Determination of heavy metals, antioxidant and total phenolic of Iraq Kurdish Region and Siirt province thyme

Despite an increased awareness of metal pollution, there are no studies about the metal content of thyme plant cultivated in Iraq and Siirt area. In this study value of thirty metals (Li, Be, B, Na, Mg, P, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Mo, Cd, Sn, Sb, Ba, La, Ce, Pt, Tl and Pb ) in thyme plant were determined and the results were subjected to various chemometric techniques for classification purposes. Samples were collected from Iraqi Kurdish Region (Qandil, Asos, Balambo, Karokh) and Siirt, Turkey (Eruh, Şirvan, Kezer, Tillo, Akdoğmuş Village, Kurtalan Üç Yol, Kurtalan Zokayt, Baykan). The ICP-MS (Thermo Scientific ICAP Q ICP-MS) instrument was used to detect the amount of metal in the samples dissolved by the microwave method. The analytical accuracy of the method was controlled by use of a standard reference material NASS-6. Principal component analysis (PCA) and cluster analysis (CA) as classification techniques results support each other. Besides; Total amount of phenolics, total flavonoid content, antioxidant activity and phenolic content of methanol extracts from four different regions of Iraqi Kurdish region and eight different areas of Siirt were examined. Total phenolic contents were assessed by Folin Ciocalteau's method and the total flavonoid content was determined by the aluminium chloride colorimetric method. The maximum value of total phenolic and total flavonoid content was found 226.83±0.21 µg gallic acid/mL and 2.59±0.02 mg rutin/mL of extract respectively. The antioxidant activity was determined by using DPPH and FRAP methods. The highest antioxidant activity (IC50) was found 1.32 mg/mL and 2.05 mg/mL respectively. Metal chelating activity was estimated by method of Rival et al, 20014 and the highest metal chelating activity percentage of extract was 22.92 %. And also, chemical composition of the phenolic compounds were determined with LC-MS/MS instrument. As a result, 29 phenolic compounds were quantitatively determined, among the 37 phenolic compounds analyzed. The predominant of them were Hesperidin (62.37±0.02 mg g-1), Quinic acid (1.53±0.01 mg g-1), tr-Ferulic acid (2.23±0.01 mg g-1), Rosmarinic acid (19.90±0.01 mg g-1), Cinnamic acid (0.81±0.01 mg g-1), Malic acid (7.62±0.09 mg g-1), Hesperetin (1.67±0.09 mg g-1). The results of the study confirm that these samples have potential biological activities and can be introduced as important sources of natural antioxidants.