Abstract
Quercetin, rutinose and an unknown product were produced through rutin degradation in the presence of ethanol by rutin-degrading enzymes (RDEs) I and II from tartary buckwheat (Fagopyrum tataricum Gaertner) seeds. The unknown product was identified as ethyl β-rutinoside by 13CNMR analysis. RDE I and II showed the highest activity in 15% (v/v) ethanol and at 50°C. Furthermore, under the conditions of 30% (v/v) ethanol and 1-2% rutin at 40°C, ethyl β-rutinoside was synthesized efficiently. Twenty-three grams of ethyl β-rutinoside was obtained from 50 g rutin upon the conditions. It was found that the addition of ethanol solution to tartary buckwheat flour was effective as a simple method of ethyl β-rutinoside synthesis. One hundred thirty-three milligrams of ethyl β-rutinoside was obtained from 20 g tartary buckwheat flour and 10 ml of 15% ethanol solution.
