Development of a High-Performance Liquid Chromatography Method to Determine the Fagopyrin Content of Tartary Buckwheat (Fagopyrum tartaricum Gaertn.) and Common Buckwheat (F. esculentum Moench)

AbstractBuckwheat contains fagopyrin, which induces photosensitization in light-skinned livestock when exposed to sunlight. Here, we developed a high-performance liquid chromatography (HPLC) method to measure the fagopyrin content of buckwheat. The HPLC profile of the fagopyrin extract purified from Tartary buckwheat ‘Rotundatum’ had 3 apparent peaks. The ultraviolet-visible (UV-vis) absorption spectrum of each peak yielded absorbance maxima ( λmax) at 547 nm and 591 nm, indicating that these peaks corresponded to fagopyrin and unidentified fagopyrin derivatives. We considered the total content reflected by the 3 peaks to be the fagopyrin content of buckwheat. We determined the fagopyrin content in the leaves of Tartary buckwheat ‘Rotundatum’ and common buckwheat ‘Miyazakiootsubu’ both by UV-vis photometric analysis and the newly developed HPLC method. The fagopyrin content is overestimated by UV-vis photometry because the extracts contain a considerable amount of chlorophyll. Thus, HPLC analysis is more ...