Flavonoid Profiles of Wild Grapes Native to Japan: Vitis coignetiae Pulliat and Vitis ficifolia Bunge var. ganebu Hatusima
Flavonoids are a group of natural compounds in plants with versatile health benefits for humans. Grapes are a dietary source of flavonoids and the flavonoid components in grape berries can depend on the grape species and cultivar. In this experiment, proanthocyanidins, flavonols, and anthocyanins were analyzed in Vitis coignetiae and V. ficifolia var. ganebu, wild grapes native to Japan, and compared with those in V. labruscana cv. Muscat Bailey A, to evaluate the potential of the wild grapes as a grape resource. Proanthocyanidin contents in seeds were lower in the two wild grapes than in Muscat Bailey A. However, the skin of V. ficifolia var. ganebu was the richest source of proanthocyanidins. Flavonol levels in the skins of the two wild grapes were lower than that in the skin of Muscat Bailey A. Colorimetry determined that the total anthocyanin content in the skin of V. ficifolia var. ganebu was 6 times and 7 times higher, respectively, than those of V. coignetiae and Muscat Bailey A. Although monoglucoside anthocyanin levels analyzed by high-pressure liquid chromatography (HPLC) were in the order Muscat Bailey A > V. ficifolia var. ganebu > V. coignetiae, most of the diglucoside and acylated monoglucoside and diglucoside anthocyanin levels identified by HPLC-mass spectrometry were highest in V. ficifolia var. ganebu. These data suggest that V. ficifolia var. ganebu might be a novel source of flavonoids and superior to V. coignetiae as a source of flavonoids.