Identification of two stilbenoids from Vitis roots

Two oligostilbenes were isolated from roots of Vitis vinifera cv. Chardonnay and their structures were identified. One compound, ampelopsin A, is a dimer of resveratrol and has been found previously only in the roots of Ampelopsis brevipedunculata var. hancei (Vitaceae). The second, hopeaphenol, can be regarded as a dimer of ampelopsin A; its presence in Vitaceae is reported here for the first time. Both compounds are present in mg per g levels in vine roots.