Trioxsalen (trimethylpsoralen (TMP), trioxysalen (
INN) or Trisoralen) is a
furanocoumarin and a
psoralen derivative. It is obtained from several plants, mainly ''
Psoralea corylifolia''. Like other psoralens it causes
photosensitization
Photosensitizers produce a physicochemical change in a neighboring molecule by either donating an electron to the substrate or by abstracting a hydrogen atom from the substrate. At the end of this process, the photosensitizer eventually returns to ...
of the skin. It is administered either
topically or
orally in conjunction with
UV-A (the least damaging form of
ultraviolet light) for
phototherapy
Light therapy, also called phototherapy or bright light therapy is intentional daily exposure to direct sunlight or similar-intensity artificial light in order to treat medical disorders, especially seasonal affective disorder (SAD) and circadi ...
treatment of
vitiligo and hand
eczema. After
photoactivation
A photoswitch is a type of molecule that can change its structural geometry and chemical properties upon irradiation with electromagnetic radiation. Although often used interchangeably with the term molecular machine, a switch does not perform wor ...
it creates
interstrand cross-links in DNA, which can cause
programmed cell death unless repaired by cellular mechanisms. In research it can be conjugated to dyes for
confocal microscopy and used to visualize sites of DNA damage. The compound is also being explored for development of
antisense oligonucleotides that can be cross-linked specifically to a mutant
mRNA sequence without affecting normal transcripts differing at even a single base pair.
Trioxsalen (abbreviated as TMP) activated by UV-A exposure is commonly used in
genetics research as an experimental
mutagen
In genetics, a mutagen is a physical or chemical agent that permanently changes nucleic acid, genetic material, usually DNA, in an organism and thus increases the frequency of mutations above the natural background level. As many mutations can ca ...
. UV/TMP generates small deletions (~1-3 Kbp), but all base transitions and transversions can also be obtained.
References
{{coumarin
Furanocoumarins
O-methylated coumarins