Diversity of phenolic profiles in the fruit skin of Prunus domestica plums and related species

The fruits of the European plum Prunus domestica exhibit a great diversity in appearance including skin colors. This study attempts to elucidate the phenylpropanoid and flavonoid profiles of 28 plum varieties belonging to P. domestica and related species as well as hybrids. A total of 49 phenolic compounds extracted from the fruit skin were quantitatively evaluated in an HPLC-DAD-based metabolomic study. The total phenolic contents of the cultivars varied among 0.4-29.9 mg/g fresh weight. The predominant anthocyanins were glycosides of cyanidin and peonidin, and rutin was the principal flavonol, whereas neochlorogenic acid and n-chlorogenic acid were the main hydroxycinnamic acids. Aside from these major phenolic classes, a group of tentatively identified flavones and several acylated flavonoids were also found. Principal component analysis revealed that anthocyanins and hydroxycinnamic acids contributed most to variety separation. The heterogeneity between the different varieties was also assessed using hierarchical cluster analysis of sample phenolics profile. A simple separation of species could not be found confirming the close relationship among them.