International Journal of Cosmetic Science最新文献

Objective: Dandruff is one of the most common dermatological conditions, which occurs in about 50% of human individuals confined only to the scalp. Microbiome studies indicate a bacterial and fungal microbiota shift compared to a healthy scalp. While antifungal treatments are effective in improving clinical signs and symptoms of scalp dandruff, maintaining a healthy scalp microbiome balance is also crucial for long-term scalp health. The objective of this study was to investigate whether a novel plant-based formula containing Ziziphus joazeiro bark extract and Apium graveolens seed extract is capable of reducing mild-to-moderate dandruff symptoms and restoring the scalp skin barrier function and its impact on the microbiota balance after a 4-week application period.

Methods: An open-label, single-centre study was performed including 40 subjects with mild-to-moderate dandruff with either oily or dry sensitive scalp. Subjects were treated for 4 weeks with a novel plant-based shampoo to demonstrate the efficacy in reduction of dandruff (scaling) and redness and stabilization of trans-epidermal water loss (TEWL). Dermatological measurements were performed as well as a scalp microbiome analysis of 20 subjects with a focus on alpha and beta diversity and abundance of core microbiota. The analysis was performed on swab samples taken prior to and 28 days after application of the product of interest.

Results: Clinical data revealed that the new plant-based shampoo was well tolerated. TEWL analysis showed a highly significant improvement (-18.60%, p = 0.00035). With respect to redness (-22.8%, p = 0.00127) and dandruff reduction (scaling, -29.23%, p = 0.000001), a significant improvement in the analysed parameters was also determined. Microbiome analysis revealed no significant changes in alpha or beta diversity, suggesting that the product has no negative impact on microbial diversity or affecting the overall structure of microbial communities within individuals. Interestingly, fungal species seem not to be involved in dandruff development within the analysed cohort. The key finding was a significant median increase in the Cutibacterium/Staphylococcus ratio (+19.57%).

Conclusion: The study indicates that mild-to-moderate dandruff symptoms can successfully be reduced with the plant-based shampoo by restoring the bacterial scalp microbiome balance, suggesting a 'microbiome-friendly' formulation tolerated excellently for oily scalp and sensitive scalp.

Background: Ultraviolet (UV) radiation accelerates skin damage and photoageing, leading to visible signs such as wrinkles, loss of elasticity and uneven pigmentation. UV radiation causes direct DNA damage, primarily through the formation of cyclobutane pyrimidine dimers (CPDs) and 6-4 photoproducts (6-4PPs), which can lead to mutations and cellular dysfunction if not repaired. While natural defence mechanisms like melanin production and DNA repair pathways mitigate this damage, prolonged or excessive UV exposure can overwhelm these defences, resulting in cumulative skin damage. The melanocortin 1 receptor (MC1R) plays a key role in melanogenesis and also appears to play a role in DNA repair. Salt-inducible kinases (SIKs), critical enzymes in the MC1R pathway, are known to influence melanin production, but their role in DNA repair and photodamage remains unclear.

Objective: This study investigated the role of SIK in DNA repair and photodamage, focusing on two novel cosmetic ingredients, SIK inhibitors, coded SLT-008 and SLT-001.

Methods: The inhibitory effects of the ingredients on SIK activity were measured using biochemical and cellular assays. Their safety profiles were evaluated through in vitro studies and clinical trials. To analyse their impact on UV-B-induced DNA damage and repair, both inhibitors were topically applied to skin extracts in an ex vivo model. Finally, clinical studies were conducted in healthy volunteers irradiated with UV-R. Efficacy was determined by measuring CPD levels, matrix metalloproteinase-1 (MMP-1), expression and erythema formation following UV exposure.

Results: Both ingredients effectively inhibited SIK activity and demonstrated good safety profiles. Ex vivo experiments revealed that immediate post-UV-B application of both ingredients significantly reduced UV-B-induced DNA damage, as shown by decreased CPDs, and promoted tissue repair. Additionally, both inhibitors suppressed MMP-1 expression, an enzyme that plays a key role in the breakdown of collagen, thereby accelerating photoageing. These findings were confirmed in the clinical study, which demonstrated that topically applied SLT-001 enhanced DNA repair, reduced MMP-1 expression and decreased erythema formation.

Conclusion: Here we described the comprehensive role of SIK inhibition in DNA and dermal repair. This highlights its crucial role in protecting skin against UV-induced photodamage and offering broad protection against actinic ageing.

Objective: Skin is exposed to multiple external factors such as solar radiation and environmental oxidative stressors. Ageing and the accumulation of stress damage lead to reduced skin health and loss of skin firmness, which contribute to wrinkling and sagging. We investigated if Galactomyces ferment filtrate (GFF) could modulate skin cell mechanical properties through changes to the actin cytoskeleton and anchoring junctions.

Methods: Proteomic analysis was performed to identify age-associated changes in cellular components in skin biopsies and GFF-mediated changes in full thickness 3D skin equivalent models. Nanoindentation was used to measure the Young's modulus (resistance to elastic deformation) of keratinocyte cells under Latrunculin B (LatB)-induced destabilization of the actin cytoskeleton. Immunofluorescence and confocal microscopy were performed on skin equivalents to validate the GFF-induced changes observed in proteomic analysis and identify expression profiles of key structural proteins within the skin.

Results: Aged skin had decreased expression of internal cellular components 'actin cytoskeleton' and 'focal adhesion'. Destabilization of actin cytoskeleton by LatB significantly reduced the Young's modulus of keratinocyte cells. Pre-treatment of keratinocytes with GFF was able to prevent LatB-induced decline of skin cell mechanical properties. Proteomic analysis of full thickness 3D skin equivalent models revealed that GFF increased the expression of 'actin cytoskeleton' and 'anchoring junctions', especially the actin-binding focal adhesion proteins. Immunofluorescence staining confirmed that GFF upregulated expression of the actin stabilizer, calponin 2 and integrin α2 in basal keratinocytes. GFF increased integrin localisation to the dermal-epidermal junction (DEJ) and colocalised with collagen IV in vitro, suggesting increased linkage between the epidermis and dermis.

Conclusion: Our data establish the actin cytoskeleton and anchoring junctions which bind it as important cellular structures which decline with age. We also identified that the cellular structures are required for the maintenance of keratinocyte Young's modulus, which could be an important property impacting skin firmness. Furthermore, we have identified that GFF promotes actin stability and builds a rigid holding structure of the anchoring junctions to increase cell-cell and epidermis-dermis anchoring in skin equivalent models. Therefore, GFF has the potential to help maintain and restore skin firmness in young and old skin, respectively.

The use of heat styling appliances is a rapidly growing segment within the hair care market. However, despite significant levels of academic investigation into the impact of high temperature on the structure and mechanical properties of the hair fibre, the industry does not yet have a standardized method of heat damage measurement to enable consumers and independent evaluation laboratories to objectively compare the performance of different heat styling tools. We discuss the available experimental methods to support such a standardized method and conclude that the well-established approach of measuring single-fibre tensile strength provides the best option. We then explore the sensitivity to heat damage of the various wet and dry single-fibre tensile parameters in order to identify the optimal combination for inclusion in our hair damage metric. Using the selected combination of 8 different wet single-fibre tensile strength parameters, we now propose a robust, reproducible and consumer-relevant 6-point heat damage scale. We demonstrate the relevance of the new damage scale to a range of on-market heated hair straighteners and explore the human perception of hair treated with heated straighteners delivering different damage levels according to the new scale. Based on this, we show a good correlation between the technical damage scale and the human perception of damage on hair tresses.

A few years ago, the 2-hydroxy-4´-methoxy dibenzoylmethane (DBM11) molecule was synthesized and studied as a replacement for avobenzone (AVB, butyl methoxydibenzoylmethane) because of the latter's instability under UVA radiation. These studies, conducted in absolute ethanol with an estimated UV irradiance of 8,56 mW/cm², demonstrated almost zero decomposition of DBM11. Thus, it is a promising candidate for use as a UVA chemical filter. However, further studies must be conducted to verify its photostability once formulated into an emulsion and to establish its toxicological profile. The first aim of this work was to scale up the synthesis of DBM11 to allow its formulation into an emulsion, which is required for the evaluation of its photostability under standardized UV irradiation conditions (close to ISO 24443), as required for sunscreen testing in the cosmetic industry. Additionally, in vitro phototoxicity assessments were conducted, with slight modifications to improve reproducibility, in accordance with OECD guidelines. These results demonstrate that DBM11 exhibits promising photostability and a favourable toxicological profile, making it a potential candidate for use as a UVA filter.

Objective: Despite accumulating data supporting the effectiveness of colloidal oatmeal-based moisturizers in improving mild-to-moderate atopic dermatitis (AD), evidence in paediatric populations is limited. This study evaluated the tolerability and effectiveness of a colloidal oatmeal-containing baby wash formulation in babies prone to AD, based on clinical and parental assessments.

Methods: In this 4-week, single-centre, nonrandomized study of babies (3-36 months) prone to AD (per an AD-prone skin recruiting questionnaire developed in-house), parents/legal guardians used the baby wash on their babies ≥3 times per week (no more than once daily), each bath lasting ≤20 min. The overall skin condition (scored from 0/excellent to 3/poor) and cutaneous tolerance scoring of dryness, redness/erythema, rash/irritation and tactile roughness on the baby's face, arms, legs and torso (each scored from 0/none to 3/severe) were assessed clinically at baseline, Week 1 and Week 4. Cutaneous tolerance scoring of burning/stinging and itching on those body sites was evaluated by the parent per the latter scale at all visits. At study end, the parental questionnaire evaluated the level of agreement/disagreement with statements regarding the baby wash. Safety measures included adverse events and changes in health (per the parents or clinicians).

Results: Of 29 infant-parent pairs enrolled, 24 (82.8%) completed the study. All 24 babies were White/Caucasian; 13 (54.2%) were male. The overall skin condition mean score showed no statistically significant change from baseline (0.54) at Weeks 1 (0.33) and 4 (0.29). Per the investigator-rated cutaneous tolerance scores, >87% of body sites exhibited no dryness, redness/erythema, rash/irritation or tactile roughness at Week 4. For each parameter, significant improvements from baseline were observed at Week 4 for the combined skin sites (p < 0.05). Per the parent-rated cutaneous tolerance scores, nearly all sites had no burning/stinging or itching at Week 4. Itching for the combined sites demonstrated significant improvements from baseline at Week 4 (p < 0.05). The parental questionnaire revealed statistically significantly more favourable experiences with the baby wash than unfavourable experiences. Four babies experienced five mild, treatment-unrelated adverse events.

Conclusion: The study findings indicate that the colloidal oatmeal-containing baby wash was well tolerated and effective when used in babies with AD-prone skin.

Centella asiatica extract (CAE) and Marigold extract (ME) have been renowned for centuries in traditional medicine, particularly in Asia, for their wound-healing, anti-inflammatory and skin-regenerative properties. This study presents the formulation and comprehensive evaluation of serums enhanced with these extracts, aiming to harness their bioactive properties for skin health. Serums were selected over creams due to their lightweight, water-based nature, which ensures faster absorption and enhanced skin penetration of active ingredients. The serums, developed in varying concentrations (0.2%, 0.5% and 1.0%), were assessed for physicochemical properties, stability, bioactivity and skin barrier enhancement. Stability tests confirmed the serums' robustness, maintaining consistent pH (5.0–6.5), viscosity and organoleptic properties over 60 days. The MTT assay revealed that both extracts were non-cytotoxic, maintaining cell viability above 100%, with formulations containing CAE, demonstrating a concentration-dependent proliferative effect, reaching nearly 120%. Antibacterial evaluation using the agar well diffusion assay showed that both extracts exhibited considerable activity, with CAE achieving greater inhibition zones, particularly against S. aureus. Antioxidant, anti-inflammatory and anti-tyrosinase activities confirmed the strong bioactive potential of both extracts in combating oxidative stress, reducing inflammation, and regulating pigmentation. Skin barrier and permeability studies demonstrated the serums' ability to improve barrier integrity and facilitate active compound delivery. These findings demonstrate the potential of Centella asiatica and Marigold extracts for multifunctional skincare formulations, combining regeneration, hydration, antioxidant and antibacterial benefits.

Sunscreens reduce the harmful effects of ultraviolet radiation (UVR) by reflecting, absorbing or scattering photons. UVR comprises ultraviolet-B (UVB), which plays a major role in sunburn and the development of skin cancers, and ultraviolet-A (UVA), which contributes to photoaging and skin damage. The application of sunscreen is among the most effective approaches to mitigating UV-induced damage. As a topical photoprotective agent, it can be classified as either inorganic (physical blockers) or organic (chemical absorbers). Physical sunscreens are particularly beneficial for people who are hypersensitive to UVA and visible light, such as those who have photosensitising diseases. Chemical sunscreens that selectively absorb UVB and/or UVA, include cinnamates, benzophenones, benzimidazoles and dibenzalacetone (DBA). DBA is a synthetic compound with potent UV-absorbing properties, making it an important component in sunscreen formulations for effective skin protection. This review provides a comprehensive analysis of DBA, focusing on its physicochemical properties, conventional synthesis methods and structural characterization using UV–Visible absorption spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, Gas Chromatography–Mass Spectrometry (GC–MS) and Nuclear Magnetic Resonance (NMR) spectroscopy. Furthermore, its potential applications in sunscreen formulations and other biological activities are critically investigated.