Correlation Analysis of Ellagic Acid with Antioxidant and Carbohydrate Substances in Different Development Stages of Blackberry and Raspberry Leaves

The purpose of this study was to preliminarily reveal the changes of ellagic acid in leaves of Rubus berries at different developmental stages. In this study, leaves of 21 varieties of blackberry, raspberry and the hybrids were used to extract the ellagic acid in the leaves by ultrasonic assisted solvent extraction method, and the content of ellagic acid was rapidly detected by UV spectrophotometry. On this basis, five varieties were selected to analyze and evaluate the relationship between antioxidant capacity, antioxidant content, carbohydrate content and ellagic acid content. The results showed that the content of ellagic acid in the tender leaves of blackberry and raspberry was higher, and it showed a downward trend with the development and aging of the leaves. The content of ellagic acid in the tender leaves of blackberry cv. 'Baosen' was the highest up to 39.622 mg/g, and the content of ellagic acid in the aging leaves of raspberry 'Haritez' was the lowest, which was 7.649 mg/g. Furthermore, the antioxidant capacity and antioxidant content of the leaves of the selected five varieties were analyzed. It was found that the change trend was similar to that of ellagic acid, while the change of carbohydrate content in the leaves was negatively correlated with that of ellagic acid. The results would provide some theoretical basis for the functional research and further development and utilization of ellagic acid in blackberry and raspberry leaves.