ASCORBYL TETRAISOPALMITATE

Whitening is a core function of cosmetics， and ingredients including acetyl glucosamine， tranexamic acid， nicotinamide， phenethyl resorcinol， glabridin， and ascorbyl tetraisopalmitate are widely used due to their clearly established whitening mechanisms. However， existing analytical methods face notable limitations： photodiode array detectors （PDA） cannot reliably detect weakly or non-ultraviolet （UV）-absorbing components； evaporative light scattering detectors （ELSD） suffer from inadequate sensitivity for low-concentration analytes； mass spectrometry （MS） is costly； and single-column cannot achieve the separation of ingredients with significantly different polarities. To address these challenges， this study established an analytical method for the determination of the six whitening ingredients in cosmetics using ultra performance liquid chromatography coupled with a photodiode array detector and a corona charged aerosol detector （UPLC-PDA-CAD）. For sample pretreatment： 0.2 g of sample was weighed， and 10 mL dichloromethane and 10 mL deionized water were added for vortex extraction of whitening ingredients. The mixture was then centrifuged for phase separation. The aqueous layer and dichloromethane layer were collected separately. The aqueous layer was washed twice with dichloromethane； all dichloromethane fractions were combined， concentrated to less than 1 mL under a nitrogen stream， and finally made up to volume with isopropanol. Both the aqueous layer and the reconstituted isopropanol solution were filtered through 0.22 μm hydrophilic polytetrafluoroethylene （PTFE） membranes before UPLC injection. For chromatographic separation， a Waters HSS T3 column （150 mm×2.1 mm， 1.7 μm） was selected. The column temperature was set at 40 ℃， the injection volume was 1 μL， and the flow rate was 0.3 mL/min. The mobile phase consisted of isopropanol， acetonitrile， and 20 mmol/L ammonium acetate solution （pH adjusted to 4.5 using formic acid）， using a gradient elution program. For detection， a tandem PDA-CAD system was used： PDA （scan range 200-400 nm） was employed for components with UV absorption， while CAD （nebulization temperature 35 °C， acquisition frequency 5 Hz） was used for components with weak UV absorption. Quantification was performed using the external standard method.Method validation results showed good linear relationships for all six whitening ingredients within their respective concentration ranges. The correlation coefficients （ r ） were all greater than 0.999. The limits of detection （LODs， S/N =3） were 5.0-50.0 µg/g， and the limits of quantification （LOQs， S/N =10） were 12.0-120.0 µg/g. Spiked recovery tests were conducted on negative cosmetic matrices （emulsion， cream， oil） at low， medium， and high levels. The recoveries ranged from 92.8% to 110.1%， and the relative standard deviations （RSDs， n =6） were 0.12%-5.45%， indicating excellent precision and accuracy. This method was applied to seven commercially cosmetics. The results revealed that all target whitening ingredients declared on the product labels were detected， with significant differences in their content. Nicotinamide was the most frequently detected compound， found in five products， and also exhibited the highest concentrations， ranging from 0.19% to 2.29%. Phenethyl resorcinol was detected in three products， with contents ranging from 0.02% to 0.52%. Ascorbyl tetraisopalmitate was detected in two products，

Excessive ultraviolet exposure triggers skin pigment deposition, potentially leading to conditions such as melasma, freckles, and post-inflammatory hyperpigmentation. The skin of individuals with these dermatological conditions exhibits reduced levels of nicotinamide nucleotide transhydrogenase (NNT). While many seek skin-whitening products to address pigmentation, existing options often fail to achieve optimal efficacy. To accomplish a synergistic whitening effect, we developed PPV, a composite formulation incorporating three depigmenting agents: Pterocarpus marsupium bark extract (PMBE), Pinus strobus bark extract (PSBE), and ascorbyl tetraisopalmitate (VC-IP). This study aimed to investigate the effects of PPV on skin whitening and elucidate its mechanisms. After administering PPV to B16F10 melanoma cells, we measured melanin content and gene expression of TYR, TRP-1, and TRP-2 using a microplate reader and qPCR. Western blotting was used to assess p-CREB, CREB, MITF, and NNT expression. The Jin's formula was used to evaluate the combined effect of the three components of PPV on NNT at the genetic level. Oxidative stress levels were evaluated with ROS, GSH/GSSG, and NADP + /NADPH assay kits, along with confocal microscopy. Transmission electron microscopy and ELISA were employed to quantify the eumelanin/pheomelanin ratio and melanosome maturation. Finally, immunodetection was performed to assess epidermal basal pigmentation, tyrosinase, and NNT expression in a human ex vivo skin model. PPV significantly influenced melanin production in melanocytes and human ex vivo skin. This effect was due to the inhibitory effect of PPV on the CREB-MITF signaling pathway and the synergistic activation effect of PMBE, PSBE, and VC-IP on the NNT gene expression in B16F10 cells. Activation of NNT led to a reduction in ROS levels and the NADP + /NADPH ratio, ultimately inhibiting melanogenesis, tyrosinase activity, and melanosome maturation in B16F10 cells. Furthermore, PPV treatment reduced pigmentation and increased NNT expression in the aged ex vivo skin model. PPV, synthesized from PMBE, PSBE, and VC-IP, exhibited an anti-melanogenic effect. This effect was attributed to the inhibition of CREB-MITF-mediated melanogenesis and the regulation of oxidative stress by NNT. The findings suggest PPV as a potential therapeutic agent for skin pigmentation disorders.

Ascorbyl tetraisopalmitate (AT), a vitamin C derivative, exhibits better stability and transdermal absorption than vitamin C and shows potential for skin whitening and wound healing. However, their low water solubility and specific storage requirements limit their application. To overcome these limitations, in this study, we aimed to develop AT-loaded ferrocene polymer nanoparticles (AT@FNPs) using biocompatible amphiphilic polymers. The nanoprecipitated nanoparticles exhibited enhanced AT stability, loading efficiency, and controlled release in reactive oxygen species (ROS)-rich wound environments. Moreover, the ROS ROS-trigger of AT@FNPs facilitated targeted drug release and ROS scavenging, thereby enhancing the antioxidant activity. The release of AT from the AT@FNPs in wounds promoted cell proliferation and accelerated wound closure in a mouse model. Overall, our findings highlight the potential of the developed ROS-triggered AT@FNPs as smart drug delivery systems for wound healing and skin treatment.

Background/Objectives: Depigmenting cosmetic products are a fast-growing segment of the health products market, driven by consumer demand to address skin hyperpigmentation. Simultaneously, interest in products with a reduced environmental impact is increasing. However, the potential environmental risks, especially in aquatic ecosystems, of depigmenting products remain unexplored. This study assesses the usage frequency of skin depigmenting agents in cosmetic products and compiles data on the biodegradability and acute aquatic toxicity of the most prevalent compounds. Methods: A market analysis of Portuguese pharmacies and parapharmacies in 2022 identified prevalent depigmenting agents. Scientific evidence on their biodegradability and acute aquatic toxicity was compiled, and when data was unavailable, in silico predictions were conducted. Results: The study identified the ten most-used depigmenting agents in cosmetic products, including hydroxy/keto acids, as well as vitamin C and derivatives, with a usage frequency surpassing 50%. While most were naturally derived and showed low environmental risk, synthetic and highly lipophilic depigmenting agents found in 35 of 70 products (ascorbyl tetraisopalmitate/tetrahexyldecyl ascorbate and resorcinol derivatives) showed a higher potential for environmental hazard. Conclusions: The findings underscore the need for further research on the presence of these cosmetic ingredients in aquatic ecosystems and a reassessment of regulatory frameworks concerning their environmental impact. Mitigation strategies should emphasize biodegradable alternatives, renewable sources, and molecular modifications to reduce toxicity while maintaining depigmenting efficacy and skin safety. This study provides original insights into commonly used depigmenting agents in the health products market and their chemical structures, offering valuable opportunities for innovation in chemical/pharmaceutical industries.

Ascorbyl tetraisopalmitate (VC-IP) is a novel form of ascorbic acid characterized by reduced water solubility due to complete acylation with palmitate. This study investigated the potential cosmetic application of VC-IP when encapsulated in lyotropic liquid crystal nanoparticles (VC-IP LCNPs) by using a high-pressure homogenization (HPH) method. The particle size, zeta potential, and polydispersity index (PDI) of the obtained VC-IP LCNPs were determined as 158.8 ± 3.2 nm, -35.1 ± 2.8 mV, and 0.12 ± 0.02, respectively. The drug loading (DL%) of the VC-IP LCNPs was approximately 35.1%. Morphological changes in LCNPs, transitioning from a sponge phase to vesicles, confirmed the successful loading of VC-IP, as demonstrated by transmission electron microscopy (Cryo-TEM) and small-angle X-ray scattering (SAXS) experiments. The sustained release of VC-IP was also observed through the Franz transdermal diffusion test, indicating that VC-IP LCNPs facilitated the sustained-release effect of VC-IP into the skin. VC-IP LCNPs exhibited good biocompatibility, showing nontoxicity to HaCaT cells and zebrafish embryos. Raman distribution imaging confirmed that VC-IP successfully penetrated the stratum corneum and reached the dermis. In assessments of whitening effects, VC-IP LCNPs significantly the reduced reactive oxygen species (ROS) content in zebrafish and melanin areas in the heads of zebrafish. Furthermore, VC-IP LCNPs effectively inhibited tyrosinase activity and the proliferation of A375 cells compared with pure VC-IP. Additionally, VC-IP LCNPs significantly reduced the melanin area in the heads of zebrafish. Therefore, the developed VC-IP LCNPs present a promising carrier for the enhanced application of active ingredients, such as VC-IP in whitening products.

The purpose of this study is to present a novel strategy to enhance collagen production in cells. To identify amino acid analogs with excellent collagen production-enhancing effects, human dermal fibroblasts (HDFs) were treated with 20 kinds of amidated amino acids and 20 kinds of free amino acids, individually at 1 mM. The results showed that glycinamide enhanced collagen production (secreted collagen level) most effectively. Glycine also enhanced collagen production to a lesser degree. However, other glycine derivatives, such as N-acetyl glycine, N-acetyl glycinamide, glycine methyl ester, glycine ethyl ester, and glycyl glycine, did not show such effects. Glycinamide increased type I and III collagen protein levels without affecting COL1A1 and COL3A1 mRNA levels, whereas transforming growth factor-β1 (TGF-β1, 10 ng mL -1 ) increased both mRNA and protein levels of collagens. Ascorbic acid (AA, 1 mM) increased COL1A1 and COL3A1 mRNA and collagen I protein levels. Unlike TGF-β1, AA and glycinamide did not increase the protein level of α-smooth muscle actin, a marker of differentiation of fibroblasts into myofibroblasts. The combination of AA and glycinamide synergistically enhanced collagen production and wound closure in HDFs to a level similar to that in cells treated with TGF-β1. AA derivatives, such as magnesium ascorbyl 3-phosphate (MAP), 3- O -ethyl ascorbic acid, ascorbyl 2- O -glucoside, and ascorbyl tetraisopalmitate, enhanced collagen production, and the mRNA and protein levels of collagens at 1 mM, and their effects were further enhanced when co-treated with glycinamide. Among AA derivatives, MAP had a similar effect to AA in enhancing wound closure, and its effect was further enhanced by glycinamide. Other AA derivatives had different effects on wound closure. This study provides a new strategy to enhance cell collagen production and wound healing using glycinamide in combination with AA.

Photoprotective formulations containing substances with antioxidant properties in combination have been used as a strategy for the improvement of photoaged skin conditions. However, there is a lack of studies evaluating the clinical efficacy of these substances in young women with signs of photoaging. Thus, the objective of the present study was to evaluate the clinical efficacy of sunscreens and cosmetic formulations containing ascorbyl tetraisopalmitate and rice peptides for the improvement of skin photoaging in young women. A double-blind, randomized placebo-controlled clinical efficacy study was conducted on 60 female subjects aged 20-30 years with skin changes related to photoaging and without photoprotective habits. The hydrolipidic layer conditions and structural and morphological characteristics of the skin were evaluated by biophysical and skin imaging techniques. The results showed that the daily use of the formulations under study improved the skin conditions by increasing skin hydration and dermis echogenicity. In addition, the application of the active substances reduced skin hyperpigmentation and increased epidermal cell renewal. In summary, the present study showed the importance of daily application of sunscreens and formulations with antioxidant properties for the prevention and attenuation of skin changes related to photoaging in young women.

Some in vitro studies have reported the potential of antioxidants for the reduction of melanogenesis. However, it is important to assess the clinical efficacy of these substances in reducing skin hyperpigmentation. Thus, the aim of this study was to evaluate the clinical efficacy of dermocosmetic formulations based on antioxidants using Reflectance confocal microscopy (RCM). Thirty-two healthy females aged 39-55 years were enrolled and divided into four groups: Vehicle (V), V with ascorbyl tetraisopalmitate (ATIP), V with Spirulina sp., and V with hydroxytyrosol-titrated olive extract. Imaging analyses by high-resolution methods and RCM were performed in the malar region of the face before and after a 42-day period of application of the studied formulations. Reflectance confocal microscopy imaging analyses showed a significant reduction of number of hyperreflective pixels and basal layer brightness after 42 days of application of formulations containing the antioxidants compared to vehicle and baseline values, suggesting an improvement of the skin pigmentation pattern. Reflectance confocal microscopy permitted the identification of skin hyperpigmentation and the assessment of the clinical efficacy of dermocosmetic formulations based on antioxidants in a noninvasive way. All formulations containing antioxidants significantly reduced skin hyperpigmentation after the period of application.

Changes induced by intrinsic and extrinsic photoaging result in signs of skin aging including altered pigmentation and wrinkles. A 3-in-1 night facial serum (NFS) was developed to treat skin aging by antioxidative and retinoid-like mechanisms. To determine the clinical and histological effects of the 3-in-1 NFS on signs of skin aging, clinically and histologically. Twenty-four subjects applied serum nightly for 12 weeks, and 12 subjects continued an extension study to 24 weeks. Clinical assessment of skin quality was performed by dermatologists. Skin biopsy was performed at 12 weeks to assess histological changes. There was a global aesthetic improvement over the duration of the study: +1.21 points at 12 weeks; +1.25 at 24 weeks. Skin texture, pigmentation, erythema, skin tone, complexion, lines, and wrinkles all significantly improved (P < .05). There was also a significant reduction in photodamage, hyperpigmentation, and wrinkle scores, most notably horizontal forehead expression lines, and marionette lines (P < .05 for all). Dermal and epidermal thickness increased without reaching statistical significance. The 3-in-1 NFS had clinically and statistically significant effects on signs of skin aging after 12 weeks, which became more pronounced after 24 weeks.

Photoaging is a complex process that is chiefly the result of oxidative stress caused by ultraviolet (UV)-generated reactive oxygen species. To counter this process, we developed a 3-in-1 night facial serum (3-in-1 NFS) containing a combination of direct and indirect antioxidants and polyphenols that is designed to attenuate UV-generated free radicals and stimulate dermal protein synthesis. In clinical trials 3-in-1 NFS improved the appearance of photoaged skin. In this study we sought to identify some of the main histologic changes responsible for this. We performed an immunolabeling analysis of some of the salient epidermal and dermal proteins in 3-in-1 NFS-treated primary epidermal keratinocytes (HEKs) and dermal fibroblasts (HDFs) in vitro, and in UV-exposed skin explants ex vivo. Numbers of apoptotic sunburn cells following exposure of 3-in-1 NFS-treated skin explants to UV radiation were also determined. We demonstrate that 3-in-1 NFS increases levels of filaggrin and aquaporin 3 in HEKs, and levels of collagen I and collagen III in HDFs in vitro. Levels of precursor procollagen type I and tropoelastin were increased in ex vivo skin explants. Numbers of apoptotic sunburn cells were significantly reduced in UV-exposed skin explants. These effects were only observed with the combination of ingredients in 3-in-1 NFS, suggesting that they have a synergistic effect on photoaged skin biology. Our results show that some of the histological hallmarks of photoaging are improved with the use of 3-in-1 NFS.

This article presents the results of experiments, which examine cell mechanisms with the goal of confirming the effective action of the active ingredients used in anti-aging cosmetics. Skin stiffness measurements with the use of an atomic force microscope on two forms of vitamin C (ascorbyl tetraisopalmitate and l-ascorbic acid) have been presented. The estimated Young's modulus for three types of cells (a control as well as cells treated with two forms of vitamin C) has shown significant differences in the stiffness of the tested cells which was confirmed in the histological staining experiment. The presented results indicate the dependence between collagen synthesis and the stiffness of cells treated with two forms of vitamin C.

The total melanin synthesis in the skin depends on various melanogenic factors, including the number of viable melanocytes, the level of melanogenic enzymes per cell, and the reaction rate of the enzymes. The purpose of this study is to examine the effects of L-cysteine (L-Cys), L-ascorbic acid (L-AA), and their derivatives on the tyrosinase (TYR) activity and autoxidation of L-3,4-dihydroxyphenylalanine (L-DOPA) in vitro and the viability and melanin synthesis of B16/F10 cells under different conditions. L-Cysteinamide (C-NH 2 ), glutathione (GSH), L-Cys, L-AA, and N -acetyl L-cysteine (NAC) inhibited the catalytic activity of TYR in vitro. L-AA, C-NH 2 , L-ascorbic acid 2- O -glucoside (AAG), and 3- O -ethyl L-ascorbic acid (EAA) inhibited the autoxidation of L-DOPA in vitro. L-DOPA exhibited cytotoxicity at 0.1 mM and higher concentrations, whereas L-tyrosine (L-Tyr) did not affect cell viability up to 3 mM. L-AA, magnesium L-ascorbyl 2-phosphate (MAP), and L-Cys attenuated the cell death induced by L-DOPA. C-NH 2 decreased the intracellular melanin level at the basal state, whereas L-AA, MAP, and AAG conversely increased it. C-NH 2 reduced the number of darkly pigmented cells via in situ L-DOPA staining, whereas L-AA, MAP, GSH, and AAG increased it. C-NH 2 decreased the intracellular melanin level at the alpha-melanocyte-stimulating hormone (α-MSH)-stimulated state, while NAC and GSH increased it. L-AA and C-NH 2 decreased the intracellular melanin level at the L-Tyr-stimulated state, but NAC and GSH increased it. L-Ascorbyl tetraisopalmitate (ATI) showed no or minor effects in most experiments. This study suggests that L-AA can either promote or inhibit the different melanogenic factors, and C-NH 2 can inhibit the multiple melanogenic factors consistently. This study highlights the multifaceted properties of L-Cys, L-AA, and their derivatives that can direct their therapeutic applications in hyperpigmentation, hypopigmentation, or both disorders.