Nupharanin, the first ellagitannin with 1,4-dehydrohexahydroxydiphenoyl-α-d-glucopyranose from Nuphar japonicum

Nupharanin (1), the first ellagitannin with dehydrohexahydroxydiphenoyl esters at the 1,4-positions of α-d-glucose, was isolated from the fresh rhizome of Nuphar japonicum. Based on spectroscopic evidence, the structure was determined to be 1,4-(S)-dehydrohexahydroxydiphenoyl-2-galloyl-3,6-(R)-hexahydroxydiphenoyl-α-d-glucopyranose. The structure was supported by spectroscopic studies of acetonyl derivatives of 1 and its partial hydrolysate. In...