Objective: In Turkish folk medicine, different species of Scorzonera (Asteraceae) have been used in the treatment of various disorders. The study aimed to investigate antidiabetic activity of Scorzonera species and if rutin is the primary component responsible of this activity.

Methods: The extracts of aerial parts of Scorzonera tomentosa, S. mollis ssp. szowitsii, S. suberosa ssp. suberosa, S. eriophora, S. acuminata, S. sublanata and S. cana var. jacquiniana were used in the experiment. Additionally, rutin, which has been analysed and detected by using HPLC qualitatively and quantitatively in some Scorzonera species, was also tested for its antidiabetic activity in the same conditions. An alloxaninduced diabetic mice test model was used in order to verify antidiabetic activity. Antidiabetic activities of the 9 groups (n=5; each) were measured at four different times: before Scorzonera extracts and rutin treatment and after 1, 2 and 4 hours of treatments.

Results: S. sublanata extract exhibited the highest antidiabetic activity and at 100 mg/kg dose, it significantly reduced blood glucose levels measured after 1, 2 and 4 hours of treatments when compared to isotonic saline solution group (diabetic control group). S. cana var. jacquiniana extract also displayed notable decrease after 4 hours of treatment. Significant lowering effect on blood glucose level was also observed by treatment with rutin in all tested times at 100 mg/kg i.p. injection. According to the HPLC analyses the highest rutin content was determined in the S. acuminata aerial parts.

Conclusion: Rutin content and the antidiabetic activity of the plant extracts were not correlated as displayed in this present study. Further studies should be performed to reveal responsible compunds for antidiabetic activity.