Optimization of Extraction Conditions of Phenolic Compounds and Antioxidant Activity From Myrtle (<i>Myrtus communis</i> L.) Fruit

The extraction of polyphenols from myrtle (Myrtus communis L.) fruits using a conventional solid-liquid extraction was optimized using a single-factor experiment approach. The influence of several parameters such as type of solvent (50% acetone, 50% methanol, 50% ethanol, and water), solvent concentration (30-100%; v/v), solvent acidity (0-0,1 N), temperature (20°C-40°C) and time (30-360 min) on the yield extraction of total phenolic content (TPC), total flavonoid content (TFC), total proanthocyanidin content (TPAC), and on the antioxidant activity: DPPH-radical scavenging activity (DPPH-RSA), ABTS-radical scavenging activity (ABTS-RSA) and ferric reducing power (FRP) was studied. The results showed that 50% acetone, 40°C, and 180 min were the best conditions for extracting TPC (87 mg GAE/g DW), TFC (12 mg QE/g DW), and TPAC (76 mg CE/g DW). Myrtle berries extracted with these conditions also exhibited the strongest antioxidant activity: DPPH-RSA (143 mg TE/g DW), ABTS-RSA (164 mg TE/g DW), and FRP (69 mg AAE/g DW). Pearson correlation coefficients showed good positive correlations between TPC, TFC, and TPAC and antioxidant activities (DPPH-RSA, ABTS-RSA, and FRP), mainly under the effect of solvent type (0.93 < r < 0.99) and solvent concentration (0.91 < r < 0.99).