Two New Steroidal Saponins from the Fresh Leaves of Agave sisalana

A new furostanol saponin, sisalasaponin C (1), and a new spirostanol saponin, sisalasaponin D (2), were isolated from the fresh leaves of Agave sisalana, along with three other known steroidal saponins and two stilbenes. Their structures were identified as (3β,5α,6α,22α,25R)-3,26-bis[(β-D-glucopyrano- syl)oxy]-22-hydroxyfurostan-6-yl β-D-glucopyranoside (1), (3β,5α,25R)-12-oxospirostan-3-yl 6-deoxy-α-L-mannopyranosyl-(14)-β-D-glucopyranosyl-(13)-[β-D-xylopyranosyl-(13)-β-D-glucopyranosyl-(12)]-β-D-glucopyranosyl-(14)-β-D-galactopyranoside (2), (3β,5α,6α,22α,25R)-22-methoxyfurostane-3,6,26-triyl tris-β-D-glucopyranoside, cantalasaponin-1, polianthoside D, (E)- and (Z)-2,3,4′,5-tetrahydroxystilbene 2-O-β-D-glucopyranosides. The last three known compounds were isolated from the fresh leaves of Agavaceae for the first time. The structures of the new compounds were elucidated by detailed spectroscopic analysis, including 1D- and 2D-NMR experiments, and chemical techniques.