Erucastrum virgatum subsp. virgatum (Brassicaceae) endemic to Sicily (Italy): biological properties and phenolic content of leaf extracts

The present work reports a comparative study between extracts obtained by different methods (ultrasonic bath-assisted extraction, maceration, decoction, and Soxhlet extraction) from the leaves of Erucastrum virgatum subsp. virgatum collected in Sicily (Italy), using ethanol and water as “green”solvents. All the extracts were found to be nontoxic after preliminary toxicity evaluation by the Artemia salina lethality bioassay. The antioxidant properties of the extracts were investigated by in vitro methods based on diverse mechanisms. All the extracts showed moderate radical scavenging activity in the 2,2-diphenyl-1-picrylhydrazyl (DPPH) test and mild reducing power, with 70% ethanol extracts exhibiting better activity than aqueous ones. Conversely, all the aqueous extracts showed stronger chelating activity than that of the 70% ethanol ones. Weak antimicrobial properties against selected Gram-positive and Gram-negative bacteria were observed only for 70% ethanol extracts. The results of the spectrophotometric determinations highlighted higher total polyphenol and flavonoid contents for all the 70% ethanol extracts compared to the aqueous ones. Furthermore, the phenolic profile of the most promising extracts was characterized by HPLC-PDA/ESI-MS analysis.