Evaluating the effect of ethanol foliar feeding on the essential oil, phenolic content, and antioxidant activities of Ducrosia anethifolia

Ducrosia anethifolia (Apiaceae) is a medicinal aromatic plant distributed in Iran and Afghanistan. This research aims to investigate the composition of the plant essential oil, determine the total flavonoid and phenolic contents, and evaluate its antioxidant activities after ethanol foliar feeding. For this purpose, 0, 10, 20, 40, and 80% v/v of aqueous ethanol solutions were sprayed on different batches of the plants. Then, the essential oils were obtained using water distillation. Compounds were analyzed by Gas chromatography-mass spectrometry technique(GC-MS) using a validated method. The method was validated as per the ICH guidelines for linearity, precision, accuracy, robustness, LOD, and LOQ. The total contents of phenols and flavonoids were measured using spectrophotometric methods. The antioxidant activity was evaluated using DPPH and FRAP assays. The results showed that n-decanal, cis-verbenyl acetate and dodecanal were the major compounds in all treatments. However, alcohol could cause significant differences in the essential oils qualitatively and quantitatively. The results showed that 40% ethanol could increase the number of phenolics and flavonoids and consequently the antioxidant activity.  Thus, ethanol foliar feeding can be used as an appropriate approach to increase the essential oil of D. anethifolia as well as its phenolic and flavonoid contents.