Effect of Light Intensity on Flavonoid Contents of Common and Tartary Buckwheat Sprouts

Total polyphenol contents of common buckwheat (Fagopyrum esculentum) and tartary buckwheat (Fagopyrum tataricum Gaertn.) sprouts were measured. Total polyphenol contents of common and tartary buckwheat sprouts were elevated with increasing light intensity up to 315 mu mol/m(2)/s of photosynthetic photon flux density. HPLC analysis indicated that the major flavonoid constituents of common buckwheat sprouts were orientin, isoorientin, vitexin, isovitexin, and rutin. Rutin contents of common buckwheat sprouts were elevated with increasing light intensity, whereas the contents of the other flavonoids (orientin, isoorientin, vitexin, and isovitexin) were not. Rutin was the only major flavonoid constituent of tartary buckwheat sprouts. Moreover, rutin contents of tartary buckwheat sprouts were also elevated with increasing light intensity.