Preparation of Hybrid Aliphatic Derivatives Derived from Date Palm Waste in the Nile Delta: Synthesis, Characterization, and Biological Activity

Abstract

Three new hybrid aliphatic derivatives (HAD-1, HAD-2, HAD-3) were made from the fatty acid fractions extracted from the date palm (Phoenix dactylifera L.) waste biomass that was collected from the Nile Valley region of Egypt. The starting materials were subsequently modified to yield optimised products via Fischer esterification and selective hydroxyl and carbonyl group modification. Isolated yields were in the range of 78.3% to 88.6%, and HPLC purity was between 96.4% and 98.5%. The structural identity of all three compounds was confirmed by FTIR, ¹H and ¹³C NMR spectroscopy, ESI-MS and elemental analysis. Thermogravimetric analysis (TGA/DSC) demonstrated multiple stages of degradation with T₅% (onset) temperatures ranging from 272°C to 298°C, suggesting sufficient thermal stability to support their use as materials. The widest spectrum of antimicrobial activity was displayed by HAD-3, which demonstrated inhibition zones of 24.3 mm against Candida albicans and 22.5 mm against Staphylococcus aureus and had minimum inhibitory concentrations (MICs) for fungal strains as low as 8 μg/mL. Antioxidant evaluations via DPPH, ABTS, FRAP, and metal chelation assays demonstrated concentration-dependent radical scavenging capabilities across all three derivatives, and HAD-3 had a DPPH IC₅₀ of 22.7 μg/mL, which was comparable to the IC₅₀ for ascorbic acid (18.4 μg/mL). Scanning electron microscopy (SEM) displayed progressive crystal ordering through the series from HAD-1 to HAD-3. Collectively, these findings demonstrate the potential for date palm agricultural waste products from the Nile Valley to function as renewable feedstocks of structurally defined bioactive aliphatic compounds within a framework of a circular bio-economy.