Determination of antioxidant activities in raw and boiled extractions of raphanus raphanistrum L. species naturally growing in Edremit Gulf (Balikesir/Turkey)

Abstract

The plants that naturally spread in Edremit Gulf are consumed by the local people in various ways either cooked or raw. In this study, Raphanus raphanistrum species from the Brassicaceae family, which is also known to be used as food, was used. DPPH and CUPRAC antioxidant activity analyses were carried out on the extracts obtained from the aerial parts of the raw and boiled fresh plant. The total phenolic contents were determined and the phenolic compounds contained and their interactions with the boiling process were determined by HPLC method. The extracts were stored in a deep freezer at -20 °C to be used in further studies. In terms of the total amount of phenolic compounds, 12.65 µg GAE/mg extract was detected in the boiled extract of R. raphanistrum species, and it has a higher value compared to the raw extract. In the boiled extract, which has a higher value in terms of total flavonoid content than raw, was found 54 µg Rutin Equivalent /mg fresh extract. Compared to the CUPRAC method, the boiled extract showed higher (68.58 µgTE/mg extract) activity. The antioxidant activity of the boiled extract was found to be higher than the DPPH method, and the EC 50 value was measured as 1975.25 µg/mL. According to HPLC method, resveratrol, rosmarinic acid, quersetin, kaempferol and naringenin substances were determined as in the raw extract. It was determined that while naringenin was destroyed in the boiled extract, were changed the amounts of other phenolic compounds.