The effect of sorbitol applications on total phenolic, flavonoid amount, and antioxidant activity in Safflower (Carthamus tinctorius L.)

Abstract

It is already known that secondary metabolites in plants are affected by many parameters such as biotic and abiotic stress conditions and can vary in quantity. Sorbitol, which is used to increase osmolality in cells, is an important source of abiotic stress. The present study was conducted to determine the effects of sorbitol applications at different doses by foliar spraying on total phenolic, total flavonoid, and antioxidant activity in Safflower (Carthamus tinctorius L.) at different times. Olein variety was used as the material in the study and different sorbitol doses (0.5 g/L, 25 g/L, 50 g/L and 100 g/L) were applied by foliar spraying. Sorbitol doses were applied in three different growth periods (before, during, and after blooming). The total amount of phenolic and flavonoid substances and DPPH free radical scavenging activity of the drugs obtained from all samples were examined after the harvest was completed. Although it was determined that the effect of increasing sorbitol doses applied in different growth periods on the total amount of phenolic and flavonoid substances and on the DPPH free radical scavenging activity was statistically not significant, the interaction of sorbitol doses x different growth periods in the total phenolic substance content was significant. The highest total phenolic content was determined as 133.00 mg GAE/g in the before blooming period of the plant in safflower. The total amount of flavonoid substance was determined as 24.46 mg QE/g in the before blooming period of the highest plant. The highest DPPH free radical scavenging activity was found to be 92.86% in the after blooming period. As a result, when the study outcomes were evaluated according to different development periods in safflower, it is possible to rank the development periods of the total phenolic substance content and total flavonoid substance amounts as before blooming > blooming period > after blooming. We can list the antioxidant activity as after blooming > blooming period > before blooming.