Abstract: In this paper, crude glycoprotein from black soybeans (designated HDJ) prepared by alkaline extraction and then alcohol precipitation was fractionated by column chromatography on DEAE-52 cellulose and Sephadex G-100 into two fractions, designated HDJS2 and HDJS5-2. Their chemical compositions were determined and their structures were characterized by spectroscopic methods. Their antioxidant activities were analyzed by reducing power, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging rate and total antioxidant capacity assays. Immunoregulatory activities were determined by the methyl thiazolyl tetrazolium (MTT) colorimetric method. The results showed that HDJS2 (3.20 × 104 Da) and HDJS5-2 (3.89 × 104 Da) were mainly composed of neutral carbohydrate and protein. The glycopeptide bond types were O-type. HDJS2 was mainly composed of mannose, glucose, galactose, arabinose and fucose together with 96.1% amino acids. HDJS5-2 was mainly composed of mannose, glucose, galactose and arabinose as well as 71.3% amino acids. HDJS2 and HDJS5-2 had antioxidant activity in a dose-dependent. In addition, both glycoproteins could promote splenocyte proliferation, suggesting that they had immunoregulatory effects.

Key words: black soybeans; glycoprotein; antioxidant activity; splenic cell proliferation