Glycosylated constituents of Iris fulva and Iris brevicaulis

Abstract

The major constituents of leaf extracts of Iris fulva KER GAWL. comprised a known flavone C-glycoside, 5,4′-dihydroxy-7-methoxyflavone-6-C- (6‴-O-(E)-p-coumaroyl-β-glucopyranosyl)(1‴→2″) -β-glucopyranoside (1) and the new monoterpene glycoside, linalyl-6′-O-(3″-hydroxy-3″-methylglutaroyl) -β-D-glucopyranoside (2), both of which were prominent components of Iris brevicaulis RAF. leaf extracts. The structure of a new polyacylated sucrose derivative (3a) obtained from the rhizomes of I. fulva was elucidated as 3-O-(E)-p-coumaroyl-β-D-fructofuranosyl-( 2↔1′)-[2″, 4″,6″-tri-O-acetyl-β-D-glucopyranosyl-(1″→3′) -(2′,6′-di-O-acetyl-4″-O-(E)-p-coumaroyl-α- Dglucopyranoside)]. Selective hydrolysis of the 4″-O-acetyl moiety of the terminal b-glucopyranosyl residue of 3a occurred after several hours in solution giving 3-O-(E)-p-coumaroyl-β-D-fructofuranosyl-(2↔1′)- [2″,6″-di-Oacetyl-β-D-glucopyranosyl-(1″→3′) -(2′,6′-di-O-acetyl-4′-O-(E)-p-coumaroyl-α-D- glucopyranoside)] (3b), which subsequently underwent further deacetylation. © 2011 Pharmaceutical Society of Japan.