Phytochemical analysis of Ziziphus jujuba leaves in six cultivars at the whole life stage by high performance liquid chromatography

Leaves of Ziziphus jujuba Mill.( Z. jujuba ) were used as a folk medicine to treat children suffering from typhoid fever, furuncle and ecthyma in China. The present study was to establish a high performance liquid chromatography-diode array detector(HPLC-DAD) method for quality control of Z. jujuba leaves. The validated method was applied to the simultaneous characterization and quantification of sixteen main constituents in thirty samples, which comprised the whole life stage of Z. jujuba leaves from six cultivars in Yulin, Shannxi Province, China. HPLC fingerprint file of Z. jujuba leaves was set up and the results indicate that the major constituents of Z. jujuba leaves are (‒)-catechin( 1 ), quercetin-3- O -robinobioside( 3 ), rutin( 4 ) and quercetin-3- O - α - L -arabinosyl-(1→2)- α - L -rhamnoside( 6 ) with the total contents of the nine flavonoids in respective batch ranging from 18.52 mg/g to 39.51 mg/g. In addition, the contents of compounds depend on both the season and the cultivar. During ripening of Z. jujuba leaves, flavo- noids of all the cultivars present a similar trend: initially decrease from 25th, Jun. to 5th, Aug., 2015, and then increase for a period of time, finally slightly fluctuate on 5th Oct. The highest contents of total flavonoids were registered on 25th Jun., 2015. Different cultivars have 50%―90% variation on the content for the three classes of compounds. Taken together, the results demonstrate that Z. jujuba leaves have great potential to be a new health-promoting resource based on flavonoids and the best sampling time of them is in June.