Effect of citral and geranial foliar application on quantity and quality of secondary metabolites of Lippia citriodora Kunth.

Biotransformation is the process of converting an inert precursor into the medicinally valuable product. In this research, a pot experiment was conducted to evaluate the effect of artificial citral and geranial spraying in concentrations of 100, 200, 300, 400 and 500 ppm, besides distilled water and without spraying (control) on essential oils quality and quantity of lemon verbena with in greenhouse conditions at Islamic Azad University – Miyaneh Branch, Iran in 2015. The first foliar application was done when the plantlets reached the height of 25. The second and the third spraying were done with 7 and 14 days span after the first spraying respectively. One week after the last spraying, lemon verbena leaves were harvested. The essential oils were extracted from the leaves by hydro distillation method by using Clevenger apparatus. Citral and geranial especially in low concentrations (100 ppm) and distilled water spraying had positive effect in essential oils yield. The chemical composition of essential oils was analyzed by GC and GC-MS methods. On the whole, 21 components were identified and the most important components were limonene, geranial and neral. Citral and geranial spraying especially in high concentrations increased limonene content and the highest limonene content was in geranial 500 ppm and citral 400 ppm in the amount of 28.24 and 24.54%, respectively. Also, the lowest limonene content was 17.83% in control. However, citral and geranial spraying had not positive effect on neral and geranial content.