Résumé:
Subject description: Seaweeds are a rich source of natural antioxidants with potent antioxidant
properties. While the one-factor method has limitations in optimizing the phenolic extract, the use of
developed mathematical models such as Response Surface Methodology (RSM) is recommended for
more effective optimization processes.
Objectives: Given the highly bioactive nature of phenolics and their numerous therapeutic
applications, the primary objective of this investigation is to optimize their recovery using Response
Surface Methodology (RSM).
Methods: Prior to RSM, the single-factor method was applied to reveal the main factors
influencing the extraction (solvent type and concentration, sample˗to˗solvent ratio, temperature, and
time of extraction). 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 of the preliminary optimization step through sequential
methodology revealed that solvent concentration, extraction duration, and temperature were the main
influencing factors. All these tested extraction parameters significantly influenced total phenolic
contents (TPC) and DPPH-free radical scavenging activity (FRSA) and ferric reducing power (FRP).
RSM analysis using Box˗Behnken design showed that the optimal extraction conditions of total
phenolic contents of algae were 23.07% acetone, 51.82 °C, and 118.02 min with values of 29.44 mg
GAE/g for total phenolic extracts, 59.48% and FRSA, and 123.45 mg AAE/100g for FRP. 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.
Conclusion: The developed mathematical models have demonstrated a high level of
significance through sequential and RSM optimization processes for phenolic antioxidants of Ficus
carica leaves. This method allows us to observe the effects of different extraction conditions on the
phenolic antioxidants
