α-Iso-Cubebene Alleviates AMD-like Retinal Injury Through Modulation of Oxidative Stress and Inflammatory Response

Although oxidative stress plays a critical role in age-related macular degeneration (AMD) progression, natural product–derived single compounds against AMD remain largely unexplored. We investigated the protective effects and underlying mechanism of α-iso-cubebene against AMD-like retinal injury. Alterations in key phenotypes for AMD were analyzed in AMD-mimicking models using ARPE-19 cells co-treated with blue light (BL) and N-retinylidene-N-retinylethanolamine (A2E), as well as BL-exposed BALB/c mice. In BL+A2E-treated ARPE-19 cells, α-iso-cubebene reduced intracellular reactive oxygen species (ROS) and nitric oxide (NO) production and restored superoxide dismutase (SOD) activity and nuclear factor erythroid 2–related factor 2 (Nrf2), suggesting enhancement of the antioxidant defense system. Furthermore, α-iso-cubebene improved cell viability, reduced apoptotic cell populations, and regulated apoptosis-related signaling pathways under oxidative stress conditions. It also attenuated cyclooxygenase-2 (COX-2)-mediated inducible nitric oxide synthase (iNOS) signaling and was associated with reduced inflammasome-related signaling. Importantly, these protective effects were consistently observed regarding the protection of histopathological structure and normalization of inflammatory cytokines in the retina of BL-exposed BALB/c mice. Collectively, our results demonstrate that α-iso-cubebene, as a potential therapeutic candidate, alleviates AMD-like retinal injury and was associated with enhanced antioxidant responses and reduced inflammatory and apoptotic signaling markers.