Metabolite distribution and correlation studies of Ziziphus jujuba and Ziziphus nummularia using LC-ESI-MS/MS.

Ziziphus jujuba and Ziziphus nummularia are two important species of the genus Ziziphus. Both plants offer great commercial value and are consumed as food around the world and used for their medicinal values such as anti-inflammatory, antioxidant and hepatoprotective activities. Comprehensive chemical profiling of Z. jujuba and Z. nummularia was done through identification of major metabolites using HPLC-QTOF-MS/MS and quantification of eight analytes using HPLC-IonTrap-MS/MS analysis. A total of 53 compounds were identified from their high-resolution mass spectra in both positive and negative ionization modes. Among these, 52 compounds were found to be present in Z. jujuba, and 45 in Z. nummularia. Chemometric analysis was also performed to assess the distribution of identified compounds and to determine how the obtained data can be used to discriminate between the two species. Moreover, a method for the quantification of eight analytes including, 6″'-feruloylspinosin (1), apigenin (2), apigenin-7-O-glucoside (3), catechin (4), jujuboside A (5), jujuboside B (6), luteolin (7) and quercetin (8) was developed. The method expressed excellent accuracy with less than 3% error and good reproducibility with less than 4% RSD. The limit-of-detection (LOD) was also found to be very low ranging between 0.06 ng/mL to 4.10 ng/mL while limit-of-quantitation (LOQ) values were in the range of 0.17 ng/mL to 12.42 ng/mL. The analyte concentrations were found to be varying from 1.32 mg/kg to 645.76 mg/kg in both species. The developed method was used to identify and quantify marker compounds in fruit and whole plant samples of both species and in their herbal products as well. The present work is unprecedented, as there is no such extensive study targeting fruits, leaves and herbal formulations together using high-resolution techniques. The study will provide great utility in drug discovery, in taxonomical identification of these plants and to develop quality control protocols for their herbal formulations.