Two new oleanane-type glycosides from Napoleonaea imperialis P. Beauv RIND

Abstract

Napoleonaea imperialis P. Beauv (family Lecythidaceae) commonly called Napoleon’s hat is a medicinal plant found in South-Eastern Nigeria. The rind was separated from the fruit and macerated using methanol. The crude methanol extract was partitioned to yield n-hexane fraction (7.4%), dichloromethane fraction (23.7%) and methanol fraction (68.7%). The dichloromethane fraction was chromatographed and further purified to afford two compounds whose structures were elucidated using ¹H, ¹³C and two-dimension NMR experiments. Isolated compounds, Napoleonaside G and Napoleonaside R, were characterized as 3-O-[D-glucopyranosyl(1→2)-D-glucopyranosyl]-21,28-diangeloyloxy-24-hydroxy-olean-11,13(18)-diene and 3-O-[D-glucopyranosyl(1→4)-D-glucopyranosyl-2''-angeloyl]-21-angeloyloxy-24,28-dihydroxy-olean-11,13(18)-diene, respectively.