Metabolic Profiling Analysis of Four Date Palm (Phoenix dactylifera L.) Cultivars from Saudi Arabia and Tunisia Using LC-MS and GC–MS Analysis

Abstract

Date palm (Phoenix dactylifera L.) is a fruit-bearing tree with numerous potential sustainable applications. Since ancient times, it has been considered a stable, secure, and sustainable food. This work provides comprehensive metabolic profiling of both parts, flesh and seed, of four P. dactylifera cultivars; Ajwa, Anbara, Sukkari, and Degelt Nour, which originated from two countries, Saudi Arabia, Tunisia. The analysis performed using mass spectrometry-untargeted metabolomics approaches, included a combination of LC-MS and GC-MS coupled to multivariate statistical analysis to reveal the differences in metabolite compositions among date varieties. The LC-MS seed results showed several classes of metabolites that belong to the flavonoids, phenolic acids, and amino acids derivatives, including citric acid, malic acid, lactic acid, hydroxyadipic acid, caffeic acid, which were at high concentrations in AJS followed by DNS and ARS. The LC-MS flesh analysis displayed that DNF had a high level of Isoquercitrin (flavonoid compound) and sinapic acid, and AJF was high concentrations level in hydroxyadipic acid and ascorbic acid. GC-MS concluded that seed samples of four date varieties are richer in metabolites classes than the flesh samples. The metabolites contributed to the seed metabolite compositions included several classes of amino acids, hydrocinnamic acids (caffeic, ferulic and sinapic acids), antioxidant phenolics, and long-chain fatty acids. The PCA and its loading analysis demonstrated the discriminating metabolites that were responsible for date varieties segregation, as HCA displayed the metabolic patterns and groups of metabolites that drive the clustering of the date samples, two groups of dates clustered together (AR and AJ) and (SR and DN). These clusterings are based on the similarities and differences observed in the metabolite compositions of the studied date samples that could be explained by differences in various metabolic responses and the environmental conditions, genotypes and geographical regions. This extensive date palm information would increase the potential of date fruits and seeds as low-cost sources of natural diet that may provide nutritious and bioactive components in the food and pharmaceutical fields to produce value-added products.