Characterization and Antioxidant Activity of Bioactive Protein Extracted from Channa striata (Bloch, 1793) by Ammonium Sulfate Fractionation

Snakehead fish (Channa striata (Bloch, 1793)) has long been recognized in traditional medicine for its ability to accelerate wound healing, particularly after surgery and childbirth. This therapeutic potential is largely attributed to its rich content of bioactive proteins, especially albumin. However, the detailed protein profile and functional properties of this species remain underexplored. This study aimed to characterize the soluble protein components extracted from Channa striata using ammonium sulfate fractionation and to evaluate their antioxidant activity. Fractionation was performed at saturation levels of 20%, 40%, 60%, and 80%, followed by dialysis and freeze-drying. The 40–60% fraction yielded the highest protein recovery (75%) and protein concentration (55%), indicating optimal enrichment of soluble proteins. SDS-PAGE analysis revealed a dominant band at ~66 kDa, consistent with albumin, while additional bands indicated the presence of other bioactive proteins. FT-IR spectra confirmed the presence of amide I and II absorption bands, indicating α-helix and β-sheet structures typical of albumin. The antioxidant activity of the protein extract was evaluated using the DPPH assay, showing a strong radical-scavenging capacity with an IC₅₀ value of 47.2 µg/mL. These findings support the potential of snakehead fish as a promising source of functional protein ingredients. The use of ammonium sulfate fractionation in this study offers a simple, cost-effective, and eco-friendly method for isolating bioactive proteins with nutritional and therapeutic relevance. This research not only contributes to the scientific understanding of Channa striata protein composition but also enhances its value as a traditional food resource with modern health applications. It offers a novel approach to developing protein-rich functional foods and highlights the untapped potential of local aquatic species for food and health industries.