In vitro antioxidant capacity and phytochemical characterization of Eryngium kotschyi Boiss

Context: Eryngium kotschyi is one of the species of Eryngium genus and was endemic to Turkey. It was known, that traditionally uses of this plant in the South-Western part of Turkey for the treatment of various diseases. Aims: To evaluate the antioxidant capacities of methanol extract and ethyl acetate, n-butanol and water sub-extracts as well as to determine the phytochemical composition and to quantify the major antioxidant compounds in the active sub-extract. Methods: Besides the total phenolic compounds and total flavonoid compounds, the antioxidant capacity of E. kotschyi was evaluated by DPPH●, ABTS+● and FRAP methods and qualitative and quantitative determination of phytochemical constituents in active sub-extract by LC-MS/MS. Results: The highest total phenolic (173.710 ± 1.088 mg gallic acid equivalent/gextract) and total flavonoid content (86.978 ± 0.650 mg catechin equivalent/gextract) was found in ethyl acetate sub-extract of E. kotschyi (EKE) and this sub-extract showed the highest antioxidant capacity on DPPH● (IC50 = 0.264 ± 0.040 mg/mL), ABTS+● (at a concentration of 0.125 mg/mL equivalent to 0.497 µM Trolox) and FRAP (at a concentration of 1 mg/mL equivalent to 1476 ± 5.292 mmol Fe2+) tests. Preliminary examination of the mass spectrums revealed the presence of 24 phytochemical compounds in this sub-extract and 7 of them was quantified. According to quantitative analyses the main compounds of EKE sub-extract were rosmarinic acid (490.820 ± 0.703 µg/mgextract), chlorogenic acid (80.405 ± 0.170 µg/mgextract), isorhamnetin 3-O-rutinoside (72.280 ± 0.33 µg/mgextract), rutin (63.020 ± 0.052 µg/mgextract) and caffeic acid (55.153 ± 0.523 µg/mgextract). Conclusions: The data suggest that EKE possess utilizable antioxidant properties in vitro. The antioxidant capacity of this sub-extract could be due to high content of phenolic and flavonoid contents.