Qualitative and quantitative composition variability of phenolic compounds in European plum (Prunus domestica L.) fruits.

The aim of the research. To determine qualitative and quantitative composition variability of phenolic compounds in fruits of European plum, which grow in Lithuanian climatic conditions and to evaluate their extracts antioxidant activity in vitro. The objectives of the research. To ascertain the most appropriate extraction conditions of anthocyanins from samples of European plum fruits. To determine qualitative and quantitative composition of anthocyanins in European plum fruit samples suing UV–Vis spectrophotometric and HPLC methods of analysis. To determine qualitative and quantitative composition of phenolic compounds in European plum fruit samples using UHPLC–MS method. To investigate antioxidant activity in vitro of European plum fruit extracts. To evaluate correlation between quantities of identified phenolic compounds of plum fruits and antioxidant activity of their extracts in vitro. To investigate the impact of rootstock on quantities of identified phenolic compounds in plum fruits. The object and methods of the research. The samples of these cultivars of European plum fuits were investigated: 'Čačanska najbolje' (grafted on Prunus cerasifera Ehrh. and 'Vangenheimo vengrinė' rootstocks), 'Čačanska Rana', 'Dambrovicų vengrinė', 'Edinburginė' (grafted on two different rootstocks), 'Favorita del Sultano', 'Herman', 'Jubileum' (grafted on two different rootstocks), 'Kijevo vėlyvoji', 'Kometa' ,'Opal', 'Rausvė', 'Stanley', 'Uleno renklodė', 'Valor' (grafted on two different rootstocks), 'Viktorija', 'Violeta', 'Zarechnaya Rannyaya'. Total anthocyanin and proanthocyanin content and antioxidant activity were determined by UV – VIS spectrophotometric analysis method. The quantities of individual phenolic compounds were determined by UHPLC–MS method. The results and conclusions of the research. The highest amount of total anthocyanin quantity was obtained by using 50 % (v/v) ethanol, 678 W ultrasound power for 73 minutes and by using 83,64 % (v/v) ethanol, 678 W ultrasound power for 40 minutes, respectively. By HPLC and UHPLC–MS methods these phenolic compounds were determined and their quantities were evaluated in plum fruits: cyanidin-3-O-glucoside, cyanidin-3-O-rutinoside, peonidin-3-O-glucoside, peonidin-3-O-rutinoside, procyanidins A2 and C1, catechin, avicularin, hyperoside, isoquercitrin, isorhamnetin-3-O-rutinoside, rutin, quercetin, chlorogenic acid. The strongest antioxidant capacity by ABTS, FRAP and CuPRAC methods was determined in extracts of cultivars 'Čačanska najbolje' (grafted on both rootstocks), 'Kometa', 'Opal' and 'Zarechnaya Rannyaya'. Strong correlations were determined between quantity of total anthocyanin content and antioxidant activities, measured by ABTS and FRAP methods. The effect of rootstock origin on anthocyanin content depends on plum cultivar and structure of individual anthocyanin

Variability in the Content of Phenolic Compounds in Plum Fruit

The aim of this study was to determine the composition and content of phenolic compounds in extracts of plum fruit. Fruit of 17 plum cultivars were analyzed. Fruit samples were collected in 2019 from fruit trees with “Myrobalan” (P. cerasifera Ehrh.) and “Wangenheim Prune” (P. domestica L.) rootstocks. The following glycosides of the flavonol group were identified: avicularin, isorhamnetin-3-O-rutinoside, isoquercitrin, hyperoside, rutin, and an aglycone quercetin. Compounds of the flavan-3-ol group were identified, such as (+)-catechin, procyanidin C1, and procyanidin A2, along with chlorogenic acid attributed to phenolic acids and a non-phenolic cyclitol–quinic acid. Of all the analytes identified in plum fruit samples, quinic acid predominated, while chlorogenic acid predominated among all the identified phenolic compounds, and rutin predominated in the flavonol group. Hierarchical cluster analysis (HCA) and principal component analysis (PCA) revealed that fruit samples of “Kubanskaya Kometa”, “Zarechnaya Raniaya”, “Duke of Edinburgh”, “Jubileum”, and “Favorita del Sultano” cultivars had di erent quantitative content of phenolic compounds from that observed in other samples. The highest total amount of phenolic compounds was found in the European plum samples of the “Zarechnaya Rannyaya” cultivar, while the amount of quinic acid was the highest in plum fruit samples of the “Jubileum” cultivar