Degradation of porphyran from Porphyra haitanensis and the antioxidant activities of the degraded porphyrans with different molecular weight.

In the present paper, ascorbate and hydrogen peroxide (H2O2) were used to degrade porphyran. It was found that porphyran could be degraded by free radical that was generated by ascorbate and H2O2 in combination. It was possible to prepare desired porphyran products with different molecular weight by adjusting ascorbate to H2O2 proportions and their concentrations. The molar ratio of 1 was demonstrated more effective than in other ratios. Higher concentrations accelerated the degradation. Moreover, results of chemical analysis and FT-IR spectra suggested that the main structure of degraded products still remained although some changes happened. The degraded and natural porphyrans possessed scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH)-radical activity and reducing power. Higher antioxidant activities were found in both systems when the molecular weight was reduced. The results indicated that the antioxidant activities were closely related to the molecular weight. The degraded porphyrans are potential antioxidant in vitro.

[Determination of trace arsenic and selenium in jellyfish by microwave digestion-hydride generation-atomic fluorescence spectrometry].

A method of hydride generation-atomic fluorescence spectrometry was proposed in the present paper for the determination of trace arsenic and selenium in jellyfish. The samples were treated by the combination of microwave digestion and lyophilization. The optimal conditions for treating and analyzing samples were established. The problem of the effect of the superfluous acid in the digesting solution on the results was solved, and the influence of coexisting foreign ions on the determination of arsenic and selenium was investigated. The accuracy of the method was confirmed by the method of standard additions. This method proved to be simple, rapid and repeatable, and is suitable for the analysis of biologic samples containing water.

Fucoidan inhibits the development of proteinuria in active Heymann nephritis.

Fucoidan, the sulphated polysaccharide extracted from brown seaweed, has various biological activities. The effect of fucoidan on the formation of proteinuria and renal functions in active Heymann nephritis was investigated in this study. Active Heymann nephritis was induced by administering brush border protein of rat proximal uriniferous tubules (FX1A). Fucoidan was administered by oral intubation to Heymann nephritis rats at three doses (50, 100 and 200 mg/kg) once daily for 4 weeks. The elevated urinary protein excretion and plasma creatinine due to the induction of Heymann nephritis were significantly reduced by fucoidan at doses of 100 and 200 mg/kg. The results indicated that fucoidan has a renoprotective effect on active Heymann nephritis and is a promising therapeutic agent for nephritis.

In vivo growth-inhibition of S180 tumor by mixture of 5-Fu and low molecular lambda-carrageenan from Chondrus ocellatus.

Lambda-carrageenan is a sulfated galactan isolated from some red algae and have been reported to have many kinds of biological activities. Chondrus ocellatus is an important economic alga in China and many other parts of the world. The sample was obtained after lambda-carrageenan from the alga was degraded by microwave and its molecular weight is 9.3 kDa. In this study, tumor inhibiting activity of low molecular weight lambda-carrageenan and its mixture with 5-Fu on mice transplanted with S180 tumor was investigated. Weight of immune organ, proliferation ratio of lymphocyte concentration of TNF-alpha and histopathology of spleen and tumor from the transplanted S180 tumor mice were also determined. Results indicated that the degraded lambda-carrageenan could enhance antitumor activity of 5-Fu and improve immunocompetence damaged by 5-Fu.

In vivo antitumor and immunomodulation activities of different molecular weight lambda-carrageenans from Chondrus ocellatus.

lambda-Carrageenan is a sulfated galactan isolated from some red algae and have been reported to have many kinds of biological activities. lambda-Carrageenan from Chondrus ocellatus, an important economic alga in China and many other parts of the world, was degraded by microwave, and obtained five products that have different molecular weight: 650, 240, 140, 15, 9.3 kDa. Analytical results confirmed that microwave degradation might not change the chemical components and structure of polysaccharides under certain condition. In this study, tumor-inhibiting activities, weight of immune organ, nature killer cells activity, lymphocyte proliferation ratio and pathological slice of spleen and tumor cells from the control group and lambda-carrageenan-treated mice of transplanted S180 and H22 tumor were investigated. The results indicated that the five lambda-carrageenan samples all showed antitumor and immunomodulation activities in different degree. Molecular weight of polysaccharides had notable effect on the activities. In addition, their antitumor and immunomodulation have some relevance and the five lambda-carrageenans probably inhibited tumor by means of activating the immunocompetence of the body. Among all the experiment results, samples with the highest activities are PC4 and PC5 whose molecular weight are 15 and 9.3 kDa.

The structure of a sulfated galactan from Porphyra haitanensis and its in vivo antioxidant activity.

The sulfated galactan fraction F1 isolated from the red seaweed, Porphyra haitanensis, showed typical porphyran structure. It has a linear backbone of alternating 3-linked beta-D-galactosyl units and 4-linked alpha-L-galactosyl 6-sulfate and 3,6-anhydro-alpha-L-galactosyl units. The L-residues are mainly composed of alpha-L-galactosyl 6-sulfate units, and the 3,6-anhydrogalactosyl units are minor. Partial methylation occurred at the C-6 position of the D-galactosyl units and at the C-2 position of the 3,6-anhydro-alpha-L-galactosyl units. Intraperitoneal administration of F1 significantly decreased the lipid peroxidation in aging mice. F1 treatment increased the total antioxidant capacity and the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in aging mice. The results indicated that F1 had significant in vivo antioxidant activity.

Effects of fucoidan on chronic renal failure in rats.

The effects of fucoidan on chronic renal failure (CRF) were investigated in vivo in a subtotal nephrectomy CRF model and a cryoinjury induced CRF model in rats. Fucoidan showed renoprotective effects in both models. Fucoidan (100 or 200 mg/kg, orally) significantly decreased elevated serum creatinine and urea nitrogen levels. Histopathological changes of renal tubules and interstitium were markedly alleviated by fucoidan and the mesangial areas were also greatly reduced. The activities of fucoidan were dose-dependent.

In vivo antioxidant activity of polysaccharide fraction from Porphyra haitanesis (Rhodephyta) in aging mice.

Sulfated polysaccharide fraction F2 from Porphyra haitanesis (Rhodephyta) showed inhibitory effect on the in vitro lipid peroxidation. In the present study, the age-related changes in the antioxidant enzyme activity, lipid peroxidation, and total antioxidant capacity (TAOC) in different organs in mice were investigated and the in vivo antioxidant effect of F2 in aging mice was checked. Increased endogenous lipid peroxidation and decreased TAOC were observed in aging mice. Intraperitoneal administration of F2 significantly decreased the lipid peroxidation in a dose-dependent manner. F2 treatment increased TAOC and the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in all the organs tested in aging mice. It is concluded that the sulfated polysaccharide fraction F2 can be used in compensating the decline in TAOC and the activities of antioxidant enzymes and thereby reduces the risks of lipid peroxidation.