WITHDRAWN: Optimization of conventional extraction of phenolic compounds and antioxidant activity from myrtle (Myrtus communis L.) fruit

Abstract

This study aimed to extract phenolic compounds from myrtle (Myrtus communis L.) fruits. The extraction of polyphenols from myrtle berries using a conventional solid-liquid extraction was optimized using single factor experiments. The influence of several parameters such as the type of solvent (50% acetone, 50% methanol, 50% ethanol and water), solvent concentration (30-100%; v/v), solvent acidity (0-0.1N), temperature (20-40°C), and time (30-360min) on the yield extraction of total phenolic content (TPC), total flavonoid content (TFC), total proanthocyanidin content (TPAC), and on the antioxidant activity including DPPH-radical scavenging activity (DPPH-RSA), ABTS-radical scavenging activity (ABTS-RSA) and ferric reducing power (FRP) were studied. The results showed that 50% acetone without acidification, 40°C and 180min are the best conditions for extracting TPC (87mg GAE/g DW), TFC (12mg QE/g DW), and TPAC (76mg CE/g DW). Myrtle berries extracted under these conditions also exhibited the strongest antioxidant activity: DPPH-RSA (7166mg TE/g DW), ABTS-RSA (164mg TE/g DW), and FRP (69mg AAE/g DW). Pearson correlation coefficients showed a good positive correlation 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). These results suggested that myrtle berries may serve as a good source of natural antioxidants with high antioxidant potential. Therefore, it could be useful in developing functional foods and nutraceuticals.