Optimizing extraction methods by a comprehensive experimental approach and characterizing polyphenol compositions of...

Area of Science:

• Marine Botany
• Natural Product Chemistry
• Food Science & Technology

Background:

• Brown seaweed Ecklonia radiata contains valuable polyphenols, particularly phlorotannins, known for their health benefits.
• Efficient extraction of these compounds is crucial for their application in various industries.
• Optimizing extraction techniques can enhance yield and bioactivity.

Purpose of the Study:

• To optimize phlorotannin and total polyphenol extraction from Ecklonia radiata.
• To evaluate the antioxidant capacities of extracts obtained through optimized methods.
• To identify key factors influencing polyphenol extraction efficiency.

Main Methods:

• Conventional solvent extraction and ultrasound-assisted extraction were employed.
• Fractional factorial designs and steepest ascent/descent methods were used for optimization.
• Central composite rotatable designs refined extraction conditions using varying ethanol concentrations.
• High-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) analyzed polyphenol profiles.
• Antioxidant activities were assessed using DPPH, OH radical scavenging, and reducing power assays.

Main Results:

• Optimized conditions significantly enhanced phlorotannin and total polyphenol yields.
• Phlorotannin content reached up to 2.596 ± 0.04 mg/g PGE, and total polyphenols up to 10.836 ± 0.02 mg/g GAE.
• Extracts demonstrated robust antioxidant activity, with high DPPH and OH radical scavenging capacities.
• Reducing power capacities were substantially increased under optimized conditions.
• HPLC and LC-MS analyses confirmed the enrichment of antioxidant compounds.

Conclusions:

• Ecklonia radiata is a promising source of bioactive polyphenols, especially phlorotannins.
• The developed extraction methods effectively maximize polyphenol yield and antioxidant potential.
• Optimized extraction strategies offer significant potential for the food, nutraceutical, and pharmaceutical industries.