DETERMINATION OF PHENOLIC CONTENT AND ANTIOXIDANT ACTIVITY OF ROSA CANINA L. FRUITS IN DIFFERENT EXTRACTION SYSTEMS
UDK: 582.711.71:547.56 Phenolic content and antioxidant activity of Rosa canina fruit extracts obtained with five different extraction systems were investigated. Extractions were done with water, and aqueous 50% methanol, 50% ethanol, 80% methanol and 80% ethanol. Antioxidant activity was investigated with DPPH, ABTS and FRAP methods using Trolox as a standard. The highest level of phenols (78.83 mg GAE/g), phenolic acids (11.21 mg CAE/g), and proanthocyanidins (29.12 mg CE/g) were found for 50% methanol extract. The highest flavonoid content (1.163 mg RE/g and 0.675 mg QE/g) was determined for 50% ethanol extracts and antocyanin content (0.139 mg CGE/g) for 80% methanol extract. The lowest level of phenols (35.89 mg GAE/g), phenolic acids (4.55 mg CAE/g) and proanthocyanidins (11.93 mg CE/g) had 80% ethanol extract. Flavonoid content (0.341 mg RE/g and 0.214 mg QE/g) was the lowest in water extract and anthocyanidin content (11.93 mg CE/g) in 50% ethanol extract. Antioxidant activity for DPPH was in a range 255.62-407.82 µmol TE/g, for ABTS 312.06-616.10 µmol TE/g and for FRAP 349.33-690.37 µmol TE/g with lowest values for 80% ethanol extract and highest values for 50% methanol extract. Phenols and proanthocyanidins showed high positive correlation with antioxidant activity for DPPH (r2 =0.927-0.9621), ABTS (r2 =0.980-0.9935) and FRAP (r2 =0.9352-0.9633). No correlation was observed for flavonoid and anthocyanidin content with antioxidant activity.