Evaluation of the antioxidant activity of the leaves of acerola, guabiroba and ora-pro-nobis

The objective of this work was to quantify the total content of phenolic compounds and the antioxidant activity of ethanolic extracts of acerola, guabiroba and ora-pro-nobis leaves. The analysis was performed by the DPPH free-radical method, aiming to find plants with potential use as natural antioxidants in foodstuff. In the extraction of phenolic compounds from leaves, acidified methanol 80% showed superior performance when compared to ethanol 80%. It was found the amounts of 1656.66, 5196.66 and 1693.33 mg GAE (gallic acid equivalent)/100 g for acerola, guabiroba and ora-pro-nobis leaves, respectively. Ethanolic extracts of guabiroba and ora-pro-nobis leaves (8.57 μg GAE/mL) presented higher antioxidant activity (92.6 and 92.76%, respectively) than BHT (10.13%), ascorbic acid (19.25%) and similar to trolox (92.79%). The extract of ora-pro-nobis presented the lowest IC50 (3.22 μg GAE/mL) showing a good ability to capture the DPPH radical.