Lipophilic flavones of Primula veris L. from field cultivation and in vitro cultures

Ten lipophilic flavones were isolated from the leaves of Primula veris from field cultivation - the newly described 3 '-hydroxy-4 ',5 '-dimethoxyflavone and 3 '-methoxy-4 ',5 '-methylenedioxyflavone, the previously known from chemical synthesis 3 ',4 '-dimethoxyflavone, 2 ',5 '-dimethoxyflavone, and also flavone, 2 '-hydroxyflavone, 2 '-methoxyflavone, 3 '-methoxyflavone, 3 ',4 ',5 '-trimethoxyflavone and 5,6,2 ',6 '-tetramethoxyflavone (zapotin) which were previously known from plants. The same flavones were found in the leaves of P. veris obtained by in vitro propagation. The structural assignments were derived from H-1 NMR, C-13 NMR, EIMS and UV spectral data and the influence of B-ring oxygen substituents on the C-2, C-3 and H-3 NMR resonances in flavones unsubstituted in the A ring is taken into consideration. (c) 2005 Elsevier Ltd. All rights reserved.