Abstract: A homogeneous polysaccharide (BCP) from black currant fruits was obtained by ultrasound-assisted extraction followed by successive purification using macroporous resin D4006, anion-exchange Q-Sepharose FF and Sephadex G-100 columns. The molecular weight of BCP was determined as 16 329 kD by HPLC. BCP consisted of galacturonic acid, rhamnose, arabinose, xylose, mannose, glucose, and galactose at a molar ratio of 0.31:0.66:1.63:0.36:0.23:0.31:1.00 as determined by gas chromatography (GC). Fourier transform infrared (FTIR) spectra revealed that BCP had the characteristic absorption peaks of polysaccharides. Qualitative tests and UV spectra indicated the absence of protein, nucleic acid, starch, and pigment. Congo red test showed that BCP lacked triple helix structure. In the concentration range of 0.2–1.2 mg/mL, BCP presented high scavenging activities toward 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH), hydroxyl, superoxide anion radicals in a concentration-dependent manner. BCP exhibited a significant ability to inhibit the formation of glycation products at three stages which was in a concentration-dependent manner and higher than that of the control aminoguanidine. Moreover, BCP showed inhibitory activity against α-amylase lower than that of the control acarbose.

Key words: black currant fruit, polysaccharides, extraction and separation, structure characterization, biological activities