Determination of antioxidant and antimicrobial activity and essential oil and phenolic components of thuja oak (Quercus infectoria) plant

The total polyphenol and total flavonoid substance amounts of the thuja cone (Quercus infectoria) were measured, as well as the antioxidant capacity; It was revealed by FRAP, CUPRAC and DPPH● radical scavenging methods. According to the data obtained, total polyphenol and flavonoid substance contents are 342.87±20.34 mgGAE/g sample, 0.75±0.07 mgQuercetin/g sample. Antioxidant properties were determined as 4.04±0.21 μmol FeSO4.7H2O/g sample for FRAP, and 13.23±0.51 mmol TEAC/g sample for CUPRAC. For DPPH● , it was observed that it exhibited very good antioxidant properties with an IC50 = 0.002 mg/mL value, and even showed an activity very close to trolox, which is used as a standard in that field. Disc diffusion and minimum inhibitory concentration (MIC) methods were used for antimicrobial activity. Thuja cone showed antibacterial activity against the test microorganisms used with a value of 250-4000 µg/mL, and antifungal activity against yeast strains with a value of 125 or 250 µg/mL, especially against Candida glabrata ATCC 2001 and Candida krusei ATCC 6258 with a value of 125 µg/mL. It has been found to have properties. As a result of elucidating the essential oil extracted from thuja with SPME and GC/MS techniques, 29 components were detected. (Z)-Anethole ether (28.55%), pentadecanolide ester (26.44%), diethyl phthalate ester (6.46%) and acetoin ketone (5.66%) compounds were identified as the main components since they had the highest ratios. HPLC-UV method was used to determine the phenolic component of Thuja oak and 15 standards were used in the analysis. Only gallic acid 2.9% (20.56 ppm) phenolic compound was found in the thuja cone. Keywords: Thuja oak, Antioxidant, Antimicrobial, Phenolic component, Essential oil, SPME, GC-MS, HPLC-UV