Zinc(II) and copper(II) complexes of β-substituted hydroxylporphyrins as tumor photosensitizers

Novel photosensitizers β-(hydroquinon-2-yl)-5,10,15,20-tetra(4-hydroxylphenyl)porphyrinato zinc(II) (Zn(II)P) and β-(hydroquinon-2-yl)-5,10,15,20-tetra(4-hydroxylphenyl)porphyrinato copper(II) (Cu(II)P) were synthesized and characterized. Their ability of producing singlet oxygen under irradiation was detected by the measurement of decomposition of 1,3-diphenylisobenzofuran (DPBF). The preliminary biological activity studies show that the Zn(II)P has photo-toxicity on human chronic myelogenous leukemia cell (K562) and could cleave supercoiled DNA (pBR 322 DNA), while the Cu(II)P has inferior biological activity. Results showed Zn(II)P having high anti-tumor activity, which presents a promising photosensitizer for photodynamic therapy.