Abstract:

In the present study, we characterized the composition and structural attributes of two polysaccharide fractions (named MPL1 and MPL2) in mulberry leaves obtained after microwave-assisted extraction and Sephadex G50 purification. The HPGPC analysis showed that the weight-average molecular weights of MPL1 and MPL2 were 11800 D and 7630 D, respectively. According to the GC analysis, both polysaccharide fractions were composed of five monosaccharide, namely D-Flu, L-Ara, L-Rha, D-Xyl and D-Glu, and their molar ratio was 58 : 9.9 : 5.8 : 5.1 : 21.2 for MPL1 and 45 : 6.74 : 17.2 : 7.3 : 24.1 for MPL2. By using the classic methods of periodate oxidation and Smith Degradation reaction, both the backbones of MPL1 and MPL2 were found to consist of 1→3 glycosyl bonds and the side chains consisted of 1→2 glycosyl bonds. C－H absorption peak of α configuration was contained in both polysaccharide fractions according to the IR analysis.

Key words: mulberry leaf polysaccharides, HPGPC, characterization, link mode