Studies on the Constituents of Syringa Species. X. Five New Iridoid Glycosides from the Leaves of Syringa reticulata (BLUME) HARA

Abstract

Five new iridoid glycosides, (8Z)-ligstroside (1), (8Z)-nüzhenide (3), 6′-O-α-D-glucopyranosylsyringopicroside (4), 3′-O-β-D-glucopyranosylsyringopicroside (5) and 4′-O-β-D-glucopyranosylsyringopicroside (6) were isolated, together with a known one, (8E)-nüzhenide (2), from the leaves of Syringa reticulata. Their structures were established on the basis of chemical and spectral data. Compounds 1 and 3 are the first findings of a (8Z)-oleoside-type secoiridoid. Compound 4 is the first naturally occurring iridoid di-glycoside having an isomaltose.