Chemical Analysis and Biological Potentials of Extracts from Colpomenia sinuosa

Background: Colpomenia sinuosa is a brown alga rich in molecules of pharmacological, nutraceutical, and functional properties. Despite its therapeutic potentials, this alga is poorly studied in this area of the Mediterranean. Objectives: The study objective was to investigate the physicochemical properties and biological potentials of different extracts of the brown seaweed C. sinuosa. Materials and Methods: Crude extracts and fractions were obtained by different types of solvent extractions. Proximal analysis was adopted to reveal the ash content. Protein and carbohydrate contents were determined by phenol‑sulfuric acid method and Lowry and Bradford methods, respectively. The mineral content was assessed by atomic absorption spectroscopy, where the total phenolic content (TPC) was determined by Folin–Ciocalteu reagent, antioxidant properties by radical scavenging assay, and antimicrobial activity by disc diffusion method. Finally, the anti‑inflammatory activity was determined by albumin denaturation test. Results: Proximal analysis revealed high levels of total ash content (20.03 ± 0.79%), protein content (10.77 ± 0.18%), total lipids (4.35 ± 0.212%), and total carbohydrates (40.367 ± 0.421%). Magnesium concentration (16.79 ± 0.721 mg/g) was highest among macro minerals. The TPC of fractions and extracts ranged from 17.78 ± 0.092 to 39.02 ± 0.199 mg gallic acid equivalents/g dry weight. The highest scavenging activity reached 84.1% ± 0.83 at 750 μg/mL. Maximal anti‑inflammatory activity was noted in aqueous extract (59.38 ± 4.35 μg/mL). Conclusion: This significant scavenging activity increased in polar extracts obtained by Soxhlet extraction. The aqueous extracts showed the highest 2,2‑diphenyl‑1‑picrylhydrazyl scavenging activity and highest albumin denaturation inhibition, whereas the highest bactericidal activity was found in the methanolic extracts. Our results represent the first report on Lebanese C. sinuosa extract as a promising source of bioactive compounds with high antioxidant potential.