Structural analysis of a homogeneous polysaccharide from Achatina fulica

- A water-soluble polysaccharide (AF-1) was isolated and purified from Achatina fulica.
- Structural of the polysaccharide was analyzed and characterized by chemical and instrumental methods.
- AF-1 is an α-(1 → 4)-D-glucan branched with a single α-D-glucose at C-6 at every five main-chain units on average.

Edible snails have been widely used as a health food and medicine in many countries. In our study, a water-soluble polysaccharide (AF-1) was isolated and purified from Achatina fulica by papain enzymolysis, alcohol precipitation and strong anion exchange chromatography. Structureof the polysaccharide was analyzed and characterized by chemical and instrumental methods, such as Fourier transform infrared spectroscopy, high performance liquid chromatography, analysis of monosaccharide composition, methylation analysis, and nuclear magnetic resonance (NMR) spectroscopy (1H, 13C, COSY, TOCSY, NOESY, HSQC and HMBC). Chemical composition analysis indicated that AF-1 is composed of glucose (Glc) and its average molecular weight is 1710 kDa. Structural analysis suggested that AF-1 is mainly consisted of a linear repeating backbone of (1 → 4) linked α-d-Glc p residues with one branch, α-d-Glc p, attached to the main chain by (1 → 6) glycosidic bonds at every five main-chain units. Further studies on biological activities of the polysaccharide are currently in progress.