Antioxidant potential and metabolite profiling of Indian seaweeds for nutraceutical applications

Seaweed are abundant in primary and secondary metabolites, including phenolics, flavonoids, proteins, carbohydrates, and amino acids. Beyond their traditional use as food, their diverse chemical composition makes them promising candidates for pharmaceutical and nutraceutical applications. This study investigates antioxidant potential, phytochemical composition, and bioactive metabolites of six abundant seaweed species collected off the Indian coastline. Comprehensive phytochemical analyses were conducted to quantify phenolics, flavonoids, carbohydrates, proteins, amino acids, and ionomic composition to assess macronutrient and micronutrient content. Gas Chromatography-Mass Spectrometry (GC–MS) was employed to profile bioactive compounds in the seaweed extracts. Among the seaweeds analysed, Grateloupia indica (Rhodophyta) revealed the highest antioxidant activity (94 % at 1 mg mL⁻¹), along with the highest phenolic content of 19.04 ± 3.05 Tannic acid equivalent (TAE) g⁻¹ of dry weight (DW) of extract and flavonoid content of 9.59 ± 0.73 Rutin equivalent (RE) g⁻¹ of DW of extract. All six seaweeds demonstrated substantial levels of proteins, essential amino acids, carbohydrates, and beneficial elemental composition. GC–MS analysis revealed the presence of various metabolites with known antioxidant, anticancer, and antimicrobial properties. Multivariate analysis facilitated the understanding of seaweed chemosystematics and phytochemical profiling of the species. The study highlights the significant nutraceutical potential of seaweeds and provides a foundation for their further exploration into their pharmaceutical and nutraceutical applications.