Comparative analysis of composition and content of flavonoid metabolites in different tissues of Chinese jujube and sour jujube based on UPLC-ESI MS/MS metabolomics

Abstract

ABSTRACT There is much variation in the distributions of secondary metabolites, such as flavonoids, among plant tissues. The flavonoids in Chinese jujube (Ziziphus jujuba Mill.) and sour jujube (Ziziphus spinosa Hu.) provide various health benefits. Variation in the distributions of flavonoids among the tissues of jujube and sour jujube has not yet been characterized. A total of 101 flavonoid metabolites, including 30 flavones, 21 flavonols, 11 flavanones, 11 isoflavanones, 8 flavanonols, 7 chalcones, 4 flavanols, 3 flavone glycosides, 2 phenolic acids, 2 ×anthones and 2 unclassified flavonoids, were identified in the fruits, leaves, flowers and seeds of Z. jujuba cv. Dongzao (DZ) and Z. spinosa cv. Liyuanzhenzhu8 (LYZZ8) using UPLC-ESI MS/MS. Principal component analysis and hierarchical cluster analysis revealed that flavonoids from the same tissues of DZ and LYZZ8 were clustered, with the exception of those from the leaves. Tissue-specific flavonoid metabolites in different tissues of DZ and LYZZ8 were identified. The main flavonoids varied among tissues, the total flavonoid content and the content of most individual flavonoids in all tissues of DZ and LYZZ8 varied (p < .05). Furthermore, 40, 50, 49 and 47 differential flavonoid metabolites were detected in the fruits, leaves, flowers and seeds of DZ and LYZZ8, respectively. Potential chemical markers for differentiating among tissues in DZ and LYZZ8 as well as among the same tissues of DZ and LYZZ8 were identified. Overall, our findings provided new insights into the flavonoid of jujube and will aid the utilization of jujube and sour jujube.