Essential oil profiles, improvement of enzymatic and non-enzymatic antioxidant systems in different populations of Salvia subg. Perovskia by irrigation management

Abstract

Salvia subg. Perovskia is an aromatic medicinal plant from the Lamiaceae family. Essential oil (EO) content and composition, along with enzymatic and non-enzymatic antioxidants, were evaluated in 18 plant populations under three levels of irrigation for two consecutive years. Based on the GC-MS analysis, the main components of EO were borneol (1.18–36.53%), followed by camphor (0.54–32.17%), 1,8-cineole (12.44–29.26%), δ-3-carene (0.39–21.20%), myrcene (0.59–16.28%), and α- pinene (0.79–12.87%) in the studied treatment. Except for malondialdehyde and hydrogen peroxide in leaves and roots, all the examined parameters showed lower values in the first harvest year compared to those of the second year. The activities of antioxidant enzymes, total phenolics, and flavonoids of the extracts were substantially enhanced as stress intensified to reach maximum values in leaves under severe stress and in roots under moderate stress conditions. The maximum root tanshinones content was observed under moderate water deficit conditions, while the highest EO content was obtained in plants exposed to severe stress conditions. Taking into account the evidence provided by this study, it can be inferred that the use of water deficit stress can serve as an effective method to stimulate and improve antioxidant properties, as well as the quantity and quality of secondary metabolites in Salvia subg. Perovskia.