Electron spin resonance (ESR/EPR) of free radicals observed in human red hair: a new, simple empirical method of determination of pheomelanin/eumelanin ratio in hair.
The definition of the concentration of pheomelanin in the skin is an issue of great interest because in the case of being influenced by UV radiation, it manifests itself as a prooxidant, causing various skin disorders including melanoma that might help to explain the relatively high incidence of skin cancer among individuals with red hair. The ESR spectra of red hair samples were investigated. It was found that at low microwave power, they are characterized by two types of spectra. Red hair ESR signals result from a superposition of two spectral shapes, a singlet spectrum as a result of the existence of eumelanin and a triplet spectrum as a result of the existence of pheomelanin. At high microwave power, only triplet spectra shape was detected, caused by saturation of the eumelanin singlet. Using different concentration ratios of black to red hair, we measured ESR spectra and plotted the ratio values in each sample against a measured 'g-factor' (experimental). We found that there is a linear relationship between these two parameters. So, it is evident that using these results, the concentration ratio of pheomelanin to eumelanin in a sample of hair can be easily determined by an almost noninvasive method. This can be considered a potential advantage for many practical activities compared with other invasive methods. The concentration dependence curve of pheomelanin (µg/mg) on gexp-factor in an ESR spectrum of hair has been designed, which allows the determination of the amount of pheomelanin in hair of any color.
Department of Biophysics, Faculty of Exact and Natural Sciences, I. Javakhishvili Tbilisi State University, 3 Chavchavadze Ave., Box 0128, Tbilisi, Georgia.
Eduard N
EN
Chikvaidze
Tamar M
TM
Partskhaladze
Temur V
TV
Gogoladze
D000465:Algorithms; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D005609:Free Radicals / Q000032:analysis*; D006197:Hair / Q000737:chemistry*; D006200:Hair Color; D006801:Humans; D008543:Melanins / Q000032:analysis*
D005609:Free Radicals; D008543:Melanins; C018362:pheomelanin; C041877:eumelanin
ESR; microwave saturation; pheomelanin versus eumelanin; red hair