Phenolic profile in leaves of Autochthonous Grapevine Cultivars (Vitis vinifera L.) from Turkey distinct of Isparta

In the current age, nutrition is a widely discussed topic, with foods rich in antioxidants being advocated to support healthy living. Phenolic compounds, which are used in treating various diseases due to their antimicrobial properties, have health-promoting properties. Consequently, producing extracts from grape varieties with high phenolic content for use in pharmaceuticals, food supplements, and cosmetics is essential for health and the economy. It is well established that grape leaves are rich in phenolic compounds. However, they are not currently utilised to their full potential and are considered mainly waste. This study was conducted in vineyards in Isparta, located in Turkey's Mediterranean Region, in 2018. The study utilised four autochthonous leaf varieties: two red ( Vitis vinifera cv. Burdur Dimriti and Vitis vinifera cv. Siyah Gemre) and two white ( Vitis vinifera cv. Razaki and Vitis vinifera cv. Tilki Kuyruğu). Total phenolic and flavanol content, as well as the presence of other phenolic compounds, were determined in the grape leaves. The study's findings indicated significant variations in the phenolic content of different grapevine leaf varieties. Total phenolic content ranged from 3.25 to 7.38 mg CE/g, while total flavanol content ranged from 67.66 to 120.24 mg CE/g. Phenolic compounds identified in the leaves included ferulic acid, gallic acid, caffeic acid, chlorogenic acid, catechin, quercetin, epicatechin, rutin, p-coumaric acid, o-coumaric acid, protocatechuic acid, hesperidin, vanillin, kaempferol, luteolin, and tannic acid, which were found to vary among the varieties.