applied sciences Article LC-ESI-MS/MS-MRM Profiling of Polyphenols and Antioxidant Activity Evaluation of Junipers of Different Origin Marta Olech 1 , Renata Nowak 1, Diana Ivanova 2 , Alexander Tashev 3, Stanislava Boyadzhieva 2, Galina Kalotova 2, George Angelov 2 and Urszula Gawlik-Dziki 4,* 1 Chair and Department of Pharmaceutical Botany, Medical University, 1 Chod´zkiStreet, 20-093 Lublin, Poland;
[email protected] (M.O.);
[email protected] (R.N.) 2 Institute of Chemical Engineering, Bulgarian Academy of Sciences, Academic George Bonchev Street, Bldg. 103, 1113 Sofia, Bulgaria;
[email protected] (D.I.);
[email protected] (S.B.);
[email protected] (G.K.);
[email protected] (G.A.) 3 Department of Dendrology, University of Forestry, 10 Kliment Ochridsky Boulevard, 1756 Sofia, Bulgaria;
[email protected] 4 Department of Biochemistry and Food Chemistry, University of Life Sciences, 8 Skromna Street, 20-704 Lublin, Poland * Correspondence:
[email protected] Received: 5 November 2020; Accepted: 10 December 2020; Published: 14 December 2020 Abstract: This study was aimed at identifying new efficient antioxidant juniper species and their metabolites, which are responsible for this activity. About 30 juniper representatives were assayed for antioxidant activity (DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,20-azino-bis(3- ethylbenzthiazoline-6-sulphonic acid) radical scavenging) and total polyphenol content (TPC). The most active species were identified, and their most abundant polyphenols were quantified by the LC-electrospray ionization (ESI)-MS/MS-multiple reaction monitoring (MRM) method. In the group of studied species, J. ashei (mountain cedar) leaf extract was outlined as the best antioxidant with the highest TPC.