Steroidal glycosides from the underground parts of Helleborus caucasicus.

Abstract Four polyhydroxylated and polyunsaturated furostanol glycosides ( 1 – 4 ), named caucasicosides A ( 1 ), B ( 2 ), C ( 3 ) and D ( 4 ), were isolated from the MeOH extract of the underground parts of Helleborus caucasicus , along with four spirostanol derivatives, a furostanol glycoside, a furospirostanol glycoside, 20-hydroxyecdysone and the bufadienolides hellebrigenin and deglucohellebrin. The structures of 1 – 4 were elucidated as furosta-5,20(22),25(27)-triene-1β,3β,11α,26-tetrol 26- O -β- d -glucopyranoside ( 1 ), 26- O -β- d -glucopyranosylfurosta-5,20(22),25(27)-triene-1β,3β,11α,26-tetrol 3- O -α- l -rhamnopyranosyl-(1→2)-β- d -glucopyranoside ( 2 ), 26- O -β- d -glucopyranosyl-22α-methoxyfurosta-5,25(27)-diene-1β,3β,11α,26-tetrol 3- O -α- l -rhamnopyranosyl-(1→2)-β- d -glucopyranoside ( 3 ), 26- O -β- d -glucopyranosylfurosta-5,20(22),25(27)-triene-1β,3β,26-triol 3- O -β- d -xylopyranosyl-(1 → 3)-α- l -rhamnopyranosyl-(1→2)-4- O -sulfo-α- l -arabinopyranoside ( 4 ). Structure elucidation was accomplished through the extensive use of 1D- and 2D NMR experiments including 1 H– 1 H (COSY, 1D-TOCSY) and 1 H– 13 C (HSQC, HMBC) spectroscopy along with ESI-MS and HR-ESI-MS. The aglycones of 1 – 4 have never been reported before.