The Carbohydrate Moieties of Some Flabelliferins (Steroidal saponins) of Palmyrah Fruit Pulp

Abstract

The trifluoro acetic acid hydrolysed flabelliferins were silylated and analyzed by GCIEIIMS. 'H and llC-NMR. Methylation studies showed that the carbohydrate moiety of F; (M.W. 722) contained arhamnosyl residue linked a - 1.4 to a glucosyl residue. which is attached to ~-sitosterol. by a ~ anomeric linkage. Study of chemical shifts and coupling constants showed that glucose (glc) had a!3 anomeric configuration. Fa was a steroidal triglycoside (M.w. 868) with a rharnnosyl terminus. The carbohydrate moiety of the saponin showed the presence of a branched structure with two rharnnosyl residues linked a-1.2 and a-l,4 to a glucosyl residue, which is attached to the aglycone by a ~ glucoside linkage. Flabelliferin FF was shown to be a monoglucoside with a !3linked glucosyl residue. Anew triglycoside FN(MW 884) was shown to have a carbohydrate moiety of two glucosyl and one rhamnosyl residues with a glucosyl terminus, the second glucosyl residue was attached to (3-sitosterol. Another flabelliferin (FE)' which was isolated for the Firsttime, was adiglucoside ofMW. 738.