Fish processing generates a large amount of by-products, accounting for approximately 70% of the total weight of fish, with nutrient-rich scales, skin, heads, and viscera.

Fish viscera are identified as the most favorable source for extracting antioxidant peptides, potentially increasing fish by-product utilization and reducing environmental waste.

The study investigates the antioxidative and anti-AD effects of peptides derived from hydrolyzed tail by-products of Sebastes schlegelii, commonly known as Korea rockfish.

Atopic dermatitis (AD) is a chronic inflammatory skin disorder that affects a significant portion of the population, causing discomfort and impairing quality of life.

Reactive oxygen species (ROS) can lead to oxidative stress, prompting interest in natural antioxidants like antioxidant peptides derived from fish by-products.

The active peptide isolated from Protamex hydrolysate, identified as MP003, has a specific amino acid sequence and demonstrated significant therapeutic effects in an AD mouse model.

Histological analysis indicated that MP003 decreased eosinophil and mast cell infiltration while downregulating pro-inflammatory cytokines (IL-1β, IL-6) and IgE levels in serum and skin tissues.

MP003 treatment also reduced the expression of STAT3, a transcription factor involved in AD pathogenesis, suggesting a potential mechanism for its therapeutic effects.

In vivo studies showed that MP003 treatment reduced key AD symptoms such as erythema, lichenification, collagen deposition, and skin thickness in DNCB-induced NC/Nga mice.

Hydrophobic amino acids play a crucial role in the antioxidant efficacy of peptides, with specific amino acid sequences enhancing their scavenging ability.

Hydrolysates were created using various enzymes, with Protamex yielding the highest ABTS radical scavenging activity at an RC50 value of 69.69 ± 0.41 µg/mL.

Fish skin and heads are also good sources of antioxidant peptides, with varying yields and antioxidant activities, but fish viscera show superior benefits for extraction.