To extract and separate polysaccharide from Sophora tonkinensis Radix et Rhizoma (SRP), determine the monosaccharide composition and content of SRP, and investigate the antitumor effects of SRP in vitro.

SRP was prepared by water extraction and alcohol precipitation. The contents of polysaccharides, flavonoids, saponins, total phenols and proteins in SRP were determined by UV-Vis spectrophotometry, the contents of alkaloids were determined by high performance liquid chromatography (HPLC), and the content of organic acid was measured by back titration method. The monosaccharide analysis method of SRP was established by HPLC. A Waters X Bridge C₁₈ column (250 mm×4.6 mm,5 μm) was used with acetonitrile: phosphate buffer (0.05 mol·L^-1, pH=6.8) at the ration of 18∶82 as mobile phase, the flow rate was 0.8 mL·min^-1, the column temperature was 30 ℃, and the detection wavelength was 245 nm. The contents of monosaccharides in SRP were determined and the mole ratio was calculated. MTT assay was used to detect the antitumor effects of SRP in vitro.

SRP, which is brown powder, was obtained by water extraction and alcohol precipitation with a yield of 3.95%. The contents of polysaccharides, flavonoids, saponins, organic acids and total phenols in SRP were 66.08%, 7.17%, 3.45%, 2.54% and 4.33%, respectively. No alkaloids and proteins were detected. SRP was composed of mannose, rhamnose, glucuronic acid, galacturonic acid, glucose, galactose and arabinose. The mole ratios were 1.25∶0.31∶0.28∶0.50∶40.47∶1.00∶10.46, and the percentage of polysaccharide was 64.97%. SRP had inhibitory effect on Hepa1-6, HepG2, HT29 and 4T1 cells in a concentration-dependent manner with IC₅₀ of 770, 1 910, 1 870 and 1 880 μg·mL^-1, respectively.

The SRP prepared in this study contained more than 60% polysaccharide and more than 80% known components, among which no alkaloids were detected. HPLC with pre-column derivatization of 1-phenyl-3-methyl-5-pyrazolo has good precision, reproducibility and accuracy, and is suitable for the monosaccharide composion analysis of SRP polysaccharides. SRP is a kind of heteroglycan with glucose and arabinose as the main components. SRP has significant cytotoxic effect by inhibiting tumor cell proliferation, suggesting that it may play a anti-tumor role. This study provides a reference for advancing the basic research of the composition and antitumor effect of SRP.