomes. Furthermore, we have revealed that tenovin-6 activation of p53 is cell type dependent, and tenovin-6 inhibition of autophagy is not dependent on its regulatory functions on p53 and SIRT1. Our results have shown that tenovin-6 is a potent autophagy inhibitor, and raised the precaution in interpreting results where tenovin-6 is used as an inhibitor of SIRT1.

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RELATIONSHIP BETWEEN ANTIOXIDANT PROPERTIES AND NUTRITIONAL COMPOSITION OF SOME GALACTOPOIETICS HERBS USED IN INDONESIA: A COMPARATIVE STUDY

International Journal of Pharmacy and Pharmaceutical Sciences ◽

10.22159/ijpps.2016v8i12.14964 ◽

2016 ◽

Vol 8 (12) ◽

pp. 236 ◽

Cited By ~ 4

Author(s):

Ade Chandra Iwansyah ◽

Rizal M. Damanik ◽

Lilik Kustiyah ◽

Muhammad Hanafi

Keyword(s):

Antioxidant Activity ◽

Chemical Composition ◽

Total Phenolics ◽

Radical Scavenging Activity ◽

Antioxidant Properties ◽

Radical Scavenging ◽

Nutritional Composition ◽

Total Flavonoids ◽

Wide Range ◽

Phenolics Content

Objective: The objectives of this research were to evaluate and compare the antioxidant activity; phenolics and flavonoids contents; and chemical composition of some galactopoietic herbs used in Indonesia and to find a possible relationship between antioxidant activity; phenolics, flavonoids and chemical composition of these plants.Methods: A wide range of analytical parameters was studied, including yield; pH; water activity (aw); total color difference; phenolics and flavonoids content; moisture; ash; protein; fat; carbohydrate; fiber; calcium; zinc; magnesium; potassium; iron content; and the data were analyzed by partial least squares (PLS) regression analysis and principal component analysis (PCA) to evaluate the correlation between the parameters and classification of the plants. Folin–cioceltaeu assay, aluminum chloride assay and DPPH scavenging assay were used to evaluate of total phenolics content and free radical scavenging activity of the ethanolic extract of galactopoietic herbs.Results: All of the galactagogue herbs, viz. Plectranthus amboinicus (Lour.) (PA), Sauropus androgynus (SA), Moringa oleifera (MO), and Carica papaya leaves (CP) exhibited good results of TPC, TFC and antioxidant activity. MO contained the highest average of total phenolics content (53.89 mg GAE/g). SA with a ratio of total flavonoids to total phenolics (TF/TP) which is 1.59 contained the highest average of total flavonoids and antioxidant activity (IC50), 43.63 mg QE/g and 126.13 μg/ml, respectively, followed by MO>CA>PA. Based on PLS and PCA analysis, antioxidant activity correlated with fat, protein, phenolics content, flavonoids content and pH, but only the total flavonoids content correlated strongly with antioxidant activity.Conclusion: This provides useful data about the studied relationships and chemical patterns in some galactopoietic herbs used and provides a helpful tool for understanding much more about the interpretation of results from the experiments and the mechanism of biosynthesis in plants.

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Hydroxyl-radical scavenging activity of hydrogen does not significantly contribute to its biological function

10.1101/2021.03.13.435216 ◽

2021 ◽

Author(s):

Qinjian Li ◽

Fei Xie ◽

Yang Yi ◽

Pengxiang Zhao ◽

Xin Zhang ◽

...

Keyword(s):

Hydroxyl Radicals ◽

Radical Scavenging Activity ◽

Radical Scavenging ◽

Published Data ◽

Oh Radicals ◽

Dependent Manner ◽

Protective Effects ◽

Beneficial Effects ◽

Wide Range ◽

Depth Study

AbstractSince Ohsawa et al. reported a biological antioxidant function of hydrogen in 2007, researchers have now shown it to exert protective effects in a wide range of human and animal disease models. Clinical observations and scientific arguments suggest that a selective scavenging property of H2 cannot adequately explain the beneficial effects of hydrogen. However, there is no experiment challenging the original published data, which suggested that molecular hydrogen dissolved in solution reacts with hydroxyl radicals in cell-free systems. Here we report that a hydrogen-saturated solution (0.6 mM) did not significantly reduce hydroxyl radicals in the Fenton system using 1 mM H2O2. We replicated the same condition as Ohsawa’s study (i.e. 5 μM H2O2), and observed a decrease in •OH radicals in both the H2-rich and N2-rich solutions, which may be caused by a decreased dissolved oxygen concentration. Finally, we determined the effect of hydrogen on a high-valence iron enzyme, horseradish peroxidase (HRP), and found that hydrogen could directly increase HRP activity in a dose-dependent manner. Overall, these results indicate that although H2 and •OH can react, the reaction rate is too low to have physiological function. The target of hydrogen is more complex, and its interaction with enzymes or other macro-molecules deserve more attention and in-depth study.

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Phytochemical screening and HPLC- UV method quantiϐication of Flavonoids in Coffee Arabica green seeds

International Journal of Research in Pharmaceutical Sciences ◽

10.26452/ijrps.v11ispl4.4395 ◽

2020 ◽

Vol 11 (SPL4) ◽

pp. 1895-1904

Author(s):

Bothiraj K V ◽

Kalaivani P ◽

Murugan K ◽

Vanitha V

Keyword(s):

Radical Scavenging Activity ◽

Radical Scavenging ◽

Biologically Active ◽

Coffee Bean ◽

Green Coffee ◽

High Concentration ◽

Antimitotic Activity ◽

Wide Range ◽

Anti Inflammatory ◽

Green Coffee Bean

The green coffee bean is the most commonly used beverages in India and it is one of the most commercialised food products. They have a rich source of biologically active compounds that are important for human health. The coffee tree or a shrub belongs to the family Rubiaceae. Commercially available, two species of green coffee bean are Coffea Arabica and Coffea canephora. Cancer is the most important cause of death. Apart from cancer, quercetin can also prevent Osteoporosis. The phytochemicals present in the green coffee bean can be used as an alternate therapy for cancer due to its antimitotic activity and free radical scavenging activity. Total antioxidant shows IC50 value 45.81. Kaempferol is a potent antioxidant that can defence against free radicals and cure chronic diseases. Flavonoids are phenolic substances that act as an antioxidant, anti-inflammatory, anti-allergenic, antiviral and also have vasodilating actions. Green coffee bean shows a high concentration of Flavonoids in hydroethanolic extraction. The aim of this study is used to analyse the presence of Flavonoids in green coffee bean by using High-performance Liquid Chromatography (HPLC). Flavonoids are potent antioxidant that can bind to a protein. Flavonoids show a wide range of biological and pharmacological activities like anti-allergic, anti-inflammatory, anti-cancer and anti-microbial activity.

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