Extraction optimization of bioactive compounds from ora-pro-nobis (Pereskia aculeata Miller) leaves and their in vitro antioxidant and antihemolytic activities

Ora-pro-nobis (Pereskia aculeata Miller) is a non-conventional food plant common in Brazil. The objective of this study was to optimize the extraction of bioactive phenolic compounds from ora-pro-nobis leaves by employing solvent mixtures. Ten extracts were obtained with water, ethanol, acetone, and their binary and ternary mixtures, evaluating the chemical composition, antioxidant activity and bioactivities in vitro. The response surface methodology was applied to model the results and calculate the optimal solvent composition, which is 60% water, 40% ethanol and 0% acetone. The optimized extract is rich in phenolic compounds (64 mg GAE/g) and proteins (823 mg/g) and presents antioxidant activity (in intracellular media as well) and inhibits lipid peroxidation (32%) along with hypotonic hemolysis (H₅₀ = 0.339%), it does not present toxicity in vitro against cancer and normal cells. This is the first report of chicoric, caffeoyl-hexaric and coumaroyl-hexaric acids and some glycosylate derivatives of flavonols in ora-pro-nobis leaves.