Antioxidant, enzyme inhibition properties and phenolic compounds of different extracts of two medicinal plants (Johrenia aromatica & Anchusa azurea var. kurdica) growing in Northern Iraq

Johrenia aromatica and Anchusa azurea var. kurdica are famous plants that is used in traditional medicine as they are used for diabetes, diuretics, wound healing and asthma. This thesis investigated the antioxidant capacity of the different parts of Johrenia aromatica and Anchusa azurea var. kurdica extracts (methanol, ethyl acetate, and water). TPC of A. azurea var. kurdica leaves extracts was found 53.58 mg REs/g extract and TFC of flower extracts was 42.28 mg REs/g extract. In addition, free radical scavenging activity of A. azurea var. kurdica flower extracts were detected as DPPH (81.56 mg TEs/g extract) and ABTS (130.59 mg TEs/g extract). Reducing power activity of A. azurea var. kurdica flower extracts were determined as 102.49 mg TEs/g extract and 96.62 mg TEs/g extract in CUPRAC and FRAP, respectively. Additionally, total antioxidant capacity of A. azurea var. kurdica flower is 48.01 mg TEs/g extract in PBD, leaves 34.05 mg TEs/g extract in MCA. In the all-antioxidant tests A. azurea var. kurdica showed a higher ratio compared to the Johrenia aromatica. ACHE and BuCHE Inhibition of Johrenia aromatica were shown as 3.65 (mg GALAE/g extract) in shoot extracts and 5.47 (mg GALAE/g extract) in root extracts. Tyrosinase inhibition of A. azurea var. kurdica root extracts was 40.82 (mg CAE/g extract), α-glucosidase inhibition of root and flower extracts were 838.93 (mg ACAE/g extract) and 369.08 (mg ACAE/g extract), respectively. Phenolic compounds had the highest levels of Rosmarinic acid in A. azurea var. kurdica flower extracts (432.821 ppm) and the chlorogenic acid of Johrenia aromatica shoot extracts was determined as 109.475 ppm, these rates are the highest compared to other phenolic compounds. Overall, the results of this thesis indicated that A. azurea var. kurdica and Johrenia aromatica can be used as natural sources of food and pharmaceutical areas.