Unveiling lipid and oxylipin composition in the coffee leaves throughout coffee cherry maturation

Abstract

This study investigates the evolution of lipids, oxylipins (phytoprostanes (PhytoPs) and phytofurans (PhytoFs)), and alkaloids in Mexican Coffea arabica leaves as coffee cherries mature. The impact of drying methods on leaf composition was also examined. Lipid extraction was performed using a binary MTBE/MeOH mixture. Fatty acid profiling was conducted by GC-FID. HPTLC was used to identify lipids (free fatty acids, acylglycerols, sterols, sterol esters, glycolipids, phospholipids, tocopherol), diterpenes (cafestol and kahweol), and alkaloids (caffeine and theobromine). A micro-HPLC-QTRAP analysis was used to identify and quantify oxylipins. The drying method influenced the leaves total lipid extraction. Freeze-dried leaves (HL) had higher lipid content than vacuum oven-dried leaves (HS). Total lipids decreased and oxylipin content varied with cherry maturity. The predominant fatty acid in coffee leaves was C18:3. This study reveals coffee leaves as a significant source of PhytoPs and PhytoFs for the first time.