Products designed to filter ultraviolet (UV) light are responsible for growing levels of anthropogenic environmental contamination. Octinoxate (ONT) is among the most common UV filtering active ingredients in cosmetics and sunscreens. The present study was designed to evaluate the toxicological effects of ONT on the photosynthetic activity of the Chlorella species of marine microalgae. These analyses identified ONT as a potent photo-toxicant, the effects of which were more pronounced upon light exposure relative to in the dark. Short-term ONT exposure had no effect on photosynthetic electron transport capacity in the dark but did significantly reduce the ribulose-1,5-bisphosphate carboxylase/oxygenase activity in Chlorella cells, suggesting that this compound can directly suppress the photosynthetic Calvin cycle. When cells were subsequently exposed to light, the disruption of this cycle resulted in an excess of excitation energy, in turn driving the excessive generation of reactive oxygen species (ROS). ROS-mediated disruption of cellular metabolism further aggravated this ONT-induced microalgal damage. As such, under natural light conditions, these microalgae cells are exposed to increased oxidative stress that impairs their growth and causes pigment bleaching. Restricting the utilization of ONT-containing sunscreens thus has the potential to better preserve the integrity of aquatic and terrestrial ecosystems.

旨在过滤紫外线 (UV) 光的产品是造成人为环境污染水平不断提高的原因。Octinoxate (ONT) 是化妆品和防晒霜中最常见的紫外线过滤活性成分之一。本研究旨在评估 ONT 对海洋微藻小球藻物种光合活性的毒理学影响。这些分析确定 ONT 是一种有效的光毒剂，相对于在黑暗中，其对光照的影响更为明显。短期 ONT 暴露对黑暗中的光合电子传输能力没有影响，但确实显着降低了小球藻中1,5-二磷酸核酮糖羧化酶/加氧酶的活性细胞，表明这种化合物可以直接抑制光合卡尔文循环。当细胞随后暴露在光线下时，该循环的中断导致激发能量过剩，进而导致活性氧 (ROS) 的过度产生。ROS 介导的细胞代谢破坏进一步加剧了这种 ONT 诱导的微藻损伤。因此，在自然光照条件下，这些微藻细胞暴露在增加的氧化应激下，这会损害它们的生长并导致色素漂白。因此，限制含有 ONT 的防晒剂的使用有可能更好地保护水生和陆地生态系统的完整性。