¹H NMR Spectroscopic Characterization of Solutions of Sepia Melanin, Sepia Melanin Free Acid and Human Hair Melanin

Abstract

A 1H nuclear magnetic resonance study of Sepia melanin, Sepia melanin free acid (Sepia MFA) and human hair melanin was carried out in deuterium oxide solution at pH 10-11. The empirical formula of Sepia MFA was calculated and used to estimate the number of protons in the aromatic region of the Sepia MFA polymeric chain and to suggest a possible monomeric unit profile.

Solid‐state cross‐polarization magic angle spinning 13C and 15N NMR characterization of Sepia melanin, Sepia melanin free acid and Human hair melanin in comparison with several model compounds

“…The solution-state 1 H NMR spectrum also exhibits broad resonances in the aromatic region and also shows a much larger ratio of aliphatic to aromatic signals. 14 The difficulty in identifying and quantifying the aromatic protons might be avoided if the melanin polymer could be separated from the associated polypeptide fragments, but there have been no reports of accomplishing this without disruption of the melanin polymer structure. The 15 N CP/MAS spectrum of Human hair [ Fig.…”

“…Model compounds 3 and 4 were chosen based on the proposed structure of Sepia MFA from solution-state studies. 14 In order to distinguish between protonated carbon atoms and quaternary carbon atoms, short CP contact time dependence and non-quaternary carbon suppression (NQS) experiments were performed.…”

Device‐Quality Electrically Conducting Melanin Thin Films

“…Interestingly, natural melanin from Sepia officinalis has also been reported to be soluble in an ammonia solution. [15] This suggests that it may be possible to use this technique to produce thin films from biological melanin. In order to probe the internal structure of the films and microscopic morphology, the films were examined using scanning electron microscopy (SEM).…”

Morphological and Chemical Composition Characterization of Commercial Sepia Melanin

“…Eumelanin and pheomelanin are both found in the skin, hair and eyes of many animal species, including humans, where they act as photoprotectants (absorbing harmful ultraviolet and visible radiation). Dark-skinned people have more melanin in their skin than light-skinned people have [4,5].…”