Isolation and identification of strawberry phenolics with antioxidant and human cancer cell anti proliferative properties

Studies suggest that consumption of berry fruits, including strawberries (Fragaria x ananassa Duch.), may have beneficial effects against oxidative stress mediated diseases such as cancer. Berries contain multiple phenolic compounds, which are thought to contribute to their biological properties. Comprehensive profiling of phenolics from strawberries was previously reported using high-performance liquid chromatography with mass spectrometry (HPLC-MS) detection. The current study reports the isolation and structural characterization of 10 phenolic compounds from strawberry extracts using a combination of Amberlite XAD16-resin and C18 columns, HPLC-UV, and nuclear magnetic resonance (NMR) spectroscopy methods. The phenolics were cyanidin-3-glucoside (1), pelargonidin (2), pelargonidin-3-glucoside (3), pelargonidin-3-rutinosid (4), kaempferol (5), quercetin (6), kaempferol-3-(6'-coumaroyl)glucoside) (7), 3,4,5-trihydroxyphenyl-acrylic acid (8), glucose ester of (E)-p-coumaric acid (9), and ellagic acid (10). Strawberry crude extracts and purified compounds 1 - 10 were evaluated for antioxidant and human cancer cell antiproliferative activities by the Trolox equivalent antioxidant capacity (TEAC) and luminescent ATIP cell viability assays, respectively. Among the pure compounds, the anthocyanins 1 (7156 mu M Trolox/mg), 2 (4922 mu M Trolox/mg), and 4 (5514 mu M Trolox/mg) were the most potent antioxidants. Crude extracts (250 mu g/mL) and pure compounds (100 mu g/mL) inhibited the growth of human oral (CAL-27, KB), colon (HT29, HCT-116), and prostate (LNCaP, DU145) cancer cells with different sensitivities observed between cell lines. This study adds to the growing body of data supporting the bioactivities of berry fruit phenolics and their potential impact on human health.