Polyphenol Complex of Plum Varieties Most Adapted to the Conditions of the South of the Russian Far East: Identification by Tandem Mass Spectrometry

The aim of the study was to isolate and identify a complex of bioactive compounds, including polyphenols and compounds of other chemical classes, from plum fruit pulp extracts to assess their potential as a source of biologically active substances of phenolic nature. Ripe fruits of the plum varieties Krasnomyasaya, Neporazhemaya, Long Yuan Mi Li, Long Yuan Tao Li, collected at the end of July 2023 at the collection variety plot of the Far Eastern Experimental Station (Primorsky Krai), were used as plant material. To obtain highly concentrated extracts, fractional maceration was used: seven-day infusion of each part of the pulp in a dark room at room temperature with three repeated extractions for each sample. Mass spectrometric analysis was performed on an ion trap with an electrospray source (positive and negative ions), separating multicomponent mixtures on a Shimadzu LC‑20 Prominence HPLC liquid chromatograph with a UV detector and a Shodex ODP‑40 4E reversed-phase column. A gradient mode of transition from water to acetonitrile was used: 0…4 min. (0% acetonitrile), 4…60 min. (25% acetonitrile), 60…75 min. (100% acetonitrile), 75…120 min. (100% acetonitrile). Mass spectra were recorded in the m/z range of 100…1700 with fragmentation up to the 4th order. A total of 74 chemical compounds were identified as a result of mass spectrometric experiments, 52 of which were classified as polyphenols. A large group of anthocyanins and catechins has been identified, indicating high antioxidant properties of the studied plant matrices. For the first time, polyphenolic compounds ibuprofen, phloretin, umbelliferone, methylgallic acid, dihydrokaempferol, herbacetin, umbelliferone hexoside, p-coumaroylquinic acid – have been isolated from the pulp of PrunusL. fruits. The results indicate high prospects for the fruits of the studied plum varieties as an object of research for the search for biologically active substances of a polyphenolic nature, potentially suitable for the creation of new drugs and biologically active additives.