Metabolism of the anti-psoriatic agent 5-methoxypsoralen in humans: comparison with rat and dog.

1. Single oral doses of 14C-5-methoxypsoralen (5-MOP) to human subjects (50 mg), rats (1 mg/kg) and dogs (1 mg/kg) were fairly well absorbed but subjected to extensive first-pass metabolism, at least in rat and human. Means of 62, 51 and 40% dose in urine and 31, 38 and 48% dose in faeces, were excreted by humans (during 5 days), rats (3 days) and dogs (1 day), respectively.

Psoralens cleave pBR322 DNA under ultraviolet radiation.

Supercoiled (SC) pBR322 was used to probe the recent claim that 5-geranoxylpsoralen (5-GOP) did not photoreact with DNA. Contrary to expectations, 5-GOP was found to damage DNA in the presence of UV-A through two competing pathways: (a) single strand breaks, identified by the conversion of supercoiled into open circular and linear DNA, and (b) cross-linking, revealed by the fluence-dependent decrease in the extent of denaturation of the double stranded supercoiled DNA to single stranded circular DNA. In addition, a fluence-dependent modification reduced the ability of the restriction enzyme EcoR I to linearize the photosensitized DNA, and alkali-labile lesions were generated.

Establishment of hairy root cultures of Psoralea species.

Eight Psoralea species (Leguminosae) were inoculated with Agrobacterium rhizogenes, strains 8196 and 9402. Hairy roots were only induced by strain 9402. Attention was focussed on Psoralea lachnostachys.

5-Methoxypsoralen enhances plasma melatonin concentrations in the male rat: non-noradrenergic-mediated stimulation and lack of effect in pinealectomized animals.

Previous studies have shown that 8-methoxypsoralen (8-MOP) is able to enhance melatonin secretion from rat pineal glands. The effect of another psoralen, 5-methoxypsoralen (5-MOP) on plasma melatonin concentrations alone or in combination with isoproterenol (Iso, 10 mg/kg BW, i.p.

Photoreactivity of 5-geranoxypsoralen and lack of photoreaction with DNA.

5-Geranoxypsoralen, commonly called bergamottin, a major furocoumarin contained in bergamot oil, is reported in vitro as a highly photoreactive psoralen. In ethanol, it exhibits quite a high triplet state quantum yield (approximately 0.37).