Protective effect of conditioner agents on hair treated with oxidative hair dye

Reconnection of cysteine in reduced hair with alkylene dimaleates via thiol-Michael click chemistry

OBJECTIVES

Conventional hair permanent waving (PW) and permanent straightening processes typically involve two steps: reduction, for breaking -S-S- bond in cystine into cysteine and oxidation for -S-S- bond reconnection. However, it is known that the hair incurs damage during the oxidation step. In this work, we proposed a novel strategy to reconnect reduced disulfide bonds in hair via the thiol-Michael click reaction, by using a symmetric Michael reagent.

METHODS

Virgin black Chinese hair was reduced using 8% wt thioglycolic acid and employed as model hair containing a high content of broken disulfide bonds. The reduced hair was treated with 1,4-n-butylene dimaleate. Raman spectroscopy and Fourier transform infrared spectroscopy (FT-IR) were used to verify the chemical changes occurred in untreated and treated hair fibre. Single-fibre mechanical properties and thermal properties of the hair were evaluated using tensile testing and differential scanning calorimetry (DSC), respectively.

RESULTS

The 1,4-n-butylene dimaleate could reconnect free thiol groups generated by disulfide bond reduction via thiol-Michael click reaction and significantly improve the mechanical strength of hair compared to that of the reduced hair. Secondary conformational resolution analysis of FT-IR results revealed that the content of α-helix structure could be restored after treatment with 1,4-n-butylene dimaleate. The intermolecular forces established by the newly generated C-S bonds compensate the broken disulfide bonds and enhance the fracture strength of the hair compared to that of reduced hair. Michael reagents of similar structure also showed similar performance in restoring the mechanical properties of reduced hair.

CONCLUSIONS

Our data suggest that 1,4-n-butylene dimaleate can restore the mechanical properties of reduced hair by reconnecting reduced disulfide bonds and restoring the secondary conformation of hair keratin.

Incorporation of doxylamine and N-doxylamine-oxide in human hair and the impact of a permanent oxidative hair dye

Knowledge of the drug incorporation in hair and impact of cosmetic treatments remains essential to correctly interpret forensic cases. The study shows the analysis of doxylamine and doxylamine-N-oxide and the evaluation of the relationship between dose and hair concentration and the impact of hair treatment (oxidative dying). The study included (A) three subjects participated to the study: a regular user (Subject 1) and two single-dose users (Subject 2, 1 single dose; and Subject 3, 2 single doses spaced 5 months apart). Subject 3 applied a permanent oxidative hair dying monthly. (B) A permanent oxidative hair dying was applied twice to the hair collected from Subject 2. (A) The average concentrations in head hair for doxylamine and its N-doxylamine-oxide, respectively, were as follows: Subject 1, 1825 pg/mg and 16 pg/mg; Subject 2, 182 and Collapse

Key Words

• N-doxylamine-oxide
• cosmetic treatment
• doxylamine
• hair
• interpretation

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Affiliation(s)

Maria Del Mar Ramirez Fernandez Department of Toxicology, National Institute of Criminalistics and Criminology, Brussels, Belgium
Sarah M R Wille Department of Toxicology, National Institute of Criminalistics and Criminology, Brussels, Belgium
Nele Samyn Department of Toxicology, National Institute of Criminalistics and Criminology, Brussels, Belgium

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A comparison of dyeing efficacy between hair-oxidation-based and hair-coating-based shampoos for the treatment of gray hair

BACKGROUND

The process of hair dyeing causes hair damage, and periodic re-dyeing is required for newly grown hair. To avoid these hassles, hair color shampoos have been developed and are widely used. In this study, we compared the effects of two hair color shampoos with different dyeing principles to analyze the function of hair color shampoos. We analyzed hair tresses treated by hair-oxidation- and hair-coating-based shampoos.

MATERIALS AND METHODS

We measured the color, tensile properties, softness, elasticity, gloss, moisture content, and protein content of the hair tresses dyed with color shampoos. The hair structures were analyzed by scanning and transmission electron microscopies (SEM and TEM) and a hydroxy radical-based method.

RESULTS

The shampoo based on hair coating enhanced the hair dyeing effect and roughness, whereas that based on hair oxidation improved the color retention and moisture content in the hair tresses. Frictional resistance, gloss, and elasticity of the hair tresses were similar for the two products. However, according to the results of the protein loss test, TEM, and hydroxyl radical staining, the shampoo based on hair oxidation showed a longer dyeing retention compared to that based on hair coating but caused cuticle damage.

CONCLUSION

These results show that the two shampoos with different dyeing principles exhibit different hair dyeing abilities and hair health indices. Therefore, we recommend that hair color shampoos should be used according to the requirements of an individual.

Application of Plant Surfactants as Cleaning Agents in Shampoo Formulations

With the increased demand for sustainable, hypoallergenic products, plant surfactants are a promising, eco-friendly option for cleaning products due to their low toxicity or even the absence of toxicity. In the present study, surfactant-rich extracts from Chenopodium quinoa, Glycine max, and Malpighia emarginata were assessed for their stability, antioxidant capacity, toxic potential, and cleaning potential in shampoo formulations. The surfactants in the extracts were isolated and characterized by NMR, UV-Vis, and FTIR spectroscopy. The results demonstrated that the extracts remained stable within the temperature and pH ranges tested. The antioxidant properties were also determined. In the analysis of irritation potential, G. max and C. quinoa exhibited low toxicity and no toxicity, respectively. The cleaning potential analysis confirmed that the extracts could be used as primary surfactants. Seven shampoo formulations were developed, which showed potential to reduce surface tension to the range of 27.1–31.7 mN/m and interfacial tension to the range of 5.4–7.3 mN/m. The wettability, percentage of solids, density, pH, and dirt dispersion of the formulas were within standard ranges, and the sebum removal capacity of the seven formulations was similar to or even better than that of a commercial shampoo.

Bacteriostasis and cleaning effect of trace ozone replacing personal care products

Ozone is widely used to inactivate bacteria, fungi, and viruses. In recent years, the treatment of itchy skin diseases (eczema and atopic dermatitis) using trace ozone has also received attention. However, the feasibility of using trace ozone to replace personal care products (PCPs) has rarely been analyzed. In this study, the applicability of trace ozone was evaluated in terms of its efficiency for microbial inactivation in three types of skin microbiomes, cleaning performance on simulated human hair and epidermis, safety for simulated human hair, and contribution to emission reduction. The results revealed that at a 10:1 ratio of ozonated water to bacterial suspension, the inactivation ratios of Malassezia, C. albicans, and S. epidermidis reached 99.63%, 83.47%, and 100%, respectively. In addition, the cleaning performance of an ozone solution (0.4 mg/L) for simulated human skin contaminated with carbon black and sebum could reach 95.89% and 95.63%, respectively, with 5 min of washing. The average scores were 0.40 and 0.37 after 5 min and 10 min of ozone treatments, respectively, indicating that trace ozone does not significantly damage simulated human hair. Results also revealed that the total emissions of COD, TP, and TN would be reduced by 1.29×10⁶, 3.55×10³, and 3.63×10³ mg/ (household · year), respectively, if PCPs are replaced by trace ozone. In short, our findings indicate that trace ozone is a potential alternative to PCPs. By replacing PCPs with trace ozone, the use of synthetic chemical products can be reduced and carbon emissions from oil extraction can be countered.

Chemical and physical treatments damage Caucasian and Afro-ethnic hair fibre: analytical and image assays

BACKGROUND

Sensory and structural characteristics of hair can be modified by chemical and physical treatments, as dyeing, brushing, but also by external factors, as sunlight radiation. However, quantitative data relating damage to the degree of hair curliness and treatments are missing.

OBJECTIVE

To evaluate the effect of chemical and physical treatments on different types of hair.

METHODS

In this study, we compared the effects of bleaching/dyeing, thioglycolate-based straightening, brushing/flat iron and UVA/Vis radiation on different types of hair: Caucasian (straight dark brown, straight blond, wavy dark brown and curly dark brown) and Afro-ethnic hair.

RESULTS

Bleaching/dyeing and UVA/Vis radiation increased combing work of Afro-ethnic hair tresses, indicating damage to the cuticle scales, which was confirmed by SEM images. Further, bleaching/dyeing caused wear on cuticles with high protein loss and reduction on the tryptophan content, independently of the hair curliness, which characterizes those procedures as very aggressive to hair structure. Straightening using ammonium thioglycolate, due to the oxidative treatment evolved, caused significant colour fading in brown/black tresses, while UVA/Vis radiation affected the colour of only blond hair tresses since they are poor in eumelanin, the photoprotective and photostable melanin molecule.

CONCLUSION

The combination of analytical and image techniques contributed to understanding how the hair shape is related to the type of damage caused by several chemical and physical treatments. These findings contribute to the development of safety cosmetics that insure the beauty of curly hair, both Caucasian and Afro-ethnic hair.

Impact of acid straightener's pH value in the hair fiber properties

BACKGROUND

Acid straightener products are widely used, and it can cause changes in the hair shaft properties. The pH value of these products established by ANVISA (Brazil's National Health Surveillance Agency) as secure is above 2.0. However, the industries are interested in working at lower pH values in order to increase the straightening effect. Unfortunately, there are a lot of products in the market with pH value under the permitted.

OBJECTIVE

Analyze two different pH values (1.0 and 2.0) of acid straightener formulation and the influence of this difference in the hair shaft properties. In order to provide information to professionals as cosmetologists, dermatologists, and hairdressers.

METHODS

Combing and colorimetric analyses, tensile strength, differential scanning calorimetry (DSC), environmental scanning electron microscope (ESEM), and tryptophan content.

RESULTS

The tresses treated at pH 1.0 had a better result in the straightening capacity, improving the combing test in 59.4%, while those at pH 2.0, only in 33.0% compared with virgin hair. However, the tensile strength, at pH 1.0 decreased by 16.0% and 9.0% to the pH 2.0. In addition, the tryptophan content was lower in the tresses treated with formulation at pH 1.0. The DSC analysis showed impairment in the straightened tresses. The images by ESEM, indicated a possible formation of a film around the fiber.

CONCLUSIONS

It was possible to conclude that the pH value interferes in the hair shaft properties. Tresses treated with pH 1.0 had more modifications than tresses treated with pH 2.0.