Influence of Soil Properties on Bioactive Compounds and Antioxidant Capacity of Brassica rupestris Raf.

Brassica rupestris Raf. is a species native to South Italy, extremely rich in vitamins, fibers, and bioactive compounds with phytoterapic properties and may represent a resource for pharmaceutical and nutraceutical industries. Thus, our aim was to evaluate if and which soil properties affected the accumulation of secondary metabolites in B. rupestris. Knowledge of the causes of plant metabolism changes in a specific area may represent an important economic opportunity. We analyzed soils (physical and chemical parameters) in two different localities of B. rupestris growth and leaves (biocompounds and antioxidant activity) of B. rupestris grown over them to identify the soil factors that drove their phytochemical production and antioxidant power. Soil properties influenced the contents but not the types of the bioactive compounds in B. rupestris. No significant correlation was found between soil physical parameters and phytochemicals in Brassica leaves. Conversely, soil chemical and biochemical properties influenced the total antioxidant capacity and the synthesis of carotenoids and glucosinolates. Soil organic matter (SOM), dehydrogenase activity (DH), fluorescein diacetate hydrolysis (FDA), microbial biomass carbon (MBC), and humic acid/fulvic acid ratio (HA/FA) were the most important soil factors influencing the amount of phytochemicals in B. rupestris. A strict relationship between soil properties and metabolic profile of B. rupestris was found. The synthesis of specific classes of metabolites in B. rupestris is a direct response to soil biochemical conditions.