Supercritical extraction from Rosa canina L. fruits: fatty acids composition and biological activities

The supercritical fluid extraction from pulp of Rosa canina L. fruits, using CO(2 )as a solvent, is presented in this study. The extraction experiment was carried out at pressures of 300 bar and a temperature of 40 degrees C, SFE[300:40]. The extract yield was 0.3% for the weight of the charge. The extraction and saponification processes produced a fraction mainly formed by free fatty acids, FA, determined by HPLC-DAD and GC-FID analyses. Pulp extract was characterised by a high level of linolenic acid, 18:3 n-3, (28.37% of total FA); linoleic acid, 18:2 n-6, (26.74%); palmitic acid, 16:0, (18.20%); and oleic acid, 18:1 n-9, (15.74%). Followed by low amounts of stearic acid, 18:0, palmitoleic acid, 16:1 n-7, lauric acid, 12:0, and myristic acid, 14:0. The amounts of the main unsaturated fatty acids, UFA, in SFE[300:40], determined by HPLC analysis, were 121.43 +/- 3.21 mg/g, 102.16 +/- 2.84 mg/g, and 49.95 +/- 2.75 mg/g of extract for 18:3 n-3, 18:2 n-6 and 18:1 n-9, respectively. Interestingly, the sample was characterised by a high proportion of polyunsaturated fatty acids, PUFA, and the ratio value of UFA to SFA, saturated fatty acids, was 2.8. The quality of the SFE[300:40] extract, in terms of its chemical composition, was compared with that obtained using n-hexane in a Soxhlet apparatus, Sx. The sample obtained by solvent extraction showed a chemical profile similar to the one obtained by means of SFE but without the added benefit of not having unwanted traces of solvent. The extracts were evaluated for antioxidant properties, polyphenol content, and inhibitory activity on the xanthine oxidase (XO) enzyme. The antioxidant properties were determined with ABTS assay. The results indicated that the SFE[300:40] extract had low antioxidant activity (EC50 = 0.241 +/- 0.022 mg/mL) and the Sx extract had no antioxidant activity. The total phenolics of SFE[300:40] extract was 17.7 mg GAE/g of weight. Both extracts showed a very low inhibition activity towards the XO enzyme.