Comparison of Melatonin Photodegradation Between Sunlight and Uv Irradiation

Melatonin is synthesized mainly in the pineal gland, retina, digestive tract, and skin. This hormone is widely prescribed for therapeutic applications such as treating circadian rhythm, intercontinental flight dysrhythmia (jet lag syndrome), and sleep disorders. As a result of the COVID-19 pandemic, the consumption of this hormone was increased up to 300% in doses higher than 5 mg day because it was used to treat insomnia and as an adjunct to treat SARS-CoV-2. Therefore, this hormone is expected to be present in surface water bodies as a pollutant. Although it is reported that melatonin can be photolabile, its photochemistry has not been exhaustively studied. For this reason, the photodegradation of melatonin in solution was evaluated in this work. Solutions of 20 and 500 μM of melatonin dissolved in water were exposed to sunlight and UVA irradiation, and the degradation was monitored by spectrophotometry and total organic carbon.