Fagopyrins in different parts of common buckwheat (Fagopyrum esculentum) and Tartary buckwheat (F. tataricum) during growth

Fagopyrins, anthraquinone derivatives present in buckwheat, are structurally similar to hypericin. The objective of this study was to determine changes of fagopyrins in flowers, leaves, and stems of common buckwheat (Fagopyrum esculentum; CB) and Tartary buckwheat (F. tataricum; TB) during growth. Flowers, leaves, and stems of buckwheats were collected until the 50th day after sowing (DAS) at intervals of 5 days. Fagopyrins were analyzed by HPLC-FLD and HPLC-ESI-MS/MS. Buckwheat flowers contained significantly higher fagopyrins than the other parts. Fagopyrins in TB flowers were significantly higher than in CB flowers. Concentration of fagopyrins in the flowers gradually decreased until the 50th DAS. Fagopyrin F was the major form of fagopyrins in buckwheats, accounting for 68–79 % in CB and 81–94 % in TB with TB flowers the highest (93–94 %). This study was the first in analyzing contents of fagopyrin F and fagopyrins in different parts of buckwheats during growth.