Amelioration of Particulate Matter-Induced Oxidative Stress by a Bioactive Hizikia fusiformis Extract: A Functional Biomaterial for Cosmeceutical Applications

Air pollution-related skin damage has heightened the demand for natural protective agents. <i>Hizikia fusiformis</i>, a brown seaweed rich in fucoidan and bioactive fatty acids (α-linolenic acid, eicosatetraenoic acid, and palmitic acid), possesses antioxidant and anti-inflammatory properties. This study investigated the protective effects of <i>H. fusiformis</i> ethanol extract (HFE) against particulate matter (PM)-induced oxidative stress, inflammation, and apoptosis in human keratinocytes. Antioxidant activity was assessed using DPPH and hydroxyl radical scavenging assays, while PM-induced cytotoxicity, ROS generation, inflammatory markers, and apoptotic pathways were evaluated using the WST-8 assay, DCFH2-DA, qPCR, western blotting, and Hoechst staining. HFE significantly reduced ROS levels, enhanced antioxidant enzyme activity, and mitigated PM-induced cytotoxicity. These effects were mediated by fucoidan and fatty acids, which modulated inflammatory pathways (NF-κB and MAPK), stabilized membranes, and inhibited apoptosis (Bcl-2, Bax, and caspase-3). Collectively, these findings highlight HFE's potential as a natural anti-pollution skincare ingredient, supporting further in vivo studies and formulation development.