Total antioxidant capacity and content of phenolic compounds in wild strawberries (Fragaria vesca) collected in Bolivia

To study the composition of wild strawberries grown at high altitude, total antioxidant capacity, total phenolic compounds, total flavonoids, and individual phenolic compounds were measured in wild strawberries (Fragaria vesca) collected between 2,650 and 3,300 m above sea level in Bolivia. Total antioxidant capacity, as assessed by the ferric-reducing antioxidant power and 2,2′ -azino-bis(3-ethylbenzotiazoline-6-sulphonic acid) methods, was in the range 16-39 μmol of Trolox equivalents/g fw by both methods. The total phenolic content was 9.7-21 μmol gallic acid equivalents/g fw, and the flavonoid content ranged between 2.8 and 4.9 μmol of catechin equivalents/g fw. The data obtained by the four methods showed several significant linear correlations confirming that flavonoids and other phenolic compounds contributed significantly to the total antioxidant capacity values. Reversed-phase high performance liquid chromatography analysis of extracts subjected to acid hydrolysis showed the presence of seven major fractions, tentatively identified as ellagic acid, cyanidin, pelargonidin, quercetin, kaempferol, gallic acid derivatives, and catechin derivatives. The data indicated that wild strawberries have a somewhat higher total antioxidant capacity content in comparison with that reported for cultivated strawberries. No obvious difference to the composition reported for wild strawberries grown at low altitude could be found.