Evaluation of antioxidant activity of brown macroalgae found in Lampung Bay, Indonesia and molecular identification using DNA barcode cox1 BLAST.

Abstract

Background: The study on identifying of brown macroalgae species, particularly those on the southern coast of Lampung Bay-Indonesia, at the molecular level and their antioxidant activity has never been conducted, so we examined it as our purpose study.

Method and results: The research uses DPPH free radical scavenging activity and molecular identification using DNA barcode cox1 BLAST. Fifteen samples of fresh brown macroalgae with five samples, respectively, were collected from Sebalang Beach, Kalianda and Pesawaran, South Lampung. The DNA was first purified, and then the gene product was amplified using specific primers, cox1F1 primer and cox1R1 primer. The DNA sequence was checked and traced using the Basic Local Alignment Search Tool (BLAST). The three most dominant species of brown macroalgae were identified, namely Sargassum plagiophyllum, Sargassum ilicifolium and Hormophysa cuneiformis. The base length obtained ranged from 1164 to 1212 bp, with a similarity percentage of 98.36% to 100%. The three types of brown macroalgae have the ability to scavenge DPPH free radicals. Ethanol solvent and extract fractions significantly influence the reduction of DPPH free radicals. The ethanolic extract fraction of S. ilicifolium exhibited the lowest EC₅₀ value (64.17 ± 1.23 mg L^-1) and has the strongest antioxidant activity, followed by H. cuneiformis (75.88 ± 0.34 mg L^-1), and S. plagiophyllum (82.97 ± 1.30 mg L^-1).

Conclusion: The difference in species of brown macroalgae had no significant effect on the EC₅₀ activity, and all three had robust antioxidant activity because their concentrations ranged between 50 and 100 mg L^-1.