GC/MS of terpenes in walnut‐tree leaves after accelerated solvent extraction

Terpenes, e. g. (+)-alpha-pinene, (-)-camphene, (-)-(-pinene, myrcene, R-(+)-limonene, eucalyptol, (+/-)-linalool, (-)-bornyl acetate, (-)-trans-caryophyllene, and alpha-humulene were determined in leaves of walnut trees from the Juglandaceae family (walnut tree, royal (J. regia L.), black (J. nigra L.), and Siebold (J. sieboldiana, var. Cordiformis Lam.) using gas chromatography with mass spectrometric detection. Terpenes were repeatedly (3 cycles, 5 min each) extracted from leaves of walnut trees by accelerated (pressurized) solvent extraction (ASE) 150 bar and 120 degrees C. The efficiency of ASE extraction was superior to that of steam distillation, solvent extraction according to Soxhlet, sonication, and extraction by agitation. Differences in relative concentrations and distribution of terpenes were studied in dependence on the species of walnut tree and on different locations.