In addition to the bifunctional adducts (cross-linkages), that furocoumarins on radiation at 365 nm form in DNA, monofunctional adducts also proved able to inhibit the nucleic acid synthesis in Ehrlich ascites tumor cells.

Cell Line↗

PubMedDate not supplied

Drug-protein interaction: 8-methoxy psoralen as photosensitizer of enzymes and amino acids.

For a better insight of the molecular basis of the photobiological effects of furocoumarins, the relevance of proteins oxydation by singlet oxygen produced by these substrates under irradiation with long u. v. light was studied. Complex oligomeric as well as simple monomeric purified enzymes with high or low molecular weight and different properties and simple amino acids were irradiated under oxygen in presence of 8-methoxy-psoralen. The effects on both proteins and amino acids were compared with those obtained under similar conditions with typical photosensitizers as methylene blue and Rose Bengal. The results indicated that the photooxydation of proteins, although possible, appears to play a minor role, if any, in the mechanism of action of furocoumarin.

Amino Acids↗

PubMedDate not supplied

Photosensitized effects of furocoumarins: the possible role of singlet oxygen.

The capacity of various furocoumarins to generate singlet oxygen in aqueous solution has been determined. The antiproliferative and the skin-photosensitizing activities of the same furocoumarins did not show any correlation with the capacity to generate the singlet oxygen, while these photobiological properties could be correlated with the capacity of furocoumarins to induce photolesions to the DNA.

Animals↗

PubMedDate not supplied

Studies on the photosensitizing properties of angelicin, an angular furocoumarin forming only monofunctional adducts with the pyrimidine bases of DNA.

The bioligical photosensitizing properties of furocoumarins are due to the formation of adducts with the pyrimidine bases of DNA under irradiation with long wavelength ultraviolet light. The greatest importance is attributed to the difunctional adducts, which form cross-linkings between the 2 strands of DNA. As angelicin, photoreacting with DNA, forms only monofunctional adducts, and therefore no cross-linkings, its photosensitizing properties have been studied in order to evaluate the ability of monofunctional adducts to produce biological effects. The results obtained studying the inhibition of DNA, RNA and protein synthesis in Ehrlich ascite tumor cells after irradiation in the presence of angelicin and psoralen (for a comparison), and the inhibition of the ability of identically treated cells to transmit the tumor showed a remarkable ability of monofunctional adducts to produce biological effects.

Animals↗