Metabolites profiling of Ziziphus leaf taxa via UHPLC/PDA/ESI-MS in relation to their biological activities

Ziziphus plants are well recognized for their nutritive and medicinal value worldwide, albeit their chemical profile has yet to be fully reported. The secondary metabolites profile of three traditionally used Ziziphus leaf accessions was investigated via ultra-high performance liquid chromatography coupled to photodiode array and electrospray ionization mass detectors (UHPLC/PDA/ESI-MS). A total of 102 metabolites were characterized revealing the first holistic approach onto Ziziphus leaf metabolome and to include the first report of several novel flavonoids and cyclopeptide alkaloids. Fragmentation pattern for cyclopeptide alkaloids was proposed via ESI-MS. Principal component analysis (PCA) revealed close metabolite resemblance among Z. spina-christi and Z. mauritiana leaf specimens found enriched in saponins and distinct from that of Z. jujuba in which quercetin-3-O-(2-pentosyl)-rhamnoside was most abundant. Further, in-vitro antioxidant, anti-inflammatory and antidiabetic assays revealed for Z. spina-christi and Z. mauritiana strong effects compared to Z. jujuba and in correlation with their metabolites repertoire.