Chemical Composition, in vitro Antioxidant, and Antidiabetic Potential of Essential Oil from Flowers of Rhaponticoides iconiensis

The present study describes in vitro antidiabetic activity, antioxidant capacity and phytochemical analyses of essential oil from flower of Rhaponticoides iconiensis (Hub.-Mor.) M.V.Agab. & Greuter. In this study, the antidiabetic activity of essential oil was carried out by α-amylase and α-glucosidase enzyme inhibition methods, the antioxidant activity was investigated with DPPH●, ABTS●+ and FRAP tests and the phytochemical composition analysis was carried out by GC/MS and GC-FID. According to the results, the highest α-amylase and ABTS+● activity even from positive control were found in essential oil (IC50=154.33±3.88 µg/mL and at a concentration of 0.25 mg/mL equivalent to 0.607±0.95 µM Trolox, respectively). Moreover, the highest antioxidant activity on FRAP (at a concentration of 1 mg/mL equivalent to 508.50±1.057 mmol Fe2+) and moderate effect on DPPH● (33.10%) tests were observed. Besides that, the results of GC/MS analyses of essential oil revealed the presence of 1-undecene, γ-eudesmol and β-caryophyllene as a major compounds. In conclusion, the essential oil from this species has potential antidiabetic and antioxidant activity and these activities may be investigated in detail in the future.