Effect of different extraction conditions on phlorotannin content and antioxidant activity of extract from brown algae ( <i>Sargassum angustifolium</i> )
Alireza Hodhodi, Aria Babakhani, Haniyeh Rostamzad
Abstract
Brown algae are a valuable source of natural antioxidant compounds, especially phlorotannins. In this study, the extraction was performed from brown algae Sargassum angustifolium by three different methods: solvent, ultrasound-assisted and microwave-assisted. The solvent extraction was performed with ethanol/water solvent in three ratios (30:70), (50:50), and (70:30). Also, the extraction was performed by ultrasound-assisted and microwave-assisted with ethanol solvent in three durations of 10, 25, and 40 min. The amount of phlorotannin content, total phenolic content, ferric reducing antioxidant power, DPPH radical scavenging activity, and total antioxidant capacity in different extracts were evaluated. The results showed that the yield of phlorotannin content was dependent on the solvent concentration, and its amount increased with the increasing polarity of the solvent. According to this, the maximum amount of phlorotannin was obtained from ethanol/water treatment (30:70) at the rate of 3.40 ± 0.00 mg phloroglucinol per gram dry weight that was significantly higher than the other two treatments (p < .05). The highest total phenol content was obtained in ethanol/water treatment (30:70) and the highest total antioxidant capacity was obtained in ethanol/water treatment (70:30). According to all factors and variables considered, the best treatment was microwave-assisted extraction in the duration of 25 and 40 min. Practical applications It was found that the extract of brown algae Sargassum angustifolium was a perfect choice for the extraction of antioxidant compounds, especially phlorotannins, for dietary and medicinal purposes.