HPLC-DAD-MS/MS profiling of phenolics from different varieties of peach leaves and evaluation of their antioxidant activity: A comparative study

Peach (Prunus persica L.) leaves have been traditionally used in folk medicine for their several biological activities that are correlated to the presence of polyphenolic compounds. The aim of the present study is to characterize phenolic compounds present in foliar extracts of seven peach varieties cultivated in Algeria by HPLC–MS and the study of their antioxidant potential. Antioxidant capacity of the foliar extracts was assessed by several tests acting by different mechanisms: Oxygen Radical Absorbance Capacity (ORAC), 2,2-DiPhenyl-PicrylHydrazyl radical (DPPH), 2,-Azinobis(3-ethylBenzoThiazoline-6-Sulfonic acid) (ABTS), Potassium Ferricyanide Reducing Antioxidant Power (PFRAP) and Iron Chelating Activity (ICA). Fourteen phenolic compounds were identified in the peach leaf extracts including cinnamic acids and flavonols. Flavonols represent the main class of phenolic compounds accounting for an average percentage higher than 95% of the overall phenolics. Kaempferol 3-glucoside is the main phenolic compound in all peach leaf extracts with an average percentage higher than 32% followed by quercetin 3-glucoside (17.9%), quercetin 3-galactoside (17.1%) and kaempferol 3-galactoside (15.4%). Results showed that variety significantly affected the phenolic content of peach leaves. Romea and Red Top varieties present the higher concentration in phenolic compounds, Dixired, Flavorcrest and Tebana a moderate one and, Cardinal and Spring Belle the lowest content. The data obtained with DPPH, ABTS, ORAC and PFRAP assays showed that polyphenols present in the all foliar peach extracts were potent antioxidative agents. Except for ICA assay, good positive correlations were found between phenolic concentration and the different measured antioxidant capacities. That means that phenolic compounds present in peach leaf cultivars were major contributors of reducing power and scavenging radicals capacities (DPPH, ABTS and ORAC). All these results allowed us to conclude that peach leaves are a good source of phenolics with active properties, as antioxidant ones. © 2019 Elsevier B.V.