Structure analysis of a heteropolysaccharide from fruits of Lycium barbarum L. and anti-angiogenic activity of its sulfated derivative

Angiogenesis plays a crucial role in tumor growth and development. Blocking angiogenesis of tumor cells has become one of the most promising approaches in cancer therapy. Here, an acidic polysaccharide designated LBP1B-S-2 with an average molecular weight of 80.00 kDa, was extracted and purified from dried mature fruits of Lycium barbarum L. by DEAE Sepharose™ Fast Flow and Sephacryl S-300 HR columns. Monosaccharide composition analysis indicated that the LBP1B-S-2 was composed of rhamnose, arabinose, galactose and glucuronic acid in a molar ratio of 3.13: 53.55: 39.37: 3.95. The backbone of LBP1B-S-2 was consisted of 1, 3-linked β-d-Galp, 1, 6-linked β-d-Galp and branches contained 1, 4-linked β-d-GlcpA, T-linked β-d-Galp, 1, 6-linked β-d-Galp, T-linked α-l-Araf, T-linked β-l-Araf, 1, 5-linked α-l-Araf and T-linked β-l-Rhap directly or indirectly attached to C-3 position of 1, 6-linked β-d-Galp or C-6 position of 1, 3-linked β-d-Galp, according to the results of partial acid hydrolysis analysis, methylation analysis, IR and NMR spectra. The sulfated derivative of LBP1B-S-2, could significantly inhibit the tube formation of human microvascular endothelial cells (HMEC-1) in vitro at concentration of (95 nM) without significant cytotoxicity.