| Fructus lycii, the fruit of Lycium barbarian L., is a well-known traditional Chinese medicine and food. The polysaccharides from it, called Lycium barbarum polysaccharides (LBP), play multiple roles in pharmacological and health care functions. In order to understand more about their structures and functions, the studies were conducted on the extraction, purification, and structural elucidation of them, and on the valuation of their functions with total LBP (LBPt), LBP fractions, LBP sub-fractions, and LBP oral tablets. The main results are as follows: 1 Extraction, purification, and structural characteristics of LBP sub-fractions.LBPt were obtained after a series of steps, such as eliminating lipids and pigments with petroleum ether, isolating monosaccharides and oligosaccharides with 80% ethyl alcohol, extracting LBP with hot water, and removing free proteins with Sevag's method, and so on. Four LBP fractions, LBP1, LBP2, LBP3 and LBP4, were got by DEAE-Cellulose column with eluent of water, 0.05 mol/L, 0.1 mol/L, and 0.25 mol/L NaCl respectively. Five sub-fractions, including LBPla, LBP2a, LBPSa, LBP4a and LBP4b, were got from the corresponding LBP fractions by Sephadex G-200 column with water as eluent. All the sub-fractions are molecular weight (MW) homogeneous illustrated by the ways of SDS-gel electrophoresis, longer Sephadex G-200 column chromatography, and high performance gel permeation chromatography. They are all white cotton-like solids.MWs of LBPla, LBP2a, LBPSa, LBP4a and LBP4b are 32399, 77482, 38385, 3484 K 13224 respectively by SDS-gel electrophoresis. They are the acid giyco-protems composed of sugar, galacturnic acid, and amino acid. Their neutral monosaccharides contents are 89.6% x 69.3% v 56.2% , 38.6% and 4h3%. The monosaccharides identified by GC-MS are arabinose (Ara), galactose (Gal), glucose (Glu), mannose (Man), rhamnose (Rha), xylose (Xyt) and sorbitose (Sor), but LBP2a has no Sor, and LBP4b has a few amount of iditose (Idi). Some monosaccharides may be -D- glucose, a -D-mannose, and -D- gatactose according to their BR. spectra. The contents of galacturnic acid in them are 3.1%, 5.3%, 4.8%, 3.4% and 2.8%. The protein contents are 3.1%, 5.3%, 4.8%, 3.4% and 2.8%. There are 19 and 18 kinds of amino acid in LBP4a and LBP4b respectively. It suggested that there are -O-glycosidic linkages between sugars and amino acids in them according to the changes of UV absorption at 240 nm after -elimination reactions treated by 0.2 mol/L NaOH, and there are -O-Ser linkages in LBP4a and LBP4b by the amino acid content changes after the treatments of 0.2 mol/L NaOH-1 mol/L NaBH4. According to the spectra of 'HNMR and 13CNMR, LBP4a consists of -4 (- -D-GalpA (l- . The sub-fractions are new glycan-conjunctions. 2 Antioxidant effects of LBP 2. 1 Effects of LBP on free radicalsLBP has the scavenging effect on hydroxyl radical ( OH). The clearing activity from low to high are as LBPt > LBP3 > LBP4 > LBP2 > LBP I at the concentration of 200 g/mL of samples. The concentration of half OH scavenging rates (SC50) of LBP 1, LBP2, LBP3, LBP4 and LBPt are about 615 g/mL, 513 u g/mL, 186 u g/mL, 408 g/mL 18 P g/mL, respectively. SC50 of LBP4a is about 449 y g/mL.They show promoting or inhibiting effects on superoxide anion ( O2") generation in relation to their concentrations. At lower concentrations, O2~ production increased with LBP increasing to high concentrations, and then, O2~ production decreased. At higher concentrations, the O2" generations were inhibited. LBPt has the highest inhibiting activity, LBP1 is the lowest, and the others show little difference. 2.2 Antioxidant effects of LBP in vitroLBP1, LBP2, LBP3, LBP4, LBPt and LBP4a had the inhibiting effects on lipid peroxidation spontaneously or induced by OH with mice liver, brain, heart and kidney as the experimental materials in vitro. Their concentrations of half inhibition rates of malondialdehyde (MDA) in liver homogentes are 2760, 957, 1071, 2736, 649 and 3397 u g/mL at spontaneous condition, and 2445, 1409, 248...
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