Psoralens and Photochemotherapy (PUVA)

Helm, Thomas N.; Camisa, Charles

doi:10.1002/9780470750704.ch14

Cited by 3 publications

(2 citation statements)

References 30 publications

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“…Photosensitizers such as psoralens (furanocoumarins), which are produced by higher plants, are of medical interest and have been used for the treatment of skin diseases such as psoriasis and vitiligo (1–3). Although photoactivated psoralens interact with proteins (4,5) and membrane components (6,7), their interactions with DNA have been of the greatest interest (8).…”

Section: Introductionmentioning

confidence: 99%

Antimicrobial DNA-binding Photosensitizers from the Common Rush, Juncus effusus¶

Hanawa

Okamoto

Towers

2002

Photochemistry and Photobiology

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Our continuing survey of phototoxins from higher plants has led to the isolation and identification from the common rush, Juncus effusus L., of the phenanthrene, dehydroeffusol (1), and the dihydrophenanthrene, juncusol (2), compounds that display enhanced antimicrobial activities in light. The antimicrobial activities (minimum inhibitory concentrations) for these compounds against methicillin‐resistant and ‐sensitive Staphylococcus aureus and Candida albicans were increased 16‐ and two‐fold, respectively, by irradiation with ultraviolet A (UVA). Photosensitized DNA‐binding activities (as possible covalent bond formation) of these compounds were determined by using restriction enzymes and a specially prepared 1.5 kb DNA fragment. Under UVA irradiation, dehydroeffusol strongly inhibited all the restriction enzymes (KpnI, XbaI, PmeI, DraI, PacI and BciVI) that have at least one 5′‐TpA sequence in their recognition sites. Weak inhibitions were found for the restriction enzymes EcoRI, SacI, BamHI, SalI, PstI and HindIII, which do not possess a 5′‐TpA sequence at their restriction sites and the restriction site sequences of which consist of all bases, A, T, G and C. Trace or no inhibition was found for AscI and SmaI, the restriction site sequences of which are composed of only C and G. The results indicate the necessity of thymine (adenine) for the photosensitized DNA‐binding activity of dehydroeffusol. A strong inhibition against SphI, which does not have a 5′‐TpA sequence in the restriction sequence, indicates that there are possibly other binding sequence(s) for dehydroeffusol. With juncusol and UVA, strong inhibitions for KpnI and BciVI and trace inhibitions for PacI, XbaI, PmeI and DraI were found. This result also showed a preference of juncusol for 5′‐TpA, but the preference could be more selective than that of dehydroeffusol depending on the surrounding sequences of 5′‐TpA in the respective restriction sites. A strong inhibition of SphI by juncusol with UVA also indicated the existence of an unknown binding sequence for this compound. Generally, the DNA‐binding activity of this compound was weaker than that of dehydroeffusol.

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Section: Introductionmentioning

confidence: 99%

Antimicrobial DNA-binding Photosensitizers from the Common Rush, Juncus effusus¶

Hanawa

Okamoto

Towers

2002

Photochemistry and Photobiology

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“…Psoralens (Fig. 1) are used to treat psoriasis with a combination of UVA irradiation (320-400nm) (known as PUVA ‡ therapy [1,2]). PUVA treatment is known to inhibit DNA synthesis at the S phase of a cell cycle (3), resulting in the inhibition of cell division.…”

Section: Introductionmentioning

confidence: 99%

Inhibition of Restriction Enzyme's DNA Sequence Recognition by PUVA Treatment†¶

Hanawa

Okamoto

Towers

2001

Photochem Photobiol

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Applying various restriction enzymes on a specially designed 1.5 kb DNA fragment revealed that the inhibitory effects of psoralens + UVA irradiation (PUVA) treatment on restriction endonuclease activities are caused by recognition inhibition. In this study restriction enzymes that have a 5'-TpA sequence at the cleaving site (KpnI, XbaI, PmeI and DraI), and the noncleaving site (PacI) in recognition sites, or have two 5'-TpA sequences at the recognition site, and a nonspecific sequence between the recognition and the cleaving sites (BciVI), were inhibited by PUVA treatment. Most of the other restriction enzymes used in this study, which do not have a 5'-TpA sequence at their restriction site, were not inhibited by PUVA treatment, although a 5'-TpA sequence is located adjacent (SmaI) or very close (BamHI, SacI and PstI) to the recognition and cleaving sites for these enzymes. Because SphI, which does not have 5'-TpA at its restriction site, was strongly inhibited by PUVA treatment, the 5'-CpA sequence is suggested to be a new binding site of psoralens after UVA irradiation.

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