Three new oligostilbenes from the seeds of Paeonia suffruticosa

Three new oligostilbenes, trans-suffruticosol D (1), cis-suffruticosol D (2), and cis-gnetin H (7), were isolated along with the eight known stilbenes, trans-resveratrol (3), trans-epsilon-viniferin (4), cis-epsilon-viniferin (5), gnetin H (6), suffruticosol A (8), suffruticosol B (9), suffruticosol C (10), and cis-ampelopsin E (11) from the seeds of Paeonia suffruticosa. Compounds 3-6 were isolated for the first time from this plant species, and compound 11 was isolated for the first time from the genus Paeonia. The structures of the new compounds were elucidated based on spectral analyses, including 1D and 2D NMR experiments. The absolute configuration of compound 1 was determined by quantum chemical calculation of the electronic circular dichroism and comparison with the experimental circular dichroism spectrum.