Cosmetics

Contact dermatitis is a highly prevalent inflammatory disease of the skin with substantial impact on patients’ quality of life and occupational function. Although randomized controlled trials (RCTs) provide the highest level of evidence for treatment evaluation, previous research has shown that the reporting quality of RCT abstracts is often suboptimal. This study aimed to assess the completeness of reporting of RCT abstracts on contact dermatitis according to the CONSORT extension for abstracts (CONSORT-A). A cross-sectional analysis of 304 abstracts indexed in PubMed between 1975 and 2024 was conducted. Each abstract was independently evaluated by two reviewers using the 17-item CONSORT-A checklist, with inter-rater agreement calculated by Cohen’s κ. The median adherence score was 5 out of 17 items (29.4%), with a range from 1 (5.9%) to 14 (82.4%). The reporting of study aims (82.9%), interventions (82.2%), and conclusions (91.1%) was frequent, whereas critical methodological elements such as participant criteria (4.6%), randomization (2.0%), trial registration (3.0%), and funding (0.7%) were rarely reported. Structured abstracts, hospital settings, significant study results, and more than seven authors were independent predictors of higher adherence in multivariate analysis. Abstracts published after 2008, when CONSORT-A was introduced, showed modest but significant improvement. These findings indicate that reporting quality of contact dermatitis RCT abstracts remains inadequate, underscoring the need for stricter journal requirements, structured abstract formats, and broader dissemination of CONSORT-A guidelines.

Skin sensitization is a critical endpoint in cosmetic safety assessment, necessitating reliable animal-free testing alternatives. Current established in chemico assays, such as the Direct Peptide Reactivity Assay and Amino acid Derivative Reactivity Assay, are limited by prolonged 24 h incubation periods and their inability to distinguish between direct electrophilic sensitizers and pro-electrophiles requiring metabolic activation or spontaneous oxidation. This study presents the design, synthesis, and validation of NNDNAC (N,N-dimethyl N-(2-(1-naphthyl)acetyl)-l-cysteine), a novel nucleophilic reactivity probe synthesized via a seven-step pathway. A modified naphthalene structure featuring N,N-dimethylamino substituent enhances nucleophilicity of the cysteine sulfur atom, enabling rapid reactivity assessment within an hour incubation using LC-DAD quantification. Comparative validation studies demonstrated that NNDNAC rapidly identified strong electrophilic sensitizers, achieving 100% and 98% depletion rates for p-benzoquinone and 2-methyl-4-isothiazolin-3-one, respectively, within 1 h. Critically, the NNDNAC assay successfully differentiated pro-electrophiles like p-phenylenediamine and 4-aminophenol, which showed negligible depletion at 1 h but significant depletion after 24 h due to auto-oxidation. Furthermore, NNDNAC classified farnesal as a weak sensitizer, aligning with established KeratinoSens™ and LLNA data. The NNDNAC probe represents a significant advancement in skin sensitization assessment, offering a time-efficient, high-throughput platform that not only accelerates screening processes but also provides crucial mechanistic insights through electrophile/pro-electrophile differentiation, significantly improving animal-free toxicological evaluations.

Skin aging is influenced by both internal and external factors, resulting in wrinkles, decreased elasticity and irregular pigmentation. Hyaluronic acid (HA), a key component of the extracellular matrix, is essential for skin hydration and structural support. Peptides, short amino acid chains, have gained attention in cosmetics due to their multifunctional biological activities. This study explored the moisturizing and metal-chelating properties of Chrono Control Penta (S-Cannabis Sativa-pentapeptide-1), a novel plant-derived peptide whose sequence is WVSPL. In vitro, it chelated iron ions up to 17.86 ± 2.50% and copper ions up to 47.08 ± 1.49% at 10 mM and 3 mM, respectively. Western blot and Enzyme-Linked Immunosorbent Assay (ELISA) analysis showed that, under H₂O₂-induced stress, Chrono Control Penta increased hyaluronan synthase 2 (HAS2) production by 81.72% in BJ-5ta fibroblasts and enhanced HA secretion by 20.11% compared to simulated aging conditions alone, respectively. Furthermore, experiments carried out with the Franz diffusion cell and human full thickness skin demonstrated the peptide’s ability to penetrate the skin layers and even diffuse laterally with a quantified peptide skin biodistribution accounting for 0.095/0.06 nM/mg in 6 h. Advanced AI-based modeling (AlphaFold2, RosettaFold) and docking analysis revealed stable peptide-peptide transporter 2 (PEPT2) interactions, supporting carrier-mediated skin permeation and linking computational predictions with experimental diffusion data. Hence, this study extends previous evidence on the cosmetic efficacy of Chrono Control Penta by (i) adding mechanistic insights into metal chelation and HAS2/HA modulation, (ii) rigorously quantifying local skin penetration and lateral diffusion with HPLC-MS/MS, and (iii) providing a plausible mechanistic link between skin biodistribution and PEPT2-mediated transport based on deep learning structural models.