Phytochemical Characterization and In Vitro Antioxidant Properties of Four BrassicaWild Species from Italy

In the present study, we evaluated for the first time the variability of antioxidant traits of
four Brassica wild species: B. incana, B. macrocarpa, B. villosa, and B. rupestris. The content of the main
water-soluble antioxidants (phenolics, ascorbic acid, and total biothiols) and the in vitro antioxidant
potential (1,1-diphenyl-2-picrylhydrazil (DPPH) and superoxide anion scavenging capacity) were
investigated. A total of 28 polyphenolic compounds were identified by LC/MS and quantitated
by HPLC/DAD analysis. Kaempferol and quercetin derivatives were the most abundant phenolics
compared to hydroxycinnamoyl gentiobiosides. In the ten populations, phenolics ranged from
163.9 to 533.9 mg/100 g dry weight (d.w.), ascorbic acid from 7.6 to 375.8 mg/100 g d.w., and total
biothiols from 0.59 to 5.13 mg/100 g d.w. The dierent classes of phytochemicals were separated
using solid-phase extraction at increasing methanol concentrations, and the antioxidant power of
fractionated extracts was evaluated. The superoxide anion scavenging activity was significantly
correlated to phenolics, particularly to flavonol derivatives, while DPPH was mainly related to
ascorbic acid content. The present findings improve the knowledge of the phytochemical composition
of Italian Brassica wild species by showing the great diversity of phytochemicals among populations
and highlighting their importance as a valuable genetic resource for developing new cultivars with
improved bioactive content.