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12:37
Pharmacologic Induction of Epidermal Melanin and Protection Against Sunburn in a Humanized Mouse Model
Published on: September 7, 2013
ON THE PIGMENT OF THE NEGRO'S SKIN AND HAIR
The Journal of Experimental Medicine
|October 30, 2009
Summary
This study analyzes the chemical composition of pigment granules in Black skin and hair. Findings suggest the pigment is protein-derived, not from hemoglobin, and differs from white skin pigment only in quantity.
Area of Science:
- Biochemistry
- Dermatology
- Genetics
Background:
- Melanin, the primary pigment in human skin and hair, determines coloration.
- Understanding the chemical nature of melanin is crucial for comprehending variations in pigmentation across different human populations.
Purpose of the Study:
- To chemically characterize the pigmentary granules found in the skin and hair of Black individuals.
- To determine the composition and origin of the pigment responsible for dark coloration.
Main Methods:
- Isolation and purification of pigmentary granules from skin and hair cells.
- Chemical analysis of granule composition, including inorganic and organic constituents.
- Solubility tests in various chemical solvents (alkalies, acids, organic solvents).
- Thermal decomposition analysis of isolated pigment.
Main Results:
- Pigmentary granules are insoluble in common solvents but yield pigment upon treatment with dilute acid followed by alkali and heat.
- Granules contain a colorless ground substance, pigment, and inorganic matter (calcium, magnesium, iron, silicic, phosphoric, and sulfuric acids).
- Isolated pigment contains minimal iron and is likely protein-derived, not a hemoglobin derivative.
Conclusions:
- The pigment in Black skin and hair is likely protein-derived, with inorganic constituents playing a role in its deposition.
- The pigment in Black individuals is chemically similar to that in White individuals, differing primarily in amount, not kind.
- This suggests that variations in skin and hair color are quantitative rather than qualitative differences in pigment composition.
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