Correlation between environmental factors, chemical composition, and antioxidative properties of caper species growing wild in Calabria (South Italy).

Twenty samples of two caper species were collected from various natural habitats of Calabria (South Italy). A sample program was designed in order to cover all taxa and morphotypes present in the studied area, trying to correlate ecological conditions, phytochemical content, and biological activities. These species were characterized through the detection, isolation, and capillary GC-GC/MS quantitative evaluation of chemical markers (phytosterols and vitamin E). The antioxidant activity of MeOH caper extracts was assayed using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and β-carotene bleaching tests. The chemical investigation showed a different composition according to the species and the populations. The best free radical (DPPH) scavenging activity was exerted by Capparis orientalis sample C4 (collected near Copanello village, granodiorite sea cliff) and Capparis sicula ssp. sicula sample C5 (collected near Tarsia village, clay soil). Sample C2 (Galatrella Valley, clay soil) showed the highest inhibition of linoleic acid oxidation with more efficacy than propyl gallate, the reference drug.