Abstract:

The paper aims to study the antioxidant activity and material basis of polyphenols in Prunus domestica ‘French’. Folin-ciocalteu was used to determine the content of free and bound phenols in various parts of‘French’prunes. Ultrahigh performance liquid chromatography-mass spectrometry (UPLC-DAD-EIS-MS) was used to identify the components, and the antioxidant activities of polyphenols in various parts of prunes were discussed. The results showed that the contents of free and bound phenols in prune flesh were (289.58±2.89) mg GAE/100 g and (78.46±0.31) mg GAE/100 g, respectively. The contents of free and bound phenols in prune peel were (313.54±6.88) mg GAE/100 g and (97.92±0.36) mg GAE/100 g, respectively. The contents of free and bound phenols in flesh and peel of prune were (300±3.90) mg GAE/100 g and (92.5±4.96) mg GAE/100 g. A total of 9 compounds were identified by UPLC-DAD-EIS-MS. Quercetin-O-glucose, oxalic acid and tartaric acid were found in the bound phenol of fruit peel. There were caffeic acid and L-malic acid in pulp binding phenol, and quinic, gallic, oxalic, and L-malic acids in the peel free phenol. Vanillin and (+) catechin were found in the free phenol of the flesh. The results of antioxidant experiments showed that when the concentration was 1.0 mg/mL, the total reducing power (2.257) and superoxide anion scavenging rate (78.70%) of free phenol in prune peel were the highest, and the hydroxyl group (90.84%) and DPPH (84.27%) had the highest free radical scavenging rate, indicating that the polyphenolic compounds in various parts of prunes had a certain antioxidant activity, and all of them increased with the increase of concentration.

Key words: Prunus domestica ‘French’, free phenol, bound phenol, polyphenol, antioxidant activity, component identification