A rapid measurement of rutin-degrading enzyme activity in extract of tartary buckwheat seeds

In order to measure rutin-degrading enzyme activity conveniently, we have developed an isoabsorptive spectrophotometric method (ISM) for rapidly monitoring rutin-degrading enzyme (RDE) activity in extract of tartary buckwheat seeds. This technique uses discrepancy in absorbency at 372 nm and 344.5 nm, both of which are isoabsorptive wavelengths of rutin, that allow for calculations of quercetin concentrations, which is the only product of the reaction catalyzed by RDE. With this method, extracts containing RDE from buckwheat seeds were analyzed, and the measured data indicated that the sample contained quercetin concentration of 9.909 μg/ml, 8.04 times and 18.08 times greater than negative control (1.232 μg/ml) and positive control (0.548 μg/ml), respectively. ISM results of measuring rutin-degrading enzyme activity in tartary buckwheat seeds correlate with those of HPLC. However, it is beneficial to HPLC as it presents a more convenient and rapid method.