AO-08: Effect of extraction conditions on the recovery of phenolic compounds and the in vitro antioxidant activity of algae (Ulva lactuca) extracts

Abstract

Subject description: The procedure for the extraction of total polyphenols is influenced by several parameters such as the chemical nature of these compounds, the appropriate extraction method, the solvent used, particle size, extraction time, and temperature. Objectives: The objective of this study is to study the effect extraction conditions on the recovery of phenolic compounds and in vitro antioxidant properties algae (Ulva lactuca) Methods: The effects of solvent type (acetone, ethanol, methanol, and water), solvent concentration (20-100%), sample/solvent ratio (0.2/20 - 1 mg/20 g/ml), extraction time (30-150 min), and temperature (25-90°C) on the extraction of total polyphenols and the antioxidant activity of algae were evaluated. The contents of total polyphenols (TP) and flavonoids were determined. While the ferric reducing power (FRP) and the free radical scavenging activity (DPPH) were used to evaluate the antioxidant activity of the extracts. Results and discussion: The results obtained show that the extraction conditions have a significant effect (p<0.05) on the content of total polyphenols, flavonoids, and the antioxidant activity of the extracts. The optimal extraction conditions are as follows: 60% acetone, 0.2 g/20 ml, 90 min, and 90°C, with values of 11.89 g GAE/100 g for total phenolic contents, 90.43 g AAE/100 g for ferric reducing power, and 70.23 g % for free radical scavenging activity (DPPH). Ferric-reducing and free radical scavenging potentials were found to be positively significantly correlated with phenolic content under the influence of all extraction parameters. Conclusion: Seaweeds are indeed a rich source of natural antioxidants with a strong antioxidant property. The one-factor method has limitations in optimizing the phenolic extract, the use of developed mathematical models like RSM (Response Surface Methodology) is recommended for more effective optimization processes