Quantitative analysis of eumelanin and pheomelanin in humans, mice, and other animals: a comparative review.

The study presents a comparison of the quantity of two types of melanin – eumelanin and pheomelanin – across a variety of animals including humans and mice. It refers to a method for quantification developed in 1985, which relies on the degradation of each melanin type to specific compounds, and their subsequent analysis using high-performance liquid chromatography. The research finds that high levels of pheomelanin are specific to yellow to red hair in mammals and red feathers in birds, while eumelanin is the primary component of epidermal melanin affecting skin color.

Understanding Melanin

• The research is based on the understanding that melanin, the pigment responsible for the color of hair, skin, and eyes in animals, exists in two forms: eumelanin and pheomelanin.
• Eumelanin is brownish-black and contributes to darker skin tones, while pheomelanin is yellow to reddish-brown and is associated with lighter skin tones, red hair, and freckles.

Quantifying Melanin

• The study utilizes a set of methods developed in 1985 for the quantitative analysis of individual melanin types in biological materials.
• These methods rely on the chemical degradation of eumelanin into pyrrole-2,3,5-tricarboxylic acid and pheomelanin into aminohydroxyphenylalanine isomers.
• The resulting compounds are then measured by high-performance liquid chromatography, a powerful analytical technique used in research and industry alike.

Findings on Eumelanin and Pheomelanin

• The research presents a comparison of the amounts of eumelanin and pheomelanin found in various tissues procured from a variety of animals including humans, mice, and others.
• It reveals that high amounts of pheomelanin are only found in mammals with yellow to red hair and birds with red feathers. However, all skin types in humans, irrespective of race and color, exhibited detectable levels of pheomelanin.
• In contrast, eumelanin is the main component of epidermal melanin which determines skin color. The color of the skin appears to be influenced more by the quantity of eumelanin than its quality.
• Interestingly, the research points to the question of why lower vertebrates, such as fish, do not synthesize pheomelanin.’;