<p>Phytochemical investigation of the leaves of <i>Armeniaca sibirica</i> (L.) Lam. led to the isolation of two new phenolic acids (<b>1</b>–<b>2</b>), together with eight known compounds (<b>3</b>–<b>10</b>) from the ethanol extracts of this plant. Structures of these compounds were elucidated through detailed spectroscopic analyses, using 1D-NMR and 2D-NMR in combination with HR-EI-MS techniques. All the compounds were evaluated for their antioxidant capabilities <i>in vitro</i> using 2, 2′-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS), 1, 1′-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging assays, and ferric-reducing antioxidant power (FRAP) methods.</p
