Purification, characterization and antiglycation activity of a novel polysaccharide from black currant.

A novel polysaccharide fraction (BCP-1) was extracted from the black currant fruit by ultrasound-assisted compound enzyme and purified by chromatography on macroporous resin D4006, anion-exchange Q-Sepharose FF and Sephadex G-100 columns. BCP-1 consisted of galacturonic acid, xylose, mannose, glucose and galactose in a ratio of 1.00:3.14:1.83:17.90:1.98 and its molecular weight was 14,050 Da. The preliminary structure features of BCP-1 were investigated by FT-IR and NMR. SEM and Congo red test showed that BCP-1 had honeycomb-like structure, but no triple helix structure. BCP-1 exhibited significant inhibitory abilities on protein glycation. Especially, BCP-1 showed obvious inhibitory effects on the formation of dicarbonyl compounds and AGEs (% inhibition of 66.95 ± 0.33% and 67.15 ± 0.40% respectively), but weaker inhibition Amadori compound production (max. 37.15 ± 0.36% inhibition). This suggested that the inhibitory action of BCP-1 on protein glycation was more effective on the later phases of dicarbonyl compounds and AGEs formation.

Optimisation of pressurised water extraction of polysaccharides from blackcurrant and its antioxidant activity.

Pressurised water extraction (PWE) of polysaccharides from blackcurrant fruits was investigated using a response surface methodology (RSM). The optimal conditions for PWE were: time 51min, pressure 1.6MPa, and temperature 52°C. Under these conditions, the experimental yield of Ribes nigrum L. polysaccharides (RNLP) was 11.68±0.12%, which closely agreed with the predicted value (11.77%). After preliminary purification with D4006 macroporous resin, RNLP I was obtained and its chemical characterisation was undertaken by GC, HPLC, and IR spectroscopy. RNLP I was composed of rhamnose, arabinose, xylose, mannose, galactose, and glucose with a molar ratio of 2.89:14.82:1.02:1.00:2.53:6.39 and its molecular weight was 1.49×10(4)kDa. The antioxidant activity of RNLP I was evaluated by free radical scavenging assays and a reducing power assay in vitro. RNLP I showed strong DPPH and superoxide radical scavenging activities and reducing power.