Integrated approaches to testing and assessment as a tool for the hazard assessment and risk characterization of cosmetic preservatives

Sex differences in CYP450-based sodium dehydroacetate metabolism and its metabolites in rats

Sodium dehydroacetate (DHA-Na), a widely used preservative, can induce sex-differentiated coagulation disorders primarily resulting from its metabolism. However, the underlying mechanisms remain poorly understood. Here, we identified several Cytochrome P450 (CYP450) sub-enzymes involved in sex differences related to DHA-Na metabolism, along with two related DHA-Na metabolites. CYP1A2, CYP3A2, and CYP2D1 were primarily responsible for DHA-Na metabolism, which was stronger in male rats than in female rats. Inhibition of these isoforms separately resulted in the DHA-Na metabolic capacity in male rats becoming equal to, or even weaker than, that in female rats. Furthermore, Cyp1a2, Cyp3a2, Cyp2d1, and Cyp2c11 expression was higher in male rats than in female rats, suggesting these enzymes are related to exhibited sex differences in DHA-Na metabolism. Moreover, 3-glycoloyl-6-methy-2,3-dihydropyran-2,4-dione (C8H8O5) and 3-imino-6-methyl-2,3-dihydropran-2,4dione (C6H5O3N) were identified as the two main DHA-Na metabolites. These findings provide crucial insights into potential mechanisms underlying sex differences in DHA-Na metabolism and its metabolites in rats.

Sodium Dehydroacetate and Dehydroacetic Acid

The Expert Panel for Cosmetic Ingredient Safety (Panel) first published a safety assessment of Sodium Dehydroacetate and Dehydroacetic Acid in 1985. The Panel previously concluded that Sodium Dehydroacetate and Dehydroacetic Acid are safe as used in the present practices of use and concentration, as stated in that report. Upon re-review in 2003, the Panel reaffirmed the original conclusion, as published in 2006. The Panel reviewed updated frequency and concentration of use data again in 2023, in addition to any newly available, relevant safety data. Considering this information, as well as the information provided in the original safety assessment and the prior re-review document, the Panel reaffirmed the 1985 conclusion.

Epidemiology and Risk Factors of Dry Eye Disease: Considerations for Clinical Management

Dry eye disease is a multifactorial condition characterised by tear film instability, hyperosmolarity and ocular surface inflammation. Understanding the epidemiology of dry eye disease and recognising both modifiable and non-modifiable risk factors can assist eye care practitioners in assessing, treating, and managing patients with the condition. This review considers current knowledge surrounding its incidence and prevalence, as well as associated demographic, systemic, ocular, and iatrogenic, and lifestyle-related modifiable risk factors. Population-based prevalence estimates vary according to the diagnostic criteria used to define dry eye disease, as well as severity and demographic characteristics of the population. Considering recent data and variable population demographics, conservative prevalence estimates suggest that 10-20% of the population over 40 years of age report moderate to severe symptoms and/or seek treatment for dry eye disease. Individuals with specific non-modifiable demographic risk factors may be at increased risk of developing dry eye disease. Advanced age, female sex and East Asian ethnicity have been identified as key non-modifiable demographic features predisposing individuals to dry eye disease. Systemic conditions that have been associated with an increased risk of dry eye disease include migraine, Sjögren syndrome, connective tissue disorders, mental health disorders, diabetes mellitus and androgen deficiency. Medications that may contribute to this risk include antidepressants, antihistamines, and hormone replacement therapy. Ocular and iatrogenic risk factors of dry eye disease include blepharitis, Demodex infestation, ocular surgery, blink completeness, contact lens wear, and topical ophthalmic medications. A range of modifiable lifestyle factors that can increase the risk of dry eye disease have also been identified, including low humidity environments, digital screen use, quality of sleep, diet, and eye cosmetic wear. Dry eye is a common disease affecting millions globally. Increasing knowledge regarding its associated risk factors can better prepare the eye care practitioner to successfully manage patients with this ocular surface disease.

A sustainable and innovative method to determine parabens in body creams for exposure and risk assessment

Methylparaben (MeP), ethylparaben (EtP), propylparaben (PrP), and butylparaben (BuP) are among the most widely used preservatives in cosmetics, drugs, and foods. These compounds have been associated with toxic effects due to the overuse of products with parabens in their formulation. The toxicity of parabens may be correlated to endocrine disruption, owing to their ability to mimic the actions of estradiol. In this paper, a simple, sustainable, robust, and innovative dispersive liquid-liquid microextraction (DLLME) technique was developed and employed to extract these xenobiotics from body cream samples, aiming to calculate the margin of safety (MoS) to assess the risk of exposure. The validated method presented suitable linearity (r > 0.99), lower limits of detection (ranging from 0.01 to 0.04 % w/w), and satisfactory precision and accuracy (ranging from 4.33 to 10.47, and from -14.25 to 13.85, respectively). Seven of the ten analysed samples presented paraben contents within the acceptable concentration according to European legislation. The MoS value obtained for PrP (37.58) suggested its reduced safety, indicating that PrP may significantly contribute to systemic exposure resulting from the use of personal care products.

Effects of sodium dehydroacetate on broiler chicken bones

Sodium dehydroacetate (DHA-Na) is a fungicidal preservative widely used in food and animal feed. DHA-Na can induce coagulation disorders in rats and poultry by inhibiting carboxylation of vitamin K-dependent proteins; it can also impair bone development in zebrafish. However, the effects of DHA-Na on broiler chicken bones remain unknown. Here, we assessed whether DHA-Na impairs bone development in broiler chickens. We administered Suji yellow chickens with 200 to 800 mg/kg DHA-Na, 2 mg/kg vitamin K, or both for 2 mo. Bone metabolite-related serum indicators, tissue micromorphology, and relevant protein expression were monitored during the treatment period. We also assessed primary chicken osteoblast activity, differentiation, and bone metabolite-related proteins after treatment with DHA-Na, vitamin K, or both. The results demonstrated that DHA-Na reduced bone index values and serum and bone osteoblast differentiation marker levels but blocked bone vitamin K cycle. DHA-Na also increased serum osteoclast differentiation marker levels, as well as the bone ratio of receptor activator of nuclear factor kappa-Β ligand to osteoprotegerin ratio. Moreover, DHA-Na reduced bone trabecular number, thickness, and area and increased trabecular separation considerably. In general, compared with the control group, the DHA-Na group demonstrated impairments in osteoblast activity and differentiation, as well as in the vitamin K cycle. By contrast, vitamin K supplementation led to considerable attenuation of the DHA-Na-induced decrease in osteogenic marker levels, along with a considerable increase in serum bone absorption marker levels and restoration of DHA-Na-induced bone microstructure damage. Vitamin K also attenuated DHA-Na-induced impairment in osteoclasts. In conclusion, the results indicated that in broiler chickens, DHA-Na supplementation can damage bones by inhibiting osteoblast function and increasing osteoclast activity; this damage can be prevented through vitamin K supplementation.

Risks of benzalkonium chlorides as emerging contaminants in the environment and possible control strategies from the perspective of ecopharmacovigilance

An unprecedented increase in the use of disinfection products triggered by the coronavirus disease 2019 (COVID-19) pandemic is resulting in aggravating environmental loads of disinfectants as emerging contaminants, which has been considered a cause for worldwide secondary disasters. This review analyzed the literature published in the last decade about occurrence, bioaccumulation, and possible environmental risks of benzalkonium chlorides (BKCs) as emerging contaminants. Results indicated that BKCs globally occurred in municipal wastewater, surface water, groundwater, reclaimed water, sludge, sediment, soil, roof runoff, and residential dust samples across 13 countries. The maximum residual levels of 30 mg/L and 421 μg/g were reported in water and solid environmental samples, respectively. Emerging evidences suggested possible bioaccumulation of BKCs in plants, even perhaps humans. Environmentally relevant concentrations of BKCs exert potential adverse impacts on aquatic and terrestrial species, including genotoxicity, respiratory toxicity, behavioural effects and neurotoxicity, endocrine disruption and reproductive impairment, phytotoxicity, etc. Given the intrinsic biocidal and preservative properties of disinfectants, the inductive effects of residual BKCs in environment in terms of resistance and imbalance of microorganisms have been paid special attention. Considering the similarities of disinfectants to pharmaceuticals, from the perspective of ecopharmacovigilance (EPV), a well-established strategy for pharmaceutical emerging contaminants, we use the control of BKC pollution as a case, and provide some recommendations for employing the EPV measures to manage environmental risks posed by disinfectant emerging contaminants.

TFOS Lifestyle: Impact of cosmetics on the ocular surface

In this report the use of eye cosmetic products and procedures and how this represents a lifestyle challenge that may exacerbate or promote the development of ocular surface and adnexal disease is discussed. Multiple aspects of eye cosmetics are addressed, including their history and market value, psychological and social impacts, possible problems associated with cosmetic ingredients, products, and procedures, and regulations for eye cosmetic use. In addition, a systematic review that critically appraises randomized controlled trial evidence concerning the ocular effects of eyelash growth products is included. The findings of this systematic review highlight the evidence gaps and indicate future directions for research to focus on ocular surface outcomes associated with eyelash growth products.

The Effects of Preservatives on Antibiotic- and Preservative-Resistant Microbes and Nitrogen/Sulfur Cycle Associated Microbial Communities in Freshwater River Sediments

The intensive use of benzoic acid (BA), 4-hydroxybenzoic acid (HB), and dehydroacetate (DHA) as additives and preservatives in cosmetics and foods causes emerging environmental pollutions. Anthropogenic releases of BA, HB and DHA are primarily emissions into water and soil. However, few studies investigate the effects of BA, HB and DHA on microbial communities in freshwater river sediments. The aim of this study is to reveal the effects of BA, HB and DHA on microbial communities in freshwater river sediments. Tetracycline-, sulfamethoxazole- and preservative-resistant microbes were increased in the river sediments treated with BA, HB and DHA. The relative abundances of methanogen- and xenobiotic-degradation-associated microbial communities were also increased in the BA-, HB- and DHA-treated sediments. The relative abundance of four nitrogen cycle associated microbial groups (anammox, nitrogen fixation, denitrification, and dissimilatory nitrate reduction) were increased after the eighth week in the BA-, HB- and DHA-treated sediments. For the sulfur cycle, the relative abundance of thiosulfate oxidation associated microbial communities were increased after the eighth week in the BA-, HB- and DHA-treated sediments. Results of this study provide insight into the effects of BA, HB and DHA on antibiotic resistance, nitrogen cycle, sulfur cycle, drug resistance and methane production in freshwater aquatic environments.

Sodium dehydroacetate-induced disorder of coagulation function in broiler chickens and the protective effect afforded by vitamin K

Sodium dehydroacetate (S-DHA) is used widely as a preservative in several products, including poultry feed. The anticoagulation effect of 200 mg/kg S-DHA in rats has been reported to accompany a reduction in hepatic expression of vitamin K epoxide reductase complex 1 (VKORC1). Poultry and mammals have different physiology and coagulation systems, and species differences in VKORC1 expression have been found. The effect of S-DHA on blood clotting of poultry has not been studies deeply. S-DHA was given to yellow-plumage broilers (YBs) as single and multiple administrations. Vitamin K3 (VK₃) was injected into YBs 2 wk after S-DHA administration. Then, the prothrombin time (PT), partial activated prothrombin time (APTT), plasma levels of vitamin K (VK), factor IX (FIX), and S-DHA, and hepatic expression of VKORC1 were obtained. Chicken hepatocellular carcinoma (LMH) cells were also exposed to S-DHA, and the cell activity, VK level, and FIX level were measured. S-DHA prolonged the PT or APTT significantly, decreased levels of VK and FIX in blood, and inhibited hepatic expression of VKORC1. The maximum changes were 1.15-fold in the PT, 1.42-fold in the APTT, 0.8-fold in the VK level, 0.7-fold in the FIX level, and 0.35-fold in VKORC1 expression compared with controls. The cell activity, VK level, FIX level, and VKORC1/VKORC1L1 expression of LMH cells were reduced significantly at S-DHA doses of 2.0 to 10.0 mM. Prolongation of the PT/APTT and lower levels of VK/FIX in YBs or the lower cell activity and VK/FIX levels in LMH cells induced by S-DHA therapy were resisted significantly by VK₃ treatment. We demonstrated that S-DHA could induce a disorder in coagulation function in YBs or in LMH cells via reduction of VKORC1/VKORC1L1 expression, and that VK could resist this anticoagulation effect.

Natural antimicrobial oligosaccharides in the food industry

An increase in the number of antibiotic resistance genes burdens the environment and affects human health. Additionally, people have developed a cautious attitude toward chemical preservatives. This attitude has promoted the search for new natural antimicrobial substances. Oligosaccharides from various sources have been studied for their antimicrobial and prebiotic effects. Antimicrobial oligosaccharides have several advantages such as being produced from renewable resources and showing antimicrobial properties similar to those of chemical preservatives. Their excellent broad-spectrum antibacterial properties are primarily because of various synergistic effects, including destruction of pathogen cell wall. Additionally, the adhesion of harmful microorganisms and the role of harmful factors may be reduced by oligosaccharides. Some natural oligosaccharides were also shown to stimulate the growth probiotic organisms. Therefore, antimicrobial oligosaccharides have the potential to meet food processing industry requirements in the future. The latest progress in research on the antimicrobial activity of different oligosaccharides is demonstrated in this review. The possible mechanism of action of these antimicrobial oligosaccharides is summarized with respect to their direct and indirect effects. Finally, the extended applications of oligosaccharides from the food source industry to food processing are discussed.

Enzyme-treated chicory for cosmetics: application assessment and techno-economic analysis

Chicory (Cichorium intybus L.) is an important industrial crop that produces large quantities of the dietary fiber inulin in its roots. Following inulin extraction, the bagasse is typically used as animal feed, but it contains numerous bioactive secondary metabolites with potential applications in healthcare and cosmetic products. Here we assessed the antimicrobial properties of chicory biomass pre-treated with various enzymes alone and in combination to release the bioactive compounds and increase their bioavailability. We found that pre-treatment significantly increased the antimicrobial activity of this industrial by-product, yielding an extract that inhibited typical skin pathogens in a cosmetic formula challenge test. We also evaluated the valorization of chicory biomass as a bioactive cosmetic ingredient. Economic feasibility was estimated by combining our experimental results with a conceptual techno-economic analysis. Our results suggest that chicory biomass can be utilized for the sustainable production of efficacious cosmetic ingredients.

Occurrence of Allergens in Cosmetics for Sensitive Skin

Sensitive skin is characterized by symptoms such as stinging and tingling in response to stimuli that usually do not cause unpleasant sensations. Epidemiological studies show that individuals with sensitive skin are more prone to developing skin allergies, although the link between both conditions is unknown. Aiming to evaluate the presence of allergens in facial-skin products for sensitive skin, a pool of 88 cosmetic products from international brands marketed in pharmacies and parapharmacies was analyzed. A list of allergens identified in product labels was compiled and grouped according to their function. Fragrances were the most common allergens, followed by skin-conditioning agents, surfactants, and preservatives. Fragrances presenting the highest use percentages were linalool, benzyl alcohol, geraniol, and citronellol. Overall, the majority of cosmetic formulations were absent of fragrance allergens, being present only in 7% of products. Other allergens were found in most products (95%). This finding should be interpreted with caution, since many of these compounds are rare sensitizers and studies demonstrating their risk for individuals with sensitive skin are lacking. With this study, useful information for health professionals is provided to support their advice and to help consumers choosing cosmetic products.

An overview of current alternative models in the context of ocular surface toxicity

The 21st century has seen a steadily increasing social awareness of animal suffering, with increased attention to ethical considerations. Developing new integrated approaches to testing and assessment (IATA) strategies is an Organisation for Economic Co-operation and Development (OECD) goal to reduce animal testing. Currently, there is a lack of alternative models to test for ocular surface toxicity (aside from irritation) in lieu of the Draize eye irritation test (OECD guideline No. 405) performed in rabbits. Five alternative in vitro or ex vivo methods have been validated to replace this reference test, but only in combination. However, pathologies like Toxicity-Induced Dry Eye (TIDE), cataract, glaucoma, and neuropathic pain can occur after exposure to a pharmaceutical product or chemical and therefore need to be anticipated. To do so, new models of lacrimal glands, lens, and neurons innervating epithelia are required. These models must take into account real-life exposure (dose, time, and tear film clearance). The scientific community is working hard to develop new, robust, alternative, in silico, and in vitro models, while attempting to balance ethics and availability of biological materials. This review provides a broad overview of the validated methods for analyzing ocular irritation and those still used by some industries, as well as promising models that need to be optimized according to the OECD. Finally, we give an overview of recently developed innovative models, which could become new tools in the evaluation of ocular surface toxicity within the scope of IATAs.