Phenolic composition and antioxidant activity of prunes and prune juice (Prunus domestica)

Phenolic compounds in foods have been associated with reduced incidences of heart disease by acting as antioxidants for low-density lipoprotein (LDL). Commercial prune and prune juice extracts (Prunus domestica cv. French) were analyzed for phenolics by reversed phase HPLC with diode array detection and tested for the ability to inhibit the Cu2+-catalyzed oxidation of human LDL. The mean concentrations of phenolics were 1840 mg/kg, 1397 mg/kg, and 441 mg/L in pitted prunes, extra large prunes with pits, and prune juice, respectively. Hydroxycinnamates, especially neochlorogenic acid, and chlorogenic acid predominated, and these compounds, as well as the prune and prune juice extracts, inhibited the oxidation of LDL. The pitted prune extract inhibited LDL oxidation by 24, 82, and 98% at 5, 10, and 20 mu M gallic acid equivalents (GAE). The prune juice extract inhibited LDL oxidation by 3, 62, and 97% at 5, 10, and 20 mu M GAE. These data indicate that prunes and prune juice may provide a source of dietary antioxidants.