Effects of Several Cosmetic Preservatives on ROS-Dependent Apoptosis of Rat Neural Progenitor Cells

Tamarix articulata extract offers protection against toxicity induced by beauty products in Hs27 human skin fibroblasts

The current study evaluates the cytotoxicity, mode of cell death and chemical analysis of selected beauty products and evaluation of the protective effect of Tamarix articulata (TA) extract against toxicity induced by beauty products in skin fibroblasts (Hs27). MTT and Crystal violet (CV) assays were used to determine the dose-dependent cytotoxic effects of beauty products against Hs27 fibroblasts. DNA fragmentation assay and annexin-V staining were conducted to determine the mode of cell killing induced by evaluated beauty products. Quantification of reactive oxygen species (ROS) and antioxidant enzyme levels were used to evaluate the oxidative stress. Chemical analysis and heavy metals were evaluated to determine beauty products. Pre-treatment with TA extract for different time points followed by time-dependent exposure with beauty products to assess the protective effect of TA extract in Hs27 cells was analyzed by MTT and CV assays. Owing to the presence of various harmful heavy metals such as arsenic (As), chromium (Cr), cadmium (Cd), nickel (Ni), and lead (Pb) in beauty products, our results revealed that all beauty products induce significant cytotoxicity over time (1, 4 h) in a dose-dependent (125, 250, 500 μg/mL) manner. DNA fragmentation assay, quantification of apoptosis by annexin-V staining, determination of ROS and antioxidant enzymes (CAT, GSH-Px and SOD) revealed that the induced cytotoxicity was caused by oxidative stress-mediated apoptosis. However, pre-incubation with a safe dose (50 μg/mL) of TA for different times (24, 48 h) followed by exposure to various doses (62.5, 125, 250, 500 μg/mL) of beauty products for different times (1, 4 h) revealed significant (*p≤0.05, **p≤0.01) protection against beauty product-mediated cytotoxicity. The effect was more pronounced for 1 h exposure to beauty products compared to 4 h. Our study demonstrates that the due to the presence of heavy metals in synthetic beauty products exhibit marked toxicity to skin fibroblasts due to oxidative stress-mediated apoptosis. However, the presence of abundant bioactive polyphenols with promising antiscavenging activity in TA extracts significantly nullifies cytotoxicity promoted by examined beauty products in skin fibroblasts (Hs27).

Mechanisms of emerging resistance associated with non-antibiotic antimicrobial agents: a state-of-the-art review

Although the development of resistance by microorganisms to antimicrobial drugs has been recognized as a global public health concern, the contribution of various non-antibiotic antimicrobial agents to the development of antimicrobial resistance (AMR) remains largely neglected. The present review discusses various chemical substances and factors other than typical antibiotics, such as preservatives, disinfectants, biocides, heavy metals and improper chemical sterilization that contribute to the development of AMR. Furthermore, it encompasses the mechanisms like co-resistance and co-selection, horizontal gene transfer, changes in the composition and permeability of cell membrane, efflux pumps, transposons, biofilm formation and enzymatic degradation of antimicrobial chemicals which underlie the development of resistance to various non-antibiotic antimicrobial agents. In addition, the review addresses the resistance-associated changes that develops in microorganisms due to these agents, which ultimately contribute to the development of resistance to antibiotics. In order to prevent the indiscriminate use of chemical substances and create novel therapeutic agents to halt resistance development, a more holistic scientific approach might provide diversified views on crucial factors contributing to the persistence and spread of AMR. The review illustrates the common and less explored mechanisms contributing directly or indirectly to the development of AMR by non-antimicrobial agents that are commonly used.

Benzalkonium Chloride Disinfectants Induce Apoptosis, Inhibit Proliferation, and Activate the Integrated Stress Response in a 3-D in Vitro Model of Neurodevelopment

We previously found that the widely used disinfectants, benzalkonium chlorides (BACs), alter cholesterol and lipid homeostasis in neuronal cell lines and in neonatal mouse brains. Here, we investigate the effects of BACs on neurospheres, an in vitro three-dimensional model of neurodevelopment. Neurospheres cultured from mouse embryonic neural progenitor cells (NPCs) were exposed to increasing concentrations (from 1 to 100 nM) of a short-chain BAC (BAC C12), a long-chain BAC (BAC C16), and AY9944 (a known DHCR7 inhibitor). We found that the sizes of neurospheres were decreased by both BACs but not by AY9944. Furthermore, we observed potent inhibition of cholesterol biosynthesis at the step of DHCR7 by BAC C12 but not by BAC C16, suggesting that cholesterol biosynthesis inhibition is not responsible for the observed reduction in neurosphere growth. By using immunostaining and cell cycle analysis, we found that both BACs induced apoptosis and decreased proliferation of NPCs. To explore the mechanisms underlying their effect on neurosphere growth, we carried out RNA sequencing on neurospheres exposed to each BAC at 50 nM for 24 h, which revealed the activation of the integrated stress response by both BACs. Overall, these results suggest that BACs affect neurodevelopment by inducing the integrated stress response in a manner independent of their effects on cholesterol biosynthesis.

Computational identification of preservatives with potential neuronal cytotoxicity

Preservatives play a vital role in cosmetics by preventing microbiological contamination for keeping products safe to use. However, a few commonly used preservatives have been suggested to be neurotoxic. Cytotoxicity to neuronal cells is commonly used as the first-tier assay for assessing chemical-induced neurotoxicity. Given the time and resources required for chemical screening, computational methods are attractive alternatives over experimental approaches in prioritizing chemicals prior to further experimental evaluations. In this study, we developed a Quantitative Structure-Activity Relationships (QSAR) model for the identification of potential neurotoxicants. A set of 681 chemicals was utilized to construct a robust prediction model using oversampling and Random Forest algorithms. Within a defined applicability domain, the independent test on 452 chemicals showed a high accuracy of 87.7%. The application of the model to 157 preservatives identified 15 chemicals potentially toxic to neuronal cells. Three of them were further validated by in vitro experiments. The results suggested that further experiments are desirable for assessing the neurotoxicity of the identified preservatives with potential neuronal cytotoxicity.

The Beast of Beauty: Environmental and Health Concerns of Toxic Components in Cosmetics

Cosmetic products are used in large quantities across the world. An increasing number of chemical compounds are being added to the formulation of cosmetic products as additives, fragrances, preservatives, stabilizers, surfactants, dye and shine to potentiate their quality, property and shelf life. Owing to their widespread use, active residues of cosmetic products are continuously introduced into the environment in several ways. Many of these chemicals are bioactive and are characterized by potential bioaccumulation ability and environmental persistence, thus exerting a major risk to humans and the health of ecosystems. Hence, the indiscriminate consumption of cosmetics may present a looming issue with significant adverse impacts on public health. This review intends to spotlight a current overview of toxic ingredients used in formulating cosmetics such as parabens, triclosan, benzalkonium chloride, 1,4-dioxane, plastic microbeads, formaldehyde, diazolidinyl urea, imidazolidinyl urea, sunscreen elements (organic and inorganic UV filters) and trace metals. Specific focus is given to illustrate the biological risks of these substances on human health and aquatic system in terms of genotoxicity, cytotoxicity, neurotoxicity mutagenicity, and estrogenicity. In addition to conclusive remarks, future directions are also suggested.

Mitochondrial Dysfunctions May Be One of the Major Causative Factors Underlying Detrimental Effects of Benzalkonium Chloride

Benzalkonium chloride (BAC) is currently the most commonly used antimicrobial preservative in ophthalmic solutions, nasal sprays, and cosmetics. However, a large number of clinical and experimental investigations showed that the topical administration of BAC-containing eye drops could cause a variety of ocular surface changes, from ocular discomfort to potential risk for future glaucoma surgery. BAC-containing albuterol may increase the risk of albuterol-related systemic adverse effects. BAC, commonly present in personal care products, in cosmetic products can induce irritation and dose-dependent changes in the cell morphology. The cationic nature of BAC (it is a quaternary ammonium) suggests that one of the major targets of BAC in the cell may be mitochondria, the only intracellular compartment charged negatively. However, the influence of BAC on mitochondria has not been clearly understood. Here, the effects of BAC on energy parameters of rat liver mitochondria as well as on yeast cells were examined. BAC, being a "weaker" uncoupler, potently inhibited respiration in state 3, diminished the mitochondrial membrane potential, caused opening of the Ca2+/Pi-dependent pore, blocked ATP synthesis, and promoted H₂O₂ production by mitochondria. BAC triggered oxidative stress and mitochondrial fragmentation in yeast cells. BAC-induced oxidative stress in mitochondria and yeast cells was almost totally prevented by the mitochondria-targeted antioxidant SkQ1; the protective effect of SkQ1 on mitochondrial fragmentation was only partial. Collectively, these data showed that BAC acts adversely on cell bioenergetics (especially on ATP synthesis) and mitochondrial dynamics and that its prooxidant effect can be partially prevented by the mitochondria-targeted antioxidant SkQ1.

Inhaled Kathon may induce eosinophilia-mediated disease in the lung

In 2011, a link between humidifier disinfectants and patients with idiopathic pulmonary fibrosis was identified in Korea, and Kathon was suggested as one of the causative agents. In this study, Kathon induced apoptotic cell death along with membrane damage at 24 h post-exposure. Additionally, on day 14 after a single instillation with Kathon, the total number of pulmonary cells and the levels of TNF-α, IL-5, IL-13, MIP-1α, and MCP-1α clearly increased in the lung of mice. The proportion of natural killer cells and eosinophils were significantly elevated in the spleen and the bloodstream, respectively, and the level of immunoglobulin (Ig) A, but not IgG, IgM, and IgE, dose-dependently increased. Therefore, we suggest that inhaled Kathon may induce eosinophilia-mediated disease in the lung by disrupting homeostasis of pulmonary surfactants. Considering that eosinophilia is closely related to cancer and fibrosis, further studies are needed to understand the relationship between them.

An insight into toxicity and human-health-related adverse consequences of cosmeceuticals - A review

In recent years, the use of cosmeceutical-based personal care and beauty products has ever increased, around the world. Currently, an increasing number of compounds are being assimilated in the formulation of cosmetic products as preservatives, fragrances, surfactants, etc. to intensify the performance, quality, value, and lifespan of cosmetics. Nevertheless, many of these chemical additives pose toxic effects to the human body, exhibiting health risks from a mild hypersensitivity to life-threatening anaphylaxis or lethal intoxication. Therefore, the indiscriminate application of cosmeceuticals has recently become a mounting issue confronting public health. The present review focuses on exposure to a large variety of toxic substances used in cosmetic formulations such as 1,4-dioxane formaldehyde, paraformaldehyde, benzalkonium chloride, imidazolidinyl urea, diazolidinyl urea, trace heavy metals, parabens derivatives, phthalates, isothiazolinone derivatives (methylchloroiso-thiazolinone, and methylisothiazolinone), methyldibromo glutaronitrile, and phenoxy-ethanol. The biological risks related to these substances that they can pose to human health in terms of cytotoxicity, genotoxicity, mutagenicity, neurotoxicity oestrogenicity or others are also discussed. Researchers from academia, consultancy firms, governmental organizations, and cosmetic companies should carry out further progress to keep updating the consumers regarding the dark-sides, and health-related harmful apprehensions of cosmetics. In addition, the industry-motivated initiatives to abate environmental impact through green, sustainable and eco-friendly product development grasp significant perspective.

Effect of Fermented Fish Oil on Fine Particulate Matter-Induced Skin Aging

Skin is exposed to various harmful environmental factors such as air pollution, which includes different types of particulate matter (PM). Atmospheric PM has harmful effects on humans through increasing the generation of reactive oxygen species (ROS), which have been reported to promote skin aging via the induction of matrix metalloproteinases (MMPs), which in turn can cause the degradation of collagen. In this study, we investigated the effect of fermented fish oil (FFO) derived from mackerel on fine PM (particles with a diameter < 2.5 µm: PM_2.5)-induced skin aging in human keratinocytes. We found that FFO inhibited the PM_2.5-induced generation of intracellular ROS and MMPs, including MMP-1, MMP-2, and MMP-9. In addition, FFO significantly abrogated the elevation of intracellular Ca²⁺ levels in PM_2.5-treated cells and was also found to block the PM_2.5-induced mitogen-activated protein kinase/activator protein 1 (MAPK/AP-1) pathway. In conclusion, FFO has an anti-aging effect on PM_2.5-induced aging in human keratinocytes.

Butterbur Leaves Attenuate Memory Impairment and Neuronal Cell Damage in Amyloid Beta-Induced Alzheimer's Disease Models

Alzheimer’s disease (AD) is the most prevalent neurodegenerative disease, and is characterized by the accumulation of amyloid beta (Aβ) as a pathological hallmark. Aβ plays a central role in neuronal degeneration and synaptic dysfunction through the generation of excessive oxidative stress. In the present study, we explored whether leaves of Petasites japonicus (Siebold & Zucc.) Maxim. (PL), called butterbur and traditionally used in folk medicine, show neuroprotective action against Aβ_25–35 plaque neurotoxicity in vitro and in vivo. We found that PL protected Aβ_25–35 plaque-induced neuronal cell death and intracellular reactive oxygen species generation in HT22 cells by elevating expression levels of phosphorylated cyclic AMP response element-binding protein, heme oxygenase-1, and NAD(P)H quinine dehydrogenase 1. These neuroprotective effects of PL were also observed in Aβ_25–35 plaque-injected AD mouse models. Moreover, administration of PL diminished Aβ_25–35 plaque-induced synaptic dysfunction and memory impairment in mice. These findings lead us to suggest that PL can protect neurons against Aβ_25–35 plaque-induced neurotoxicity and thus may be a potential candidate to regulate the progression of AD.