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Sulfated rhamnoglucan heteropolysaccharide of Spirulina platensis attenuates methimazole-induced hypothyroidism in rats

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... The sacran rigidity can be derived from the xyloglucan structure as shown in Figure 4. It is considered that sacran has similar structures to rhamnoglucan produced by Spirulina [40], which is also a cyanobacterium that produces sulfated polysaccharides. The rhamnoglucan structure is shown on the right side of Figure 4. Since galactose and mannose exist in small compositions of 0.6 and 1.0, it is speculated that galactose and mannose exist randomly as side chains. ...
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Sacran is a supergiant cyanobacterial polysaccharide that forms mesogenic supercoil rods that exhibit liquid crystalline (LC) gels at deficient concentrations of around 0.5 wt%, and has several bioactive stimuli-responsive functions. Here, we attempted to form oriented microfibers of sacran by electrospinning, following structural analyses of the sacran rods. A heterogeneous acid-hydrolysis method using a protonated cation-exchange resin was adopted to examine the short-time exposition of concentrated acid to sacran rods. From the supernatant, the oligomeric fraction that was soluble in water and methanol was isolated. The oligomeric fraction had a main sugar ratio of α-Glc:β-Glc:α-Xyl:β-Xyl:α-Rha of 2:5:1.5:1.5:4 (Glc:Xyl:Rha = 7 (=4 + 3):3:4), and it was speculated that the sacran structure includes rhamnoglucan and xyloglucan (4:3), which are generally rigid enough to exhibit LC. To make oriented microfibers of LC sacran, solubility testing was performed on sacran to find good new solvents of polyhydroxy alcohols such as ethylene glycol, 1,2-propanediol, and glycerol. The oriented film was prepared from a sacran aqueous solution where calcium compound particles deposited on the film are different from polyhydroxy alcohol solutions. Although sacran could not form microfibers by itself, polymer composite microfibers of sacran with poly(vinyl alcohol) were prepared by electrospinning. Cross-polarizing microscopy revealed the molecular orientation of the microfibers.
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Crude polysaccharides from Spirulina platensis (SP) were isolated by maceration with a hot alkali solution and further fractionated by DEAE-52 cellulose and Sephadex G-100 chromatography into two purified fractions PSP-1 and PSP-2. The monosaccharide composition analysis indicated that SP was mainly composed of rhamnose and glucose, while PSP-1 and PSP-2 were composed only of glucose. The composition analysis of PSP-1 and PSP-2 by HPLC, FT-IR, and NMR showed that PSP-1 and PSP-2 were branching dextran, and their structures were (1 → 4)-linked-α-D-Glcp as the main chain, and C-6 replaced the single α-D-Glcp as the linear structure of the branch chain. The glucans (SP/PSP-1/PSP-2) can significantly improve the phagocytic ability of macrophages, enhance iNOS activity, promote NO production, and increase IL-6 mRNA expression, so they may possess certain immunomodulatory activity.
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Consumption of marine alga-based polysaccharides as additional functional foods can endow with health benefits by diminishing the risk of chronic diseases. A polygalacto-fucopyranose characterized as [→1)-2, 4-SO3-α-Fucp-(3 → 1)-{2-SO3-α-Fucp-(3→}] with [(4 → 1)-6-OAc-β-Galp-(4→] side chain isolated from marine alga Sargassum wightii exhibited potential antihypertensive activity. Upon treatment with studied polygalactofucan (50 mg/kg BW), serum hypertension biomarkers troponin-T (1.3 pg/mL), troponin-I (1.2 μg/dL) and angiotensin-II converting enzyme (0.18 pg/mL) were significantly recovered in hypertensive rats compared to disease control. Serum cardiovascular risk indices of diseased rats were significantly decreased (< 10%, p < 0.05) after administration of the studied galactofucan (50 mg/kg BW) related to hypertension group (> 17%), and were comparable with standard antihypertensive agent telmisartan (8.3–10.2% at 2 mg/kg BW). The studied compound was safe for consumption as obvious from the high LD50 value (>5 g/kg), and could be developed as a prospective functional food ingredient attenuating the pathophysiological attributes causing hypertension-related conditions.
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The antioxidant activity of Spirulina platensis polysaccharide (SPP) was investigated in Caenorhabditis elegans. Nuclear magnetic resonance, Fourier-transform infrared, multi-angle laser light scattering, and GC-MS were used to identify the structural characteristics of SPP. It was composed of the →2)-α-L-Rhap-(1→, →4)-β-D-Manp-(1→, →6)-β-D-Glcp-(1→, →4)-β-Xylp-(1→, →3)-β-L-Araf-(1→, and →2)-β-L-Fucp-(1→, respectively. The modulation of gut microbiota in C. elegans was determined using 16S rRNA gene high-throughput sequencing. The malondialdehyde (MDA) content was significantly decreased, while the total superoxide dismutase (T-SOD) and reactive oxygen species (ROS) levels were improved after SPP supplementation. The cellular mitochondrial content and apoptosis were significantly down-regulated. The obvious increased levels of the DAF-16 and SKN-1 mRNAs were observed in the SPP-treated group, while the levels of miR-48 and miR-51 were significantly reduced. Moreover, SPP administration significantly increased the abundance of Flavobacterium, Achromobacter, Empedobacter, Anaerolinea, and Pseudoalteromonas of the intestinal flora. Based on these results, S. platensis polysaccharides may be used as a functional food to ameliorate diseases related to oxidative stress.
Article
Herein, selenium-containing polysaccharide from Spirulina platensis (Se-SPP) was prepared and its structural characteristics and protective role against Cd-induced toxicity in vivo and in vitro were investigated. Se-SPP was alkali-extracted from selenium-containing Spirulina platensis which was cultured in Zarrouk medium supplemented with Na2SeO3. The contents of carbohydrate, protein, uronic acid, sulfate and elements (including Se, C, H, O, N, and S) as well as the monosaccharide composition, molecular weight, surface morphology and FT-IR spectra of Se-SPP was compared to that of selenium-free polysaccharide (SPP). The results revealed that SPP and Se-SPP were both high-molecular-weight heteropolysaccharide with similar molecular weight and monosaccharide composition but significantly different selenium content, indicating that the covalently-bonding of a small amount of selenium did not destroy the original structure of polysaccharide. Furthermore, CdCl2 was utilized to build Cd-intoxicated cells model in vitro and rats model in vivo respectively. Then, the protective effect of Se-SPP against cadmium-induced toxicity was assessed. The results demonstrated that Se-SPP treatment provided significant protection against Cd-induced toxicity, which was superior compared to that of SPP or Na2SeO3 alone. The enhancement of protective role may be affected by the covalently-bonding of selenium to polysaccharide.
Article
A novel polysaccharide, designated as MOP-3, was extracted and isolated from the leaves of Moringa oleifera. Structural characterization showed that MOP-3 had a molecular weight (MW) of 4.033 × 106 Da and was composed of arabinose, glucose and galactose with a molar ratio of 47.73:1.00:57.65. Methylation and nuclear magnetic resonance (NMR) analysis revealed that the main glycosidic linkage types of MOP-3 were (1→3,6)-β-D-Galp, (1→6)-β-D-Galp, (1→5)-α-L-Araf, and T-α-L-Araf. MOP-3 containing no lipopolysaccharides showed no direct cytotoxicity to the macrophage RAW 264.7 cells within the tested concentrations. The immunomodulatory assay suggested that MOP-3 could significantly enhance pinocytic capacity and increase the secretion of reactive oxygen species (ROS), nitric oxide (NO), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) by up-regulating the corresponding mRNA expression levels in RAW 264.7 cells. Our findings demonstrated that MOP-3 could potentially be used as a functional food for the hypoimmunity therapies.
Article
The aim of this study is to probe new functions of a polysaccharide from Spirulina platensis (PSP) on constipation and intestinal microbiota in mice. Diphenoxylate-induced constipation in mice was treated with different doses of PSP, followed by examining the defecation patterns, levels of acetyl cholinesterase (AchE), nitric oxide (NO), and tissue section histopathology. The composition of intestinal microbiota was determined by genome sequencing analysis of the 16S rDNA. This study found that the average molecular weight of PSP was 29, 600 Da, and mainly monosaccharides of PSP were rhamnose (24.7%), glucose (16.15%) and galactose (13.32%). The beneficial effects of PSP treatment include defecation improvement, increase of AchE activity, reduction of NO concentration, renovation of the damaged intestinal villus and affection on the expression of some related genes in the constipated mice. In addition, PSP had significant effects on the gut microbiota, showing the enhancement in abundance of beneficial bacteria including Akkermansia, Lactobacillus, Butyricimonas, Candidatus Arthromitus and Prevotella, and the reduction in abundance of harmful bacteria such as Clostridium and Dorea. The present s uncovered a new function of PSP, indicating that PSP could be used in constipation therapies.
Article
Hypothyroidism is a commonly encountered clinical condition with variable prevalence. It has profound effects on cardiac function that can impact cardiac contractility, vascular resistance, blood pressure, and heart rhythm. With this review, we aim to describe the effects of hypothyroidism and subclinical hypothyroidism on the heart. Additionally, we attempt to briefly describe how hypothyroid treatment affects cardiovascular parameters.
Article
The elderly are prone to developing nutritional deficiencies of vitamins, minerals, and proteins as well as energy. The addition of Spirulina biomass to food is of interest because of the microalga's nutritional content. Therefore, this study sought to develop chocolate flavor shake-type powdered food, enriched with Spirulina. The chemical composition of the products was analyzed, and they were subjected to sensory testing and shelf life estimation. Food developed presented a mean 42% (w·w− 1) protein and 46% (w·w− 1) carbohydrates content. The average acceptance rates were 7.68 and 7.77, for shakes with and without Spirulina, respectively. The shelf life was estimated at 19 months for the product with incorporated biomass and 24 months for product without Spirulina. Sensory analysis showed that the addition of Spirulina in foods was well accepted by the target public. Products with added microalgal biomass can provide energy and protein and can contribute to the elderly population's nutritional requirements. Industrial relevance The preparation of food products for specific population groups pose major challenges for the food industry. These processes involve large investments in research, but tend to generate competitive advantages for the investing companies. One of the groups that deserve special attention are the elderly, who may present a number of specific nutritional deficiencies that must be supplied by diet. Within this scenario, the enrichment products for seniors with Spirulina becomes very interesting, because it makes food a source of protein and carbohydrates, as well as providing a number of dietary bioactive compounds, essential fatty acids and vitamins.
Article
Thyroid hormones modulate every component of the cardiovascular system necessary for normal cardiovascular development and function. When cardiovascular disease is present, thyroid function tests are characteristically indicated to determine if overt thyroid disorders or even subclinical dysfunction exists. As hypothyroidism, hypertension and cardiovascular disease all increase with advancing age monitoring of TSH, the most sensitive test for hypothyroidism, is important in this expanding segment of our population. A better understanding of the impact of thyroid hormonal status on cardiovascular physiology will enable health care providers to make decisions regarding thyroid hormone evaluation and therapy in concert with evaluating and treating hypertension and cardiovascular disease. The goal of this review is to access contemporary understanding of the effects of thyroid hormones on normal cardiovascular function and the potential role of overt and subclinical hypothyroidism and hyperthyroidism in a variety of cardiovascular diseases.
Article
The study investigated the role of Spirulina platensis in reversing sodium fluoride-induced thyroid, neurodevelopment and oxidative alterations in offspring of pregnant rats. The total antioxidant activity, phycocyanins, and β carotene content were quantified in Spirulina. Thirty female pregnant rats were allocated to six groups and treatment initiated orally from embryonic day (ED) 6 to postnatal day (PND) 15. Treatment groups included control, Spirulina alone, sodium fluoride (20mg/kg) alone, and sodium fluoride along with Spirulina (250 and 500mg/kg). Serum fluoride levels were determined on ED 20 and PND 11. Offspring were subjected to behavioural testing, estimation of thyroid levels, oxidative measurements in brain mitochondrial fraction and histological evaluation of the cerebellum. Fluoride-induced alterations in thyroid hormones, behaviour and increased oxidative stress. Spirulina augmented the displacement of fluoride, facilitated antioxidant formation, improved behaviour and protected Purkinje cells. Supplementing Spirulina during pregnancy could reduce the risk of fluoride toxicity in offspring.
Article
To optimize polysaccharide extraction from Spirulina sp., the effect of solid-to-liquid ratio, extraction temperature and time were investigated using Box-Behnken experimental design and response surface methodology. The results showed that extraction temperature and solid-to-liquid ratio had a significant impact on the yield of polysaccharides. A polysaccharides yield of around 8.3% dry weight was obtained under the following optimized conditions: solid-to-liquid ratio of 1:45, temperature of 90°C, and time of 120min. The polysaccharide extracts contained rhamnose, which accounted for 53% of the total sugars, with a phenolic content of 45mg GAE/g sample.
Article
An antiviral sulfated polysaccharide, calcium spirulan (Ca-SP), isolated from Spirulina platensis, was subjected to further purification. Ca-SP was found to be composed of rhamnose, 3-O-methylrhamnose (acofriose), 2,3-di-O-methylrhamnose, 3-O-methylxylose, uronic acids, and sulfate. The backbone of Ca-SP consisted of 1,3-linked rhamnose and 1,2-linked 3-O-methylrhamnose units with some sulfate substitution at the 4-position. The polymer was terminated at the nonreducing end by 2,3-di-O-methylrhamnose and 3-O-methylxylose residues.
Article
Rochelle salt, normally present in the dinitrosalicylic acid reagent for reducing sugar, interferes with the protective action of the sulfite, but is essential to color stability. The difficulty may be resolved either by eliminating Rochelle salt from the reagent and adding it to the mixture of reducing sugar and reagent after the color is developed, or by adding known amounts of glucose to the samples of reducing sugar to compensate for the losses sustained in the presence of the Rochelle salt. The optimal composition of a modified dinitrosalicylic acid reagent is given.
Article
Ultrasonic technique was employed to extract polysaccharides from longan fruit pericarp (PLFP). The optimal conditions for ultrasonic extraction of PLFP were determined by response surface methodology. Box–Behnken design was applied to evaluate the effects of three independent variables (ultrasonic power, time and temperature) on the recovery and 1,1′-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of PLFP. The correlation analysis of two mathematical-regression models indicated that quadratic polynomial model could be employed to optimize the ultrasonic extraction of PLFP. From response surface plots, ultrasonic power, time and temperature exhibited independent and interactive effects on the extraction of PLFP. The DPPH radical scavenging activity of PLFP could be improved by application of various ultrasonic power, time and temperature, which was possible due to the degradation of polysaccharides to different extent. The optimal conditions to obtain the highest recovery and the strongest DPPH radical scavenging activity of PLFP were 120 W, 22 min and 60 °C, as well as 241 W, 18 min and 51 °C, respectively. Under these optimal conditions, the experimental values agreed with the predicted ones by analysis of variance. It indicated high fitness of two models used and the success of response surface methodology for optimizing PLFP extraction.
Article
Significance: The understanding of physiological and pathological processes involving protein oxidation, particularly under conditions of aging and oxidative stress, can be aided by proteomic identification of proteins that accumulate oxidative post-translational modifications only if these detected modifications are connected to functional consequences. The modification of tyrosine (Tyr) residues can elicit significant changes in protein structure and function, which, in some cases, may contribute to biological aging and age-related pathologies, such as atherosclerosis, neurodegeneration, and cataracts. Recent advances: Studies characterizing proteins in which Tyr has been modified to 3-nitrotyrosine, 3,4-dihydroxyphenylalanine, 3,3'-dityrosine and other cross-links, or 3-chlorotyrosine are reviewed, with an emphasis on structural and functional consequences. Critical issues: Distinguishing between inconsequential modifications and functionally significant ones requires careful biochemical and biophysical analysis of target proteins, as well as innovative methods for isolating the effects of the multiple modifications that often occur under oxidizing conditions. Future directions: The labor-intensive task of isolating and characterizing individual modified proteins must continue, especially given the expanding list of known modifications. Emerging approaches, such as genetic and metabolic incorporation of unnatural amino acids, hold promise for additional focused studies of this kind.
Article
Post-translational oxidative protein modifications which are more marked during aging and/or high-calorie (HC) diets affect protein function and metabolism. Protein function and metabolism are different according to the type of muscle proteins. Oxidative muscle protein modifications may thus be associated with age-related sarcopenia, and HC may be implicated in the development of sarcopenia by emphasizing protein modifications. Understanding the role of protein modifications in the process of sarcopenia and metabolism associated with a high fat diet may be elucidated by investigations with skeletal muscle protein subfractionations. To study this hypothesis, carbonylated protein (CP) and 3-nitrotyrosine (3-NT) levels were measured in mixed, sarcoplasmic, myofibrillar and mitochondrial protein fractions of quadriceps in rats aged 6months (A) and 25months (O) fed a normal calorie (NC) or HC diet for 3months (AN, AH, ON, OH n=7-8). Muscle weight was lower in the older rats (AN: 0.79±0.03g, ON: 0.43±0.12g, P<0.05), but no HC effect was observed. CP did not differ between groups while 3-NT accumulated significantly in ON compared with AN, especially in mitochondria (2.4±0.5, 1.3±0.1, 1.9±0.4, 2.9±1.2 -fold in mixed, sarcoplasmic, myofibrillar and mitochondrial fractions respectively, P<0.05). 3-NT in mixed protein was negatively correlated with muscle mass (r(2)=-0.812). 3-NT accumulation during HC was observed only in specific proteins of mitochondria (100kDa) (1.0±0.6, 1.7±0.9, 3.3±1.4 and 7.0±2.5 -fold in AN, AH, ON and OH, respectively, P<0.05). Hence cumulative 3-NT in skeletal muscle protein appears associated with the development of age-related muscle loss. Mitochondrial proteins are more prone to nitration during aging and nutritional stress.
Article
Tyrosine nitration is a covalent post-translational protein modification derived from the reaction of proteins with nitrating agents. Tyrosine nitration has been used as a marker of oxidant burden in human diseases. However, it remains unclear whether protein nitration is responsible for alterations in protein function that imparts an increased risk for disease development or unfavorable outcomes. Emerging data implicate tyrosine nitration as a mediator of immune responses suggesting a novel biological function for this protein modification.
Article
The reaction of lipid peroxides in animal tissues with thiobarbituric acid was dependent on pH of the reaction mixture as was the case for linoleic acid hydroperoxide. The optimum pH was found to be 3.5. Taking this fact into consideration, a standard procedure for the assay of lipid peroxide level in animal tissues by their reaction with thiobarbituric acid was developed as follows. Ten percent ( tissue homogenate was mixed with sodium dodecyl sulfate, acetate buffer (pH 3.5), and aqueous solution of thiobarbituric acid. After heating at 95°C for 60 min, the red pigment produced was extracted with n-butanol-pyridine mixture and estimated by the absorbance at 532nm. As an external standard, tetramethoxy-propane was used, and lipid peroxide level was expressed in terms of nmol malondialdehyde. Using this method, the liped peroxide level in the liver of rats suffering from carbon tetrachloride intoxication was investigated. The results were in good agreement with previously reported data obtained by measuring diene content.
Article
We describe a modified method for determining triglycerides in serum, in which alumina is used to adsorb interfering substances, and the glycerol content of triglycerides is determined colorimetrically. In contrast to all previous Hantzsch condensation procedures in which periodate and acetylacetone are used, the working periodate and the working acetylacetone reagents are stable for at least six months because they are differently formulated. The principle that governs this increased stability applies to all Hantzsch condensation methods for triglycerides.
Article
The purification of homogeneous glutathione S transferases B and C from rat liver is described. Kinetic and physical properties of these enzymes are compared with those of homogeneous transferases A and E. The letter designations for the transferases are based on the reverse order of elution from carboxymethylcellulose, the purification step in which the transferases are separated from each other. Transferase B was purified on the basis of its ability to conjugate iodomethane with glutathione, whereas transferase C was purified on the basis of conjugation with 1,2 dichloro 4 nitrobenzene. Although each of the 4 enzymes can be identified by its reactivity with specific substrates, all of the enzymes are active to differing degrees in the conjugation of glutathione with p nitrobenzyl chloride. Assay conditions for a variety of substrates are included. All four glutathione transferases have a molecular weight of 45,000 and are dissociable into subunits of approximately 25,000 daltons. Despite similar physical properties and overlapping substrate specificities of these enzymes, only transferases A and C are immunologically related.
Article
A simple colorimetric assay for catalase activity has been described using K2Cr2O7/acetic acid reagent. Kat. f values of different enzyme sources were determined by the colorimetric method and compared with the values obtained by titrimetric methods.
Article
An enzymatic method is described for determination of total serum cholesterol by use of a single aqueous reagent. The method requires no prior treatment of sample and the calibration curve is linear to 600 mg/dl. Cholesterol esters are hydrolized to free cholesterol by cholesterol ester hydrolase (EC 3.1.1.13). The free cholesterol produced is oxidized by cholesterol oxidase to cholest 4 en 3 one with the simultaneous production of hydrogen peroxide, which oxidatively couples with 4 aminoantipyrine and phenol in the presence of peroxidase to yield a chromogen with maximum absorption at 500 nm. The method is reproducible, and the results correlate well with those obtained by automated Liebermann Burchard procedures and the method of Abell et al. The present method affords better specificity than those previously reported and has excellent precision.