Oxidative Modification in Human Hair: The Effect of the Levels of Cu (<scp>II</scp>) Ions, <scp>UV</scp> Exposure and Hair Pigmentation

Grosvenor, Anita J.; Marsh, Jennifer; Thomas, Ancy; Vernon, James A.; Harland, Duane P.; Clerens, Stefan; Dyer, Jolon M.

doi:10.1111/php.12537

Cited by 17 publications

(13 citation statements)

References 25 publications

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“…The data strongly suggest that copper ions increase •OH radical photogeneration in hair under wet conditions. This result supports previous studies, which showed that copper ions in hair adsorbed from tap water increased the degree of damage caused by sunlight, in particular by increasing the amount of protein lost from hair during shampooing .…”

Section: Resultssupporting

confidence: 92%

UV damage to hair and the effect of antioxidants and metal chelators

Millington

Marsh

2020

Intern J of Cosmetic Sci

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Objective To study the effects of addition of a redox metal, copper, antioxidants and metal chelators on the formation of free radicals in natural white Caucasian hair subsequently exposed to UV light. Three different methods, electron paramagnetic resonance (EPR), a fluorescent probe for hydroxyl radical formation (terephthalate) and free radical photoyellowing, were used. These methods utilized different UV sources and reaction conditions, and so can give insights into the different mechanisms of action occurring during UV oxidation of hair. In addition, this study demonstrates how antioxidants and chelators can be screened to determine whether they can protect hair from UV damage. Results The three methods gave somewhat different results, illustrating the importance of reaction conditions and wavelength on the photochemical mechanisms, and the efficacy of additives to influence these reactions. EPR results showed that N‐acetylcysteine (NAC) pre‐treatment eliminated the intensity of the signal because of sulphur and carbon free radicals in white hair both before and after exposure to UVB radiation. Doping the hair with copper ions had no effect on the intensity of the EPR signal under dry conditions. Terephthalate fluorescent probe data showed that under wet conditions, irradiation of white hair with UVA produced significant amounts of hydroxyl radicals. Pre‐treatment of hair with NAC reduced the number of •OH radicals produced by natural white hair compared to an untreated control. In contrast to the EPR result, white hair doped with copper ions produced significantly higher levels of •OH radicals under wet conditions. It appears that the ability of copper ions to catalyse the photogeneration free radicals in hair is highly dependent on water content. Photoyellowing data showed a benefit for oxalic acid but no difference for NAC and an increase in yellowing for EDTA. Conclusion The micro‐EPR and terephthalate fluorescent probe methods are both effective techniques to study production of free radicals by hair exposed to UV light under wet and dry conditions, respectively. Both assays are simple methods for determining the effectiveness of potential protective hair treatments against UV damage, but because they assess free radical damage under dry vs wet conditions, the chemistry created on UV exposure is different. This gives insights into mechanism of action, but results may not be consistent between the two methods for actives added for reduction of UV damage. NAC pre‐treatment did reduce free radical generation in UV‐exposed hair under both wet and dry conditions. Photoyellowing data are more complicated as it is a less direct measure of UV damage and is highly dependent on irradiation source. Using UVB irradiation is experimentally convenient but may not be appropriate, because UVB wavelengths comprise only 0.3% of terrestrial sunlight. The photochemistry of hair exposed to sunlight involves concurrent photobleaching and photoyellowing processes and is far more complex. Under UVB irradiation condit...

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Section: Resultssupporting

confidence: 92%

UV damage to hair and the effect of antioxidants and metal chelators

Millington

Marsh

2020

Intern J of Cosmetic Sci

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“…The loading plots indicated that the elements Cu and S were relevant for this clustering of samples, as well as the scattering of Rh Kα (0.62 Å). The detection of Cu can be also associated to the oxidative alteration in hair treated, which increases the content of ions Cu (II), independent of the hair color …”

Section: Resultsmentioning

confidence: 99%

Wavelength dispersive X‐ray fluorescence (WDXRF) and chemometric investigation of human hair after cosmetic treatment

Santos¹,

Sperança

Pereira³

2018

X-Ray Spectrometry

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Variations in the chemical composition of 63 different human and 6 different synthetic hair samples were investigated using wavelength dispersive X‐ray fluorescence (WDXRF) spectra profiles. To evaluate the effect of cosmetic treatment on the strands, the human hair samples were bleached, but the synthetic ones were not. To better investigate the data, exploratory analyses were calculated using principal component analysis for the WDXRF spectra. Eight normalizations/standardizations were applied in the WDXRF to verify the clustering tendency. Bleaching was tested, because it is one way in which people mask their real hair color. After the data were standardized, an enhancement of the data discrimination was verified. Furthermore, the explained variance was higher in the first principal components. The WDXRF spectra were able to distinguish samples with distinct features, including synthetic, dyed, and straightened hair. The findings of this study hold promise for forensics due to desirable aspects such as nondestructivity and the possibility of a large hair sample database.

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“…[ ] It is important to note that some breakdown products are photosensitizers [ ] as are the trace metals copper and iron. [ ]…”

Section: Physics: the Hair Phenotype From Macro To Molecular Scalementioning

confidence: 99%

Wanted, dead and alive: Why a multidisciplinary approach is needed to unlock hair treatment potential

Lim

Harland

Dawson

2019

Experimental Dermatology

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Human recorded history is littered with attempts to improve the perceived appearance of scalp hair. Throughout history, treatments have included both biological and chemical interventions. Hair “quality” or “perceived appearance” is regulated by multiple biological intervention opportunities: adding more hairs by flipping follicles from telogen to anagen, or delaying anagen follicles transiting into catagen; altering hair “apparent amount” by modulating shaft diameter or shape; or, in principle, altering shaft physical properties changing its synthesis. By far the most common biological intervention strategy today is to increase the number of hairs, but to date this has proven difficult and has yielded minimal benefits. Chemical intervention primarily consists of active material surface deposition to improve shaft shine, fibre‐fibre interactions and strength. Real, perceptible benefits will best be achieved by combining opportunity areas across the three primary sciences: biology, chemistry and physics. Shaft biogenesis begins with biology: proliferation in the germinative matrix, then crossing “Auber's Critical Line” and ceasing proliferation to synthesize shaft components. Biogenesis then shifts to oxidative chemistry, where previously synthesized components are organized and cross‐linked into a shaft. We herein term the crossing point from biology to chemistry as “The Orwin Threshold.” Historically, hair biology and chemistry have been conducted in different fields, with biological manipulation residing in biomedical communities and hair shaft chemistry and physics within the consumer care industry, with minimal cross‐fertilization. Detailed understanding of hair shaft biogenesis should enable identification of factors necessary for optimum hair shaft production and new intervention opportunities.

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Oxidative Modification in Human Hair: The Effect of the Levels of Cu (II) Ions, UV Exposure and Hair Pigmentation

Cited by 17 publications

References 25 publications

UV damage to hair and the effect of antioxidants and metal chelators

UV damage to hair and the effect of antioxidants and metal chelators

Wavelength dispersive X‐ray fluorescence (WDXRF) and chemometric investigation of human hair after cosmetic treatment

Wanted, dead and alive: Why a multidisciplinary approach is needed to unlock hair treatment potential

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