Hydrolysis of flavanone glycosides and degradation of the corresponding aglycones from dried immature Citrus fruit by human fecal flora in vitro.

The hydrolysis of the flavanone glycosides contained in dried immature Citrus fruit, originating from Citrus aurantium L (Family Rutaceae), and degradation of their aglycones in human fecal flora have been analyzed. High-performance liquid chromatography was used to determine the flavanone glycosides and their corresponding aglycones in human fecal flora. The separation of compounds was performed with an ODS column by isocratic and stepwise gradient elution with 0.5 % (v/v) acetic acid-acetonitrile. As a result, the hydrolysis rate of hesperidin and narirutin (flavanone rutinoside) was faster than that of naringin and neohesperidin (flavanone neohesperioside). When the half-life time of each flavanone glycoside was carefully calculated (under the mixed conditions with the human fecal flora), hydrolysis of the flavanone rutinoside turned out to be approximately two times faster than of flavanone neohesperioside. The observed degradation rates of both aglycones was found not to be different. Therefore, it seems that the hydrolysis rate of flavanone glycosides in dried immature citrus fruit with human fecal flora is closely related to the steric hindrance of the sugar. This finding might be effectively used for further pharmacokinetics research on the flavanone glycosides of dried immature Citrus fruit.