Supercritical extraction of volatile and fixed oils from Petroselinum crispum L. seeds: chemical composition and biological activity

The supercritical fluid extraction (SFE) of volatile and fixed oil from milled parsley (Petroselinum crispum L.) seeds, using CO2 as solvent, is presented in this study. Extraction experiments were carried out in two steps: at pressures of (90 or 300) bar and temperature of 40 °C. The first extraction step, performed at 90 bar, produced a volatile fraction mainly formed by apiole (82.1%) and myristicin (11.4%). The volatile oil yield was 2.6% by weight of the charge. The second extraction step, carried out at 300 bar produced a fixed oil at a yield of 0.4% by weight. The most represented fatty acids in P. crispum fixed oil were 18:1 n-12 (49.9%), 18:2 n-6 (18.2%), 18:1 n-9 (11.8%), and 16:0 (7.4%). In particular, the unsaturated fatty acids 18:1 n-12 and 18:1 n-9 averaged 182.2 mg/g and 92.1 mg/g of oil extract, respectively. The quality of the oils extracted by SFE, in terms of its chemical composition, was compared to the oils obtained by hydrodistillation (HD) in a Clevenger apparatus and by solvent extraction (SE) using n-hexane in a Soxhlet apparatus. The antioxidant properties were determined by means of the ABTS assay. The results indicated that the fixed oil possessed low antioxidant activity (EC50 = 0.4 mg/mL) and the volatile oil had no antioxidant activity. The total phenolic content, expressed as concentration of gallic acid (gallic acid equivalent, GAE), of the fixed oil was 1.5 mg/g. The fixed oil found to have inhibitory effects against α-glucosidase, the volatile oil is active on acetylcholinesterase (AChE), tyrosinase, and α-glucosidase. Both samples have weak inhibitory activity on α-amylase and no activity on butyrylcholinesterase (BChE).