RIFM fragrance ingredient safety assessment, cinnamaldehyde, CAS Registry Number 104-55-2

Modulation of Autophagy on Cinnamaldehyde Induced THP-1 Cell Activation

Cinnamaldehyde (CIN), which is a cosmetic fragrance allergen regulated by the European Union, can induce allergic contact dermatitis in consumers, reducing their quality of life. Autophagy may be associated with the dendritic cell (DC) response to chemical sensitizers. We hypothesized that CIN would activate DCs through autophagy during skin sensitization. In this study, Tohoku Hospital Pediatrics-1 cells (THP-1 cells) were used as an in vitro DC model, and we evaluated the expression of cell activation markers, intracellular oxidative stress, and autophagy pathway-related genes in response to CIN in THP-1 cells. CIN exposure activated THP-1 cells, which presented increases in CD54 and CD86 expression and ROS generation. Transcriptomic analysis revealed that the genes that were differentially expressed after CIN stimulation were mostly associated with autophagy. The autophagy markers LC3B, p62, and ATG5 had upregulated mRNA and protein levels after CIN exposure. Furthermore, the effects of the autophagy inhibitor Baf-A1 and the autophagy activator rapamycin were investigated on CIN-treated cells. Pretreatment with Baf-A1 in THP-1 cells impaired autophagic flux and dramatically promoted cell activation and oxidative stress triggered by CIN. Conversely, rapamycin inhibited cell activation and the ROS content in CIN-challenged cells while increasing autophagy levels via a reduction in mTOR expression. These results suggest that the autophagy pathway has a pivotal influence on the regulation of CIN-induced activation in THP-1 cells, which provides new insight into the pathogenesis and precise therapeutic strategies for ACD.

In Silico Phototoxicity Prediction of Drugs and Chemicals by using Derek Nexus and QSAR Toolbox

Phototoxicity testing is crucial for evaluating the potential harmful effects of pharmaceuticals and chemicals on human skin when exposed to sunlight. Traditional in vivo models involving mice, rats, guinea pigs, as well as in vitro assays such as the 3T3 Neutral Red Uptake phototoxicity assay and methods based on the use of reconstructed human epidermis, have been established for phototoxicity testing. While these approaches are extremely valuable, they are costly in terms of both time and resources. Consequently, in silico approaches based on the use of predictive software tools can offer more rapid and cost-effective phototoxicity screening solutions. With this goal in mind, the current study evaluated two in silico tools - Derek Nexus 6.1.0/Derek Knowledge Base 2020 1.0 (Lhasa Limited, UK) and the QSAR Toolbox (v 4.5) developed by the Organisation for Economic Co-operation and Development (OECD) - for their capacity to predict the phototoxicity of several substances from diverse classes. Derek Nexus and the QSAR Toolbox were both found to be very useful for predicting the phototoxicity of drugs and other chemicals. Derek Nexus predicted phototoxicity of the compounds, with a sensitivity of 63%, specificity of 93%, Positive Predictive Values of 90% and Negative Predictive Value of 69%, overall accuracy of 77% and balanced accuracy of 78%. The QSAR Toolbox achieved sensitivity of 73%, specificity of 85%, Positive Predictive Value of 85% and Negative Predictive Value of 74%, overall accuracy of 79% and balanced accuracy of 79%. The results show that Derek Nexus and the QSAR Toolbox can be usefully incorporated in the workflow of phototoxicity testing for pharmaceuticals and chemicals.

Identification of anti-SARS-CoV-2 agents based on flavor/fragrance compositions that inhibit the interaction between the virus receptor binding domain and human angiotensin converting enzyme 2

Coronavirus disease 2019 (COVID-19) pandemic poses a threat to human beings and numerous cases of infection as well as millions of victims have been reported. The binding of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein receptor binding domain (RBD) to human angiotensin converting enzyme 2 (hACE2) is known to promote the engulfment of the virus by host cells. Employment of flavor/fragrance compositions to prevent SARS-CoV-2 infection by inhibiting the binding of viral RBD (vRBD) to hACE2 might serve as a favorable, simple, and easy method for inexpensively preventing COVID-19, as flavor/fragrance compositions are known to directly interact with the mucosa in the respiratory and digestive systems and have a long history of use and safety assessment. Herein we report the results of screening of flavor/fragrance compositions that inhibit the binding of vRBD to hACE2. We found that the inhibitory effect was observed with not only the conventional vRBD, but also variant vRBDs, such as L452R, E484K, and N501Y single-residue variants, and the K417N+E484K+N501Y triple-residue variant. Most of the examined flavor/fragrance compositions are not known to have anti-viral effects. Cinnamyl alcohol and Helional inhibited the binding of vRBD to VeroE6 cells, a monkey kidney cell line expressing ACE2. We termed the composition with inhibitory effect on vRBD-hACE2 binding as "the molecularly targeted flavor/fragrance compositions". COVID-19 development could be prevented by using these compositions with reasonable administration methods such as inhalation, oral administration, and epidermal application.

Combinative ex vivo studies and in silico models ProTox-II for investigating the toxicity of chemicals used mainly in cosmetic products

Human data on remains sparse and of varying quality and reproducibility. Ex vivo experiments and animal experiments currently is the most preferred way to predict the skin sensitization approved by the regulatory agencies across the world. However, there is a constant need and demand to reduce animal experiments and provide the scope of alternative methods to animal testing. In this study, we have compared the predictive performance of the published computational tools such as ProTox-II, SuperCYPsPred with the data obtained from ex-vivo experiments. From the results of the retrospective analysis, it can be observed that the computational predictions are in agreement with the experimental results. The computational models used here are generative models based on molecular structures and machine learning algorithms and can be applied also for the prediction of skin sensitization. Besides prediction of the toxicity endpoints, the models can also provide deeper insights into the molecular mechanisms and adverse outcome pathways (AOPs) associated with the chemicals used in cosmetic products.

Use of alternative test methods in a tiered testing approach to address photoirritation potential of fragrance materials

The safety assessment of fragrance materials for photoirritation utilized by The Research Institute for Fragrance Materials has recently been modified and is described in detail. Materials demonstrating significant absorbance in the ultraviolet and visible light (UV/VIS) range (290-700 nm) may present a concern for photoirritation and require further investigation. If there are no photoirritation data or data are insufficient, then data on read-across materials are considered before a tiered approach for testing begins. The hazard-based 3T3-Neutral Red Uptake (NRU) Phototoxicity Test (OECD TG 432) is used as a first-tier assay; if it predicts photoirritation, it is followed by the reconstructed human epidermis (RhE) phototoxicity assay (OECD TG 498). The RhE phototoxicity assay is used to determine a No Observed Effect Level (NOEL) for photoirritation that is used in a confirmatory human photoirritation test. Data are presented on 108 fragrance materials exhibiting significant UV/VIS absorbance and evaluated in the 3T3-NRU Phototoxicity Assay. Twenty-one materials were predicted to be phototoxic; twenty were evaluated in the RhE Phototoxicity Assay to establish a NOEL. Fourteen materials were then evaluated in a confirmatory human phototoxicity test. The tiered testing approach presented represents a scientifically pragmatic method to minimize the likelihood of photoirritation from fragrance materials.

Ectopic Odorant Receptor Responding to Flavor Compounds: Versatile Roles in Health and Disease

Prompted by the ground-breaking discovery of the rodent odorant receptor (OR) gene family within the olfactory epithelium nearly 30 years ago, followed by that of OR genes in cells of the mammalian germ line, and potentiated by the identification of ORs throughout the body, our appreciation for ORs as general chemoreceptors responding to odorant compounds in the regulation of physiological or pathophysiological processes continues to expand. Ectopic ORs are now activated by a diversity of flavor compounds and are involved in diverse physiological phenomena varying from adipogenesis to myogenesis to hepatic lipid accumulation to serotonin secretion. In this review, we outline the key biological functions of the ectopic ORs responding to flavor compounds and the underlying molecular mechanisms. We also discuss research opportunities for utilizing ectopic ORs as therapeutic strategies in the treatment of human disease as well as challenges to be overcome in the future. The recognition of the potent function, signaling pathway, and pharmacology of ectopic ORs in diverse tissues and cell types, coupled with the fact that they belong to G protein-coupled receptors, a highly druggable protein family, unequivocally highlight the potential of ectopic ORs responding to flavor compounds, especially food-derived odorant compounds, as a promising therapeutic strategy for various diseases.

Environmental Distribution of Personal Care Products and Their Effects on Human Health

Personal care products (PCPs) are generally used for personal hygiene, cleaning, grooming, and beautification. These include hair and skin care products, baby care products, UV blocking creams, facial cleansers, insect repellents, perfumes, fragrances, soap, detergents, shampoos, conditioners, toothpaste, etc., thus exposing humans easily. Personal preferences related to PCPs usage frequency are highly variable and depend on socioeconomic status and lifestyle factors. The increasing availability and diversity of PCPs from the retailer outlets consequently result in higher loading of PCPs into wastewater systems and, therefore, the environment. These compounds persistently and continuously release biologically active and inactive ingredients in the atmosphere, biosphere, geosphere, and demonstrating adverse effects on human, wild, and marine life. Advanced techniques such as granular activated carbon filtration and algae-based system may help biotransformation and remove PCP contaminants from water with improved efficiency. Additionally, harmony among PCPs related regulations of different countries may encourage standard checks to control their manufacturing, sale, and distribution across the borders to ensure consumers' safety. Furthermore, all intended ingredients, their concentrations, and instructions for frequency of use as per age groups may be clearly labeled on packages of PCPs. In conclusion, the emerging environmental contaminants of PCPs and their association with the growing risks of negative effects on human health and globally on the environment emphasize the chemical-free simple lifestyle.