Mercury, hydroquinone and clobetasol propionate in skin lightening products in West Africa and Canada

Role of the PARP1/NF-κB Pathway in DNA Damage and Apoptosis of TK6 Cells Induced by Hydroquinone

Hydroquinone(HQ) is a widely used industrial raw material and is a topical lightening product found in over-the-counter products. However, inappropriate exposure to HQ can pose certain health hazards. This study aims to explore the mechanisms of DNA damage and cell apoptosis caused by HQ, with a focus on whether HQ activates the nuclear factor-κB (NF-κB) pathway to participate in this process and to investigate the correlation between the NF-κB pathway activation and poly(ADP-ribose) polymerase 1(PARP1). Through various experimental techniques, such as DNA damage detection, cell apoptosis assessment, cell survival rate analysis, immunofluorescence, and nuclear-cytoplasmic separation, the cytotoxic effects of HQ were verified, and the activation of the NF-κB pathway was observed. Simultaneously, the relationship between the NF-κB pathway and PARP1 was verified by shRNA interference experiments. The results showed that HQ could significantly activate the NF-κB pathway, leading to a decreased cell survival rate, increased DNA damage, and cell apoptosis. Inhibiting the NF-κB pathway could significantly reduce HQ-induced DNA damage and cell apoptosis and restore cell proliferation and survival rate. shRNA interference experiments further indicated that the activation of the NF-κB pathway was regulated by PARP1. This study confirmed the important role of the NF-κB pathway in HQ-induced DNA damage and cell apoptosis and revealed that the activation of the NF-κB pathway was mediated by PARP1. This research provides important clues for a deeper understanding of the toxic mechanism of HQ.

Decoding Cosmetic Complexities: A Comprehensive Guide to Matrix Composition and Pretreatment Technology

Despite advancements in analytical technologies, the complex nature of cosmetic matrices, coupled with the presence of diverse and trace unauthorized additives, hinders the application of these technologies in cosmetics analysis. This not only impedes effective regulation of cosmetics but also leads to the continual infiltration of illegal products into the market, posing serious health risks to consumers. The establishment of cosmetic regulations is often based on extensive scientific experiments, resulting in a certain degree of latency. Therefore, timely advancement in laboratory research is crucial to ensure the timely update and adaptability of regulations. A comprehensive understanding of the composition of cosmetic matrices and their pretreatment technologies is vital for enhancing the efficiency and accuracy of cosmetic detection. Drawing upon the China National Medical Products Administration's 2021 Cosmetic Classification Rules and Classification Catalogue, we streamline the wide array of cosmetics into four principal categories based on the following compositions: emulsified, liquid, powdered, and wax-based cosmetics. In this review, the characteristics, compositional elements, and physicochemical properties inherent to each category, as well as an extensive overview of the evolution of pretreatment methods for different categories, will be explored. Our objective is to provide a clear and comprehensive guide, equipping researchers with profound insights into the core compositions and pretreatment methods of cosmetics, which will in turn advance cosmetic analysis and improve detection and regulatory approaches in the industry.

Exogenous Ochronosis: Characterizing a Rare Disorder in Skin of Color

Exogenous ochronosis is a rare dyschromia that primarily impacts those with skin of color. It is characterized by blue-black pigmentation and is associated with the long-term application of skin-lightening creams containing hydroquinone. Commonly confused with other dyschromias, the use of skin lightening topicals can cause paradoxical skin darkening in patients with known exogenous ochronosis. This is highly distressing to patients, often worsening the underlying dyschromia and making treatment more difficult. A 10-year retrospective analysis was conducted that revealed 25 patients with exogenous ochronosis. The average patient used a skin lightening cream for 9.2 years, with exogenous ochronosis most commonly arising on the cheeks (68%), forehead (24%), and temples (20%). Furthermore, this study identified that patients with exogenous ochronosis may respond well to treatment with Q-switched Alexandrite laser and microneedling. The incidence of exogenous ochronosis is likely to increase as demographics shift and access to a wide range of over-the-counter topicals becomes more available, both in the United States and worldwide. Therefore, it is imperative to better characterize exogenous ochronosis to identify best treatment practices for all patients.

Our evolved understanding of the human health risks of mercury

Mercury (Hg) is a chemical of health concern worldwide that is now being acted upon through the Minamata Convention. Operationalizing the Convention and tracking its effectiveness requires empathy of the diversity and variation of mercury exposure and risk in populations worldwide. As part of the health plenary for the 15th International Conference on Mercury as a Global Pollutant (ICMGP), this review paper details how scientific understandings have evolved over time, from tragic poisoning events in the mid-twentieth century to important epidemiological studies in the late-twentieth century in the Seychelles and Faroe Islands, the Arctic and Amazon. Entering the twenty-first century, studies on diverse source-exposure scenarios (e.g., ASGM, amalgams, contaminated sites, cosmetics, electronic waste) from across global regions have expanded understandings and exemplified the need to consider socio-environmental variables and local contexts when conducting health studies. We conclude with perspectives on next steps for mercury health research in the post-Minamata Convention era.

Photochemical reaction of glucocorticoids in aqueous solution: Influencing factors and photolysis products

Glucocorticoids (GCs), as endocrine disruptors, have attracted widespread attention due to their impacts on organisms' growth, development, and reproduction. In the current study, the photodegradation of budesonide (BD) and clobetasol propionate (CP), as targeted GCs, was investigated including the effects of initial concentrations and typical environmental factors (Cl^-, NO₂^-, Fe³⁺, and fulvic acid (FA)). The results showed that the degradation rate constants (k) were 0.0060 and 0.0039 min^-1 for BD and CP at concentration of 50 μg·L^-1, and increased with the initial concentrations. Under the addition of Cl^-, NO₂^-, and Fe³⁺ to the GCs/water system, the photodegradation rate was decreased with increasing Cl^-, NO₂^-, and Fe³⁺ concentrations, which were in contrast to the addition of FA. Electron resonance spectroscopy (EPR) analysis and the radical quenching experiments verified that GCs could transition to the triplet excited states of GCs (³GCs*) for direct photolysis under irradiation to undergo, while NO₂^-, Fe³⁺, and FA could generate ·OH to induce indirect photolysis. According to HPLC-Q-TOF MS analysis, the structures of the three photodegradation products of BD and CP were elucidated, respectively, and the phototransformation pathways were inferred based on the product structures. These findings help to grasp the fate of synthetic GCs in the environment and contribute to the understanding of their ecological risks.

Advances on Hormones in Cosmetics: Illegal Addition Status, Sample Preparation, and Detection Technology

Owing to the rapid development of the cosmetic industry, cosmetic safety has become the focus of consumers' attention. However, in order to achieve the desired effects in the short term, the illegal addition of hormones in cosmetics has emerged frequently, which could induce skin problems and even skin cancer after long-term use. Therefore, it is of great significance to master the illegal addition in cosmetics and effectively detect the hormones that may exist in cosmetics. In this review, we analyze the illegally added hormone types, detection values, and cosmetic types, as well as discuss the hormone risks in cosmetics for human beings, according to the data in unqualified cosmetics in China from 2017 to 2022. Results showed that although the frequency of adding hormones in cosmetics has declined, hormones are still the main prohibited substances in illegal cosmetics, especially facial masks. Because of the complex composition and the low concentration of hormones in cosmetics, it is necessary to combine efficient sample preparation technology with instrumental analysis. In order to give the readers a comprehensive overview of hormone analytical technologies in cosmetics, we summarize the advanced sample preparation techniques and commonly used detection techniques of hormones in cosmetics in the last decade (2012-2022). We found that ultrasound-assisted extraction, solid phase extraction, and microextraction coupled with chromatographic analysis are still the most widely used analytical technologies for hormones in cosmetics. Through the investigation of market status, the summary of sample pretreatment and detection technologies, as well as the discussion of their development trends in the future, our purpose is to provide a reference for the supervision of illegal hormone residues in cosmetics.

Awareness, Perception, and Utilization of Skin Lightening Agents Among Females of Asmara, Eritrea: A Cross-Sectional Study

Background

The use of skin lightening agents (SLAs) is common among African females with black skin color. Although they usually contain harmful ingredients and can cause complications, their use remains to be a common practice. This study was conducted to assess the awareness, perception, and utilization of SLAs among females residing in Asmara, Eritrea.

Methods

A cross-sectional analytical study using a quantitative approach was conducted in representative samples of all beauty salons available in Asmara from May to July, 2021. The study participants were selected using two-stage stratified cluster sampling and data were collected through a face-to-face interview using a structured questionnaire. Descriptive analysis and logistic regression, at bivariate and multivariate level, were performed.

Results

The study enrolled 721 females and 684 completed the study. The majority of the respondents had the perception that SLAs can make someone light colored (84.4%), look beautiful (67.8%), trendy and fashionable (55.0%), and white skin is more attractive than dark skin (58.8%). About two-thirds (64.2%) reported they had previously used SLAs, mainly influenced by friends (60.5%). Approximately 46% were current users, while 53.6% stopped it mainly due to adverse effects, fear of adverse effects and ineffectiveness. A total of 150 products including natural ingredients were mentioned being used to lighten the skin, and Aneeza, Natural face, and Betamethasone containing brands were among the top used products. The occurrence of at least one adverse effect due to the use of SLAs was 43.7%, while 66.5% were satisfied with the use of SLAs. Additionally, employment status and perception of SLAs were found to be determinants of being a current user.

Conclusion

Utilization of SLAs, including products containing harmful or medicinal ingredients, was prevalent among the females of Asmara city. Thus, coordinated regulatory interventions are recommended to tackle unsafe practices and raise public awareness to promote the safe use of cosmetics.

Effect of Chicken Egg White-Derived Peptide and Hydrolysates on Abnormal Skin Pigmentation during Wound Recovery

Abnormal skin pigmentation commonly occurs during the wound healing process due to the overproduction of melanin. Chicken egg white (CEW) has long been used to improve skin health. Previous published works had found CEW proteins house bioactive peptides that inhibit tyrosinase, the key enzyme of melanogenesis. The current study aimed to evaluate the anti-pigmentation potential and mechanism of the CEW-derived peptide (GYSLGNWVCAAK) and hydrolysates (CEWH_mono and CEWH_di), using a cell-based model. All of these peptide and hydrolysates inhibited intracellular tyrosinase activity and melanin level up to 45.39 ± 1.31 and 70.01 ± 1.00%, respectively. GYSLGNWVCAAK and CEWH_di reduced intracellular cAMP levels by 13.38 ± 3.65 and 14.55 ± 2.82%, respectively; however, CEWH_mono did not affect cAMP level. Moreover, the hydrolysates downregulated the mRNA expression of melanogenesis-related genes, such as Mitf, Tyr, Trp-1 and Trp-2, but GYSLGNWVCAAK only suppressed Tyr gene expression. Downregulation of the genes may lower the catalytic activities and/or affect the structural stability of TYR, TRP-1 and TRP-2; thus, impeding melanogenesis to cause an anti-pigmentation effect in the cell. Outcomes from the current study could serve as the starting point to understand the underlying complex, multifaceted melanogenesis regulatory mechanism at the cellular level.

Status of cosmetic safety in Malaysia market: Mercury contamination in selected skin whitening products

BACKGROUND

Concern on cosmetic safety has been a subject of interest in recent years and is commonly associated with the exposure of the consumers to chemicals and impurities such as mercury contamination. Moreover, cancellations of notified cosmetic products were recurrently being reported by the Malaysia authority, namely the National Pharmaceutical Regulatory Authority (NPRA). Among the cosmetic categories was skin whitening product, which is still in high demand whilst reported to cause health risks. Besides, low number of studies on cosmetic safety and mercury contamination were recorded in Malaysia. The lack of scientific evidence on the safety and risks of the ingredients used in cosmetic formulation is a major concern to many consumers.

OBJECTIVE

The aim of this study was to identify the presence of mercury in skin whitening products, and to identify products containing mercury with the concentration exceeding the limitation of 1 ppm.

METHODOLOGY

A total of 104 whitening products were selected from the market via random sampling technique. The mercury concentration was determined by accredited laboratory, and the results were later compared with the cosmetic guideline of Malaysia and the list of banned products issued by NPRA.

RESULTS

A total of 51.9% (n = 54) whitening products were found registered under the NPRA Quest system and remaining 48.1% (n = 50) were non-registered products. None of the whitening products listed mercury as an ingredient, but laboratory analysis showed 15.4% (n = 16) of the products contained mercury with the concentration exceeding the maximum limit of 1 ppm. A total of 87.5% of the whitening products (14 out of 16) containing high mercury concentration were non-registered products which were not registered in NPRA Quest system. The exceeded concentration recorded ranged between 1.81 ppm and 838 123 ppm. Besides that, 50% (8 out of 16) of the products were found in the list of banned products issued by the NPRA of Malaysia.

CONCLUSIONS

This study presents the status of cosmetic products, particularly the skin whitening products available in Malaysia market. Concern arises when some of the products were found to have presence of harmful substances such as mercury. Even though the presence of mercury in a cosmetic product can either be non-intentional or intentionally used by the manufacturer in the cosmetic formulation, the impact of the ingredient can cause health risk to the users.

A Systematic Review of Mercury Exposures from Skin-Lightening Products

BACKGROUND

The Minamata Convention on Mercury (Article 4) prohibits the manufacture, import, or export of skin-lightening products containing mercury concentrations above 1 ppm. However, there is a lack of knowledge surrounding the global prevalence of mercury-added skin-lightening products.

OBJECTIVE

The objective of this study was to increase our understanding of worldwide human mercury exposure from skin-lightening products.

METHODS

A systematic search of peer-reviewed scientific literature was performed for relevant articles in four databases (PubMed, Web of Science Core Collection, Scopus, and TOXLINE). The search strategy, eligibility criteria, and data-extraction methods were established a priori. The search identified 2,303 unique scientific articles, of which 41 were ultimately deemed eligible for inclusion after iterative screens at the title, abstract, and whole-text levels. To facilitate data extraction and synthesis, all papers were organized according to four data groups a) "Mercury in products," b) "Usage of products," c) "Human biomarkers of exposure," and d) "Health impacts."

RESULTS

This review was based on data contained in 41 peer-reviewed scientific papers from 22 countries worldwide published between 2000 and 2022. In total, we captured mercury concentration values from 787 skin-lightening product samples [overall pooled central median mercury level was 0.49μg/g; interquartile range (IQR): 0.02-5.9] and 1,042 human biomarker measurements from 863 individuals. We also synthesized usage information from 3,898 individuals and self-reported health impacts associated with using mercury-added products from 832 individuals.

DISCUSSION

This review suggests that mercury widely exists as an active ingredient in many skin-lightening products worldwide and that users are at risk of variable and often high exposures. These synthesized findings identify data gaps and help increase our understanding of the health risks associated with the use of these products. https://doi.org/10.1289/EHP10808.

Analysis of Prohibited and Restricted Ingredients in Cosmetics

The general public uses cosmetics daily. Cosmetic products contain substances (ingredients) with various functions, from skincare to enhancing appearance, as well as ingredients that preserve the cosmetic products. Some cosmetic ingredients are prohibited or restricted in certain geographical regions, such as the European Union and the United States of America, due to their potential to cause adverse effects such as cancer, birth defects, and/or developmental and reproductive disorders. However, the ingredients may be used in other regions, and, hence, the monitoring of the cosmetic ingredients actually used is important to ensure the safety of cosmetic products. This review provides an overview of recent analytical methods that have been developed for detecting certain ingredients that are restricted or prohibited by the U.S. Food and Drug Administration (FDA) and/or EU legislation on cosmetic products.

A mechanistic approach for toxicity and risk assessment of heavy metals, hydroquinone and microorganisms in cosmetic creams

The demand and importance of fairness creams as a major cosmetic have increased significantly in recent years. However, some of these cosmetics contain heavy metals, hydroquinone and microorganism that can cause various health problems. Therefore, the aim of this study is to determine and examine the concentration of metals (i.e. Cd, Pb, Cr, Ni, Zn, Hg), hydroquinone and microorganisms in nine different fairness creams produced by local and international brands. The health risk assessment of the tested substances for consumers was accessed through systemic exposure dosage (SED), margin of safety (MoS), lifetime cancer risk (LCR), hazard quotient (HQ) and hazard index (HI). The concentration of Zn and Hg were found the highest and measured in the range of 17.82-138.06 mg.kg^-1 and 2.3-141 mg.kg^-1, respectively. The concentrations of other metals were determined as 0.06-0.67 mg.kg^-1 of Cd, 0.43-1.55 mg.kg^-1 of Cr, 0.14-1.43 mg.kg^-1 of Ni and 0.3-1.34 mg.kg^-1 of Pb. HPLC results showed a significant presence of hydroquinone in the range of 0.12-7.2%. The total viable counts of cosmetic samples showed the substantial presence of microorganisms, and 44% of the collected samples surpassed the permissible limit of 100 cfu/g recommended by European Union. Many of the collected samples exceeded the MoS, HQ and HI tolerance limits. However, the LCR value in all samples was significantly higher than the acceptable limit. Therefore, it is advised to avoid overuse of these products in order to ensure human safety and reduce the risks to skin health.

Spreading of Dangerous Skin-Lightening Products as a Result of Colourism: A Review

The use of bleaching products can have a medical or cosmetic purpose; in the latter case, skin whitening is most widespread in countries where darker skin tones prevail and can be driven by psychosocial, cultural and economic reasons. Skin-whitening products containing highly toxic active ingredients (in particular mercury derivatives, hydroquinone and corticosteroids) are easily found on the market; the use of these depigmenting agents can be followed by a variety of adverse effects, with very serious and sometimes fatal complications, and is currently an emerging health concern in many countries. This article concisely discusses the reasons for the current prevalence of skin lightening products and provides an overview of the skin lightening agents that pose a threat to human health. The review also reports market surveillance data on the circulation of banned skin lighteners in Europe, obtained through the Safety Gate system.

Fragrance, Sunscreens, Botanicals, and Potential Allergens in Bestseller 'Fairness' Creams in the Indian Market: A Consumer Exposure Study

Background

The skin lightening industry has seen exponential growth in India. Consumers often present to the dermatologist with adverse cutaneous reactions to these 'fairness' (skin lightening) creams. The composition of these creams has not received sufficient attention.

Objective

To identify fragrance, sunscreens, botanicals and potential allergens in the bestseller 'fairness' creams available in the Indian market.

Methods

Twenty fairness (or whitening or lightening) creams were selected based on the 'bestseller' creams of one of the largest electronic commerce websites in India, and availability in local stores and unlabelled brands were excluded. Fragrance, sunscreens, botanicals and potential allergens were identified from the ingredient labels.

Results

Twenty bestseller fairness creams were included. The number of the listed ingredients in the fairness creams ranged from 6 to 49 (mean = 32.2). The most frequently listed ingredients included water, fragrance or parfum, glycerin, tocopherol/tocopherylacetate and titanium dioxide. Hydroquinone, monobenzyl hydroquinone, corticosteroids, tretinoin and mercury were not listed in any of the creams. Unspecified fragrance was listed in 19 (95%) creams and linalool (8,40%) was the most frequent specified fragrance. Titanium dioxide (14, 70 %) was the most common inorganic sunscreen and ethylhexyl methoxycinnamate (12 creams or 60% of creams) was the most common organic sunscreen. Twenty-seven botanicals were identified. Eight ingredients were potential allergens according to the Indian Cosmetic and Fragrance Series. The cost of the creams ranged from 95 to 1,095 in Indian rupees (mean 300.5).

Conclusions

Consumers are exposed to a vast range of compounds in the quest for a lighter skin tone. Several potential allergens, particularly fragrance allergens, are present in addition to the eight allergens that were identified with the Indian Cosmetic and Fragrance Series. Increased awareness of the composition of skin lightening creams available in the market and strict regulation of these creams is needed.

Mercury in skin-care products in India and consumer exposure risks

We report concentrations of mercury in skin-care products in India and the associated health risks. Mercury concentrations were 0.11 μg/kg (median; 5th percentile-95th percentile = 0.04-0.58 μg/kg; n = 24) in body lotions, 0.22 μg/kg (0.04-0.38 μg/kg, n = 10) in moisturizing lotions, 0.67 μg/kg (0.30-1.33 μg/kg, n = 8) in blemish balms, 0.16 μg/kg (0.06-7.43 μg/kg, n = 11) in bleaches, 0.13 μg/kg (0.04-0.98 μg/kg, n = 34) in skin lightning (fairness) creams manufactured within the country, and 9.24 × 10⁶ μg/kg (2.92 × 10⁶-3.17 × 10⁷ μg/kg, n = 14) in imported skin lightning (fairness) creams, much higher than the 1 ppm (1 ppm = 10³ μg/kg) regulatory limit. Probabilistic human health risk assessment for adult women (age > 21 y) revealed that computed hazard quotients from dermal exposure to the high-mercury fairness creams were >100 in all cases. The mass of mercury entering into the society via skin-care products is highly sensitive to the mass of high-mercury fairness creams that is imported to India; ten tonnes of import can introduce 29-317 kg of mercury every year. As such, analysis and labeling of mercury contents in skin-care products by manufacturers, and raising awareness among regulatory authorities to restrict the import of high-mercury fairness creams, is required.

Tyrosinase and Melanogenesis Inhibition by Indigenous African Plants: A Review

The indiscriminate use of non-regulated skin lighteners among African populations has raised health concerns due to the negative effects associated with skin lightener toxicity. For this reason, there is a growing interest in the cosmetic development of plants and their metabolites as alternatives to available chemical-derived skin lightening formulations. Approximately 90% of Africa’s population depends on traditional medicine, and the continent’s biodiversity holds plant material with various biological activities, thus attracting considerable research interest. This study aimed to review existing evidence and document indigenous African plant species capable of inhibiting the enzyme tyrosinase and melanogenesis for potential incorporation into skin lightening products. Literature search on melanin biosynthesis, skin lightening, and tyrosinase inhibitors resulted in the identification of 35 plant species were distributed among 31 genera and 21 families across 15 African countries and 9 South African provinces. All plants identified in this study showed competent tyrosinase and melanogenesis inhibitory capabilities. These results indicate that African plants have the potential to serve as alternatives to current chemically-derived skin lighteners.

Skin-lightening practices among shoppers in select markets in Kumasi, Ghana: A cross-sectional survey

Background

Despite warnings about its harmful adverse effects and the implementation of regulatory bans, anecdotal reports suggest high use of skin-lightening agents in Kumasi, Ghana.

Objective

To estimate the prevalence and motivation for skin-lightening agent use and nonuse among shoppers in Kumasi, Ghana.

Methods

This is a cross-sectional survey of a convenience sample of shoppers in 3 of Kumasi's largest markets.

Results

Of the 350 shoppers who were approached, 334 consented, for a response rate of 95%. Data were analyzed on 331 completed surveys. A total of 40.4% of individuals reported current or past use of skin-lightening products, and 26.6% of men reported history of product use compared with 56.5% of women. Female sex was significantly associated with skin-lightening product use (odds ratio 3.59; 95% confidence interval 2.26-5.70). Users of skin-lightening agents were more likely to agree with statements that associated lighter skin with beauty, self-esteem, attractiveness, and wealth.

Limitations

Using a nonrandomized convenience sampling method on a single city limits the generalizability of the results. Response, recall, and social desirability biases may have skewed the results, especially given the stigma associated with skin-lightening agent use.

Conclusion

The practice of skin lightening among all participants is high and is associated with perceptions of increased beauty, attractiveness, self-esteem, and wealth.

Mercury Exposure Associated with Use of Skin Lightening Products in Jamaica

BACKGROUND

Skin bleaching is a major health concern among Jamaicans. A common ingredient in skin lightening products is mercury. Mercury is a toxic substance that can cause damage to the gastrointestinal tract, nervous system and kidneys.

OBJECTIVE

The objectives of this study were to use different analytical techniques to measure mercury concentrations in popular skin lightening products used in Jamaica and to assess individual levels of mercury exposure based on product usage.

METHODS

Sixty skin lightening products were purchased from different vendors across various locations in Jamaica. Each product was initially screened for mercury using a portable handheld energy dispersive X-ray fluorescence (XRF) analyzer. In addition, 25 out of 60 products were further measured using cold vapor atomic absorption spectroscopy (CVAAS). Questionnaires were distributed to users of skin lightening products to determine their usage patterns.

RESULTS

Six products had mercury concentrations above the United States Food and Drug Administration (FDA) allowable limit of 1 ppm, of which three products contained alarmingly high concentrations (i.e. > 400 ppm). The majority of products (57 out of 60) had mercury concentrations below 10 ppm. The mercury concentrations in skin lightening products ranged from 0.05 ppm to 17,547 ppm. In our sample, 51% of women and 49% of men used skin products more than once per day.

CONCLUSIONS

On average, creams contained more mercury than lotions and soaps. Individuals who use skin lightening products in Jamaica may be at risk for high mercury exposure, as some popular products were found to have mercury concentrations above the allowable limit.

COMPETING INTERESTS

The authors declare no competing financial interests.

Depigmentation and Anti-aging Treatment by Natural Molecules

Natural molecules are becoming more accepted choices as cosmetic agents, many products in the market today claim to include natural components. Plants include many substances that could be of a value in the whitening of the skin and working as anti-aging agents. A wide range of articles related to natural skin whitening and anti-aging agents have been reviewed. Many plant-derived and natural molecules have shown to affect melanin synthesis by different mechanisms, examples include Arbutin, Ramulus mori extract, Licorice extract, Glabridin, Liquiritin, Kojic acid, Methyl gentisate, Aloesin, Azelaic acid, Vitamin C, Thioctic acid, Soya bean extracts, Niacinamide, α and β-hydroxy acids, Lactic acid, Chamomile extract, and Ellagic acid. Some of the widely used natural anti-aging products as natural antioxidants, collagen, hyaluronic acid, and coenzyme Q can counteract the effects of reactive oxygen species in skin cells and have anti-aging properties on the skin. It was concluded that many natural products including antioxidants can prevent UV-induced skin damage and have whitening and anti-aging effects. It is very important to develop and stabilize appropriate methods for the evaluation of the whitening and anti-aging capacity of natural products and their exact mechanism of action to ensure real efficacy based on evidence-based studies. The attention should be oriented on the formulations and the development of an appropriate vehicle to ensure suitable absorption of these natural products in addition to evaluating the suitable concentration of these molecules required having the desired effects without causing harmful side effects.

The global prevalence and correlates of skin bleaching: a meta-analysis and meta-regression analysis

PURPOSE

To estimate and investigate the global lifetime prevalence and correlates of skin bleaching.

METHODS

A meta-analysis and meta-regression analysis was performed based on a systematic and comprehensive literature search conducted in Google Scholar, ISI Web of Science, ProQuest, PsycNET, PubMed, and other relevant websites and reference lists. A total of 68 studies (67,665 participants) providing original data on the lifetime prevalence of skin bleaching were included. Publication bias was corrected using the trim and fill procedure.

RESULTS

The pooled (imputed) lifetime prevalence of skin bleaching was 27.7% (95% CI: 19.6-37.5, I²  = 99.6, P < 0.01). The highest significant prevalences were associated with: males (28.0%), topical corticosteroid use (51.8%), Africa (27.1%), persons aged ≤30 years (55.9%), individuals with only primary school education (31.6%), urban or semiurban residents (74.9%), patients (21.3%), data from 2010-2017 (26.8%), dermatological evaluation and testing-based assessment (24.9%), random sampling methods (29.2%), and moderate quality studies (32.3%). The proportion of females in study samples was significantly related to skin bleaching prevalence.

CONCLUSION

Despite some limitations, our results indicate that the practice of skin bleaching is a serious global public health issue that should be addressed through appropriate public health interventions.

Modulators of mercury risk to wildlife and humans in the context of rapid global change

Environmental mercury (Hg) contamination is an urgent global health threat. The complexity of Hg in the environment can hinder accurate determination of ecological and human health risks, particularly within the context of the rapid global changes that are altering many ecological processes, socioeconomic patterns, and other factors like infectious disease incidence, which can affect Hg exposures and health outcomes. However, the success of global Hg-reduction efforts depends on accurate assessments of their effectiveness in reducing health risks. In this paper, we examine the role that key extrinsic and intrinsic drivers play on several aspects of Hg risk to humans and organisms in the environment. We do so within three key domains of ecological and human health risk. First, we examine how extrinsic global change drivers influence pathways of Hg bioaccumulation and biomagnification through food webs. Next, we describe how extrinsic socioeconomic drivers at a global scale, and intrinsic individual-level drivers, influence human Hg exposure. Finally, we address how the adverse health effects of Hg in humans and wildlife are modulated by a range of extrinsic and intrinsic drivers within the context of rapid global change. Incorporating components of these three domains into research and monitoring will facilitate a more holistic understanding of how ecological and societal drivers interact to influence Hg health risks.

Skin-lightening practices among female high school students in Ghana

OBJECTIVE

The practice of skin lightening (SL) persist despite warnings about its harmful health effects. Adolescents are particularly vulnerable and at risk of prolonged use of SL products. We explored SL practices among high school students in Ghana, West Africa.

STUDY DESIGN

Cross-sectional survey.

METHODS

We used a self-administered questionnaire in a survey on SL practices among randomly selected female students in five Senior High Schools in the Brong Ahafo Region of Ghana. We determined prevalence and used bivariate and multivariate analysis to identify factors associated with the practice.

RESULTS

A total of 410 students with a mean age of 17.6 years (±1.6) participated in the study. While 71.5% of students indicated that they had been approached by relatives and friends to use SL creams, 65.6% admitted to actually using it. Most (85.5%) students identified at least five friends who were using SL products at the time of the survey. Between 22.0% and 44.0% of students knew female teachers who practiced SL. Students in first year were twice as likely to practice SL compared with students in third year (odds ratio [OR] = 1.90, 95% confidence interval [CI] 1.15-3.13). Compared with those who had never been approached, students who had been approached by relatives and friends to use SL products were likely to be using it (OR = 2.24, 95% CI 1.43-3.53). Students who had sisters who used SL products were twice as likely to be users themselves (OR = 1.82, 95% CI 1.12-2.95).

CONCLUSION

The practice of SL among female students in this study is high, and about the same as reported among adults in Ghana and other parts of sub-Saharan Africa. This suggests that the practice is well entrenched. A ban on the sale of SL products to adolescents in Ghana should be considered.

UV-Radiation: From Physics to Impacts

Ultraviolet (UV) radiation has affected life at least since the first life forms moved out of the seas and crawled onto the land. Therefore, one might assume that evolution has adapted to natural UV radiation. However, evolution is mostly concerned with the propagation of the genetic code, not with a long, happy, and fulfilling life. Because rickets is bad for a woman giving birth, the beneficial effects of UV-radiation outweigh the adverse effects like aged skin and skin tumors of various grades of malignancy that usually only afflict us at older age. Anthropogenic damage to the stratospheric ozone layer and frighteningly high rates of melanoma skin cancer in the light-skinned descendants of British settlers in Australia piqued interest in the health impacts of UV radiation. A changing cultural perception of the beauty of tanned versus light skin and commercial interests in selling UV-emitting devices such as tanning booths caught public health experts off-guard. Counseling and health communication are extremely difficult when dealing with a “natural” risk factor, especially when this risk factor cannot (and should not) be completely avoided. How much is too much for whom or for which skin type? How even measure “much”? Is it the (cumulative) dose or the dose rate that matters most? Or should we even construct a more complex metric such as the cumulative dose above a certain dose rate threshold? We find there are still many open questions, and we are glad that this special issue offered us the opportunity to present many interesting aspects of this important topic.

Chemical Speciation of Selenium and Mercury as Determinant of Their Neurotoxicity

The antagonism of mercury toxicity by selenium has been well documented. Mercury is a toxic metal, widespread in the environment. The main target organs (kidneys, lungs, or brain) of mercury vary depending on its chemical forms (inorganic or organic). Selenium is a semimetal essential to mammalian life as part of the amino acid selenocysteine, which is required to the synthesis of the selenoproteins. This chapter has the aim of disclosing the role of selenide or hydrogen selenide (Se^-2 or HSe^-) as central metabolite of selenium and as an important antidote of the electrophilic mercury forms (particularly, Hg²⁺ and MeHg). Emphasis will be centered on the neurotoxicity of electrophile forms of mercury and selenium. The controversial participation of electrophile mercury and selenium forms in the development of some neurodegenerative disease will be briefly presented. The potential pharmacological use of organoseleno compounds (Ebselen and diphenyl diselenide) in the treatment of mercury poisoning will be considered. The central role of thiol (-SH) and selenol (-SeH) groups as the generic targets of electrophile mercury forms and the need of new in silico tools to guide the future biological researches will be commented.