Anti-Photoaging Effects of a Polysaccharide from Kappaphycus alvarezii In Vitro and In Vivo

Area of Science:

• Marine Biotechnology
• Dermatology
• Biochemistry

Background:

• The red alga *Kappaphycus alvarezii* yields polysaccharides with potential skincare benefits.
• High molecular weight of native polysaccharides limits their skin penetration and efficacy.
• Developing low-molecular-weight derivatives is crucial for enhanced bioavailability.

Purpose of the Study:

• To produce and evaluate a low-molecular-weight polysaccharide (KP-90) from *Kappaphycus alvarezii* for anti-photoaging effects.
• To investigate KP-90's protective mechanisms against UV-induced skin damage in vitro and in vivo.
• To explore the potential of marine biomass valorization for novel cosmetic ingredients.

Main Methods:

• Free-radical degradation was used to obtain low-molecular-weight KP-90.
• In vitro assays involved UVB/UVA-irradiated HaCaT cells and human dermal fibroblasts.
• In vivo studies utilized a UVB/UVA-irradiated nude mice model.

Main Results:

• KP-90 significantly improved cell viability and reduced oxidative stress markers (ROS, MDA) in irradiated cells.
• KP-90 restored antioxidant enzyme activity (SOD, CAT, GSH-Px).
• KP-90 downregulated matrix metalloproteinases (MMP-1, -3, -9) and pro-inflammatory cytokines (TNF-α, IL-6, IL-1β).
• In vivo, KP-90 alleviated epidermal hyperplasia, increased collagen I and hyaluronic acid, and improved wrinkles and skin laxity.

Conclusions:

• KP-90 demonstrates significant anti-photoaging properties by mitigating oxidative stress, inflammation, and extracellular matrix degradation.
• KP-90 promotes skin repair and enhances visible signs of aging, validating its potential as a cosmetic ingredient.
• This study highlights a successful strategy for valorizing marine biomass into high-value skincare compounds.