Structural analysis of water-soluble glucans from the root of Angelica sinensis (Oliv.) Diels

Two water-soluble glucans (designated APS-1cI and APS-1cII) were extracted from the roots of Angelica sinensis (Oliv.) Diels and further purified by anion-exchange and gel-filtration chromatography. Their molecular weights were determined to be 1.7 x 10(5) and 3.9 x 10(4) Da, respectively. The structures of the purified glucans were investigated by a combination of chemical and instrumental analysis, such as methylation analysis, periodate oxidation, GC-MS, as well as FTIR and NMR spectroscopy (H-1, C-13, H-H COSY, HSQC, HMBC, TOCSY and NOESY). The data obtained indicated that APS-1cI was a linear alpha-glucan composed of only (1 -> 6)-alpha-D-G1cp, and APS-1cII had a repeating unit consisting of (1 -> 4)-alpha-D-Glcp and (1 -> 6)-alpha-D-Glcp in a molar ratio of 4:1. Such glucans isolated from A. sinensis (Oliv.) Diets have not been previously reported. (c) 2006 Published by Elsevier Ltd.