Determination of the qualitative phenolic compound composition of Prunus padus L. fruits

Abstract

Introduction. Prunus padus L., also known as bird cherry, is a common plant in northern Europe. Bird cherry flowers, bark, leaves and fruits are rich in minerals, vitamins and compounds with high antioxidant activity, phenolic compounds among them [1]. The definition of phenolic compounds is broad, as it represents every natural phenolic compound that contains a common chemical structure of an aromatic ring with one or more hydroxyl substituents [2]. Studies confirm favorable effects of P. padus for prevention of cardiovascular diseases and hypertension, as well as antioxidant, anti-inflammatory, antimicrobial, antidiabetic effects [3]. The aim of this study was to determine the qualitative phenolic compound composition in fruits of Prunus padus L. Materials and methods. P. padus fruits were collected in Ńilalė district in 2023 at 4 different phenological periods (79: fruit development, fruits reached about 90% final size; 81: fruit maturity, fruit at full size, beginning of fruit coloring; 85: fruit maturity, coloring advanced; 87: fruit maturity, fruit becomes ripe for picking [4]). The collected fruits were frozen and then freeze-dried. Qualitative analysis of flavonols and phenolic acid, anthocyanins was performed using a Waters 2695 Alliance chromatographic system equipped with a Waters 2998 photodiode array detector. Results and their discussion. A total of 12 compounds were detected by HPLC in extracts from fruit samples of P. padus at different phenological stages (figures 1 and 2). Only flavan-3-ol, procyanidin B2, was detected in the sample collected at the fruit development stage. Four phenolic acids were identified in all samples: neochlorogenic acid, chlorogenic acid, 1,5-dicaffeoylquinic acid, pcoumaric acid. In addition, five flavonoids were identified: rutin, hyperoside, isoquercitrin, quercetin-3-glucuronide, isorhamnetin-3-glucoside. Unlike the other flavonoids, isoramnetin-3-glucoside was identified only at the stage of fruit development and at fruit maturity, fruit at full size, beginning of fruit coloring. The anthocyanins cyanidin-3-galactoside and cyanidin-3-glucoside were identified in samples of fruit at advanced coloring stage and in fruits ripe for picking. To compare this study‘s results to the ones found in literature, in a study by Siejak et al. cyanidin, cyanidin-3-glucoside, cyanidin-3-rutinoside, chlorogenic acid, quercetin, and quercetin glycoside were identified in the extract of P. padus fruit [5]. Mikulic-Petkovsek et al. identified 5-p-coumaroylquinic acid, caffeic acid hexoside, 1 p-coumaric acid hexoside, 1,5-caffeoylquinic acid, dicaffeoylquinic acid, epicatechin, quercetin acetyl hexoside, quercetin dihexoside, querectin-3-galactoside, quercetin-3-glucoside, quercetin-3-rhamnoside, quercetin-3-rutinoside, isorhamnetin3-rutinoside, kaempferol hexoside, kaempferol glucoside, kaempferl-3-rutinoside, apigenin rhamnoside, cyanidin-3-galactoside, cyanidin-3-rutinoside, cyaniin-3- glucoside, cyanidin rhamnosyl hexoside in P. padus fruit extract [3]. However, some of these phenolic compounds have been identified for the 1st time. Conclusions. A total of twelve compounds were detected by HPLC in extracts from fruit samples of P. padus at different phenological stages. These compounds include one flavan-3-ol, four phenolic acids, five flavonoids, two anthocyanins.