Giresun’da Yetişen Fındık Ağacı (corylus Avellana L.) Yapraklarında Bazı Fenolik Bileşiklerin Ve Antioksidan Aktivitelerinin Araştırılması

Hazelnut (Corylus avellana L.) is an essential product with high economic value in global production. However, studies on hazelnut leaves have been limited so far. In this study, three types of (Yağlı (Tombul), Sivri and Haz) hazelnut tree leaves collected from two regions of Giresun were extracted with infusion method. Evaporation of the extracts and preparation of the samples in the glove box prior to analysis is one of the most critical points of this study. It was aimed to determine the amounts of phenolic compounds, the total amount of phenolic content and antioxidant activities in the extracts. The determination of phenolic compounds was determined by Liquid Chromatography-Mass Spectrometry (LC-MS/MS), and total phenolic content was determined by Folin-Ciocâlteu method. Antioxidant activity, 2,2-azino-bis(3ethylbenzo-thiazoline-6-sulfonic acid (ABTS•+), 2,2-diphenyl-1-picrylhydrazil (DPPH•) radical scavenging activities and iron (III) reduction/antioxidant power) tested with FRAP methods. The chubby hazelnut tree leaves (TFE) extract collected from Espiye Merkez has the highest ABTS•+ radical scavenging (SC50: 0.00023±3.9E-06 mg mL-1) and FRAP (882.75±8.24 µM TEAC) (Trolox Equivalent Antioxidant Capacity) exhibited antioxidant activity. In addition, raw hazelnut tree leaves (HFE) (SC50: 0.00033±1.3E-06 mg mL-1) and chubby hazelnut tree leaves (TFE) (SC50: 0.00034±1.7E-06 mg mL-1) collected from Espiye Merkez extracts exhibited almost the same DPPH• scavenging activity. TFE extract had the highest total phenolic content (163.33±4.36 GAE (Gallic Acid Equivalent) µg mL-1 and 228.67±6.11 CE (Catechin Equivalent) µg mL-1). Gallic acid, catechin, epicatechin, taxifolin, ellagic acid, quercetin and caffeic acid were detected in the analyzed leaves. The catechin amounts were 192.05±1.74 and 367.63±2.6 µg g-1 in the chubby (TFG) and pointed hazelnut leaves (SFY), respectively.