Psoralea corylifolia or babchi was an herb historically used to magically cure several skin
diseases, commonly found in traditional Ayurvedic and Chinese medicine. Ironically, it has since
been discovered that it produces psoralen, which is a type of furanocoumarin. A chemical
generally derived from plants, furanocoumarins can induce phototoxic reactions in humans.
When a person has direct contact with a plant that produces psoralen, their epidermal or skin
cells will take up the chemical and intercalate it into DNA via the minor and major grooves. This
becomes extremely problematic when a person then has exposure to ultraviolet light because
that light will cause DNA to form covalent rather than hydrogen bonds. With these covalent
cross links, it becomes harder for DNA to replicate because they cannot separate as easily
anymore. This complication with replication results in skin cell injury as damaged cells can no
longer be replaced and ultimately cell death.
Despite the safety concerns associated with psoralen, it was actually still used as an oral or
topical ointment to treat psoriasis, vitiligo, and even cutaneous T cell lymphoma. In the 1950s,
8-methoxsalen, a common form of psoralen, was used in combination with ultraviolet light
treatment (PUVA) to treat the most severe psoriasis, a condition where scaly patches of skin
form due to an overactive immune system.
Some of the known side effects of using psoralen include nausea, headaches,
dizziness, fatigue, and depression. Some particularly extreme but rare effects consist of an
increased risk of developing basal cell carcinoma and melanoma. Furthermore, in other case
studies, more incidents of acute liver injury have been correlated to an increased use of
powders and teas prepared from Psoralea corylifolia, a key ingredient in many Chinese
Currently, psoralen is not typically used to treat skin conditions out of concerns over the safety
of ultraviolet light therapy and the availability of newer drugs to care for psoriasis. Overall, it is
very clear that your skin is often at the mercy of the unpredictable qualities of wildlife. One plant
can rob the ability of epidermal cells to replicate after being damaged, leading to an overall
reduction in skin cells over time. Amazingly, the mere act of brushing against a plant can alter skin cells at the most fundamental level.
Mackenzie Chen is a 2nd Year student at the University of Virginia. Edited by Isaac Yoo.