Crabapple trees belong to the Malus genus (Rosaceae) and bear fruits that are sparingly consumed and used in the preparation of fruit beverages. Cyclooxygenase (COX) enzyme inhibitory and antioxidant bioassay-guided fractionation of the aqueous and methanol extracts of Malus x kornicensis and Malus x Indian Summer yielded (+)-catechin (1), (-)-epicatechin (2), cyanidin-3-O-beta-galactopyranoside (3), and amygdalin (4). Pure compounds 1-4 were obtained by HPLC, identified by LC-ES/MS, CD, and NMR spectroscopic methods and evaluated for their COX enzyme inhibitory and antioxidant activities. In COX-1 and -2 enzyme inhibitory assays, compounds 1-3 (all at 80 microM) showed activities of 20.4, 46.3%; 57.6, 47.9%; and 8.2, 13.7%, respectively, compared to naproxen (54.3, 41.3%; 10 microM), ibuprofen (47.5, 39.8%; 10 microM), Celebrex (46.2, 66.3%; 1.67 ppm), and Vioxx (23.8, 88.1%, 1.67 ppm). In the antioxidant assay, the catechins (1-2) and anthocyanin (3) (all at 40 microM) showed activities of 61.3, 62.5, and 60.1%, respectively. The synthetic antioxidants, tert-butylhydroquinone (TBHQ), butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), and vitamin E (all tested at 10 microM), gave 75.2, 80.1, 70.0, and 10.2% activities, respectively. The cyanogenic glycoside, amygdalin (4), and its hydrolysis products, mandelonitrile (5) and benzaldehyde (6), were not active in the antioxidant or COX enzyme inhibitory assays at 80 microM concentrations.