Kemijski sastav i antioksidativna aktivnost Fraxinus ornus L. i Fraxinus excelsior L.

Abstract

In this work, the total content of phenolics, flavonoids, and phenolic acids in the leaves and bark extracts of <i>Fraxinus ornus</i> L. and <i>Fraxinus excelsior</i> L. was determined. In addition, the identification and quantification of phenolic acids was performed using the HPLC-DAD technique. Samples were tested for antioxidant activity using the ABTS and DPPH methods. Eight extract samples were prepared by Soxhlet and ultrasound extraction using 70 % ethanol as solvent. The content of phenolic compounds ranged from 7.59 for <i>F. ornus</i> to 88.93 mg GAE/g for <i>F. excelsior</i> in the bark extracts obtained by Soxhlet extraction. The highest content of total flavonoids in <i>F. ornus</i> and <i>F. excelsior</i> was found in the leaves extracts obtained by ultrasound extraction, which was 5.68 and 1.74 mg GAE/g extract, respectively. The results also showed that the highest content of total phenolic acids was found in <i>F. ornus</i> (105.33 mg CAE/g) and <i>F. excelsior</i> (97.97 mg CAE/g) in the bark extract obtained by Soxhlet extraction. The highest content of gallic acid (112.96 ± 1.32 mg g<sup>–1</sup> extracts) and chlorogenic acid (246.94 ± 0.82 mg g<sup>–1</sup> extracts) was found in the <i>F. ornus</i> bark extract obtained by ultrasound extraction. As for antioxidant activity, the bark extract obtained by Soxhlet extraction of <i>F. ornus</i> showed the best antioxidant activity by ABTS method with IC<sub>50</sub> value of 0.062 mg ml<sup>–1</sup>. The results of the DPPH method show that the leaves extract obtained by Soxhlet extraction had the best antioxidant activity for the <i>F. ornus</i> sample, with an IC<sub>50</sub> value of 0.23 mg ml<sup>–1</sup>.