Study on the constituents of flavonoid aglycones in the leaves of Sophora japonica f. pendula.

Objective To develop a method of RP-HPLC for determination of three kinds of flavnoid aglycones,quercitin,kaempferol,and isorhamnetin simultanenously and to discover changes of them in the leaves of Sophora japonica f. pendula. in different growth periods.Methods The leaves of Sophora japonica f. pendula. were collected at different time point.Flavonoids in the leaves were extracted by successive extraction with methanol. The extracts were acid-hydrolyzed before being tested with RP-HPLC.Results The constituent of flavnoid aglycones in the leaves of Sophora japonica f. pendula. was quite similar to that in ginkgo leaves,but the content of them in the former was much higher than that in the latter. Among three flavonoid aglycones determined,the content of quercitin was the highest and that of isorhamnetin was the lowest. The contents of these flavonoid aglycones reached maximum in the months of April and May and declined gradually later.Conclusion The leaf of Sophora japonica f.pendula.has aboundant of flavonoids in the leaves of Sophora japonica f. pendula. The contents of them change along with the growth periods. April and May should be the optimal collecting time of leaves of Sophora japonica f. pendula. for extraction of flavonoids.