Detection and Tissue Distribution of Anti-Ulcer Pectic Polysaccharides from Bupleurum falcatum by a Polyclonal Antibody

Abstract

Anti-sera against the “ramified” region (PG-1) of an anti-ulcer polysaccharide (bupleuran 2IIc), which was purified from the roots of Bupleurum falcatum L., were obtained by immunization of rabbits, and a polyclonal anti-bupleuran 2IIc/PG-1-antibody of the IgC class was purified by Protein G and “ramified” region (PG-1) immobilized affinity chromatographies. The antigenic specificity of anti-bupleuran 2IIc/PG-1-IgG was examined by a two-site sandwich ELISA which was developed as an improved method for microanalysis of bupleuran 2IIc using a biotinylated antibody. Another pectin from B. falcatum and anti-complementary pectins from Angelica acutiloba and Glycyrrhiza uralensis also showed significant reactivity to anti-bupleuran 2IIc/PG-1 -IgG, although these reactivities were lower than that of bupleuran 2IIc. Other polysaccharides tested such as apple pectin, araban, yeast mannan, pullulan, etc., had negligible reactivity. The KDO-containing region and oligogalacturonides, which were obtained by endo-α-(1→4)-polygalacturonase digestion of bupleuran 2IIc, were also not significantly recognized by anti-bupleuran 2IIc/PG-1-IgG. When bupleuran 2IIc was administrated to the mice i.v., the polysaccharide disappeared from the circulation within 24 h and was mainly detected in the liver by the two-site sandwich ELISA. However the clearance of bupleuran 2IIc from the circulation was delayed by pretreatment with iota-carrageenan. When the crude polysaccharide fraction (BR-2), containing mainly bupleurans 2IIb and 2IIc from B. falcatum, was administrated orally to the mice, the polysaccharides were detected in the liver and Peyer's patch.

Key words

Anti-ulcer pectic polysaccharide - Bupleurum falcatum L. - Apiaceae - polyclonal antibody - two-site sandwich ELISA