POLLEN-TUBE GROWTH-INHIBITORS FROM PIONE GRAPE PISTILS

The methanolic extract from the pistils of a tetraploid grape, cv. Pione (Vitis vinifera X V. labrusca), was fractionated by a cellulose column using eight eluents. The acetone and 50% MeOH eluates showed strong inhibitory activities toward grape pollen tube growth. After further separation of the acetone eluate by a Sephadex LH-20 column and ODS column chromatography, two major active principals, PGI-1 and PGI-3, were obtained as pure components. They were identified as quercetin glycosides by physicochemical analyses using UV and NMR spectrometers, though identity of the sugar moieties have not been established. These compounds completely blocked the pollen tube growth at 12.5 mu g/mL.