98. Structure Elucidation of Two Triterpenoid Saponins from Leaves of Schima superba Gardn. et Champ

Two new oleanane-type triterpenoid saponins with two angeloyls at C-21, C-22, and a branch of tetrasaccharide moiety (Rha, Cal, Glc, GlcA, or Rha, Xyl, Glc, GlcA) at C-3 were isolated from leaves of Schima superba Gardn. et Champ. Their structures were established using one- and two-dimensional NMR and high resolution electrospray ionization mass spectrometry as 21,22-di-O-angeloyl-R₁-barrigenol-3-O–{β-d-glucopyranosyl-(1→2)-β-d-galactopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→4)]}-β-d-glucuronopyranoside, named schimasuoside A(1), 21,22-di-O-angeloyl-R₁-barrigenol-3-O-{β-d–glucopyranosyl-(1→2)-β-d–xylopyranosyl-(1→2)-[α-l-rhamnopyranosyl-(1→4)]}-β-d-glucuronopyranoside, named schimasuoside B (2). There are strong antifungal effect of their mixture on Magnaporthe oryzae.