Oxidation Analysis of l-Cysteine with a Chiral Sensor Based on Quantum Weak Measurement

l-Cysteine, distinguished by its possession of reactive sulfhydryl groups within its molecular structure, plays a significant role in both biological systems and the pharmaceutical industry. It stands not only as a natural component integral to the constitution of glutathione but also as the principal precursor for the synthesis of l-cystine through an oxidation reaction. This study endeavors to introduce a novel approach to l-cysteine analysis, capitalizing on its optical activity, whereby an optical rotation detection system grounded in the principles of quantum weak measurement is proffered. The optical rotation angle corresponding to the concentration of chiral solutions can be accurately ascertained through spectral analysis. In practical implementation, a chiral sensing system, boasting a sensitivity of 372 nm/rad, was meticulously constructed, leveraging the concept of weak value amplification. Then, the real-time monitoring of chemical reactions involving l-cysteine and dimethyl sulfoxide was performed. Under the specific experimental conditions outlined in this investigation, it was observed that the oxidation process culminated within approximately 12 h. The application of weak measurement-based chiral sensors holds immense potential, providing robust technical support for real-time monitoring in fields such as chiral analysis and the synthesis of chiral pharmaceutical compounds.

N-Succinyl-S-Farnesyl-L-Cysteine (SFC): A Novel Isoprenylcysteine Analog with In Vitro Anti-Inflammatory Activity and Clinical Skin Protecting Properties

Over the past 15 years, small molecule isoprenylcysteine (IPC) analogs have been identified as a potential new class of topical anti-inflammatories. Clinical studies have demonstrated that IPCs are both safe and effective in promoting healthy skin when applied topically. This work aims to demonstrate N-Succinyl-S-farnesyl-L-cysteine (SFC) as a novel IPC molecule that provides a broad spectrum of benefits for skin. Human promyelocytic cell line HL-60, human dermal microvascular endothelial cells (HDMECs), human dermal fibroblasts (HDFs), and normal human epidermal keratinocytes (NHEKs) were exposed in culture to various inducers to trigger reactive oxygen species, cytokines, or collagenase production. A 49-subject randomized double-blind, vehicle-controlled, split face trial was performed with 1% SFC gel, or 5% niacinamide and vehicle applied for 12 weeks to evaluate anti-wrinkle and anti-aging endpoints. We demonstrated that SFC inhibited GPCR and TLR-induced pro-inflammatory cytokine release in NHEKs and HDMECs from several inflammatory inducers such as UVB, chemicals, cathelicidin, and bacteria. SFC successfully reduced GPCR-induced oxidation in differentiated neutrophils. Moreover, photoaging studies showed that SFC reduced UVA-induced collagenase (pro-MMP-1) production in HDFs. Clinical assessment of 1% SFC gel demonstrated improvement above the vehicle for wrinkle reduction, hydration, texture, and overall appearance of skin. N-Succinyl-S-farnesyl-L-cysteine (SFC) is a novel anti-inflammatory small molecule and is the first farnesyl-cysteine IPC shown to clinically improve appearance and signs of aging, while also having the potential to ameliorate inflammatory skin disorders.

SIG-1273 protects skin against urban air pollution and when formulated in AgeIQ™ Night Cream anti-aging benefits clinically demonstrated

BACKGROUND

SIG-1273 is a novel cosmetic active that provides a broad spectrum of benefits to the skin. Considering the chronic skin exposure to pollution in urban areas, we sought to determine if SIG-1273 could provide additional protection against skin aging by inhibiting pollutant-induced cytotoxicity and inflammation.

OBJECTIVE

Determine if SIG-1273 possesses antipollution properties in vitro and evaluate the potential anti-aging benefits of Age IQ™ Night Cream clinically in human subjects.

METHODS

In vitro studies utilizing normal human epidermal keratinocytes (NHEKs), were co-treated with urban dust (SRM 1649b) and SIG-1273 (toxicity protection measured by MTS assay). A water-soluble fraction of urban dust (UD-WS) induces pro-inflammatory cytokine release (IL-8) from NHEKs (measured via ELISA). An 8-week, 37-subject clinical trial was performed with 0.05% SIG-1273 formulated in Age IQ™ Night Cream and applied topically to assess its potential to reduce the appearance of aging.

RESULTS

In vitro studies using NHEKs demonstrate SIG-1273 protects against urban dust-induced cell toxicity, reducing cell death by 66% and concentration dependently inhibits UD-WS-induced IL-8 production (IC₅₀  = 20 nmol/L), outperforming niacinamide, ascorbic acid, and α-tocopherol, commonly used actives in antipollution skin-care products. Clinical assessment of Age IQ™ Night Cream shows it is effective in improving the appearance of facial skin aging including fine lines and wrinkles, skin texture, skin clarity/brightness, and firmness/elasticity.

CONCLUSIONS

SIG-1273, is demonstrated here for the first time to possess antipollution properties. Included as a key active ingredient in Age IQ™ Night Cream, this novel topical formulation provides benefits to individuals with aging skin.

SIG1459: A novel phytyl-cysteine derived TLR2 modulator with in vitro and clinical anti-acne activity

Cutibacterium (formerly Propionibacterium acnes) is a major contributor to the pathogenesis of acne. C. acnes initiates an innate immune response in keratinocytes via recognition and activation of toll-like receptor-2 (TLR2), a key step in comedogenesis. Tetramethyl-hexadecenyl-cysteine-formylprolinate (SIG1459), a novel anti-acne isoprenylcysteine (IPC) small molecule, is shown in this study to have direct antibacterial activity and inhibit TLR2 inflammatory signalling. In vitro antibacterial activity of SIG1459 against C. acnes was established demonstrating minimal inhibitory concentration (MIC = 8.5 μmol\L), minimal bactericidal concentration (MBC = 16.1 μmol\L) and minimal biofilm eradication concentration (MBEC = 12.5 μmol\L). To assess SIG1459's anti-inflammatory activity, human keratinocytes were exposed to C. acnes and different TLR2 ligands (peptidoglycan, FSL-1, Pam3CSK4) that induce pro-inflammatory cytokine IL-8 and IL-1α production. Results demonstrate SIG1459 inhibits TLR2-induced IL-8 release from TLR2/TLR2 (IC₅₀  = 0.086 μmol\L), TLR2/6 (IC₅₀  = 0.209 μmol\L) and IL-1α from TLR2/TLR2 (IC₅₀  = 0.050 μmol\L). To assess the safety and in vivo anti-acne activity of SIG1459, a vehicle controlled clinical study was conducted applying 1% SIG1459 topically (n = 35 subjects) in a head-to-head comparison against 3% BPO (n = 15 subjects). Utilizing the Investigator Global Assessment scale for acne as primary endpoint, results demonstrate 1% SIG1459 significantly outperformed 3% BPO over 8 weeks, resulting in 79% improvement as compared to 56% for BPO. Additionally, 1% SIG1459 was well tolerated. Thus, SIG1459 and phytyl IPC compounds represent a novel anti-acne technology that provides a safe dual modulating benefit by killing C. acnes and reducing the inflammation it triggers via TLR2 signalling.

Effects of the Usage of l-Cysteine (l-Cys) on Human Health

This review summarizes recent knowledge about the use of the amino acid l-Cysteine (l-Cys) through diet, nutritional supplements or drugs with the aim to improve human health or treat certain diseases. Three databases (PubMed, Scopus, and Web of Science) and different keywords have been used to create a database of documents published between 1950 and 2017 in scientific journals in English or Spanish. A total of 60,885 primary publications were ultimately selected to compile accurate information about the use of l-Cys in medicine and nutritional therapies and to identify the reported benefits of l-Cys on human health. The number of publications about the use of l-Cys for these purposes has increased significantly during the last two decades. This increase seems to be closely related to the rise of nutraceutical industries and personalized medicine. The main evidence reporting benefits of l-Cys usage is summarized. However, the lack of accurate information and studies based on clinical trials hampers consensus among authors. Thus, the debate about the role and effectiveness of supplements/drugs containing l-Cys is still open.

N-Acetylglutaminoyl-S-farnesyl-L-cysteine (SIG-1191): an anti-inflammatory molecule that increases the expression of the aquaglyceroporin, aquaporin-3, in human keratinocytes

Isoprenylcysteine (IPC) small molecules were discovered as signal transduction modulating compounds ~25 years ago. More recently, IPC molecules have demonstrated antioxidant and anti-inflammatory properties in a variety of dermal cells as well as antimicrobial activity, representing a novel class of compounds to ameliorate skin conditions and disease. Here, we demonstrate a new IPC compound, N-acetylglutaminoyl-S-farnesyl-L-cysteine (SIG-1191), which inhibits UVB-induced inflammation blocking pro-inflammatory cytokine interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) production. To investigate further the previously reported hydrating potential of IPC compounds, SIG-1191 was tested for its ability to modulate aquaporin expression. Specifically, aquaporin 3 (AQP3) the most abundant aquaporin found in skin has been reported to play a key role in skin hydration, elasticity and barrier repair. Results show here for the first time that SIG-1191 increases AQP3 expression in both cultured normal human epidermal keratinocytes as well as when applied topically in a three-dimensional (3D) reconstructed human skin equivalent. Additionally, SIG-1191 dose dependently increased AQP3 protein levels, as determined by specific antibody staining, in the epidermis of the 3D skin equivalents. To begin to elucidate which signaling pathways SIG-1191 may be modulating to increase AQP3 levels, we used several pharmacological pathway inhibitors and determined that AQP3 expression is mediated by the Mitogen-activated protein kinase/Extracellular signal-regulated kinase kinase (MEK) pathway. Altogether, these data suggest SIG-1191 represents a new IPC derivative with anti-inflammatory activity that may also promote increased skin hydration based on its ability to increase AQP3 levels.

In vitro and clinical evaluation of SIG1273: a cosmetic functional ingredient with a broad spectrum of anti-aging and antioxidant activities

BACKGROUND

Isoprenylcysteine (IPC) small molecules were identified as a new class of anti-inflammatory compounds over 20 years ago. Since then, they have been developed as novel cosmetic functional ingredients (CFI) and topical drug candidates. SIG1273 is a second generation CFI that has previously been shown to provide a broad spectrum of benefits for the skin through its anti-inflammatory and antimicrobial properties.

OBJECTIVE

To determine whether SIG1273 possesses anti-aging properties in vitro and evaluate the tolerability and activity of SIG1273 when applied topically to human subjects.

METHODS

To model photoaging in vitro, human dermal fibroblasts (HDFs) were exposed in culture to UVA to induce collagenase (MMP-1) production. An in vitro wound-healing model was based on the activation of HDF migration into cell-free tissue culture surface. Hydrogen peroxide-induced oxidative stress was performed using HDFs to measure intracellular ROS activity. Radical scavenging capacity was determined using a colorimetric antioxidant assay kit (ABTS method). Lastly, a 4-week, 29-subject study was performed in which SIG1273 was applied topically as a cream to assess its tolerance and activity in reducing the appearance of aging.

RESULTS

In vitro studies demonstrate SIG1273 inhibits UVA-induced MMP-1 production, hydrogen peroxide-induced oxidative stress and promotes wound healing. Moreover, SIG1273 was shown to be a radical scavenging antioxidant. Clinical assessment of SIG1273 cream (0.25%) showed it was well tolerated with significant improvement in the appearance of fine lines, coarse wrinkles, radiance/luminosity, pore size, texture/smoothness, hydration and increased firmness.

CONCLUSIONS

SIG1273 represents a novel CFI with antioxidant, anti-aging, and anti-inflammatory properties that when applied topically is well tolerated and provides benefits to individuals with aging skin.