Metabolites profiling of date palm (Phoenix dactylifera L.) commercial by-products (pits and pollen) in relation to its antioxidant effect: a multiplex approach of MS and NMR metabolomics

Introduction Phoenix dactylifera L. (date palm) is one of the most valued crops worldwide for its economical and nutraceutical applications of its date fruit (pericarp). Currently date pits, considered as a waste product, is employed as coffee substitute post roasting. Whereas, pollen represents another valuable by-product used as a dietary supplement. Objectives In this study, a large-scale comparative metabolomics approach was performed for the first characterization and standardization of date palm by-products viz., date pits and pollen. Moreover, roasting impact on date pit metabolite composition was also assessed. Methods Metabolites profiling of pits and pollen was determined via a multiplex approach of UPLC-MS and NMR, coupled to multivariate analysis, in relation to its antioxidant activities. Results Chemical analyses led to the identification of 67 metabolites viz., phenolic acids, flavonols, fatty acids, sphingolipids, steroids and saponins of which 10 are first time to be reported. The enrichment of steroids in date pollen accounts for its fertility promoting properties, whereas date pit was found a rich source for antioxidant polyphenols using metabolomics.