Fan Xiao

Macroalage as a source of alpha-glucosidase inhibitors

Alpha-glucosidase inhibitors were screened from organic solvent extracts of macroalgae by a spectrophotometrical method with p-nitrophenyl-D-glucopyranosidase as the substrate. The result indicates that organic crude extracts from some macroalgae such asRhodomela confervoides (Huds.) Silva,Gracilaria textorii (Suringar) De Toni,Plocamium telfairiae Harv.,Dictyopteris divaricata (Okam.) Okam,Ulval pertusa andEnteromorpha intestinalis (L.) Link et al. show strong inhibitory activity of alpha-glucosidase at concentration of 79.6 μg/ml.

Studies on extraction procedure and antioxidative activity of phlorotannins fromSargassum kjellmanianum

Known only in phaeophyceae, phlorotannins (brown algal polyphenols) are natural products with potential uses in pharmacology. This study yielded an extraction procedure to obtain high purity, high molecular weight phlorotannins fromSargassum kjellmanianum and revealed the characteristics of their infrared and flourescence spectra. The antioxidative activity of phlorotannins, which was about 2.6 times as strong as that of 0.02% BHT (tert-butyl-4-hydroxytoluene), showed potential for preventing oil rancidification.

Effects of composition and structure of alginates on adsorption of divalent metals

AbstractResults of a series of experiments (on the adsorption of divalent metal ions by dried alginic acid, Na and Ca alginates of different composition and block structure) conducted in this systematic study of the effects of the composition and structure of alginates on the static adsorption equilibrium of divalent metal ions indicate that the properties of alginate adsorption to divalent metal ions are highly different, depending not only on the cations used, but also on the form and structure of the alginates. There is close correlation between the adsorption properties and the structure of the alginates. The selectivity coefficient of Na alginate for Cd-Sr ion exchange tends to increase with the increase of theM/G ratio in alginate, whereas the adsorption capacity of Ca alginate for Cu2+ ion decrease with the increase of the G-block or the average length of the G-block

Element composition ofSargassum thunbergii

(\bar N_G )

The betaines from Chinese seaweeds

and the total adsorption capacity of alginic acid is found to vary in the same order as theFMM(diad frequency) in alginate in the mixed solution of Sr2+, Ba2+ and Cd2+.

Iodine content ofSargassum in Southern China

Extracts of 21 marine invertebrates belonging to Coelenterata, Mollusca, Annelida, Bryozoa, Echiura, Arthropoda, Echinodermata and Urochordata were screened for the studies on their antitumor and immune regulation activities. Antitumor activity was determined by MTT method and immune regulation activity was studied using T- and B-lymphocytes in mice spleenin vitro. It was found that the n-butanol part ofAsterina pectinifera, the acetic ether part ofTubuaria marina, 95% ethanol extract ofAcanthochiton rubrolineatus have a high inhibition rate of 96.7%, 63.9% and 50.5% respectively on tumor cell line HL-60 at the concentration of 0.063 mg/ml. The inhibition rate of the acetic ether part ofTubuaria marina on the tumor cell line A-549 is 65.4% at concentration of 0.063 mg/mL. The 95% ethanol extract ofMeretrix meretrix has so outstanding promoting effect on T-lymphocytes that their multiplication increases 25% when the sample concentration is only 1 μg/ml. On B-lymphocytes, the 95% extract ofRapana venosa, at concentration of 100 μg/ml, has a promotion percentage of 60%. On the other hand, under the condition of no cytotoxic effect, the 95% ethanol extracts ofAcanthochiton rubrolineatus andCellana toreum can reach 92% inhibition rate on T lymphocyte at concentration of 100 μg/ml, while the inhibition rate on B lymphocyte of the 95% extract ofAcanthochiton rubrolineatus reaches 92% at the same concentration.

Determination of amino acids in twoPolysiphonia species and study of enzymatic hydrolysis method

Results of neutron activation analysis (NAA) ofSargassum thumbergii samples collected from the Qingdao Taipingjiao coast on March 20, 1996 showed that (1)Sargassum thunbergii can to some extent accumulate potassium and calcium (the accumulation coefficient was 10); (2) it can accumulate almost all trace elements, especially iron, managanese and zinc; (3) it can accumulate strontium, aluminium thorium, and rare earth elements.

Prepn process of chitinamine oligosaccharide

Chemical means were used to extract polyphenols from healthy brown algae collected in littoral seawater. Experiments on corrosion of A3 steel, the time-potential curve, and polarization curve in polyphenols seawater showed stronger cathodic polarization compared with that in common seawater. This indicates that brown algae polyphenols might feasibly be used as corrosion inhibitor in seawater.