Pycnogenol® Mitigates Oxidative Stress and Improves Skin Defenses Against Environmental Pollutants: An Ex-Vivo Human Skin Explant Study

Oxidative stress is a major factor in skin aging and various skin pathologies. Environmental pollutants exacerbate this stress by generating reactive oxygen species (ROS), disrupting the skin’s redox balance. Pycnogenol®, a French maritime pine bark, extract is standardized to contain 70 ± 5% procyanidins and known to mitigate oxidative damage and inflammation. This study aims to evaluate the potential antipollution and antioxidant effects of Pycnogenol® on skin. Ex vivo human skin explants were treated with varying concentrations of Pycnogenol® (0.5%, 1%, and 2%) and then exposed to a mixture of pollutants. The expression of stress markers Nrf2 (Nuclear Factor Erythroid 2-Related Factor 2) and AHR (Aryl Hydrocarbon Receptor) were evaluated using immunostaining. Lipid peroxidation levels were measured by quantifying malondialdehyde (MDA) concentrations. The extract significantly decreased Nrf2 expression by 40% (p = 0.003) and 23% (p = 0.048) with a dose of 2% and 1%, respectively. After pollutant exposure, Pycnogenol® (0.5%, 1%, and 2%) reduced Nrf2 over-expression in a dose–response manner by 29% (p = 0.03), 58% (p = 0.004) and 64% (p = 0.002) respectively. Pycnogenol® at 0.5%, 1%, and 2% significantly reduced AHR over-expression by 61% (p < 0.0001), 76% (p < 0.0001) and 85% (p < 0.0001), respectively. Pycnogenol® (1%, and 2%) decreased MDA levels following pollutant exposure by 17% (p = 0.06) and 25% (p = 0.01) respectively. In a dose-dependent manner, Pycnogenol® exhibited a strong protective effect against pollution, significantly reducing pollutant-induced basal oxidative stress (MDA) and over-expression of Nrf2 and AHR, key factors in oxidative stress and detoxification. Pycnogenol® also increased AHR expression in the absence of pollutants, which may reflect an adaptive cellular response.