Total Synthesis and Neuritogenic Activity Evaluation of Ganglioside PNG-2A from the Starfish Protoreaster nodosus

Abstract

The total synthesis of ganglioside PNG-2A from the starfish Protoreaster nodosus and its neuritogenic activity toward neuron-like cells is described. The unique galactose-enriched glycan moiety, in which an 8-O-methyl sialic acid residue is sandwiched between galactose residues, was constructed through an efficient 8-O-methylation and subsequent di-tert-butylsilylene-assisted α-glycosylation at the 4-OH of the sialic acid residue with a Galfβ(1,3)Gal donor. In vitro biological evaluation in a rat adrenal pheochromocytoma (PC12) cell line revealed that the synthesized PNG-2A potentiated the neurite outgrowth of PC12 cells in the presence of nerve growth factor (NGF).