Heterologous biosynthesis of elsinochrome A sheds light on the formation of the photosensitive perylenequinone system

Formation of the three C–C bridges between the two naphthol monomers for elsinochrome (1) involves three distinct classes of oxidases.

Elsinochrome A photosensitizers: Alternative drugs for photodynamic therapy

Photodynamic therapy (PDT) has already been a multifunctional modality for various tumors and nontumorous diseases. However, the development of photosensitizers is relatively delayed, compared with the tremendous progress in laser technology. Elsinochrome A (EA), a perylenequinonoid pigment from China, has all the typical advantages of perylenequinones. Moreover, singlet oxygen quantum yield of EA is superior to other kinds of photosensitizers and EA could be artificially biosynthesized at present, which make it an alternative candidate for PDT. In this review, the photophysics, photochemistry, photobiology and chemical or biological syntheses of EA photosensitizers are briefly presented. Besides, the future prospects of EA photosensitizers are also proposed.

DNA binding and photo-induced DNA cleavage activity of Elsinochrome A in visible light

The interaction of Elsinochrome A (EA) with calf thymus DNA (CT-DNA) has been investigated by UV-vis spectra and fluorescence spectra. The results show that EA can bind with CT-DNA and binding sites are destroyed after irradiation by visible light, which indicates that EA is a promising candidate for photodynamic therapy. In addition, the binding mechanism is studied using fluorescence quenching test and ethidium bromide (EB) replace assay experiments. The results suggest that EA and CT-DNA are binding with a strong force and the major binding mode of EA with DNA could be the electrostatic binding.