358 JOURNAL OF COSMETIC SCIENCE FLUORESCENCE AND COLORATION OF GREY HAIR Susan Daly1,Ph.D., Robert Bianchini1, Ph.D., Thomas Polefka1, Ph.D. L. Jwnbelic1 and Janusz Jachowicz2, Ph.D. OBJECTIVE 1 Johnson &Johnson, Consumer Products Division, Skillman, NJ 2 Better Cosmetics, LLC Grey hair has been a subject of considerable interest in the cosmetic industry. There has been a significant amount of scientific research on melanin pigmentation [I]. In contrast, there has been only a small amount of information published on the physico-chemical properties of grey hair [2]. In this study we collected gray hair from eleven individuals and separated it into non-pigmented and pigmented fibers. Our objective was to analyze the fluorescence spectra of the hair - pigmented, non­ pigmented, and blended - in order to, first, identify chromphores responsible for the fluorescence, second, assess the effect of melanin on the fluorescence, and, third, compare fluorescence properties with the hair coloration and the extent of yellowing in the unpigmented fibers. A final objective of the study was to quantitatively assess the rates of chromophore (tryptophan) photo-degradation in each tress by monitoring the fluorescence intensity along the length of the fibers. METHODOLOGY Grey hair samples were collected from 11 individuals and separated into unpigmented and pigmented fibers by International Hair Importers, Inc. Commercially blended grey hair was also analyzed. Fluorescence measurements were obtained by using a double grating Fluorolog-2 fluorescence spectrophotometer (Model 212, Spex Industries, Edison, NJ, USA) and a bifurcated fiber optics accessory to collect the spectra directly from the surface of hair at various distances from the fiber root. The measurements were performed in the emission mode by irradiating hair in the wavelength range of 260 to 400 nm. Fluorescence measurements were related to pigmentation and yellowness of the tress via color measurements with a Hunter colorimeter. RESULTS The fluorescence spectra of the un-pigmented hair samples obtained by the excitation at 290 nm showed a peak at 356 nm (tryptophan), and multi-peak emissions in the range from 395 to 500 nm. The spectra obtained by excitation at 320 nm (Figure I) showed emission peaks that correspond to the oxidative or metabolic conversion products of tryptophan at 395 nm (unidentified), 420 nm (N-formylkynurenine), 460 nm (kynurenine), and 495 nm (3-hydroxykynurenine). For comparison, the spectrum of pure 3- hydroxykynurenine is also included in the figure. The data consistently showed lower fluorescence intensity values for pigmented hair than for unpigmented hair due to the fluorescence quenching effect of melanin.

i I J 2008 ANNUAL SCIENTIFIC SEMINAR 9.00E+o6 8.00E+o6 7.00E+o6 6.00E+o6 S.OOE+o6 4.00E+o6 3.00E+o6 ·· 2.00E+o6 1.00E+o6 O.OOE+oo 300 350 400 450 soo ,so 600 �[11111] Figure I Comparison of the fluorescence spectra of on-pigmented hair from individual #2 obtained at the excitation wavelength 320 nm and 12 inches from the root part with the spectrum of pure powder of3- hydroxykynurenine . Peak assignment: 395 nm -unidentified, 425 nm - N-fonnylkynurenine, 460 nm - kynurenine, and 495 nm - 3-hydroxykynurenine. 359 Hair coloration of the 11 unpigmented samples varied significantly in terms of the degree of yellowness. Likewise, the fluorescent properties of different hair tresses also varied significantly in terms of the tryptophan intensity at 356nm and the intensity in the 395-500 nm range. Quantitative measurements of coloration to determine the Yellowness Index (YI) revealed a linear correlation between YI and the ratio of fluorescence intensities l44o/h56, suggesting that the yellow coloration of the fibers is related to the degradation of tryptophan in the fiber. Finally, the rate of the tryptophan degradation for each individual sample was determined by evaluation of the fluorescence emission spectra at various positions along the length of the hair tresses from root to tip. The calculated rate of photo-decomposition was relatively fast for un-pigmented hair (8· 104 - 1.5· 10" 3 [day· 1] (as calculated for hair obtained from various individuals) and slower for pigmented hair. CONCLUSION Fluorescence of grey hair, in both un-pigmented and melanin pigmented fibers, is caused by tryptophan and its metabolic or photo-oxidation conversion products including chromophores such as N-formylkynurenine, kynurenine, and 3-hydroxykynurenine. Un-pigmented hair produces higher fluorescence intensity than pigmented hair. Yellow coloration of grey hair is related to tryptophan degradation. References: [l]- R.Crippa, V.Horak, G.Prota, P.Svoronos, and L.J.Wolfram, Chemistry of melanins, The Alkaloids, Vol.26, Chapter 6, p.253, Academic Press, 1989. [2] - B.Hollfelder, G.Blankenburg, L.J. Wolfram, and H.Hocker, Chemical and physical properties of pigmented and non-pigmented hair ("grey hair"), Int.J.Cosmet. Sci., 87-89 (1995).