Detection and tissue distribution of anti-ulcer pectic polysaccharides from Bupleurum falcatum by polyclonal antibody.

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 IgG 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 acutilaba 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-alpha-(1-->4)-polygalacturonase digestion of bupleuran 2IIc, were also not significantly recognized by anti-bupleuran 2IIc/PG-1-IgG. When bupleuran 2IIc was administered 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.