scholarly journals Anti-α-Glucosidase and Antiglycation Activities of α-Mangostin and New Xanthenone Derivatives: Enzymatic Kinetics and Mechanistic Insights through In Vitro Studies

Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 547
Author(s):  
Francine Medjiofack Djeujo ◽  
Valeria Francesconi ◽  
Maddalena Gonella ◽  
Eugenio Ragazzi ◽  
Michele Tonelli ◽  
...  
Keyword(s):  
Protein Glycation ◽  
Dependent Manner ◽  
Protective Effects ◽  
Concentration Dependent Manner ◽  
Glucosidase Activity ◽  
Chronic Hyperglycemia ◽  
Inflammatory State ◽  
Oxidation Damage ◽  
Α Helix

Diabetes mellitus is characterized by chronic hyperglycemia that promotes ROS formation, causing severe oxidative stress. Furthermore, prolonged hyperglycemia leads to glycation reactions with formation of AGEs that contribute to a chronic inflammatory state. This research aims to evaluate the inhibitory activity of α-mangostin and four synthetic xanthenone derivatives against glycation and oxidative processes and on α-glucosidase, an intestinal hydrolase that catalyzes the cleavage of oligosaccharides into glucose molecules, promoting the postprandial glycemic peak. Antiglycation activity was evaluated using the BSA assay, while antioxidant capacity was detected with the ORAC assay. The inhibition of α-glucosidase activity was studied with multispectroscopic methods along with inhibitory kinetic analysis. α-Mangostin and synthetic compounds at 25 µM reduced the production of AGEs, whereas the α-glucosidase activity was inhibited only by the natural compound. α-Mangostin decreased enzymatic activity in a concentration-dependent manner in the micromolar range by a reversible mixed-type antagonism. Circular dichroism revealed a rearrangement of the secondary structure of α-glucosidase with an increase in the contents of α-helix and random coils and a decrease in β-sheet and β-turn components. The data highlighted the anti-α-glucosidase activity of α-mangostin together with its protective effects on protein glycation and oxidation damage.

Properties of neuroprotective cell-permeant Ca2+ chelators: effects on [Ca2+]i and glutamate neurotoxicity in vitro

1994 ◽  
Vol 72 (4) ◽  
pp. 1973-1992 ◽  
Author(s):  
M. Tymianski ◽  
M. P. Charlton ◽  
P. L. Carlen ◽  
C. H. Tator
Keyword(s):  
Time Course ◽  
Dependent Manner ◽  
Protective Effects ◽  
Tetraacetic Acid ◽  
Acetoxymethyl Ester ◽  
Neuroprotective Effects ◽  
Concentration Dependent Manner ◽  
Fura 2 ◽  
Glutamate Neurotoxicity

1. Cell-permeant Ca2+ chelators such as 1,2-bis-(2-amino-phenoxy)ethane- N,N,N',N'-tetraacetic acid acetoxymethyl ester (BAPTA-AM) protect neurons against excitotoxic and ischemic neuronal injury in vitro and in vivo. Here we provide the first steps toward characterizing the mechanisms by which these agents produce their neuroprotective effects. 2. Cultured mouse spinal neurons were simultaneously loaded with the Ca2+ indicator fura-2 and with one of three permeant chelators derived from the fast Ca2+ buffer BAPTA, or with ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid acetoxymethyl ester (EGTA-AM). Adding these chelators did not interfere with the fluorescence spectrum of fura-2 and had no effect on baseline [Ca2+]i. 3. The neurons were challenged with 250 microM L-glutamate for 50 min, producing a marked transient [Ca2+]i increase followed by a decay of [Ca2+]i to a lower “plateau.” About 80% of control neurons succumbed to this excitotoxic insult. Neurons that survived adjusted their plateau [Ca2+]i to lower levels than those that succumbed. 4. Neurons that were pretreated with permeant Ca2+ chelators became more resistant to these neurotoxic challenges. 5. We examined whether this reduction in glutamate neurotoxicity could be related to the given buffer's known Ca2+ affinity (Kd), its Ca2+ binding kinetics, and its ability to attenuate glutamate-induced [Ca2+]i increases. 6. Pretreatment of neurons with BAPTA analogues having Kds ranging from 100 to 3,600 microM 1) attenuated the amplitude and 2) lengthened the time constant describing the rise and decay of the glutamate-evoked [Ca2+]i transient. The magnitude of these effects paralleled the affinity of the chelator for Ca2+. 7. BAPTA-AM and its analogues dramatically attenuated the early neurotoxicity of glutamate, reducing cell deaths by up to 80%. However, in contrast with the graded effects of chelators having different Ca2+ affinities on Ca2+ transients, all BAPTA analogues were equally protective. These protective effects did not relate to the chelators' Ca2+ affinity within a Kd range of 100 nM (for BAPTA) to 3,600 nM (for 5,5'-dibromo BAPTA). 8. BAPTA-AM protected neurons in a concentration-dependent manner with 50% protection obtained with 10 microM, a concentration having no effect on the [Ca2+]i transient amplitude. 9. EGTA, a slow Ca2+ buffer with a similar Ca2+ affinity to BAPTA produced the same effects as BAPTA on [Ca2+]i transient kinetics. However, it was far less protective than BAPTA. 10. The time course of early glutamate neurotoxicity was altered by the BAPTA analogues, but not EGTA. BAPTA analogues caused a small increase in cell deaths in the first minutes of each experiment, followed by relative sparing from further neurodegeneration. 11. The ability of low Ca2+ affinity chelators such as 5,5'-dibromo BAPTA to protect neurons without markedly attenuating measured [Ca2+]i increases conflicts with the hypothesis that global elevations in [Ca2+]i are responsible for triggering neurotoxicity.(ABSTRACT TRUNCATED AT 400 WORDS)

Protective Effects on Mitochondria and Anti-Aging Activity of Polysaccharides from Cultivated Fruiting Bodies of Cordyceps militaris

2010 ◽  
Vol 38 (06) ◽  
pp. 1093-1106 ◽  
Author(s):  
Xing-Tai Li ◽  
Hong-Cheng Li ◽  
Chun-Bin Li ◽  
De-Qiang Dou ◽  
Ming-Bo Gao
Keyword(s):  
Hydroxyl Radicals ◽  
Cordyceps Militaris ◽  
Mitochondrial Swelling ◽  
Dependent Manner ◽  
Protective Effects ◽  
Fruiting Bodies ◽  
Concentration Dependent Manner ◽  
Mitochondrial Injury

Cordyceps militaris (L.) Link is an entomopathogenic fungus parasitic to Lepidoptera larvae, and is widely used as a folk tonic or invigorant for longevity in China. Although C. militaris has been used in traditional Chinese medicine for millennia, there is still a lack convincing evidence for its anti-aging activities. This study was performed to investigate the effects of polysaccharides from cultivated fruiting bodies of C. militaris (CMP) on mitochondrial injury, antioxidation and anti-aging activity. Fruiting bodies of C. militaris were cultivated artificially under optimized conditions. The spectrophotometric method was used to measure thiobarbituric acid reactive substances (TBARS), mitochondrial swelling, and activities of scavenging superoxide anions in vitro. D-galactose (100 mg/kg/day) was injected subcutaneously into back of the neck of mice for 7 weeks to induce an aging model. The effects of CMP on the activities of catalase (CAT), surperoxide dismutase (SOD), glutathione peroxidase (GPx) and anti-hydroxyl radicals were assayed in vivo using commercial monitoring kits. The results showed that CMP could inhibit mitochondrial injury and swelling induced by Fe2+ -L-Cysteine in a concentration- dependent manner and it also had a significant superoxide anion scavenging effect. Moreover, the activities of CAT, SOD, GPx and anti-hydroxyl radicals in mice liver were increased significantly by CMP. These results indicate that CMP protects mitochondria by scavenging reactive oxygen species (ROS), inhibiting mitochondrial swelling, and increasing the activities of antioxidases. Therefore, CMP may have pharmaceutical values for mitochondrial protection and anti-aging. CMP was the major bioactive component in C. militaris.

scholarly journals Protective Effects of Aqueous Extracts of Flos lonicerae Japonicae against Hydroquinone-Induced Toxicity in Hepatic L02 Cells

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Yanfang Gao ◽  
Huanwen Tang ◽  
Liang Xiong ◽  
Lijun Zou ◽  
Wenjuan Dai ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Viability ◽  
Dependent Manner ◽  
Aqueous Extracts ◽  
Protective Effects ◽  
Concentration Dependent Manner ◽  
Flos Lonicerae ◽  
L02 Cells ◽  
Flos Lonicerae Japonicae

Hydroquinone (HQ) is widely used in food stuffs and is an occupational and environmental pollutant. Although the hepatotoxicity of HQ has been demonstrated both in vitro and in vivo, the prevention of HQ-induced hepatotoxicity has yet to be elucidated. In this study, we focused on the intervention effect of aqueous extracts of Flos lonicerae Japonicae (FLJ) on HQ-induced cytotoxicity. We demonstrated that HQ reduced cell viability in a concentration-dependent manner by administering 160 μmol/L HQ for 12 h as the positive control of cytotoxicity. The aqueous FLJ extracts significantly increased cell viability and decreased LDH release, ALT, and AST in a concentration-dependent manner compared with the corresponding HQ-treated groups in hepatic L02 cells. This result indicated that aqueous FLJ extracts could protect the cytotoxicity induced by HQ. HQ increased intracellular MDA and LPO and decreased the activities of GSH, GSH-Px, and SOD in hepatic L02 cells. In addition, aqueous FLJ extracts significantly suppressed HQ-stimulated oxidative damage. Moreover, HQ promoted DNA double-strand breaks (DSBs) and the level of 8-hydroxy-2′-deoxyguanosine and apoptosis. However, aqueous FLJ extracts reversed HQ-induced DNA damage and apoptosis in a concentration-dependent manner. Overall, our results demonstrated that the toxicity of HQ was mediated by intracellular oxidative stress, which activated DNA damage and apoptosis. The findings also proved that aqueous FLJ extracts exerted protective effects against HQ-induced cytotoxicity in hepatic L02 cells.

scholarly journals Atheroprotective action of a modified organoselenium compound: in vitro evidence

2016 ◽  
Vol 88 (3 suppl) ◽  
pp. 1953-1965 ◽  
Author(s):  
JADE DE OLIVEIRA ◽  
MARCOS R. STRALIOTTO ◽  
GIANNI MANCINI ◽  
CLAUDIA P. FIGUEIREDO ◽  
ANTÔNIO L. BRAGA ◽  
...  
Keyword(s):  
Foam Cell ◽  
Oxidized Ldl ◽  
Ldl Oxidation ◽  
Foam Cell Formation ◽  
Dependent Manner ◽  
Protective Effects ◽  
Organoselenium Compound ◽  
Organoselenium Compounds ◽  
Concentration Dependent Manner

ABSTRACT Oxidation of low-density lipoprotein (LDL) has been strongly suggested to play a significant role in the pathogenesis of atherosclerosis. Thus, reducing LDL oxidation is a potential approach to decrease the risk of the atherosclerosis. Organoselenium compounds have demonstrated promising atheroprotective properties in experimental models. Herein, we tested the in vitro atheroprotective capability of a modified organoselenium compound, Compound HBD, in protecting isolated LDL from oxidation as well as foam cells formation. Moreover, the glutathione peroxidase (GPx)-like activity of Compound HBD was analyzed in order to explore the mechanisms related to the above-mentioned protective effects. The Compound HBD in a concentration-dependent manner reduced the Cu2+-induced formation of conjugated dienes. The protein portion from LDL were also protected from Cu2+-induced oxidation. Furthermore, the Compound HBD efficiently decreased the foam cell formation in J774 macrophage cells exposed to oxidized LDL. We found that the atheroprotective effects of this compound can be, at least in part, related to its GPx-like activity. Our findings demonstrated an impressive effect of Compound HBD against LDL-induced toxicity, a further in vivo study to investigate in more detail the antioxidant and antiatherogenic effects of this compound could be considered.

Modifications of cellular responses to lysophosphatidic acid and platelet-activating factor by plasma gelsolin

2007 ◽  
Vol 292 (4) ◽  
pp. C1323-C1330 ◽  
Author(s):  
Teresia M. Osborn ◽  
Claes Dahlgren ◽  
John H. Hartwig ◽  
Thomas P. Stossel
Keyword(s):  
Platelet Activating Factor ◽  
Protective Role ◽  
Actin Binding ◽  
Dependent Manner ◽  
Protective Effects ◽  
Concentration Dependent Manner ◽  
Blood Concentrations ◽  
Plasma Gelsolin

Gelsolin is a highly conserved intracellular actin-binding protein with an extracellular isoform, plasma gelsolin (pGSN). Blood concentrations of pGSN decrease in response to diverse tissue injuries. Depletion of pGSN to critical levels precedes and often predicts complications of injuries such as lung permeability changes and death. Administration of recombinant pGSN ameliorates such complications and reduces mortality in animal models. One proposed mechanism for pGSN's protective effects is that it inhibits inflammatory mediators generated during primary injuries, since pGSN binds bioactive mediators, including lysophospatidic acid (LPA) and endotoxin in vitro. However, no direct evidence in support of this hypothesis has been available. Here we show that recombinant pGSN modestly inhibited LPA-induced P-selectin upregulation by human platelets in the presence of albumin ( P < 0.0001). However, physiologically relevant pGSN concentrations inhibit platelet-activating factor (PAF)-mediated P-selectin expression by up to 77% ( P < 0.0001). pGSN also markedly inhibited PAF-induced superoxide anion (O2−) production of human peripheral neutrophils (PMN) in a concentration-dependent manner ( P < 0.0001). A phospholipid-binding peptide derived from pGSN (QRLFQVKGRR) also inhibited PAF-mediated O2− generation ( P = 0.024). Therefore, pGSN interferes with PAF- and LPA-induced cellular activation in vitro, suggesting a mechanism for the protective role of pGSN in vivo.

scholarly journals Investigation of Hepatoprotective and Antioxidant Activity of Celosia argentea against Tissue Injury Caused by Rifampicin Administration

2019 ◽  
pp. 1-11 ◽  
Author(s):  
Abiodun Olusoji Owoade ◽  
Adewale Adetutu ◽  
Olubukola Sinbad Olorunnisola ◽  
Olufemi Ogundeji Ogundipe
Keyword(s):  
Tissue Injury ◽  
Radical Scavenging ◽  
Hdl Cholesterol ◽  
Dependent Manner ◽  
Protective Effects ◽  
Sod Activity ◽  
Concentration Dependent Manner ◽  
Celosia Argentea ◽  
Liver And Kidney

This study evaluated the antioxidant and possible protective effects of Celosia argentea against tissue injury caused by rifampicin administration. The antioxidant property of the aqueous extract of C. argentea was assessed in-vitro using 2,2-Diphenyl-1- picrylhydrazyl (DPPH), and 2,2-azino-bis (3-ethylbenzthiazoline-6-sufonic acid) (ABTS) assays. The results obtained revealed the free radical scavenging ability of the extract against the radicals in a concentration-dependent manner. Administration of rifampicin to rats for 28 days induced a significant increase in the activities of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and increase cholesterol levels in the plasma, liver and kidney while HDL cholesterol was decreased. It also elevated the levels of malondialdehyde (MDA) and decreased superoxide dismutase (SOD) activities in the liver and kidney. However, co-administration of C. argentea extract to rifampicin treated rats significantly reversed all these rifampicin induced changes. The levels of AST, ALT, ALP and cholesterol in the plasma, liver and kidney were decreased while HDL cholesterol level was increased. In addition, SOD activity was elevated while MDA was depressed when compared to the rifampicin treated rats. The extract of C. argentea was found to be rich in phenolic content and was proved to have no toxic effects on rats when administered alone to normal rats at a dose level of 400mg/kg/day. This study demonstrated that C. argentea leaf extract ameliorates rifampicin-induced hepatotoxicity and could be exploited in the management of hepatotoxic effect associated with rifampicin treatment.

scholarly journals Nucleus pulposus cell senescence is alleviated by resveratrol through regulating the ROS/NF-κB pathway under high-magnitude compression

2018 ◽  
Vol 38 (4) ◽  
Author(s):  
Yanhai Jiang ◽  
Guozhang Dong ◽  
Yeliang Song
Keyword(s):  
Nucleus Pulposus ◽  
Bone Matrix ◽  
Nucleus Pulposus Cell ◽  
Cell Senescence ◽  
Ros Generation ◽  
Dependent Manner ◽  
Protective Effects ◽  
Concentration Dependent Manner ◽  
High Magnitude

Mechanical overloading is a risk factor of disc degeneration. Studies have demonstrated that resveratrol helps to maintain the disc cell’s healthy biology. The present study aims to investigate whether resveratrol can suppress mechanical overloading-induced nucleus pulposus (NP) cell senescence in vitro and the potential mechanism. The isolated rat NP cells were seeded in the decalcified bone matrix (DBM) and cultured under non-compression (control) and compression (20% deformation, 1.0 Hz, 6 h/day) for 5 days using the mechanically active bioreactor. The resveratrol (30 and 60 μM) was added into the culture medium of the compression group to investigate its protective effects against the NP cell senescence. NP cell senescence was evaluated by cell proliferation, cell cycle, senescence-associated β-galactosidase (SA-β-Gal) activity, telomerase (TE) activity, and gene expression of the senescence markers (p16 and p53). Additionally, the reactive oxygen species (ROS) content and activity of the NF-κB pathway were also analyzed. Compared with the non-compression group, the high-magnitude compression significantly promoted NP cell senescence, increased ROS generation and activity of the NF-κB pathway. However, resveratrol partly attenuated NP cell senescence, decreased ROS generation and activity of the NF-κB pathway in a concentration-dependent manner under mechanical compression. Resveratrol can alleviate mechanical overloading-induced NP cell senescence through regulating the ROS/NF-κB pathway. The present study provides that resveratrol may be a potential drug for retarding mechanical overloading-induced NP cell senescence.

Lipoxin A4 methyl ester protects PC12 cells from ketamine-induced neurotoxicity via the miR-22/BAG5 pathway

2021 ◽  
pp. 096032712110516
Author(s):  
Xue-song Wang ◽  
Long-cheng Li ◽  
Xue Zhang ◽  
Jin Gao
Keyword(s):  
Methyl Ester ◽  
Pc12 Cells ◽  
In Vitro Assays ◽  
Protective Mechanism ◽  
Dependent Manner ◽  
Protective Effects ◽  
Concentration Dependent Manner ◽  
Pheochromocytoma Pc12 ◽  
High Doses

Objective Ketamine is an anesthetic that induces neurotoxicity when administered at high doses. In this work, we explored the protective effects of lipoxin A4 methyl ester (LXA4 ME) against ketamine-induced neurotoxicity and the underlying protective mechanism in pheochromocytoma (PC12) cells. Methods PC12 cells were treated with 50 μM of ketamine and different LXA4 ME concentrations of LXA4 ME (5–50 nM) for 24 h, and their viability, apoptosis, and oxidative status were assessed. Results Quantitative real-time polymerase chain reaction experiments showed that ketamine downregulated miR-22 expression and upregulated Bcl-2-associated athanogene 5 (BAG5) in PC12 cells in a concentration-dependent manner. LXA4 ME induced the opposite effects, thus attenuating ketamine-induced neurotoxicity. Further in vitro assays showed that miR-22 directly targeted BAG5, thus promoting cell viability by suppressing cell apoptosis and oxidative stress. Under expression miR-22 or upregulation of BAG5 antagonized the effects of LXA4 ME. Conclusion LXA4 ME can protect PC12 cells from ketamine-induced neurotoxicity by activating the miR-22/BAG5 signaling pathway. Thus, LXA4 ME can be used as a protective drug against ketamine-induced neural damage.

scholarly journals Protective Effects of Extracts fromFructus rhodomyrtiagainst Oxidative DNA DamageIn VitroandIn Vivo

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Yuebin Ke ◽  
Xinyun Xu ◽  
Shuang Wu ◽  
Juan Huang ◽  
Yijie Geng ◽  
...  
Keyword(s):  
Dna Damage ◽  
Oxidative Dna Damage ◽  
Antioxidant Properties ◽  
Dependent Manner ◽  
Protective Effects ◽  
Concentration Dependent Manner ◽  
Spleen Lymphocytes ◽  
Endogenous Antioxidant

Objective. To evaluate the potential protective effects of extracts fromFructus rhodomyrti(FR) against oxidative DNA damage using a cellular system and the antioxidant ability onpotassiumbromate- (KBrO3-) mediated oxidative stress in rats.Methods. The effects of FR on DNA damage induced by hydrogen peroxide (H2O2) were evaluated by comet assay in primary spleen lymphocytes cultures. The effects of FR on the activities of SOD, CAT, and GPx and the levels of GSH, hydroperoxides, and 8-OHdG were determined in the plasma and tissues of rats treated with KBrO3.Results. FR was shown to effectively protect against DNA damage induced by H2O2  in vitro, and the maximum protective effect was observed when FR was diluted 20 times. Endogenous antioxidant status, namely, the activities of SOD, CAT, and GPx and the levels of GSH were significantly decreased in the plasma, the liver, and the kidney of the KBrO3-treated rats, while the pretreatment of FR prevented the decreases of these parameters. In addition, the pretreatment of FR was also able to prevent KBrO3-induced increases in the levels of hydroperoxides and 8-OHdG in the plasma, the liver, and the kidney in rats.Conclusions. Our findings suggested that FR might act as a chemopreventive agent with antioxidant properties offering effective protection against oxidative DNA damage in a concentration-dependent mannerin vitroandin vivo.

scholarly journals TAK-875 Mitigates β-Cell Lipotoxicity-Induced Metaflammation Damage through Inhibiting the TLR4-NF-κB Pathway

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Xide Chen ◽  
Yuanli Yan ◽  
Zhiyan Weng ◽  
Chao Chen ◽  
Miaoru Lv ◽  
...  
Keyword(s):  
Islet Cells ◽  
Cell Damage ◽  
The Body ◽  
Inflammatory Factors ◽  
Dependent Manner ◽  
Protective Effects ◽  
Concentration Dependent Manner ◽  
Major Mechanism ◽  
B Subunit

Metabolic inflammatory damage, characterized by Toll-like receptor 4 (TLR4) signaling activation, is a major mechanism underlying lipotoxicity-induced β-cell damage. The present study is aimed at determining whether G protein-coupled receptor 4 (GPR40) agonist can improve β-cell lipotoxicity-induced damage by inhibiting the TLR4-NF-κB pathway. Lipotoxicity, inflammation-damaged β-cells, obese SD, and TLR4KO rat models were used in the study. In vitro, TAK-875 inhibited the lipotoxicity- and LPS-induced β-cell apoptosis in a concentration-dependent manner, improved the insulin secretion, and inhibited the expression of TLR4 and NF-κB subunit P65. Besides, silencing of TLR4 expression enhanced the protective effects of TAK-875, while TLR4 overexpression attenuated this protective effect. Activation of TLR4 or NF-κB attenuated the antagonism of TAK-875 on PA-induced damage. Moreover, the above process of TAK-875 was partially independent of GPR40 expression. TAK-875 reduced the body weight and inflammatory factors, rebalanced the number and distribution of α or β-cells, inhibited the apoptosis of islet cells, and inhibited the expression of TLR4 and NF-κB subunit P65 in obese rats. Further knockout of the rat TLR4 gene delayed the damage induced by the high-fat diet and synergy with the action of TAK-875. These data suggest that GPR40 agonists antagonized the lipotoxicity β-cell damage by inhibiting the TLR4-NF-κB pathway.

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