Human hair proteins as natural reactive oxygen species scavengers for in vitro applications

Abstract

Human hair proteins are recognized for their intrinsically high cysteine content. They can be solubilized while preserving their highly reductive thiol groups for free radical scavenging applications. The presence of aromatic and nucleophilic amino acids such as methionine, serine, phenylalanine, and threonine further contribute to the antioxidative potential of this material. Herein, utilizing the DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) and acellular 2′,7′‐dichlorodihydrofluorescein diacetate (H2DCFDA) assays, keratins are demonstrated to possess the highest radical scavenging activity among the studied hair proteins. Consequently, protection against hydrogen peroxide‐induced oxidative stress in human dermal fibroblasts (HDFs) cultured in human hair keratin supplemented media is demonstrated. Quenching of reactive oxygen species in the HDF is observed using the CellROX Green dye and the expression levels of antioxidant (HMOX1, SOD2, GPX1) and tumor suppressor (TP53) genes is analyzed using qPCR. Collectively, this study presents further evidence and demonstrates the in vitro application potential of hair proteins, especially keratins, as an antioxidizing supplement.

A facile method to fabricate versatile keratin cryogels for tissue engineering applications

“…Based on the DPPH radical scavenging activity presented in figure 4(c), both HHK and ODA exhibited significantly lower EC 50 values relative to L-cysteine. As recently reported by our group, the antioxidant ability of HHK can be attributed to the presence of sulfhydryl groups (-SH) in cysteine amino acid residues along the protein chain [48]. Cysteine sulfhydryl groups pose as redox-regulatory entities because of their ability to undergo various nucleophilic reactions upon deprotonation into the thiolate anion.…”

Colorimetric sensing of calcium carbide over banana peels using 5,5′-dithiobis-(2-nitrobenzoic acid) (DTNB) as a rapid chemoreceptor: a point of care tool for food fraud analysis

“…61 It can also be used to determine the number of free sulfhydryl groups in proteins. 62 Despite the widespread use of Ellman's reagent in various sensing applications, no study has been published on using Ellman reagent-based sensors to detect CaC 2 on fruit skin after CaC 2 artificial ripening.…”

Pattern of ROS generation and interconversion on wet stigmas in basal and divergent angiosperms

“…The relevance of benzidine staining was confirmed on two objects -tobacco and lily -dynamical staining was additionally carried out with DCFH fluorescent dye and NBT. The first dye is mostly used as a non-specific one (Lai et al 2022), however, according to indirect data, on stigmas it shows hydrogen peroxide to a greater extent (McInnis et al 2006), while the second one is used to visualize superoxide radical in flower tissues (Cui et al 2022). Both stains generally repeated benzidine dynamics showing a significant increase in ROS in lily and a small increase in tobacco.…”

“…Total ROS generation on stigmas of Lilium and Nicotiana was assessed by DCFH staining (30 min, 5 µM). DCFH-DA (Sigma, Darmstadt, Germany) was deesterified in an alkaline medium (10 mM NaOH, 1 h) (Smirnova et al 2009), which made it suitable for detecting extracellular ROS (Lai et al 2022). Pistils at different stages of maturity were stained simultaneously with the same dye solution, the upper part of the stigma was cut off and immediately observed with a widefield fluorescence microscope Axioplan 2 imaging MOT (Carl Zeiss, Jena, Germany) equipped with AxioCam a mercury lamp and Pro08 camera (ADF Optics, Zhejiang, China).…”