Radical scavenging activity of raspberry (Rubus idaeus L.) fruit extracts

Thirty-one raspberry (Rubus idaeus L.) plants were collected in different natural habitats of Lithuania located in 17 districts and replanted in the experimental field. The fruits from different accessions were extracted with ethanol and the extracts were tested for their antioxidant activity (AA) by using ABTS·+ radical cation decolourisation and DPPH·radical scavenging methods. All tested raspberry fruit extracts were antioxidatively active; their radical scavenging capacity at the applied concentrations varied from 52.9 to 92.6% in DPPH·reaction system and from 52.5 to 97.8% in ABTS·+system. The total amount of phenolic compounds in fruits varied from 5.6 to 13.7 mg of gallic acid equivalents in 1 g of plant extract. However, strong correlation between the radical scavenging capacity and the total amount of phenolic compounds in the fruit extracts was not observed, which indicates remarkable differences in the composition and antioxidant power of phenolic compounds present in the fruits harvested from raspberry accessions collected from different natural habitats. Most likely, environmental conditions and genetic factors should play an important role for the accumulation of active compounds in raspberry fruits