Structure elucidation and complete NMR spectral assignments of two new dammarane-type tetraglycosides from Panax quinquefolium

Two new saponins were isolated from leaves of Panax quinquefolium and their structures were elucidated as 3β, 12β, 20S‐trihydroxy‐25‐methoxydammar‐23‐ene 3‐O‐{[β‐D‐glucopyranosyl(1→2)‐β‐D‐glucopyranosyl]‐20‐O‐[α‐L‐arabinopyranosyl(1→6)]‐β‐D‐glucopyranoside (1) and 3β, 20S‐dihydroxy‐12β, 23R‐epoxydammar‐24‐ene 3‐O‐{[β‐D‐glucopyranosyl(1→2)‐β‐D‐glucopyranosyl]‐20‐O‐[β‐D‐xylopyanosyl(1→6)]‐β‐D‐glucopyranoside (2) on the basis of 1D and 2D NMR (including 1H, 13C‐NMR, 1H1H COSY, HSQC, TOCSY, HMBC, and NOESY), ESI‐MS spectrometry and chemical methods. Copyright © 2008 John Wiley & Sons, Ltd.