Role of melatonin in respiratory diseases (Review)

Melatonin, primarily secreted by the pineal gland, is an anthracemal compound. Its chemical name is N‑acetyl‑5‑methoxytryptamine. Great advances in melatonin‑related research have been made, including the understanding of its roles in the rhythm of the sleep/wake cycle, retardation of aging processes, as well as antioxidant and/or anti‑inflammatory effects. Melatonin exerts a wide range of physiological effects related to the high lipophilicity of melatonin itself. Melatonin has strong radical scavenging activity, which serves an important role in pulmonary disorders. Pulmonary disorders are among the diseases that threaten human health. Especially in developing countries, due to environmental factors such as smoke and dust, the incidences of pulmonary disorders are high. Melatonin has been reported to have great potential to treat patients with pulmonary disorders. The present review discusses the relationship between melatonin and pulmonary disorders, including coronavirus disease‑2019, chronic obstructive pulmonary disease, non‑small cell lung cancer and pulmonary fibrosis.