Rutin and flavonoid contents in three buckwheat species Fagopyrum esculentum, F-tataricum, and F-homotropicum and their protective effects against lipid peroxidation

This study was conducted to investigate the rutin content of three buckwheat species: Fagopyrum esculentum, Fagopyrum tataricum and Fagopyrum homotropicum, and to evaluate their antioxidant capacity. In total, 11 cultivars/accessions were analyzed. The contents of both rutin and total flavonoids were significantly different depending on species, 0.02% and 0.04% in F esculentum, 0.10% and 0.35% in F homotropicum, and 1.67% and 2.04% in F tataricum, respectively. Three buckwheat species exhibited a dose-response effect in inhibiting low-density lipoprotein (LDL) peroxidation. The antioxidant activity decreased in the order: F tataricum > F homotropieum > F esculentum. Linear regression analysis revealed a correlation between antioxidant activity and rutin content (R-2 = 0.98) or total flavonoids content (R-2 = 0.77) in all buckwheat cultivars/accessions. This work shows that rutin plays an important role in antioxidant activity of buckwheat seed. It provides useful information for buckwheat breeding to develop high rutin content varieties. (c) 2006 Elsevier Ltd. All rights reserved.