Comparative Antioxidant Activities and Total Phenolic Content of Hypericum perforatum, H. scabrum and H. heterophyllum from Different Regions of Türkiye

Authors : Osman Tuncay Ağar, Bekir Tosun, Tunahan Demirci
Pages : 609-620
Doi:10.55262/fabadeczacilik.1785409
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Publication Date : 2025-10-30
Article Type : Research Paper
Abstract :The genus Hypericum is a rich source of bioactive compounds, particularly phenolics and flavonoids, which play a key role in antioxidant activity. While H. perforatum (St. John’s Wort) has been extensively investigated, comparative evaluations of Turkish representatives of the genus, including the widespread H. scabrum and the endemic H. heterophyllum, remain limited. This study compared the antioxidant capacities and total phenolic content (TPC) of these three species collected from different regions of Türkiye. Aerial parts were extracted with 70% ethanol using ultrasonic-assisted extraction, and the TPC was determined by the Folin–Ciocalteu method. Antioxidant activities were assessed by DPPH and ABTS radical scavenging assays, with Trolox as the reference standard. H. perforatum exhibited the highest TPC (201.4 ± 2.8 mg GAE/g extract) and antioxidant activity (IC₅₀: 9.82 ± 0.76 µg/mL for DPPH; 7.01 ± 0.98 µg/mL for ABTS), followed by H. heterophyllum (141.9 ± 1.9 mg GAE/g; 17.16 ± 0.67 and 10.10 ± 1.15 µg/mL). H. scabrum showed the lowest TPC (129.1 ± 2.1 mg GAE/g) and weakest activity (24.17 ± 0.65 and 9.21 ± 1.22 µg/mL). Pearson’s correlation analysis revealed strong negative associations between TPC and IC₅₀ values (r = –0.94 for DPPH; r = –0.90 for ABTS), confirming phenolics as the main contributors to radical scavenging potential. These findings highlight clear interspecific differences in antioxidant capacity within Hypericum, reaffirming the pharmacological value of H. perforatum and pointing to the underexplored potential of H. heterophyllum.
Keywords : Hypericum perforatum, Hypericum scabrum, Hypericum heterophyllum, toplam fenolik içerik, antioksidan aktivite, DPPH, ABTS

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