Context: There are 33 Geranium species growing in Turkey characterized by the presence of polyphenolic compounds. Some Geranium (Geraniaceae) species are used as antidiabetics, hemostatics, antihemorrhoidals, antidiarrheics and for the treatment of pain, fevers, and gastrointestinal ailments, or are consumed as food.
Objective: The in vitro antioxidant activity and antihemolytic effect of ethyl acetate (EtOAc), n-butanol (BuOH), methanol (MeOH) and water extracts of Geranium tuberosum L. subsp. tuberosum (Geraniaceae), a medicinal food plant, have been evaluated.
Materials and methods: The two antioxidant enzyme activities of human erythrocyte, namely superoxide dismutase (SOD) and catalase (CAT), after in vitro incubation with the extracts, were examined in order to see whether the observed effects are related to altered enzymatic efficiency. Reduced glutathione (GSH) levels were also measured as oxidative stress marker. Antihemolytic activity of extracts was shown by hemolysis assay in erythrocytes. Furthermore, total phenolic content of extracts was measured by Folin-Ciocalteu method.
Results: All extracts enhanced GSH levels, and the activity of SOD and CAT. The EtOAc extracts seems to be the most potent antioxidant at 100 µg/mL (SOD activity 173.736 ± 8.33, CAT activity 133.218 ± 3.31, GSH level 2.264 ± 2.21). However, apart from the MeOH extracts at 100 µg/mL (68.699 ± 3.93), they didn't increase the resistance of erythrocytes to H(2)O(2) induced cytotoxicity. Therefore, while a significant antioxidant effect was observed in these samples, antihemolytic effect was not determined.
Discussion and conclusion: The title plant has shown high antioxidant activity without cytotoxicity up to 100 µg/mL, thus could be a potent source as natural antioxidant.