scholarly journals Factors Differentiating the Antioxidant Activity of Macular Xanthophylls in the Human Eye Retina

Antioxidants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 601
Author(s):  
Justyna Widomska ◽  
Wieslaw I. Gruszecki ◽  
Witold K. Subczynski
Keyword(s):  
Antioxidant Activities ◽  
Molar Ratio ◽  
Spatial Distributions ◽  
Retinal Damage ◽  
Human Diet ◽  
Protective Function ◽  
Spatially Distributed ◽  
High Concentrations ◽  
Eye Retina ◽  
Central Fovea

Macular xanthophylls, which are absorbed from the human diet, accumulate in high concentrations in the human retina, where they efficiently protect against oxidative stress that may lead to retinal damage. In addition, macular xanthophylls are uniquely spatially distributed in the retina. The zeaxanthin concentration (including the lutein metabolite meso-zeaxanthin) is ~9-fold greater than lutein concentration in the central fovea. These numbers do not correlate at all with the dietary intake of xanthophylls, for which there is a dietary zeaxanthin-to-lutein molar ratio of 1:12 to 1:5. The unique spatial distributions of macular xanthophylls—lutein, zeaxanthin, and meso-zeaxanthin—in the retina, which developed during evolution, maximize the protection of the retina provided by these xanthophylls. We will correlate the differences in the spatial distributions of macular xanthophylls with their different antioxidant activities in the retina. Can the major protective function of macular xanthophylls in the retina, namely antioxidant actions, explain their evolutionarily determined, unique spatial distributions? In this review, we will address this question.

scholarly journals Why Is Zeaxanthin the Most Concentrated Xanthophyll in the Central Fovea?

Nutrients ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1333
Author(s):  
Justyna Widomska ◽  
John Paul SanGiovanni ◽  
Witold K. Subczynski
Keyword(s):  
Cell Function ◽  
Fold Increase ◽  
Redox Balance ◽  
Biochemical Properties ◽  
Age Related Macular Degeneration ◽  
Molar Ratio ◽  
Retinal Eccentricity ◽  
Age Related ◽  
High Concentrations ◽  
Central Fovea

Diet-based xanthophylls (zeaxanthin and lutein) are conditionally essential polar carotenoids preferentially accreted in high concentrations (1 mM) to the central retina, where they have the capacity to impart unique physiologically significant biophysical biochemical properties implicated in cell function, rescue, and survival. Macular xanthophylls interact with membrane-bound proteins and lipids to absorb/attenuate light energy, modulate oxidative stress and redox balance, and influence signal transduction cascades implicated in the pathophysiology of age-related macular degeneration. There is exclusive transport, sequestration, and appreciable bioamplification of macular xanthophylls from the circulating carotenoid pool to the retina and within the retina to regions required for high-resolution sensory processing. The distribution of diet-based macular xanthophylls and the lutein metabolite meso-zeaxanthin varies considerably by retinal eccentricity. Zeaxanthin concentrations are 2.5-fold higher than lutein in the cone-dense central fovea. This is an ~20-fold increase in the molar ratio relative to eccentric retinal regions with biochemically detectable macular xanthophylls. In this review, we discuss how the differences in the specific properties of lutein and zeaxanthin could help explain the preferential accumulation of zeaxanthin in the most vulnerable region of the macula.

Apoprotein C effect on triglyceride transport in tandem-perfused rat hind end and liver

1984 ◽  
Vol 247 (3) ◽  
pp. G305-G310
Author(s):  
W. J. Kortz ◽  
J. R. Nashold ◽  
M. R. Greenfield ◽  
H. Hilderman ◽  
S. H. Quarfordt
Keyword(s):  
Fatty Acid ◽  
Free Fatty Acid ◽  
Fatty Acyl ◽  
Liver Fat ◽  
Molar Ratio ◽  
Perfusion System ◽  
In Vitro Perfusion ◽  
Arterial Inflow ◽  
High Concentrations

The metabolism of double-labeled triglyceride in a synthetic emulsion was defined in an in vitro perfusion system of rat hind end and liver described previously [Am. J. Physiol. 245 (Gastrointest. Liver Physiol. 8): G106-G112, 1983]. The metabolism of [3H]glycerol-[14C]triolein was defined in the absence of added apoproteins and with additions of human CII and both CII and CIII. Without apoprotein, a pronounced lipolysis of the triglyceride was recognized by high concentrations of radiolabeled glycerol and free fatty acid in the perfusate. The removal of an aliquot of hind-end venous effluent 5 min after adding the labeled triglyceride emulsion to the arterial inflow demonstrated a brisk lipolysis of the substrate when incubated outside the perfusion system. The addition of CII protein to the emulsion before its introduction into the tandem system eliminated perfusate lipolysis, both within the perfusion system and in incubations of aliquots withdrawn from the system. Intravascular lipolysis was not seen with triglyceride emulsions containing both CII and CIH or when an aliquot of hind-end venous effluent was incubated with triglycerides that had not been exposed to the perfusion system. The intravascular lipolysis observed for the [14C]triglyceride added to the tandem system without apoproteins was associated with relatively greater recoveries of 14C-fatty acyl in liver, fat, and muscle and relatively greater recoveries of 14CO2 than when CII alone or both CII and CIII were added with the triglyceride. The addition of CIII to CII in a 1:1 molar ratio increased the recovery of 14C-fatty acyl in muscle and the recovery as 14CO2.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Antioxidant and Cytotoxic Activities of Myrtaceae Essential Oils Rich in Terpenoids From Brazil

2021 ◽  
Vol 16 (2) ◽  
pp. 1934578X2199615
Author(s):  
Lucas Botelho Jerônimo ◽  
Jamile S. da Costa ◽  
Laine C. Pinto ◽  
Raquel C. Montenegro ◽  
William N. Setzer ◽  
...  
Keyword(s):  
Essential Oils ◽  
Cancer Cells ◽  
Antioxidant Activities ◽  
Human Cancer ◽  
Psidium Guajava ◽  
Cytotoxic Activities ◽  
Chemical Compositions ◽  
Main Compound ◽  
Human Cancer Cells ◽  
High Concentrations

This work analyzed the chemical compositions and evaluated the antioxidant and cytotoxic activities of essential oils (EO) of Eugenia patrisii (Epat), Eugenia stipitata (Esti), Myrcia splendens (Mspl), Myrcia sylvatica (Msyl), Psidium guajava (Pgua), and Psidium guineense (Pgui-1 and Pgui-2) from the Brazilian Amazon. Sesquiterpenoids were found in high concentrations in the oils of E. patrisii and M. splendens, which were rich in E-caryophyllene (32.0% and 45.8%); E. stipitata and M. sylvatica, which displayed germacrene D (11.8%) and germacrene B (24.5%); and P. guajava that showed epi-β-bisabolol (16.1%) as the main compound. However, P. guineense samples (Pgui-1 and Pgui-2) were rich in monoterpenoids such as limonene (Pgui-1: 30.2%; Pgui-2 30.4%) and α-pinene (Pgui-1: 22.5%; Pgui-2: 17.7%). The samples showed a weak and moderate antioxidant activities in the DPPH assay, displaying inhibition rates from 11.5% to 38.6% (at 10 mg/mL). All samples were cytotoxic against human cancer cells by the MTT method. Epat oil showed higher activity against melanoma (SKMEL-19, IC505.8 µg/mL), gastric (AGP01, IC503.2 µg/mL), and colon (HCT116, IC506.7 µg/mL). Meanwhile, the samples Pgua and Pgui were more active against breast cancer cells (MCF7, IC5012.4 µg/mL and 11.6 µg/mL, respectively).

scholarly journals Antioxidant Activities and Selenogene Transcription in the European Sea Bass (Dicentrarchus labrax) Liver Depend, in a Non-linear Manner, on the Se/Hg Molar Ratio of the Feeds

2021 ◽  
Author(s):  
Marinelle Espino ◽  
Harkaitz Eguiraun ◽  
Oihane Diaz de Cerio ◽  
José Antonio Carrero ◽  
Nestor Etxebarria ◽  
...  
Keyword(s):  
Antioxidant Activities ◽  
Dicentrarchus Labrax ◽  
Thioredoxin Reductase ◽  
Sea Bass ◽  
Molar Ratio ◽  
Antioxidant Systems ◽  
European Sea Bass ◽  
Thioredoxin System ◽  
Non Linear ◽  
Linear Manner

AbstractFeeding 3.9 and 6.7 mg Hg/kg (Se/Hg molar ratios of 0.8 and 0.4, respectively) for 14 days negatively affected Dicentrarchus labrax growth and total DNTB- and thioredoxin-reductase (TrxR) activities and the transcription of four redox genes (txn1, gpx1, txnrd3, and txnrd2) in the liver, but a diet with 0.5 mg Hg/kg (Se/Hg molar ratio 6.6) slightly increased both reductase activities and the transcription of txn1, gpx1, and txnrd2. Feeding 6.7 mg Hg/kg for 53 days downregulated the genes of the thioredoxin system (txn1, txnrd3, and txnrd2) but upregulated gpx1, confirming the previously proposed complementarity among the antioxidant systems. Substitution of 20% of the feed by thawed white fish (hake) slightly counteracted the negative effects of Hg. The effects were not statistically significant and were dependent, in a non-linear manner, on the Se/Hg molar ratio of the feed but not on its Hg concentration. These results stress the need to consider the Se/Hg molar ratio of the feed/food when evaluating the toxicity of Hg.

scholarly journals Determination of Chemical Constituents and Antioxidant Activities of Leaves and Stems from Jatropha cinerea (Ortega) Müll. Arg and Jatropha cordata (Ortega) Müll. Arg

Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 212
Author(s):  
Yeimi Cecilia Vega-Ruiz ◽  
Corina Hayano-Kanashiro ◽  
Nohemí Gámez-Meza ◽  
Luis Angel Medina-Juárez
Keyword(s):  
Antioxidant Activity ◽  
Antioxidant Activities ◽  
Biological Effects ◽  
Chemical Constituents ◽  
Weather Conditions ◽  
Antioxidant Compounds ◽  
Leaf Extracts ◽  
Methanolic Extracts ◽  
Northwestern Region ◽  
High Concentrations

Jatropha species have been shown to be an important source of secondary metabolites with different biological effects. Jatropha cinerea (Ortega) Müll. Arg and Jatropha cordata (Ortega) Müll. Arg are distributed in the Northwestern region of Mexico, are adapted to extreme weather conditions and are widely used (stems, leaves, and sap) in traditional medicine. The aim of the present study was to carry out the phytochemical characterization and the evaluation of the antioxidant activity in methanolic extracts of stems and leaves from J. cinerea and J. cordata. The compounds present in the extracts of both species were characterized by ESI-IT-MS/MS and quantified by HPLC-DAD. The results showed that the stem extracts of both species are rich in phenolic acids, while the leaf extracts are rich in flavonoids. Some of the main compounds found were gallic acid, gentisic acid, 3,4-Dihydroxybenzoic acid, vitexin, isovitexin, and catechol. Both species showed high concentrations of phenols and total flavonoids and antioxidant activity. J. cordata showed the highest antioxidant capacity and the highest concentration of phenolic compounds. Overall, both Jatropha species are a natural source of antioxidant compounds with potential biotechnological uses.

Structural characteristics of tetanolysin and its binding to lipid vesicles

1982 ◽  
Vol 152 (2) ◽  
pp. 888-892
Author(s):  
S Rottem ◽  
R M Cole ◽  
W H Habig ◽  
M F Barile ◽  
M C Hardegree
Keyword(s):  
Structural Characteristics ◽  
Lipid Vesicles ◽  
Molar Ratio ◽  
Molar Ratios ◽  
High Concentrations

Tetanolysin binding to lipid vesicles was found to depend on the molar ratio of cholesterol to phospholipid, being low in vesicles containing up to 20 mol% cholesterol and high in vesicles containing more than 33 mol%. High concentrations of purified tetanolysin preparations formed arc- and ring-shaped structures. The structures were not readily detectable in diluted preparations unless incubated with lipid vesicles containing high molar ratios of cholesterol to phospholipid. It is suggested that the toxin is concentrated on the vesicles to local concentrations high enough to form the arcs and rings.

scholarly journals Green and Efficient PEG-Based Ultrasonic-Assisted Extraction of Polysaccharides from Tree Peony Pods and the Evaluation of Their Antioxidant Activity In Vitro

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Xiaonan Zhang ◽  
Qingfeng Ban ◽  
Xibo Wang ◽  
Zhongjiang Wang
Keyword(s):  
Galacturonic Acid ◽  
Antioxidant Activities ◽  
Irradiation Time ◽  
Ultrasound Irradiation ◽  
Molar Ratio ◽  
Precolumn Derivatization ◽  
Tree Peony ◽  
Assisted Extraction ◽  
Ultrasonic Assisted ◽  
Ultrasonic Assisted Extraction

We adopted and developed an ultrasonic-assisted extraction method to obtain polysaccharides from tree peony pods using polyethylene glycol (PEG) as the solvent. The technological parameters have been designed as a single factor to enhance the tree peony pod polysaccharide extraction yield. Specific conditions (ultrasound irradiation power, 250 W; ultrasound irradiation time, 30 min; reaction temperature 50°C; liquid-solid ratio, 25 mL/g; and concentration of PEG, 0.2 g/mL) generated an experimental yield of 14.14%  ± 0.44%. Subsequently, the monosaccharide composition of the tree peony pod polysaccharides was determined by HPLC using a 1-phenyl-3-methyl-5-pyrazolone precolumn derivatization method. The results indicated that tree peony pod polysaccharides contained mannoses, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose, arabinose, and fucose with a molar ratio of 1.44 : 2.87 : 0.32 : 18.99 : 3.99 : 10.21 : 0.96 : 1.85 : 0.21. The tree peony pod polysaccharides obtained are mainly galacturonic acid and galactose, which are acidic polysaccharides. Finally, the antioxidant activities (DPPH and FRAP) of the tree peony pod polysaccharides were assessed, and the compounds exhibited moderate antioxidant activities.

scholarly journals Antioxidant and Pro-Oxidant Activities of Melatonin in the Presence of Copper and Polyphenols In Vitro and In Vivo

Cells ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 903 ◽  
Author(s):  
Jiajia Wang ◽  
Xiaoxiao Wang ◽  
Yufeng He ◽  
Lijie Jia ◽  
Chung S. Yang ◽  
...  
Keyword(s):  
Dna Damage ◽  
Hydroxyl Radical ◽  
Density Functional ◽  
Antioxidant Activities ◽  
Chelating Agent ◽  
Redox System ◽  
Radical Scavenger ◽  
Dual Function ◽  
High Concentrations

Melatonin is a well-documented antioxidant. Physicochemical analysis using the density functional theory suggests that melatonin is a copper chelating agent; however, experimental evidence is still in demand. The present study investigated the influence of melatonin on reactive oxygen species (ROS) generated from polyphenol autoxidation in the presence of copper. Surprisingly, we found that melatonin paradoxically enhanced ROS formation in a redox system containing low concentrations of copper and quercetin (Que) or (−)-epigallocatechin-3-gallate (EGCG), due to reduction of cupric to cuprous ion by melatonin. Addition of DNA to this system inhibited ROS production, because DNA bound to copper and inhibited copper reduction by melatonin. When melatonin was added to a system containing high concentrations of copper and Que or EGCG, it diminished hydroxyl radical formation as expected. Upon addition of DNA to high concentrations of copper and Que, this pro-oxidative system generated ROS and caused DNA damage. The DNA damage was not prevented by typical scavengers of hydroxyl radical DMSO or mannitol. Under these conditions, melatonin or bathocuproine disulfonate (a copper chelator) protected the DNA from damage by chelating copper. When melatonin was administered intraperitoneally to mice, it inhibited hepatotoxicity and DNA damage evoked by EGCG plus diethyldithiocarbamate (a copper ionophore). Overall, the present study demonstrates the pro-oxidant and antioxidant activities of melatonin in the redox system of copper and polyphenols. The pro-oxidant effect is inhibited by the presence of DNA, which prevents copper reduction by melatonin. Interestingly, in-vivo melatonin protects against copper/polyphenol-induced DNA damage probably via acting as a copper-chelating agent rather than a hydroxyl radical scavenger. Melatonin with a dual function of scavenging hydroxyl radical and chelating copper is a more reliable DNA guardian than antioxidants that only have a single function of scavenging hydroxyl radical.

scholarly journals Optimized microwave reflux extraction and antioxidant activities of piperine from black and white piper nigrum

2017 ◽  
Vol 19 ◽  
pp. 139 ◽  
Author(s):  
Olalere Olusegun Abayomi ◽  
Abdurahman Hamid Nour ◽  
Alara Oluwaseun Ruth ◽  
Omar Abed Habeeb
Keyword(s):  
Particle Size ◽  
Chemical Engineering ◽  
Antioxidant Activities ◽  
Irradiation Time ◽  
Power Level ◽  
Radical Scavenging ◽  
Molar Ratio ◽  
Piper Nigrum ◽  
White Pepper ◽  
Black And White

<p>In this study, the microwave reflux technique was employed to extract piperine from black and white pepper. This is due to its ability to combine the microwave and the conventional solvent extraction together with a high degree of selectivity and quality extract. The extraction process was optimized using theL<sub>9</sub>-Taguchi experimental design. This investigated the effects of four independent factors (irradiation time (x<sub>1</sub>), microwave power level (x<sub>2</sub>), feed particle size (x<sub>3</sub>) and molar ratio (x<sub>4</sub>)) on piperine yield. Antioxidant activity of the oleoresin extracts were later evaluated using DPPH (1, 1-diphenyl-1-picrylhydrazyl) radical scavenging assay. The optimum extraction condition in black pepper refluxation was attained at 90 min irradiation time (x<sub>1</sub>), 350 W power level (x<sub>2</sub>), 0.105 mm feed particle size (x<sub>3</sub>) and 10 mL/g molar ratio (x<sub>4</sub>) with an extremum ranking in decreasing order of x3&gt; x<sub>4</sub>&gt; x<sub>2</sub>&gt; x<sub>1</sub>.However,from the white pepper refluxation an optimum condition was achieved at 120 min irradiation time (x<sub>1</sub>), 350 W power level (x<sub>2</sub>), 0.300 mm feed particle size (x<sub>3</sub>) and 6 mL/g molar ratio (x<sub>4</sub>) with a corresponding decreasing extremum order of x<sub>1</sub>&gt; x<sub>4</sub>&gt; x<sub>2</sub>&gt; x<sub>3</sub>.From the results obtained from concentration-dependent radicals scavenging activity it was concluded that white oleoresins extract were much higher in inhibitory activity than that of black oleoresin extract.</p><p>Chemical Engineering Research Bulletin 19(2017) 139-144</p>

scholarly journals Inhibition of hydroxyapatite formation in collagen gels by chondroitin sulphate

1985 ◽  
Vol 228 (2) ◽  
pp. 463-469 ◽  
Author(s):  
G K Hunter ◽  
B L Allen ◽  
M D Grynpas ◽  
P T Cheng
Keyword(s):  
Type I Collagen ◽  
Chondroitin Sulphate ◽  
Collagen Gel ◽  
Calcium Pyrophosphate ◽  
Molar Ratio ◽  
Crystal Formation ◽  
Type I ◽  
Collagen Gels ◽  
High Concentrations ◽  
Hydroxyapatite Formation

Crystal growth in native collagen gels has been used to determine the role of extracellular matrix macromolecules in biological calcification phenomena. In this system, type I collagen gels containing sodium phosphate and buffered at pH 7.4 are overlayed with a solution containing CaCl2. Crystals form in the collagen gel adjacent to the gel-solution interface. Conditions were determined which permit the growth of crystals of hydroxyapatite [Ca10(PO4)6(OH)2]. At a Ca/P molar ratio of 2:1, the minimum concentrations of calcium and phosphate necessary for precipitation of hydroxyapatite are 10 mM and 5 mM, respectively. Under these conditions, precipitation is initiated at 18-24h, and is maximal between 24h and 6 days. Addition of high concentrations of chondroitin 4-sulphate inhibits the formation of hydroxyapatite in collagen gels; initiation of precipitation is delayed, and the final (equilibrium) amount of precipitation is decreased. Inhibition of hydroxyapatite formation requires concentrations of chondroitin sulphate higher than those required to inhibit calcium pyrophosphate crystal formation.

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