First of all, these compounds are likely toxic and/or mutagenic. This one is no exception, it's used as an immunosuppresant.
As a value added content, it also inhibits cytochrome P450 meaning a world of interactions. (see grapefruit juice)
Edit: Get another minor vasodilator and platelet inhibitor instead.
Edit2: The trade name of this compound is Psoralen and it has quite a few nasty side effects.
In response to that, I have just discovered 2 major problems associated with this herb. The first is: photocarcinogenicity (specifically involving psoralen):
Natl Cancer Inst Monogr. 1984 Dec;66:117-26.
Cutaneous phototoxicity due to psoralens.
Gange RW, Parrish JA.
Abstract
Psoralen phototoxicity has several features which distinguish it from other cutaneous responses to UV radiation, with or without an exogenous photosensitizing agent. Erythema resulting from psoralen phototoxicity shows a longer latent period between irradiation and onset, during which no visible cutaneous changes are present. The dose-response curve is steeper, with blistering reactions occurring in some subjects after as little as three to four times the minimum phototoxic dose of UV radiation at 320-400 nm (UVA). The acute phase of psoralen phototoxicity is followed by a more marked increase in epidermal pigmentation than is seen after most other phototoxic reactions or following UV irradiation alone. The pathways leading to the development of cutaneous phototoxicity have not been identified. The importance of the cross-linking of DNA as the initiating event is suggested but not proved by comparative data on different psoralen compounds with different cross-linking abilities and by wavelength-dependent selective photochemistry. The subsequent pathways leading to erythema and the mediators which are liberated have not been identified. In contrast to erythema induced by UVA and UV at 290-320 and at 220-290 nm (UVB and UVC, respectively), no evidence for the involvement of prostaglandins has been demonstrable. Histopathologic studies show changes in the epidermis and dermis, with damage to keratinocytes and an inflammatory infiltrate in the dermis, both of which occur later and are of longer duration than the damage induced by UVA, UVB, or UVC alone. Despite the widespread application of psoralen phototoxicity in humans in the form of PUVA treatment, much work remains to be done before we can elucidate the important mechanisms and pathways leading to the inflammatory and therapeutic responses which are induced in the skin. Improvement of our knowledge in this area is central to the evolution of safer and more effective forms of photochemotherapy.
PMID: 6531018 [PubMed - indexed for MEDLINE]
Proc Natl Acad Sci U S A. 1985 Sep;82(18):6158-62.
A possible mechanism of psoralen phototoxicity not involving direct interaction with DNA.
Laskin JD, Lee E, Yurkow EJ, Laskin DL, Gallo MA.
Abstract
Psoralens in combination with ultraviolet light (UVA; 320-400 nm) are used in the photochemical treatment of a variety of skin diseases including vitiligo, a skin depigmentational disorder, and psoriasis, a disease of accelerated epidermal cell proliferation. Although it is generally assumed that the major site of action of the psoralens is DNA, we have obtained evidence that another site may be the primary target for these compounds. We have identified specific, saturable, high-affinity binding sites for 8-methoxypsoralen on HeLa cells and have detected specific binding of 8-methoxypsoralen to four other human cell lines and five mouse cell lines. In HeLa cells, specific binding is reversible and independent of the ability of the compound to intercalate into DNA. In addition, binding sites become covalently modified by the psoralen after UVA exposure. Specific binding of 8-[methoxy-3H]methoxypsoralen constitutes 79% of the label bound to the cells. Scatchard analysis indicated two classes of psoralen binding sites: high-affinity sites with a Kd of 19 X 10(-9) M (1.8 X 10(5) sites per cell) and low-affinity sites with a Kd of 4 X 10(-6) M (7.1 X 10(6) sites per cell). Four structurally related psoralen analogs block 8-methoxypsoralen binding in a manner that parallels their biological activity. Based on these findings, we hypothesize that specific binding sites for psoralens on mammalian cells mediate, at least in part, psoralen-induced phototoxicity.
PMID: 3862124 [PubMed - indexed for MEDLINE]PMCID: PMC391011Free PMC Article
J Photochem Photobiol B. 1990 Jun;6(1-2):237-47.
Photocarcinogenicity of psoralens used in PUVA treatment: present status in mouse and man.
Young AR.
Institute of Dermatology, United Medical School of Guy's Hospital, University of London, U.K.
Abstract
There is good evidence that 8-methoxypsoralen is photocarcinogenic in psoriatic patients undergoing long-term photochemotherapy (PUVA) in the U.S.A. However, this conclusion has not been supported by two major European studies which have indicated that PUVA is a tumour promoter of damage initiated by other agents. Variation in PUVA treatment protocols in the U.S.A. and Europe may partly account for the different conclusions. There is much interest in the therapeutic potential of monofunctional psoralens. It is hoped that these may reduce long-term risk. Monofunctional and cross-linking psoralens have been shown to be photocarcinogenic in mouse skin. The relative risk of different compounds may be assessed in the mouse, but it is important to base comparisons on dose protocols that have been shown to be therapeutically effective.
PMID: 2121937 [PubMed - indexed for MEDLINE]
The second major problem is the inhibition of Mitochondrial Complex 1:
Ann N Y Acad Sci. 2007 Apr;1100:486-96.
Psoralea corylifolia L. inhibits mitochondrial complex I and proteasome activities in SH-SY5Y cells.
Tang SY, Gruber J, Wong KP, Halliwell B.
National University of Singapore, University Hall, Lee Kong Chian Wing, UHL 05-02G, 21 Lower Kent Ridge Road, Singapore. bchbh@nus.edu.sg
Abstract
The growing interest in alternative medicines, including traditional medicinal plants, has caused some health concerns due to poor awareness in the general population of the possible side effects from inappropriate practices. Psoralea corylifolia L. has been used in Chinese and Indian traditional medicine for the treatment of various inflammatory diseases of the skin and to improve vitality. Our data show that the extract obtained from the seeds of Psoralea corylifolia L. decreased mitochondrial complex I and proteasome activities; and oxidative stress might be an early event.
PMID: 17460213 [PubMed - indexed for MEDLINE]
Edited by agwoodliffe, 08 April 2011 - 09:38 PM.
