Determination of antioxidant activities of plants growing at different altitudes of Ergan Mountain (Erzincan)

This study was conducted within the boundaries of Erzincan province, focusing on plant species naturally distributed across an altitude range of 1500 m to 3000 m on Mount Ergan. A total of 12 plant species were selected from different altitudes: at 1500 m (Glaucium leiocarpum Boiss., Astragalus ornithopodioides Lam., Alcea calvertii (Boiss) Boiss.), at 2000 m (Globularia trichosantha Fisch. & C.A. Mey., Hypericum scabrum L., Tanacetum mucroniferum Hub.Mor. et Grierson, Inula oculus-christi L., Onobrychis cornuta (L.) Desv., Barbarea auriculata Hausskn. ex Bornm.), and at 3000 m (Scorzonera sericea DC., Hedysarum erythroleucum Boiss., Astragalus nezaketiae A. Duran & Aytaç). Leaf, stem, and root samples were collected, and methanol extractions were prepared to analyze total phenolic content (TPC), total flavonoid content (TPF), and antioxidant activities (DPPH and FRAP assays). Among the analyzed species, Globularia trichosantha exhibited the highest antioxidant activity, with DPPH activity measured at 47.86±1.70 in leaves, 108.09±1.29 in stems, and 60.57±0.74 in roots. Phenolic content was determined as 82.56±0.46 in leaves, 56.71±2.12 in stems, and 59.75±2.11 in roots. FRAP activity was recorded as 54.87±1.54 in leaves, 41.09±3.06 in stems, and 48.95±2.73 in roots. Flavonoid content was 59.81±2.31 in leaves and 31.62±3.55 in stems of Globularia trichosantha, while the root of Hypericum scabrum exhibited a flavonoid content of 35.71±2.73. Statistical analysis using SPSS 22 revealed significant differences in the phenolic and flavonoid contents, as well as antioxidant activities, among plants from different altitudes. A strong positive correlation was observed between bioactive components and antioxidant activities. These findings indicate that altitude has a significant impact on the bioactive compounds and antioxidant potential of the studied plants. In particular, Hypericum scabrum, Tanacetum mucroniferum, and Globularia trichosantha, found at 2000 m, demonstrated notable antioxidant performance, highlighting their potential for pharmaceutical research and applications.