Polyanionic characteristics of purified sulphated homofucans from brown algae

Sulphated fucans were fractionated from different brown algae using quaternary ammonium detergents. Purified fractions from different species had the same general chemical composition, that of a typical sulphated homofucans, or fucoidan. The interaction of univalent and divalent counter-ions with fucoidan was investigated by viscometry and polarimetry, and by measuring the counter-ion activites and conductance coefficients in salt-free solutions. The activity and conductance coefficients were found to be independent of the polyanion concentration and approximately the same within each family of counter-ions. This indicates that cation binding in salt-free solutions of fucoidan is purely electrostatic. The conductivity results were in good agreement with the Manning's condensation polyelectrolyte model. The density charge parameter was 2.08 and the mean length of the monomeric unit was 4.5 Å. Both the reduced viscosity and the optical rotation were dependent on the valency of the counter-ions used. Coupled with the data obtained from light-scattering measurements. ( and R_g = 1760 Å), our results suggest that fucoidan in aqueous solution is an extended, flexible coil.     

Sulphated polysaccharide synthesis in brown algae

Summary Histochemical and autoradiographic techniques have been used to investigate the sites of synthesis, transport and location of sulphated polysaccharides in some larger brown seaweeds.The most rapid uptake of ³⁵SO₄ occurred when material was incubated in medium with 10^-4M carrier sulphate, negligable uptake occurring from seawater.Autoradiography using ³⁵SO₄ has shown that in Pelvetia sulphated material is synthesised by all cell types, particularly epidermal cells. In Laminaria spp. this activity is confined to specialized secretory cells which discharge into mucilage canals. In both instances the process of carbohydrate sulphation appears to occur in the Golgi-rich perinuclear region.     

Effect of Sargassum polycystum (Phaeophyceae)-sulphated polysaccharide extract against acetaminophen-induced hyperlipidemia during toxic hepatitis in experimental rats

The effect of Sargassum polycystum crude extract on lipid metabolism was examined against acetaminophen-induced (800 mg/kg body wt., intraperitoneally) hyperlipidemia during toxic hepatitis in experimental rats. The animals intoxicated with acetaminophen showed significant elevation in the levels of cholesterol, triglycerides and free fatty acid in both serum and liver tissue. The levels of tissue total lipids and serum LDL-cholesterol were also elevated with depleted levels of serum HDL-cholesterol and tissue phospholipid. The acetaminophen-induced animals showed significant alterations in the activities of lipid metabolizing enzymes serum lecithin cholesterol acyl transferase (LCAT) and hepatic triglyceride lipase (HTGL). The levels of liver tissue fatty acids (saturated, mono and polyunsaturated) such as palmitic acid, stearic acid, oleic acid, linoleic acid, arachidonic acid and linolenic acid monitored by gas chromatography were considerably altered in acetaminophen intoxicated animals when compared with control animals. The prior oral administration of Sargassum polycystum (200 mg/kg body wt./day for a period of 15 days) crude extract showed considerable prevention in the severe disturbances of lipid profile and metabolizing enzymes triggered by acetaminophen during hepatic injury. Liver histology also showed convincing supportive evidence regarding their protective nature against fatty changes induced during acetaminophen intoxication. Thus the present study indicates that the protective nature of Sargassum polycystum extract may be due to the presence of active compounds possessing antilipemic property against acetaminophen challenge. (Mol Cell Biochem 276: 89–96, 2005)     

Structural features of a sulphated,fucose-containing polysaccharide from the brown seaweed dictyota dichotoma

A sulphated heteropolysaccharide (～15% of the acid-extractable material) isolated from the brown alga Dictyota dichotoma contains residues of D-glucuronic acid, D-galactose, D-mannose, D-xylose, and L-fucose¹. Partial hydrolysis of the polysaccharide with acid gave one neutral and two acidic oligosaccharides. The behaviour towards periodate of the polysaccharide before and after partial hydrolysis, alkali-treatment, and methanolysis has been studied. Evidence is thereby provided that the polysaccharide is partially sulphated and composed of (1→4)-linked residues of D-glucuronic acid, D-galactose, D-mannose, and D-xylose, and (1→2)-linked L-fucose.     

Protective effects of ginkgo biloba against acetaminophen-induced toxicity in mice

Background: The analgesic acetaminophen (AAP) causes a potentially fatal, hepatic centrilobular necrosis when taken in overdose. It was reported that these toxic effects of AAP are due to oxidative reactions that take place during its metabolism. Objective: In this study, we aimed to investigate the possible beneficial effect of Ginkgo biloba (EGb), an antioxidant agent, against AAP toxicity in mice. Methods: Balb/c mice were injected i.p. with: (1) vehicle, control (C) group; (2) a single dose of 50 mg/kg Ginkgo biloba extract, EGb group; (3) a single dose of 900 mg/kg i.p. acetaminophen, AAP group, and (4) EGb, in a dose of 50 mg/kg after AAP injection, AAP + EGb group. Serum ALT, AST, and tumor necrosis factor-alpha (TNF-α) levels in blood and glutathione (GSH), malondialdehyde (MDA) levels, myeloperoxidase (MPO) activity, and collagen contents in liver tissues were measured. Formation of reactive oxygen species in hepatic tissue samples was monitored by using chemiluminescence (CL) technique with luminol and lusigenin probe. Tissues were also examined microscopically. Results: ALT, AST levels, and TNF-α were increased significantly (p < 0.001) after AAP treatment, and reduced with EGb. Acetaminophen caused a significant (p < 0.05–0.001) decrease in GSH levels while MDA levels and MPO activity were increased (p < 0.001) in liver tissues. These changes were reversed by EGb treatment. Furthermore, luminol and lusigenin CL levels in the AAP group increased dramatically compared to control and reduced by EGb treatment (p < 0.01). Conclusion: Our results implicate that AAP causes oxidative damage in hepatic tissues and Ginkgo biloba extract, by its antioxidant effects protects the tissues. Therefore, its therapeutic role as a “tissue injury-limiting agent” must be further elucidated in drug-induced oxidative damage.     

Antiviral property and mechanisms of a sulphated polysaccharide from the brown alga Sargassum patens against Herpes simplex virus type 1

A sulphated polysaccharide (SP-2a) from the brown alga Sargassum patens (Kütz.) Agardh (Sargassaceae) was found to significantly inhibit the in vitro replication of both the acyclovir (ACV)-sensitive and -resistant strains of Herpes simplex virus type 1 (HSV-1), in dose-dependent manners, with 50% inhibitions occurring with 1.5–5.3 μg/ml of the polysaccharide. SP-2a exhibited extracellular virucidal activity only against the ACV-sensitive strains, but not the resistant strain, at the concentration of 100 μg/ml. The strongest antiviral activities against the different strains of HSV-1 were observed when this polysaccharide was present during and after adsorption of the virus to host cells. The inhibitory effect of SP-2a on virus adsorption occurred dose-dependently in all the HSV-1 strains tested, and the adsorption of the ACV-resistant DM2.1 strain was reduced by 81.9% (relative to control) with 4 μg/ml of the polysaccharide. This study clearly demonstrated that the antiviral mode of action of SP-2a is mediated mainly by inhibiting virus attachment to host cells, and this sulphated polysaccharide might have different modes of action against the ACV-sensitive and -resistant strains of HSV-1.     

Anti-oxidative effect of a protein from Cajanus indicus L against acetaminophen-induced hepato-nephro toxicity

Overdoses of acetaminophen cause hepato-renal oxidative stress. The present study was undertaken to investigate the protective effect of a 43 kDa protein isolated from the herb Cajanus indicus, against acetaminophen-induced hepatic and renal toxicity. Male albino mice were treated with the protein for 4 days (intraperitoneally, 2 mg/kg body wt) prior or post to oral administration of acetaminophen (300 mg/kg body wt) for 2 days. Levels of different marker enzymes (namely, glutamate pyruvate transaminase and alkaline phosphatase), creatinine and blood urea nitrogen were measured in the experimental sera. Intracellular reactive oxygen species production and total antioxidant activity were also determined from acetaminophen and protein treated hepatocytes. Indices of different antioxidant enzymes (namely, superoxide dismutase, catalase, glutathione-S-transferase) as well as lipid peroxidation end-products and glutathione were determined in both liver and kidney homogenates. In addition, Cytochrome P450 activity was also measured from liver microsomes. Finally, histopathological studies were performed from liver sections of control, acetaminophen-treated and protein pre- and post-treated (along with acetaminophen) mice. Administration of acetaminophen increased all the serum markers and creatinine levels in mice sera along with the enhancement of hepatic and renal lipid peroxidation. Besides, application of acetaminophen to hepatocytes increased reactive oxygen species production and reduced the total antioxidant activity of the treated hepatocytes. It also reduced the levels of antioxidant enzymes and cellular reserves of glutathione in liver and kidney. In addition, acetaminophen enhanced the cytochrome P450 activity of liver microsomes. Treatment with the protein significantly reversed these changes to almost normal. Apart from these, histopathological changes also revealed the protective nature of the protein against acetaminophen induced necrotic damage of the liver tissues. Results suggest that the protein protects hepatic and renal tissues against oxidative damages and could be used as an effective protector against acetaminophen induced hepato-nephrotoxicity.     

Fucoidan a sulfated polysaccharide from brown algae is a potent modulator of connective tissue proteolysis

Fucoidans are sulfated fucosylated polymers from brown algae cell wall that exhibit some heparin/heparan sulfate properties. We previously demonstrated that these polysaccharides were able in vitro to stimulate dermal fibroblast proliferation and extracellular matrix deposition. Here, we investigated the action of a 16kDa fucoidan fraction on parameters involved in connective tissue breakdown. This fucoidan is able to inhibit gelatinase A secretion and stromelysin 1 induction by interleukin-1beta on dermal fibroblasts in culture. Furthermore, we observed that fucoidan increases the rate of association of MMPs with their specific inhibitors namely TIMPs. Using tissue sections of human skin in ex vivo experiments, we evidenced that this polysaccharide was able to minimize human leukocyte elastase activity resulting in the protection of human skin elastic fiber network against the enzymatic proteolysis due to this serine proteinase. These results suggested that fucoidan could be used for treating some inflammatory pathologies in which uncontrolled extracellular matrix degradation takes place.     

Isolation of water-soluble alginate from brown algae

Summary Water-soluble alginate was obtained from an aqueous extract of Kjellmaniella crassifolia by precipitation with HCl, calcium acetate or 20% ethanol in the presence of 0.05 M MgCl₂ Of these precipitation procedures, MgCl₂-ethanol gave the purest alginate preparation as judged by electrophoresis. The thin-layer and gas-liquid chromatography of its acid hydrolysate, and the IR spectra analysis of the whole alginate, suggested that the water-soluble alginate is similar to ordinary water-insoluble and alkali-soluble alginate such as Kelco alginate.However, the alginate obtained in the present work contained a great excess of mannuronic acid residues, giving an M:G ratio of about 13. Its molecular weight distribution was rather broad as with Kelco alginate, but the molecular weight of its major component was estimated to be 500 000 amu, whereas that Kelco alginate measured on the same column under the same condition was 1 700 000 amu. This suggests that water-soluble alginate was far smaller in average molecular size than Kelco alginate.     

Anticoagulant activity of fucoidans from brown algae

The anticoagulant activity of polysaccharide fucoidans from 11 species of brown algae was studied. The anticoagulant activity was measured by the activated partial thromboplastin time (APTT), prothrombin time, and thrombin time. Inhibitory action of these fucoidans significantly varied from one species to another. Fucoidans from Laminaria saccharina and Fucus distichus exhibited high anticoagulant activity, while fucoidans from Cladosiphon okamuranus and Analipus japonicus were almost inactive. Other fucoidans exhibited intermediate inhibitory activity. The inhibitory effect of fucoidans on thrombin and factor Xa was investigated in the presence or in the absence of natural thrombin inhibitor, antithrombin III (AT III). In contrast to the best-studied anticoagulant, heparin, most of these fucoidans inhibited thrombin in the absence of AT III. In the presence of AT III the inhibitory effect of fucoidans considerably increased. In contrast to heparin, fucoidans weakly influenced factor Xa activity in the presence of AT III and their inhibitory effect was not observed in the absence of AT III. There was no correlation between the anticoagulant activities of this series of fucoidans and their anti-inflammatory action, studied earlier. It is suggested that these two types of fucoidan activities depend on different structural features of fucoidans. Results of this study demonstrate a possibility of preparation of fucoidans with high anti-inflammatory activity but low anticoagulant activity. Anticoagulant activity of the fucoidans did not exhibit direct dependence on the content of fucose, the other neutral sugars and sulfates; no dependence was also found between the anticoagulant activity and the structure of the backbone of their molecules.     

Antioxidant and hepatoprotective potential of Pouteria campechiana on acetaminophen-induced hepatic toxicity in rats

Pouteria campechiana (Kunth) Baehni. is used as a remedy for coronary trouble, liver disorders, epilepsy, skin disease, and ulcer. Therefore, the present study aims to investigate the antioxidant and hepatoprotective effect of polyphenolic-rich P. campechiana fruit extract against acetaminophen-intoxicated rats. Total phenolic and flavonoid contents of egg fruit were estimated followed by the determination of antioxidant activities. Treatment with P. campechiana fruit extract effectively scavenged the free radicals in a concentration-dependent manner within the range of the given concentrations in all antioxidant models. The presence of polyphenolic compounds were confirmed by high-performance thin-layer chromatography (HPTLC). The animals were treated with acetaminophen (250 mg/kg body weight; p.o.) thrice at the interval of every 5 days after the administration of P. campechiana aqueous extract and silymarin (50 mg/kg). Acetaminophen treatment was found to trigger an oxidative stress in liver, leading to an increase of serum marker enzymes. However, treatment with P. campechiana fruit extract significantly reduced the elevated liver marker enzymes (aspartate transaminase, alanine transaminase, and alkaline phosphatase) and increased the antioxidant enzymes (viz., superoxide dismutase and catalase) and glutathione indicating the effect of the extract in restoring the normal functional ability of hepatocytes. These results strongly suggest that P. campechiana fruit extract has strong antioxidant and significant hepatoprotective effect against acetaminophen-induced hepatotoxicity.     

Cytotoxic activity of some marine brown algae against cancer cell lines

The aim of this study was to investigate the in vitro cytotoxic activity of total extract of MeOH (70%) and partition fractions of hexan, chloroform (CHCL3), ethylacetate (EtOAc) and MeOH-H2O of brown algae species (Sargassum swartzii, Cystoseira myrica, Colpomenia sinuosa) found in the Persian Gulf against in different cell lines including HT-29, Caco-2, T47D, MDA-MB468 and NIH 3T3 cell lines by MTT and AnnexinV-PI assay. The hexan fraction of S. swartzii and C. myrica showed selective cytotoxicity against proliferation of Caco-2 cells (IC50 < 100 μg/ml) T47D cell line (IC50<100 μg/ml), respectively. S. swartzii and C. myrica were also observed for increasing apoptosis in Caco-2 and T47D cells. Total extract and fractions of C. sinuosa did not show any significant cytotoxicity against the studied cell lines. MDA-MB468 cells were more sensitive to C. myrica than was T47D (IC50 99.9 ± 8.11 vs. 56.50' ± 0.88). This reflects an estrogen receptor independent mechanism for cytotoxicity of the extract. The IC50 of the hexan fraction of C. myrica on T47D parent cells was lower than it was on T47D-TR cells (IC50 99.9 ± 8.11 vs. 143.15 ± 7.80). This finding suggests a role for the MDR-1 in the development of possible future tolerance to the extract.     

Protective effects of Parinari curatellifolia flavonoids against acetaminophen-induced hepatic necrosis in rats

In the present study, we investigated the hepatoprotective potential of Parinari curatellifolia Planch (Chrysobalanaceae) in experimental rats in order to ascertain the validity of folkloric claims of its effectiveness in the treatment of hepatic-related disorders. Flavonoid extract of P. curatellifolia seed, PCF (10-, 20- or 30 mg/kg body weight) or silymarin (25 mg/kg), dissolved in corn oil, was administered by gavage to experimental animals once daily for 14 consecutive days before liver damage was chemically induced through the administration of acetaminophen (2 g/kg p.o.) on the 14th day. Hepatoprotection was assessed by analyzing liver homogenate and serum for markers of hepatotoxicity – alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamyl transferase (GGT) and lactate dehydrogenase (LDH) activities as well as prothrombin time (PT). Evaluation of biochemical indices of oxidative stress – level of lipid peroxides (LPO), activities of superoxide dismutase (SOD) and catalase, along with histological assessment of hepatic tissue sections were also carried out. Results revealed that all doses of PCF significantly (P < 0.001) and dose dependently prevented acetaminophen-induced increase in serum activities of hepatic enzymes (ALT, AST, GGT, LDH) and PT. Furthermore, PCF (10- and 20 mg/kg) significantly (P < 0.001) reduced lipid peroxidation in liver tissue and restored the activities of the antioxidant enzymes SOD and catalase toward normal levels. Histopathology of the liver tissue showed that PCF mitigated the toxicant-induced hepatocellular necrosis, reduced inflammatory cell infiltration and enhanced hepatocyte regeneration. The results indicated that P. curatellifolia flavonoids demonstrated remarkable hepatoprotective activity in acute liver injury caused by acetaminophen.     

Immunomodulatory activity of brown algae Turbinaria ornata derived sulfated polysaccharide on LPS induced systemic inflammation

BackgroundInflammation and oxidative stress are common pathologies in a wide range of chronic diseases. Polysaccharides are known to exhibit antioxidant and anti-inflammatory potential and are suggested to possess immunomodulatory potential.PurposeHerein, the immunomodulatory activity of a sulfated polysaccharide (PS) separated from a brown marine algae Turbinaria ornata is studied in LPS instigated systemic inflammation in experimental rats.Study design and methodsMale SD rats are pretreated with different doses of PS (2.5, 5, 10 mg/kg bw) for a week followed by inducing systemic inflammation using LPS (10 mg/kg i.p.). Blood withdrawn after 8 h of LPS injection is subjected to hematological analysis (WBC, HCT, and PLT). After 24 h of LPS induction, cardiac tissue was isolated and subjected to biochemical, molecular, and histopathological analysis. Effect of PS pre-treatment (2.5, 5, 10 mg/kg bw) was checked by assessing serum parameters (AST, CK-MB, and γGT), antioxidant markers (LPO, GSH, SOD, Grx) and inflammatory markers (IL1β, IL6, IL10, NFκB), followed by analyzing the iNOS, PI3k and Akt to identify the probable mode of action.ResultsElevated levels of AST, CK-MB, and γGT in serum were significantly reduced on PS pretreatment. LPS significantly raised the LPO and Grx levels in heart tissue whereas, PS pre-treatment significantly reduced LPO and Grx levels. GSH and SOD levels were reduced upon LPS induction and were brought to near normal by HD of PS. PS also reduced the mRNA levels of IL6, Trx, and increased IL10 levels in the heart tissue substantiating its anti-inflammatory and antioxidant potency. Further, IL1β, NFκB, iNOS, and pPI3k/pAkt expressions were significantly modulated by PS in the cardiac tissue substantiating the immunomodulatory effect. A trend of improvement in the inflammatory pathology was also observed in the heart tissue compared to LPS control, as confirmed by histopathology analysis.ConclusionAltogether, this study concludes the immunomodulatory potential of PS from the marine macroalgae Turbinaria ornata significantly and prevents LPS induced systemic inflammation in the cardiac tissue presumably influenced by the glucopyranose and fucopyranose subunits in the polysaccharide.     

藻类中多糖对双歧杆菌的促生长作用

目的 探讨藻类中提取多糖对双歧杆菌的促生长作用。方法 以时间和多糖浓度为影响因素，了解不同藻类中多糖对双歧杆菌的促生长作用，对其量效关系进行分析。结果 温度在37℃，多糖浓度在0％～2％，双歧杆菌数随多糖浓度的增加而上升；多糖浓度继续升高，则反而下降。结论 不同藻类中多糖在一定浓度下能很好地促进双歧杆菌生长。