Research Progress on Skin Protective Activities of Marine Collagen Peptides

Marine collagen peptides feature low molecular weight, easy absorption, high bioavailability and favorable biological activities. They have been widely applied in functional foods, biomedicine and cosmetics.

This paper elaborates the skin-protective effects of marine collagen peptides from the perspectives of antioxidant, whitening, anti-aging, anti-inflammatory activities, wound-healing capacity and tissue repair. It also introduces their in vivo absorption, metabolic patterns and safety profiles, aiming to provide theoretical support for the development and application of marine collagen peptides in marine functional cosmetics.

Skin Protective Effects of Marine Collagen Peptides

Antioxidant Activity

Imbalance of reactive oxygen species (ROS) in the body is a key factor triggering skin aging. External environmental factors such as ultraviolet radiation and pollutants induce excessive ROS production in the skin and depletion of endogenous antioxidant enzymes[1].

In addition, ROS-mediated oxidative stress can lead to lipid peroxidation and DNA damage, and trigger the expression of matrix metalloproteinases (MMPs). MMPs degrade collagen and elastin in the extracellular matrix, disrupt the structure and integrity of the dermal layer, and consequently cause skin aging[2].

Existing studies have demonstrated that marine collagen peptides exert free radical scavenging effects in vitro. For instance, Chen Bei et al.[3] found that skin collagen peptides derived from Takifugu bimaculatus with molecular weight less than 1 kDa possess free radical scavenging capacity. Collagen peptides from cod bone exhibit stronger DPPH radical scavenging activity than superoxide anion radical scavenging activity[4].

Meanwhile, cellular and animal studies have verified the antioxidant activity of marine collagen peptides. Hydrolysates from red snapper scales can reduce malondialdehyde (MDA) levels while elevating superoxide dismutase (SOD) and catalase contents to achieve antioxidant effects[5]. Abalone peptides can scavenge intracellular ROS in UVB-irradiated HaCaT cells and inhibit UVB-induced cellular DNA damage[6].

Whitening Activity

Melanin is a natural pigment present in the skin. Moderate melanin helps protect skin against ultraviolet radiation, yet excessive melanin generation and accumulation contribute to pigmentary disorders such as melasma, freckles and even malignant melanoma. Melanin biosynthesis is closely associated with tyrosinase (TYR), tyrosinase-related protein 1 (TRP-1) and tyrosinase-related protein 2 (TRP-2)[7].

Domestic and international research confirms that marine collagen peptides reduce melanin production by inhibiting tyrosinase activity. Purified peptides from Meretrix meretrix after molecular sieve column chromatography show strong tyrosinase inhibitory activity, thereby lowering melanin content to realize whitening effects[8]. Collagen peptides extracted from milkfish (Chanos chanos) scales suppress melanin formation via tyrosinase inhibition[9].

Reduction of Skin Collagen Loss

Collagen is the major structural component of human skin. With aging and external environmental exposure, decreased collagen density and thickness become primary drivers of skin aging.

Hydroxyproline (Hyp) is a signature amino acid of collagen, and reduced Hyp level serves as a hallmark of aged skin. Studies have proven that marine collagen peptides can markedly increase Hyp content and stimulate skin collagen synthesis. Pacific cod skin gelatin hydrolysates promote type I procollagen synthesis by upregulating transforming growth factor-β type II receptor[10]. Collagen peptides isolated from cod skin downregulate MMP-1 expression by inhibiting phosphorylation of mitogen-activated protein kinase (MAPK) pathway-related proteins[11].

Anti-inflammatory Activity

Skin peeling, redness, pruritus, acne and other cutaneous conditions are mostly attributed to skin inflammation. Inflammation is a physiological defensive response. However, persistent chronic inflammation will deteriorate skin status and impair the skin barrier.

Chen et al.[10] investigated the effects of Pacific cod skin collagen hydrolysates (CH) on pro-inflammatory cytokine expression in photoaged skin. The results showed that CH reduced levels of interleukin-1α and tumor necrosis factor-α, mitigating skin inflammation.

Wound Healing and Tissue Repair

Marine collagen and its hydrolysates exhibit promising repairing efficacy for UV-exposed skin damage. In vitro cell experiments revealed that peptides from jellyfish and cod skin elevate cellular collagen and hyaluronic acid contents and repair damaged cells[12].

Absorption and Metabolism of Marine Collagen Peptides

Research indicates that oral intake of collagen peptides effectively improves skin conditions, increases skin hydration, enhances skin elasticity, remodels dermal collagen architecture and alleviates melasma in female subjects[13-15]. A clinical trial reported significantly elevated blood Hyp concentrations in volunteers after oral administration of deep-sea fish skin collagen peptides[13].

After oral administration of fish collagen or collagen peptides to mice, collagen peptide fragments can be detected in blood and skin tissues. For example, researchers used ¹⁴C-labeled silver carp skin collagen to trace metabolic processes in mice, and Hyp-containing peptides were detected in skin fibroblasts, proving that collagen peptides reach target skin cells in vivo[16]. Oral administration of fish scale collagen peptides to mice induced notable increases of Gly-Pro and Pro-Hyp dipeptides in blood[17].

Conclusion

Marine collagen peptides possess favorable antioxidant, whitening, anti-inflammatory and tissue-repairing properties, holding tremendous application prospects for both topical cosmetics and oral nutricosmetics.

Commercialization of cosmetics formulated with marine collagen peptides supports intensive processing and value addition of marine by-products, and contributes to the development of a modern marine industrial chain.

References

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