5methoxypsoralen

5-methoxypsoralen, also known as bergapten, is a naturally occurring furanocoumarin. It is found in various plants, including Angelica archangelica (angelica) and Citrus bergamia (bergamot). 5-methoxypsoralen is a photosensitizer, meaning it can absorb ultraviolet (UV) light and then transfer this energy to surrounding molecules. This property has led to its use in photochemotherapy for certain skin conditions.

In medical applications, 5-methoxypsoralen is often combined with UV-A radiation, a treatment known as PUVA (psoralen plus UV-A). PUVA is primarily used to treat conditions like psoriasis, vitiligo, and cutaneous T-cell lymphoma. The mechanism involves the psoralen intercalating into DNA and, upon UV-A irradiation, forming covalent cross-links within and between DNA strands. This DNA damage can inhibit cell proliferation and modulate immune responses, which is beneficial in treating these dermatological disorders.

However, the use of 5-methoxypsoralen is associated with potential side effects. These can include skin irritation, redness, blistering, and increased sensitivity to sunlight. Long-term or repeated exposure to PUVA therapy has also raised concerns about an increased risk of skin cancer, particularly squamous cell carcinoma, due to DNA damage. Due to these risks, its medical use is carefully monitored and typically reserved for severe cases unresponsive to other treatments.