New oligosaccharides prepared by acid hydrolysis of the polysaccharides from Nerium indicum Mill and their anti-angiogenesis activities.

To discover drug candidates with anti-angiogenesis activity for cancer therapeutics, three galactooligosaccharides (OJ1-OJ3) were prepared by acid hydrolysis of the polysaccharides from Nerium indicum Mill. Their structures were characterized using sugar analysis, methylation analysis, and both 1D and 2D NMR spectroscopy, complemented by mass spectrometry. They were hexasaccharide (OJ1), a pentasaccharide (OJ2), and an undecasaccharide (OJ3), which was a new linear galactan. Bioactivity testing in vitro showed that OJ2 and OJ3 significantly inhibited the HMEC-1 (human microvascular endothelial cell) cell tube formation.