Biochemical and nutritional profiling of selected tropical green seaweeds

Abstract

The nutritional composition and anti-inflammatory properties of six tropical green seaweeds viz., Ulva lactuca, Ulva linza, Halimeda macroloba, Halimeda gracilis, Chaetomorpha antennina and Chaetomorpha linum were evaluated. U. lactuca exhibited the highest carbohydrate content (66.1%), while U. linza (12.89%) and U. lactuca (12.06%) showed the highest protein content, indicating their potential as plant-based protein sources. H. gracilis contained the highest ash content (35.12%), highlighting its mineral richness, particularly calcium, magnesium and phosphorus. Lipid content was low across all species, but U. linza exhibited the highest polyunsaturated fatty acid content (22.94%), with α-linolenic acid (13.72%) which could support cardiovascular health. Mineral analysis revealed high calcium levels in C. linum (18.99 mg 100 g-1), contributing to bone health. Pigment analysis showedU. linza contained the highest chlorophyll-a (7.60 μg ml-1) and total carotenoids (0.30 μg ml-1), adding antioxidant potential to its bioactivity. Chaetomorpha linum exhibited the strongest anti-inflammatory activity (IC50 = 1.60 mg ml-1), with bioactivity correlating to the favorable n-3/n-6 fatty acid ratio. Amino acid analysis identified U. linza as the richest source of essential amino acids, particularly methionine (6.37 mg g-1) and valine (6.30 mg g-1), making it an excellent candidate for dietary supplements. The results of the study suggest that green seaweeds belonging to the family Ulvaceae could be a potential non-conventional source for dietary products and functional food supplements. Keywords: Anti-inflammatory activities, Chlorophyta seaweeds, Essential amino acid, Non-conventional nutritional sources, Polyunsaturated fatty acid