Steroidal saponins from a cultivated form of Agave sisalana

Three new steroidal saponins, dongnosides C-E, were isolated from the methanol extracts of the fermented residues of leave-juices of Agave sisalana form Dong No 1. On the basis of chemical and spectral evidence, the structures of dongnosides E, D and C were determined as tigogenin-3-O-β-d-xylopyranosyl(1→2)[β-d-glucopyranosyl(1→3)]β-d-glucopyranosyl(1→4)β-d-galactopyranoside, tigogenin-3-O-β-d-xylopyranosyl(1→3)β-d-xylopyranosyl(1→2)[β-d-glucopyranosyl (1→3)β-d-glucopyranosyl(1→4)β-d-galactopyranoside and tigogenin-3-O-α-l-rhamnopyranosyl (1→4)β-d-xylopyranosyl(1→2)[β-d-glucopyranosyl (1→3)]β-d-glucopyranosyl(1→4)β-d-galactopyranoside, respectively.