Synthetic musk fragrances (SMD) are compounds added to products to enhance their scent. They are often found in detergents, fabric softeners, and cosmetic products. Due to the daily use of fragrances, the introduction of SMD into the environment cannot be avoided. People are exposed to SMD mostly through the application of cosmetic products and to a certain extent also through consuming marine organisms, which leads to bioaccumulation of fragrances in fatty tissues. In the environment, SMD are subjected to various pathways and mechanisms of degradation, with oxidation and reduction being the dominant reactions. The resulting degradation products can be even more toxic than the parent compound, which is why they were included in our research. SMD have high log P values, which makes them resistant to environmental degradation and prone to bioaccumulation. In the Master's thesis, we determined the ecotoxicological profile, environmental impact, and endocrine toxicity of twenty-one representative SMD and their degradation products. We used the computer programs VegaNIC, Endocrine Disruptome, and ECOSAR, and based on the predicted results, we evaluated which of the SMD is potentially the safest and which is the least safe. The endocrine potential of SMD was determined based on the binding affinity of the compounds to 14 human nuclear receptors. We found that the tested SMD have the highest binding affinity to AR, AR an, ERα, ERβ, and ERβ an receptors. In addition to the binding affinity of individual fragrances to receptors, we also considered the predicted log P value, the BCF factor, acute toxicity, and the occurrence of these compounds in the environment. By increasing the value of the log P parameter, the probability of fragrance accumulation in the adipose tissue increases, as well as the probability of bioaccumulation of such compounds in the environment. The bioaccumulative potential of fragrances can also be predicted based on a high value of the BCF factor. The toxicity of the researched fragrances was assessed based on the acute toxicity data obtained from the calculated LC50 values. A low LC50 value indicates a greater acute toxicity of the fragrance and a greater risk to aquatic organisms. Based on the predicted results, we estimated that the safest musk fragrance is MC-4, as it shows a low potential for bioaccumulation, and has the lowest probability of binding to most nuclear receptors. The latter suggests a low endocrine effect of this fragrance. We otherwise found that the compound MC-4 is toxic to a certain type of fish, which highlights the fact that even relatively safe SMD can possess certain side effects. The compound HHCB, its degradation product HHCB lactone, and ambrettolide were ranked among the most toxic SMD. In view of the ecotoxicological properties and occurrence of SMD in the environment, HHCB and HHCB lactone represent the greatest risk to the environment and the organism. Despite the current low occurrence in the environment, we must also take into account ambrettolide from the point of view of endocrine potential. The results we obtained by in silico methods indicate that in the future it will be necessary to carry out more studies on SMD and their degradation products. At the same time, they represent an excellent tool for directing further in vivo and in vitro studies.
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