Interactions Between Damaged Hair Keratin and Juglone as a Possible Restoring Agent: A Vibrational and Scanning Electron Microscopy Study

The study explored the potential of juglone, a compound found in walnut extracts, as a restoring agent for hair keratin damaged by permanent or discoloration processes. The restoration mechanism involves a chemical reaction between juglone and the thiol moieties of cysteine residues in hair. The hair was treated with a reducing agent, methyl thioglycolate (MT), or with bleaching agents followed by sodium hydrogen sulfite to simulate common hair treatments. Results showed that these treatments increased the content of free cysteine residues, which can react with juglone. Scanning Electron Microscopy (SEM) analyses confirmed that hair samples treated with juglone had a more regular hair surface and more imbricated scales, suggesting that juglone could be used as a restoring agent for damaged hair keratins.