ANTIOXIDANT ACTIVITY AND CONTENT OF SELECTED MICRONUTRIENTS IN THE FRONDS OF Asplenium ceterach

This study aimed to evaluate the total phenolic compound content and antioxidant capacity of the ethanolic extract of Asplenium ceterach fronds, as well as the content of selected micronutrients (Fe, Cu, Zn, and Mn) in fronds collected in the Republic of Srpska (Bosnia and Herzegovina). The extract's total phenolic compound (TPC) concentration was 16.08 ± 0.08 mg GAE/gDW. It demonstrated DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity with an IC₅₀ value of 29.28 ± 2.20 mg/mL. The hydrogen peroxide scavenging capacity was significantly lower (IC₅₀ = 1420.56 ± 35.72 μg/mL), indicating moderate effectiveness against this reactive oxygen species. The extract also showed hydroxyl radical scavenging ability, with 56.26 ± 1.05% residual •OH radicals under the tested conditions. Reducing power assays revealed that at 500 µg/mL, the extract reduced Fe³⁺ to 1420.20 ± 53.67 mmol/L Fe²⁺ equivalents, while its Cu²⁺ reducing capacity was 423.14 ± 29.20 µg Trolox/mL at a TPC concentration of 300 µg/mL. The micronutrient levels in A. ceterach were as follows: Fe (164.57 ± 4.08 mg/kg) > Zn (15.61 ± 0.43 mg/kg) > Mn (12.39 ± 0.19 mg/kg) > Cu (1.62 ± 0.12 mg/kg). Our in vitro findings suggest that the ethanolic extract of A. ceterach could serve as a potential natural source of antioxidant compounds.