Preparation, Identification And Primary Anti-tumor Bioactivity Screening Of Polysaccharides From The Chinese Madecine-Sargassum Pallidum

Sargassum pallidum is used for Chinese traditional medicine for hundreds of years. It has been known to produce different polysaccharides, namely fucoidans, alginates and laminarans. Several biological activities have been attributed to the fucoidans: anticoagulant, antithrombotic, anti-inflammatory, antitumoral, antraceptive, and antiviral. Fucoidans (SPC60 (precipitated with 60% ethanol), SPC70, SPH60 and SPH70) were fractionated precipitation from the water extraction, the residue was extracted with Na2CO3 solution and produced SPA(alginate). The characteristic differences between SPC and SPH were investigated, and the results indicated that the different extraction and fractionation would produce different fucoidans. Crude fucoidans were purified and fractionated to polysaccharides (P3 and P4) by anion exchange column (Q-Sepharose Fast Flow) and chromatography column (Sephadex G-200 and Sepharose CL 6B). The differences between SPH70P3 and SPH70P4 were studied and revealed that crude fucoidan can separate into heterogeneous fucoidans. Total carbohydrates contents, HPGPC, Monosaccharides compositions, FT-IR, Methylation and Periodate oxidation analysis confirmed the characteristic of SPH70P4: contained 82.15% total carbohydrates, 16.38% sulfate, 3.42% uronic acid; molecular weight is 410 kD; carbohydrate compositions are Rha, Fuc, Xyl, Man, Glu and Gal, the molar ratio is 0.63:4.01:0.91:3.58:1.00:2.58; had absorbance at 840 cm"1 in IR; the linkage is: The fucoidan constituent is mainly composed of 1 →2,4 and 1 → 3-linked fucopyranosyl, 1 → 2,3,4 and 1 → 3,4,6-linked mannopyranose and 1 → 3,6-linked galactopyranose units, the glucopyranose is on the branches. The sulfation pattern with substitution principally at position 2 and/or position 3 of fucopyranosyl.We also studied the primary anti-tumor activities of these fucoidan segments by means of MTT, SPH70P4 had the best activities to the cancer cells (A549 and P388),but had not evident activities. The results proved that the activities of fucoidans have important connection with the sulphate content.