Comparison of phenolic compounds and antioxidant activity of two grapvine root cultivars Rasha and Qzel Ozum

Nowadays, the use of tissue culture technique in the production of plant secondary metabolites, such as phenolic compounds, as a natural food additive has become very widespread in the food industry. The aim of this study was to investigate and compare the content of phenolic compounds and antioxidant activity of grapevine Rasha and Qzel Ozum cultivars that were produced by tissue culture under in vitro condition. For this purpose, the terminal buds of grape cultivars were cultured in Murashige - Skoog Medium to produce complete seedlings. Then the methanolic extract was prepared from healthy grapevine leaves and to perform polyphenol composition tests using high performance liquid chromatography with ultraviolet detector, functional groups using Fourier-transform infrared spectroscopy, total phenol content, total flavonoids, total anthocyanins, total carotenoids, acid content, ascorbic acid, free radical scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH), and hydroxyl  (OH−). The results showed that the amount of total phenolic compounds, total flavonoids, total anthocyanin and total carotenoids of methanolic extracts of Rasha cultivar were 50.35±0.10, 29.72±0.05, 10.41±0.20, and 1.82±0.50 mg/g, respectively, and in Qzel Ozum cultivar were 23.06±0.31, 20.76±0.15, 7.28±0.15, and 94.94±0.42 mg/g, respectively. Ascorbic acid, DPPH and OH− free radicals scavenging activity in methanolic extracts of Rasha leaves were 1.83±0.04, 25.38±1.52, and 75.04±2.74 %, respectively, and in Qzel Ozum leaves were 0.85±0.01, 18.71±2.05 and 68.96±3.61 %, respectively. As a general result, the results showed that the grape leaves of the Rasha cultivar were more than the grapevine leaves of Qzel Ozum cultivar in terms of all studied characteristics (p <0.05). This study also showed that grape leaves are rich in phenolic compounds and natural antioxidants and have the potential to be used in the food and pharmaceutical industries.