Download Structural Studies of Hair-Extracted and Synthetic Melanin

Structural Studies of Hair-Extracted and Synthetic Melanin and Its Implication to Drug Design
Tadeu Szpoganicz
Mentor: Patrick J. Farmer
Melanin is a photo-protective pigment ubiquitously present in the hair, skin, eyes, and even in
the brain, where it carries many functions, such as quenching free radicals and providing
protection against UV radiation. The structure of melanin is not well understood, partially
because melanin is a heterogeneous material that is difficult to handle; nonetheless, knowledge
about the structural organization of this pigment is important for drug design and the
understanding of different diseases such as macular degeneration and melanoma, and even the
common graying of hair. Melanin is known to bind metal ions, which can cause several prooxidant effects reportedly implicated in Parkinson’s disease, and this pro-oxidant effect is
recognized as an important attribute to use against melanoma. Metal binding by melanin is also
an important tool to obtain structural information. In this study, the binding of Al(III) by melanin
has been studied via 1H NMR of melanin precursors complexed with Al(III), potentiometric
titrations of aluminum-melanin complexes, and the crystallization of melanin precursors
complexed with Al(III). Natural melanin has also been enzymatically extracted from hair, and
melanosomal morphology has been studied via TEM imaging in which the melanosomes display
a granular appearance. ICP analysis of metal content in natural melanin is also provided.
Altogether, the structural and metal-binding affinities studies of this work provide an insight to
the spatial organization of melanin monomers complexed to metal ions; this kind of knowledge
is a valuable resource to drug design, including metal-based drugs to target melanoma.