Synthesis of Plant Phenol-derived Polymeric Dyes for Direct or Mordant-based Hair Dyeing

Summary

Here, we present a protocol to use pre-synthesized polymeric products derived from fungal laccase-catalyzed polymerization of plant phenols, either with or without mordant agents (e.g., FeSO₄), to induce detergent-resistant keratin hair dyeing within 2.5 hours.

Abstract

Effective hair dyeing through in situ incubation of keratin hair with the products of fungal laccase-catalyzed polymerization of plant phenols has been previously demonstrated. However, the dyeing process takes a long time to complete compared to commercial hair-dyeing products. To overcome this bottleneck, pre-synthesized polymeric products of the oxidative reaction of Trametes versicolor laccase on catechin and catechol, either with or without mordant agents (e.g., FeSO₄), were here employed to achieve permanent keratin hair dyeing in various colors and shades. The laccase action in acidic sodium acetate buffer led to a deep black coloration after coupling reactions between the plant phenols. The colored dye products were then desalted and concentrated with ultrafiltration. The dyes, with or without mordant agents, caused a significant increase in ΔE values (i.e., color difference value) in gray human hair within 2.5 hours. In addition, different keratin colors and shades were induced depending upon the mordanting and pH changes. The dyed hair also exhibited a strong resistance to detergent treatments, indicating that our methods can give rise to permanent hair dyeing. Overall, our work has provided novel insight into developing eco-friendly hair-dyeing methods as alternatives to commercial toxic diamine-based dyes.

Introduction

Laccases are oxidases that are active towards phenolic and polyphenolic compounds. They have been identified in various living organisms, including plants, fungi, insects, and bacteria. Their enzymatic actions contribute to several morphogenetic phenomena¹. The enzymes catalyze single-electron oxidation of the substrates, resulting in the formation of radicals that are further coupled to small organics and to solid surfaces. Such coupling processes lead to syntheses of oligomers and polymers and to surface functionalizations^{2, 3}. When laccase substrates are from natural sources, such as plant phenolics, the enzymatic reactions are of great intere....

Protocol

1. Preparation of Plant Phenol-derived Polymeric Dyes

1. Dissolve catechol (0.1 g) and (+)-catechin hydrate (0.1 g) in 32 ml of 100 mM sodium acetate buffer (pH 5.0) and 8 ml of absolute ethanol.
2. Add 10 mg of T. versicolor laccase to the catechol- and catechin-containing buffer. Mix vigorously and pour the solution into a square Petri dish. Incubate the dish at room temperature in a shaking incubator (25 rpm) for 24 hr. Dramatic color change of the solution from transparent to dark black can be observed with the naked eye after laccase-induced coupling reactions.
3. Centrifuge the solution for 10 min at 20,000 x g in order to spin do....

Results

First, the dyeing ability of polymeric dyes was compared to that of plant-derived monomers (i.e., catechin and catechol). The polymeric dyes induced a significant change in the color of gray keratin hair (Figure 2A and Figure 3), while the innate gray color of the hair remained very stable with plant monomers (data not shown). The effects of mordanting agents on the dyeing abilities of polymeric products were then evaluated. As s.......

Discussion

Interestingly, our method reduced the time it took to dye keratin hair with oxidant-induced polymerizations of natural phenolics. It also induced diverse colors in the hair through simple manipulations of the polymeric dyes, such as changing the pH and applying mordant.

In situ incubation of keratin hair with laccase-catalyzed oxidation of plant phenols requires overly long incubation times to attain effective dyeing⁷. Such slow dyeing kinetics may be due to the poor bindin.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Sodium dodecyl Sulfate	Promega	H5114
Laccase from Trametes versicolor	Sigma	38429-1G	Enzyme activity is denoted as 0.53 U/mg
(+)-catechin hydrate	Sigma	C1251-5G
1,2-dihydroxybenzene (catechol)	Sigma	135011-5G
Ammonia water	Duksan	701	Ammonia contents is denoted as 25 ~ 30%
Acetic acid, glacial	Duksan	448
Iron(II) sulfate heptahydrate	JUNSEI	83380-1250
Ultracell 5 kDa	Amicon	PLCC06210
Stirred ultrafiltration cells	Millipore	Model 8200
Human gray hair	PheonixKorea	Not available
Colorimeter	SPEC	JCS-10
Square dish	SPL	10125	125 * 125 * 20 (mm)