Allergy-suppressing Activity of Oligosaccharides in Sweet Potato-Shochu Distillery By-product

We obtained anti-allergic oligosaccharides from a sweet potato-shochu distillery by-product (SDB). Oral administration of oligosaccharides A and B in SDB to ovalbumin/aluminum-sensitized mice for 4 weeks resulted in a significant decrease in serum IgE concentration. The release of β-hexosaminidase from rat basophilic leukemia cell line RBL-2H3 was also suppressed by the addition of oligosaccharides A and B to the cell culture. The molecular weights of oligosaccharides A and B were about 730 and 530, respectively, determined from the retention time on Bio-Gel P-2. Oligosaccharide A was composed of galactose, glucose and uronic acid in a molar ratio of 2:1:1. Oligosaccharide B was composed of galactose, glucose and arabinose (1:1:1 molar ratio) or galactose, glucose and uronic acid (1:1:1 molar ratio), showing that oligosaccharide B is a heterogeneous mixture of other oligosaccharides. Oligosaccharides A and B exhibited growth-stimulating activity with Bifidobacterium lactis BB-12. The present results indicate that the oligosaccharides in SDB are promising ingredients for the effective control of allergic diseases via suppression of IgE production and inhibition of basophilic leukemia cells degranulation.