Optical behavior investigation of lanthanide complexes: possible biomedical applications

Abstract

Hypericin (Hp), a natural chromophore found in plants of genus Hypericum; and hypocrellin A (HA), a chromophore from the fungus Hypocrella bambusae, have been gaining much notability due to their photosensitizing activities. It is known that HA can form a complex with lanthanum ion, which shows a large quantum yield of singlet oxygen generation and a red-shifted absorption window when it is compared with HA. For this reason, the influence of the addition of lanthanum ion, europium ion and hydrogen peroxide to the properties of the HA and Hp has been investigated by means of optic spectroscopy methods. Thus, it was possible to determine the potentiality of such complexes for use in biomedical applications.