title: Trace metal ions in hair from frequent hair dyers in China and the associated effects on photo-oxidative damage.
abstract: Human hairs are subject to oxidative modification when exposed to sunlight. In the present study, samples of human hair from Chinese volunteers that included frequent hair dyers and non-dyers were analyzed for metal ions such as iron, copper, magnesium, aluminum, zinc and lead. The generation of hydroxyl radicals during UVA (315-400 nm) photoageing was quantified and oxidative damages characterized by proteomic and SEM analysis. It was concluded that high levels of metal ions, particularly those derived from iron and copper, identified in the dyed hairs are associated with enhanced photoformation of hydroxyl radicals and resultant photooxidative damage of the hair. Reactive oxygen species, including hydroxyl radicals, generated via an electron transfer mechanism with hair photosensitizers react with hair proteins. Proteomic analysis of hair samples from frequent hair dyers, regardless of age and gender, showed an almost 1.6 fold increase in the protein oxidative modification levels compared to the undyed samples. As a result, a more pronounced physical damage including fragmentation and cross-linkage of cuticle scales was observed on the surface of dyed hair samples during the photoageing. This work is aimed at better understanding the role of metal ions in dyed hairs and their possible role in photosensitizing hair proteins. The results from this study are anticipated to contribute to the improved development of hair coloring cosmetics and hair care products.
authors.affiliation: Beijing Key Laboratory of Plant Resources Research and Development, School of Science, Beijing Technology and Business University, Beijing, China. Electronic address: tangying@th.btbu.edu.cn.
authors.forename: Ying
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Food & Bio-Based Products, AgResearch, New Zealand; Biomolecular Interaction Centre, University of Canterbury, Christchurch, New Zealand; Riddet Institute, Massey University, Palmerston North, New Zealand; Wine, Food & Molecular Biosciences, Lincoln University, Lincoln, New Zealand.
authors.forename: Jolon M
authors.initials: JM
authors.lastname: Dyer
authors.affiliation: Food & Bio-Based Products, AgResearch, New Zealand.
authors.forename: Santanu
authors.initials: S
authors.lastname: Deb-Choudhury
authors.affiliation: Beijing Key Laboratory of Plant Resources Research and Development, School of Science, Beijing Technology and Business University, Beijing, China.
authors.forename: Qiao
authors.initials: Q
authors.lastname: Li
mesh_terms: D000328:Adult; D000368:Aged; D002681:China; D002853:Chromatography, Liquid; D005260:Female; D006197:Hair / Q000737:chemistry*; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D008670:Metals / Q000032:analysis*; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D018384:Oxidative Stress; D055668:Photochemical Processes; D017382:Reactive Oxygen Species / Q000032:analysis; D014131:Trace Elements / Q000032:analysis*; D055815:Young Adult
chemical_list: D008670:Metals; D017382:Reactive Oxygen Species; D014131:Trace Elements
keywords: Heavy metals; Human hair; Hydroxyl radical; Proteomic analysis