Abstract:

Methanol, ethanol and acetone were used to extract total flavonoids from powder and husks of different cultivars of buckwhent (tartary buckwheat and common buckwheat), respectively. The yield, spectral characteristics and DPPH free radicalscavenging activities of extracted total flavonoids were compared. The results indicated that the extraction rate by acetone is the highest, followed that by alcohol and methanol in turn. Except that the yield of total flavonoids extracted from tartary buckwheat powder is 2.99% ± 0.13%, all the yields of total flavonoids extracted from sweet buckwheat powder, sweet buckwheat husk and tartary buckwheat husk are about 1.10%. Ultraviolet scanning spectra of methanol and alcohol extracts are alike, showing typical characteristics of flavonoids, but they are not similar to the spectrum of acetone extract. According to chemical reaction characteristics, it was inferred that: (1) tartary buckwheat powder may contain flavonols; (2) tartary buckwheat husk may contain flavones; (3) and sweet buckwheat powder and its husk may contain flavanones. DPPH free-radical scavenging effects of extracts from powder or husks of different cultivars of buckwheat with different solvents are alike. The DPPH free radical scavenging rates decrease in the following order: acetone＞alcohol＞methanol.

Key words: total flavonoids, extraction, spectral characteristic, DPPH free radical