Novel pigmented molecules from parrot feathers with anti-oxidant photoprotective actions

The majority of birds use both melanin and carotenoid pigments to become coloured. In contrast, parrots harbour unusual bright-coloured pigments in their feathers instead of carotenoids. Previously, we have investigated the chemical structures and the biosynthetic pathway of these pigments in parrots. By means of UV-Vis/HPLC, as well as Mass/Raman Spectroscopy performed on the pigment purified from Ara Macao red plumage, it was concluded that a mixture of polyenals, named psittacofulvins, was responsible for the colour. These polyunsaturated molecules share with carotenoids and retinoids some structural features, and, possibly, antioxidant properties and effects on cell proliferation. Congeners named parrodienes, which possess a polyenic structure and alcohol functional groups were synthesised and also assayed for their antioxidant and photoprotective aspects. In particular, we have investigated the effects of two members of the parrodienes family, such as 2,4,6-octatrienol and 2,4,6,8,10-dodecapentaenol in an in vitro model of skin photo-accelerated senescence. A single exposure of human fibroblasts to UVA in the presence of 8-methoxypsoralen mimics the photoaging process, as showed by the appearance of a senescence-like cell phenotype. The investigated compounds have been added to photo-irradiated fibroblasts after irradiation for the following 4 weeks. We analysed the up-take of 2,4,6-octatrienol and 2,4,6,8,10-dodecapentaenol, chemical and enzymatic cell antioxidants, such as glutathione and catalase, as well as hallmarks of cell senescence, such as flattened cell morphology, senescence-associated beta-galactosidase, and matrix metalloproteinases. Our results indicate that in photo-irradiated fibroblasts 2,4,6-octatrienol and 2,4,6,8,10-dodecapentaenol contrast the impairment of cell antioxidant defence system, and modulate morphological and biochemical features of photo-induced ageing.