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 3 beta, 12 beta, 20S-trihydroxy-25-methoxydammar-23-ene 3-O-([beta-D-glucopyranosyl(1 -> 2)-beta-D-glucopyranosyl]-20-O-[alpha-L-arabinopyranosyl(1 -> 6)]-beta-D-glucopyranoside (1) and 3 beta, 20S-dihydroxy-12 beta, 23R-epoxydammar-24-ene 3-O-{[beta-D-glucopyranosyl(1 -> 2)-beta-D-glucopyranosyl]-20-O-[beta-D-xylopyanosyl(1 -> 6)]-beta-D-glucopyranoside (2)on the basis of (1)D and (2)D NMR (including (1)H, (13)C-NMR, (1)H-(1)H COSY, HSQC,TOCSY, HMBC,and NOESY), ESI-MS spectrometry and chemical methods. Copyright (C) 2008 John Wiley & Sons, Ltd.