Introduction: Oxidative stress is currently considered one of the main causes in the development of many chronic diseases, which has stimulated a growing interest in antioxidants, especially those derived from plants. Although antioxidant activity has been reported separately for the species Pelargonium radula and Geranium macrorrhizum, direct comparative studies between them are lacking.
Aim: The aim of this article is to evaluate the comparative in vitro antioxidant activity of extracts from P. radula and G. macrorrhizum using four complementary antioxidant assays.
Materials and Methods: Aerial parts of both species, collected in Central Bulgaria, were extracted with 70% ethanol. Antioxidant activity was assessed using DPPH, TEAC, CUPRAC, and FRAP assays, and the results were expressed as μmol Trolox equivalents per gram of dry extract (μmol TE/g DE).
Results: G. macrorrhizum consistently showed higher antioxidant activity than P. radula in all applied assays. Depending on the analytical method used, the antioxidant capacity of G. macrorrhizum was approximately 2.7–3.9 times higher than that of P. radula. The highest antioxidant capacities for both species were recorded by the CUPRAC assay, reaching 12,826.99 ± 747.65 μmol TE/g DE for G. macrorrhizum and 3,259.41 ± 145.31 μmol TE/g DE for P. radula. Similar trends were observed in DPPH, TEAC, and FRAP assays.
Conclusion: This study presents the first direct comparison of the antioxidant activity of extracts from P. radula and G. macrorrhizum under identical extraction and analysis conditions. The results show that G. macrorrhizum exhibits higher antioxidant activity and provide biological support for previously reported differences in the phytochemical composition of the two species. These results indicate that G. macrorrhizum is the more promising source of natural antioxidants among the species studied.
Gulcin I. Antioxidants and antioxidant methods: An updated overview. Arch Toxicol. 2020;94(3):651-715. doi: 10.1007/s00204-020-02689-3.
Kotha RR, Luthria DL, Kaul SC, Wadhwa R. Oxidative stress and antioxidants—A critical review on in vitro antioxidant assays. Antioxidants (Basel). 2022;11(12):2388. doi: 10.3390/antiox11122388.
Kiokias S, Proestos C, Oreopoulou V. Phenolic acids of plant origin—A review on their antioxidant activity in vitro (o/w emulsion systems) along with their in vivo health biochemical properties. Foods. 2020;9(4):534. doi: 10.3390/foods9040534.
Pineda-Ramírez N, Alarcón-Aguilar A, Almanza-Pérez JC, Medina-Campos ON, Pedraza-Chaverri J, Ortiz-Plata A, et al. Antioxidant properties and protective effects of some species of the Annonaceae, Lamiaceae, and Geraniaceae families against neuronal damage induced by excitotoxicity and cerebral ischemia. Antioxidants (Basel). 2020;9(3):253. doi: 10.3390/antiox9030253.
Nikolova M, Tsvetkova R, Ivancheva S. Evaluation of antioxidant activity in some Geraniacean species. Bot Serb. 2010;34(2):123-5.
Miliauskas G, Venskutonis PR, van Beek TA. Antioxidative activity of Geranium macrorrhizum. Eur Food Res Technol. 2004;218(3):253-261.
Sharopov F, Setzer WN, Wink M. Antioxidant activity and cytotoxicity of methanol extracts of Geranium macrorrhizum and chemical composition of its essential oil. J Med Act Plants. 2017;5(1-4):1-10. doi: 10.1007/s00217-003-0836-7.
Zeljković SC, Šišková J, Komzáková K, Maksimovic M. Chemical composition and antioxidant activity of Geranium macrorrhizum in relation to ploidy level and environmental conditions. Plant Syst Evol. 2020;306(2):1-12. doi: 10.1007/s00606-020-01649-9.
Georgiev T, Zhelev I, Andonova V, Zlateva S, Karamalakova Y, Georgieva E, et al. Antioxidant potential and oxidative stress modulation of Geranium macrorrhizum L. oil extract in gentamicin-induced nephrotoxicity. Pharmaceuticals. 2025;18(9):1283. doi: 10.3390/ph18091283.
Petlevski R, Zovko Končić M. Antioxidant activity of Pelargonium radula (Cav.) L’Herit and its effect on antioxidants level in glucose-induced oxidative stress. In: Trends in Natural Products Research – A PSE Young Scientists’ Meeting. Kolympari: The Phytochemical Society of Europe; 2011.
Petlevski R, Vinković Vrček I, Čolić Barić I, Zovko Končić M. Composition and antioxidant activity of aqueous and ethanolic Pelargonium radula extracts. S Afr J Bot. 2013;85:17-22. doi: 10.1016/j.sajb.2012.11.009.
Ćavar S, Maksimović M. Antioxidant activity of essential oil and aqueous extract of Pelargonium graveolens L’Her. Food Control. 2012;23(1):263-7. doi:10.1016/j.foodcont.2011.07.031.
Iancu C, Arsene AL, Udeanu DI, Dehelean CA, Danciu C, Cioancă O, et al. Antioxidant and anticancer effect of some Pelargonium species extracts. Farmacia. 2023;71(2):314-21. doi: 10.31925/farmacia.2023.2.11.
Apak R, Güçlü K, Demirata B, Ozyürek M, Celik SE, Bektaşoğlu B, et al. Comparative evaluation of various total antioxidant capacity assays applied to phenolic compounds with the CUPRAC assay. Molecules. 2007;12(7):1496-547. doi: 10.3390/12071496.
Munteanu IG, Apetrei C. Analytical methods used in determining antioxidant activity: A review. Int J Mol Sci. 2021;22(7):3380. doi: 10.3390/ijms22073380.
Sethi S, Joshi A, Arora B, Bhowmik A. Significance of FRAP, DPPH, and CUPRAC assays for antioxidant activity determination in apple fruit extracts. Eur Food Res Technol. 2020;246(3):591-8. doi:10.1007/s00217-020-03432-z.
Sabotinova D, Boycheva P, Ivanova N, Andonova V, Georgiev V, Zhelev I. Comparative phytochemical analysis of the aerial parts of Pelargonium radula and Geranium macrorrhizum cultivated in Bulgaria using GC-MS and HPLC. Pharmaceuticals (Basel). 2026;19:346. doi: 10.3390/ph19030346.
Krasteva G, Georgieva M, Pavlov A, Georgiev V. Metabolite profiling of Gardenia jasminoides Ellis in vitro cultures with different levels of differentiation. Molecules. 2022;27(24):8906. doi: 10.3390/molecules27248906.
Kowalczyk A, Tuberoso CIG, Jerković I. The role of rosmarinic acid in cancer prevention and therapy: Mechanisms of antioxidant and anticancer activity. Antioxidants (Basel). 2024;13(11):1313. doi: 10.3390/antiox13111313.
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