Simultaneous qualitative and quantitative analysis of triterpenic acids, saponins and flavonoids in the leaves of two Ziziphus species by HPLC–PDA–MS/ELSD

The leaves of Ziziphus jujuba and Z. jujuba var. spinosa have been utilized as crude drugs for their health benefits in China for thousands of years. To control their quality, a reliable method based on high-performance liquid chromatography coupled with photo diode array and electrospray ionization tandem mass spectrometry detection (HPLC–PDA–ESI-MS/MS) was developed for exploration of the chemical profiles of these jujube leaves. As the results, fourteen constituents including three flavonoids, two saponins and nine triterpenic acids were identified or tentatively characterized. Then, twelve of them such as quercetin-3-O-rutinoside, zizyphus saponins I and II, ceanothic acid, alphitolic acid, maslinic acid, 2α-hydroxyursolic acid, zizyberanalic acid, epiceanothic acid, ceanothenic acid, betulinic acid, and oleanolic acid were selected as the chemical markers and were determined using an HPLC coupled with evaporative light scattering detection (ELSD) method. The separation was carried out on a Waters Sunfire C18 column with 0.2% acetic acid and acetonitrile as the mobile phase under gradient elution. The operating conditions of ELSD were set as 80 °C for drift tube temperature and 2.7 l/min for nitrogen flow rate. The developed method was fully validated in terms of linearity, sensitivity, precision, repeatability as well as recovery, and subsequently applied to evaluate the quality of eight batches of Z. jujuba and Z. jujuba var. spinosa leaves from different collections.