angelicin

Angelicin is a natural organic compound in the furanocoumarin family, specifically an angular isomer of the better-known psoralen. It is one of the two main structural classes of psoralen-type compounds, the other being the linear psoralen. Angelicin’s biological activity is driven by its ability to absorb ultraviolet A (UVA) light and form covalent bonds with nucleic acids, a property that underlies its phototoxic potential.

Chemically, angelicin consists of a benzopyran framework fused to a γ-pyrone ring in an angular rather than linear arrangement. This angular configuration influences how angelicin intercalates into DNA and the types of photoadducts it forms. Upon UVA exposure, angelicin can create covalent DNA adducts, with monoadduct formation being more common and interstrand crosslinking occurring less efficiently than with linear psoralen.

Natural occurrence and sources: Angelicin occurs in several plants of the Apiaceae and related families, notably in Angelica species such as Angelica archangelica. It is present in varying amounts in psoralen-containing herbs and seeds.

Biological and medical context: The phototoxic properties of angelicin arise from its UVA-activated DNA interactions, which can damage skin and other tissues. While psoralen derivatives have a long history in photochemotherapy (PUVA therapy), angelicin is less commonly used clinically due to its comparatively lower efficiency in crosslinking DNA. In research, angelicin is studied to understand structure–activity relationships among furanocoumarins and their photo-induced biological effects.

Safety: Handling angelicin requires caution to avoid UVA exposure, as with other photosensitizing furanocoumarins. It is not approved as a pharmaceutical agent for routine medical use.