Stilbenes in and .

Stilbenes in the roots of and were studied. Root samples were extracted with 100% methanol and analyzed by HPLC and LC-MS. In this way, -resveratrol dimers (/ 455 Da [M + H]), trimers (/ 681 Da [M + H]) and tetramers (/ 907 Da [M + H]) were identified in the extracts. Using LC-NMR in stop-flow mode, pallidol and -ε-viniferin as dimers were identified. After the separation of individual peaks and their measurement by H NMR, and -miyabenol A as a tetramer and -miyabenol C as a trimer were identified. In the case of miyabenol A, it is a chromatographically inseparable mixture of and isomers in the ratio of 2:3 according to H NMR measurement. In the case of -miyabenol C, the -miyabenol C configuration was confirmed. The remaining unidentified peak with a practically identical UV-VIS spectrum to that of -miyabenol C is most likely another isomer of miyabenol C.