The Structural Comparison Of Angelica Sinensis Polysaccharide Before And After The Synthesis Of APIC

Angelica polysaccharide (ASP) is the active composition of Angelica sinensis (oliv.) Diels. According to the listing iron supplement, Angelica polysaccharide iron complex (APIC) is synthesized. APIC is proved to have conspicuous dual hematonic effects by pharmacological experiments. The purpose of this paper is to determine the structures of ASP before and after the synthesis of APIC, find out the differences between these two parts, and refer theoretical evidence to molecular mechanism of APIC.PART I Extraction, purification, isolation and structural determination of ASP1 and ASP2Through some purification methods, pure ASP (to some extant) is obtained. Then ASP was eluted on Sephadex G-50 gel-filtration column and separated into ASP1 and ASP2, according to their different molecular weights.The molecular weight of ASP1 is 7.8×104, which was determined by high-performance gel-permeation chromatography; the result of hydrolysis showed that ASP1 is composed of arabinose, glucose, and galactose in the ratio of 1:5.68:3.91; Smith degradation indicated that 1→4 and 1→6 linkage are contained in ASP1; the result of methylation inferred that ASP1 has a liner structure with a backbone composed of glucose and galactose. IR spectrum showed that ASP1 consists ofα-type andβ-type glycosidic linkages without mannose; NMR spectra suggested that the following structures may be contained in ASP1:-α-Ara-(1→4)-β-Gala- / -β-Gala-(1→4)-α-Glu- / -α-Glu-(1→6)-β-Gala-The molecular weight of ASP2 is 1620 determined by gel-filtration column; the result of hydrolysis showed that ASP2 is composed of glucose; HIO4 oxidation-Smith degradation indicated that 1→4 linkage and 1→6 linkage are contained in ASP2; the result of methylation inferred that ASP2 has a liner structure with a backbone composed of glucose. IR spectrum showed that ASP2 consists ofα-type glycosidic linkage without mannose; NMR spectra suggested that the following structures may be contained in ASP2:-α-Glu-(1→6)-α-Glu-PART II Isolation, purification and structural determination of outer sheath polysaccharide from APICAPIC is composed of iron core and hydrophilic outer sheath polysaccharide chains. Covered with hydrophilic outer sheath polysaccharide chains, the iron core has polymeric iron core of FeOOH in its center, which is chelated with polysaccharide chains.APIC was eluted on Sephadex G-50 gel-filtration column and separated into the iron core and outer sheath polysaccharide (ASP3).The molecular weight of ASP3 is 1620 determined by gel-filtration column; the result of hydrolysis showed that ASP3 is composed of glucose; Smith degradation indicated that 1→4 linkage and 1→6 linkage are contained in ASP3; the result of methylation inferred that ASP3 has a liner structure with a backbone composed of glucose. IR spectrum showed that ASP3 consists ofα-type glycosidic linkage without mannose; NMR spectra suggested that there are three residues in ASP3.PART III The structural comparison of outer sheath polysaccharide in APIC and Angelica polysaccharidesThe molecular weight of ASP1 is about 7.8×104; The molecular weight of ASP2 and APS3 is about 1620.ASP1 is composed of arabinose, glucose, and galactose (1:5.68:3.91); both ASP2 and ASP3 are composed of glucose.ASP1 has a liner structure with a backbone composed of glucose; both ASP2 and ASP3 have a liner structure with a backbone composed of glucose.ASP1 consists ofα-type andβ-type glycosidic linkages without mannose; ASP2 and ASP3 consist ofα-type glycosidic linkages without mannose.Angelica polysaccharide consists of ASP1 and ASP2; After elution, APIC isseparated into iron core and outer sheath polysaccharide (ASP3). In the synthesis of APIC, ASP1 chelated with polymeric iron core to form stable iron core molecular. Meanwhile, ASP2 enveloped the iron core and composed the outer sheath polysaccharide.