Abstract
Background: Ziziphus jujuba Mill. var. spinosa (Bunge) Hu ex H. F. Chow. (ZS) is a valuable plant with diverse economic applications, as all its organs contain bioactive secondary metabolites. The seeds, known as Suanzaoren in traditional Chinese medicine, are utilized as both a medicinal and edible resource, while the fruit pulp and leaves serve as significant raw materials in the food industry. Increasing market demand for Suanzaoren has led to expanded cultivation, though current production practices emphasize seed utilization, resulting in the underutilization of pulp and leaf tissues. In agricultural systems, developing elite varieties is an effective strategy for enhancing crop yield and quality. Breeding initiatives should establish specific objectives aligned with particular end uses, such as seed, pulp, or leaf production. Germplasm serves as the foundational material for breeding programs, so its selection must correspond to intended applications. Evaluating existing germplasm resources based on chemical composition profiles will provide a basis for developing improved ZS varieties. Objective: This study aimed to systematically compare the characteristic chemical composition in the seeds, pulp, and leaves of ZS. By quantifying key chemical components-such as flavonoid glycosides and saponins in seeds, organic acids and phenolic compounds in pulp, and flavonol glycosides and phenolic acids in leaves-we evaluated the quality of ZS germplasm resources. The resulting compositional profiles provide a concrete basis for selecting and breeding elite cultivars tailored to specific end uses, including seed, pulp, or leaf production. Methods: Chemical characterization was performed using ultra-high-performance liquid chromatography coupled with hybrid quadrupole-orbitrap mass spectrometry (UPLC-Q-Exactive Orbitrap MS/MS). Quantitative analysis of chemical composition was conducted using high-performance liquid chromatography with evaporative light scattering detection (HPLC-ELSD). Multivariate statistical analyses-including principal component analysis (PCA), orthogonal partial least squares discriminant analysis (OPLS-DA), and entropy-weighted technique for order preference by similarity to an ideal solution (entropy-weighted TOPSIS)(EWT)-were employed for comprehensive data evaluation. Results: A comprehensive phytochemical analysis of Ziziphi spinosae (ZS) was conducted, identifying 144 distinct compounds across the seeds, pulp, and leaves. Of these, 114 were found in the seeds, 84 in the leaves, and 79 in the pulp. The seeds were particularly rich in flavonoid glycosides, such as spinosin and 6‴-feruloylspinosin, as well as saponins like jujuboside A and B. The pulp was dominated by organic acids, including citric acid, and phenolic compounds, while the leaves were abundant in flavonol glycosides, including rutin, and phenolic acids such as isochlorogenic acid B. Based on the chemical composition profiles, the ZS germplasms were evaluated for specific applications. ZS24, ZS22, and ZS3 were identified as the most suitable for seed production, ZS3, ZS6, and ZS9 for pulp utilization, and ZS20, ZS3, and ZS18 for leaf-based applications. With respect to the integrated utilization of multiple plant parts (roots, stems, and leaves), ZS6, ZS3, and ZS24 demonstrated the highest potential. Conclusions: The identification of superior germplasm resources provides strategic direction for the breeding of elite ZS cultivars. These findings will enable the comprehensive utilization of ZS plant resources and support the high-quality development of related industries.