Determination of antioxidant system status in Tarsus Beyazı(Vitis vinifera L.) leaves

In this thesis, antioxidant defense system status of Tarsus White (Vitis vinifera L.) leaves were investigated before (April, 2022) and after (May, 2022) pruning. For this purpose, phenolic compound determination, total phenolic substance determination, total antioxidant capacity, antioxidant enzyme activities (ascorbate peroxidase, APx; catalase, CAT; superoxide dismutase, SOD and glutathion S-transferase, GST), total thiol (T-SH), non protein thiol (NP-SH), lipid peroxidation (thiobarbituric acid reactive substances, TBARS) and protein levels were analyzed spectrophotometrically. In this study, quercetin, rutin, succinic acid, trans-ferulic acid, caffeic acid, p-coumaric acid, epicatechin and catechin phenolic compounds were detected in leaf samples. Some of these phenolic compounds were increased after pruning (May). Additionally, after pruning, thiol contents (T-SH and NP-SH) and protein levels fell while overall antioxidant capacity and antioxidant enzyme activity (CAT, SOD, and GST) increased. Due to its high content of total phenolic compounds and enzymatic activity, it can be concluded from the results that Tarsus White (V. vinifera L.) grape leaves are a natural source of antioxidants, and pruning boosts the antioxidant system's capacity.