Protogenkwanin 4′-glucoside,a new type of natural flavonoid with a non aromatic B-ring

From fertile sprouts of $\text{Equisetum arvense}$ L. (Equisetaceae) a flavonoid has been isolated and called protogenkwanin 4′-glucoside (2-(4-β-D-glucosyloxy-1-hydroxy-2,5-cyclohexadienyl)-5-hydroxy-7-methoxy chromone). Its structure has been established on the basis of chemical and spectroscopical evidences.