Spirulina-Derived Peptide Shows Strong Anti-Photoaging Effects in Skin Cells and Mice

Exposure to Ultraviolet (UV) irradiation, particularly UVB, is a primary driver of skin photoaging, leading to visible signs like wrinkles, loss of elasticity, and hyperpigmentation. This complex biological process involves increased oxidative stress, inflammation, and the accelerated degradation of vital skin components like collagen and elastin by enzymes known as matrix metalloproteinases (MMPs). Despite the availability of various anti-aging solutions, there's a continuous and pressing need for novel, effective, and low-toxicity compounds, especially those derived from natural sources. This study specifically addresses the gap in identifying and characterizing natural peptides with potent anti-photoaging activity and a favorable safety profile that can mitigate UVB-induced skin damage.

The study yielded compelling results, demonstrating that AAH exhibited significantly lower toxicity in HaCaT cells compared to the positive control, matrixyl, with cell viability remaining robust at 81.52% for AAH-treated cells versus a mere 5.32% for matrixyl-treated cells. In the in vivo model of UVB-irradiated mice, AAH treatment led to a substantial reduction in oxidative damage, evidenced by a decrease in malondialdehyde (MDA) content by 49% compared to UVB-irradiated controls. Furthermore, AAH significantly boosted the activity of key endogenous antioxidant enzymes: superoxide dismutase (SOD) activity increased by 103%, catalase (CAT) activity by 49%, and glutathione peroxidase (GSH-Px) activity by a remarkable 116%. The most impactful finding was that AAH not only effectively mitigated oxidative stress but also significantly reduced the expression of collagen-degrading enzymes, decreasing MMP-1 by 27% and MMP-3 by 29%, indicating a direct protective effect against the breakdown of the skin's extracellular matrix. Beyond these specific markers, an iTRAQ-based proteomic analysis identified 60 differentially expressed proteins in response to AAH treatment, which were subsequently mapped into an intricate interaction network composed of two core sub-networks. This suggests that AAH exerts its anti-photoaging effects through broad modulation of multiple cellular pathways involved in the skin's response to UVB damage and repair mechanisms.