Glutathione for skin lightening: a regnant myth or evidence-based verity?

Enzymatic browning in apple products and its inhibition treatments: A comprehensive review

Apple (Malus domestica) is widely consumed by consumers from various regions. It contains a high number of phenolic compounds (majorly hydroxybenzoic acids, hydroxycinnamic acids, flavanols, flavonols, dihydrochalcones, and anthocyanins) and antioxidant activity, which are beneficial for human health. The trends on healthy and fresh food have driven the food industry to produce minimally processed apple, such as fresh-cut, puree, juice, and so on without degrading the quality of products. Enzymatic browning is one of the problems found in minimally processed apple as it causes the undesirable dark color as well as the degradation of phenolics and antioxidant activity, which then reduces the health benefits of apple. Proper inhibition is needed to maintain the quality of minimally processed apple with minimal changes in sensory properties. This review summarizes the inhibition of enzymatic browning of apple products based on recent studies using the conventional and nonconventional processing, as well as using synthetic and natural antibrowning agents. Nonconventional processing and the use of natural antibrowning agents can be used as promising treatments to prevent enzymatic browning in minimally processed apple products. Combination of 2-3 treatments can improve the effective inhibition of enzymatic browning. Further studies, such on as other potential natural antibrowning agents and their mechanisms of action, should be conducted.

Metabolic Basis and Clinical Evidence for Skin Lightening Effects of Thiol Compounds

Melanin pigment is a major factor in determining the color of the skin, and its abnormal increase or decrease can cause serious pigmentation disorders. The melanin pigment of the skin is divided into light pheomelanin and dark eumelanin, and a big difference between them is whether they contain sulfur. Melanin synthesis starts from a common reaction in which tyrosine or dihydroxyphenylalanine (DOPA) is oxidized by tyrosinase (TYR) to produce dopaquinone (DQ). DQ is spontaneously converted to leukodopachrome and then oxidized to dopachrome, which enters the eumelanin synthesis pathway. When DQ reacts with cysteine, cysteinyl dopa is generated, which is oxidized to cysteinyl DQ and enters the pheomelanin synthesis pathway. Therefore, thiol compounds can influence the relative synthesis of eumelanin and pheomelanin. In addition, thiol compounds can inhibit enzymatic activity by binding to copper ions at the active site of TYR, and act as an antioxidant scavenging reactive oxygen species and free radicals or as a modulator of redox balance, thereby inhibiting overall melanin synthesis. This review will cover the metabolic aspects of thiol compounds, the role of thiol compounds in melanin synthesis, comparison of the antimelanogenic effects of various thiol compounds, and clinical trials on the skin lightening efficacy of thiol compounds. We hope that this review will help identify the advantages and disadvantages of various thiol compounds as modulators of skin pigmentation and contribute to the development of safer and more effective strategies for the treatment of pigmentation disorders.

Lasers, lights, and compounds for melasma in aesthetics

Melasma is a chronic and relapsing skin condition. Although melasma is usually asymptomatic, it can be associated with immense psychosocial stress and greatly impact a patient's quality of life. Over the years, many different treatments have been used, ranging from daily photoprotection, topical lightening creams, and oral agents to laser and light-based therapies; however, efficacy is often limited with such treatments, and there is currently no effective modality to prevent recurrence. Although treatment strategies had originally centered on the use of hydroquinone, newer modalities now include oral tranexamic acid and lasers. We examined previous and ongoing debates related to melasma treatments and have reviewed the current efficacy and safety of available treatments. Critical components essential to the successful management of melasma are the setting of patient expectations and assurance of treatment compliance.

HCV poly U/UC sequence-induced inflammation leads to metabolic disorders in vulvar lichen sclerosis

Multi-omics analysis reveals the elevation of HCV poly U/UC sequences, which induces abnormal inflammation and related metabolic disorder in vulvar lichen sclerosis.

Vulvar lichen sclerosis (VLS) is a dermatologic disorder that affects women worldwide. Women with VLS have white, atrophic papules on the vulva. They suffer from life-long intense pruritus. Corticosteroids are the first-line of treatments and the most effective medicines for VLS. Although VLS has been speculated as an autoimmune disease for a long time, its pathogenesis and the molecular mechanism is largely unknown. We performed a comprehensive multi-omics analysis of paired samples from VLS patients as well as healthy donors. From the RNA-seq analysis, we found that VLS is correlated to abnormal antivirus response because of the presence of Hepatitis C Virus poly U/UC sequences. Lipidomic and metabolomic analysis revealed that inflammation-induced metabolic disorders of fatty acids and glutathione were likely the reasons for pruritus, atrophy, and pigment loss in the vulva. Thus, the present study provides an initial interpretation of the pathogenesis and molecular mechanism of VLS and suggests that metabolic disorders that affect the vulva may serve as therapeutic targets for VLS.

Combination of topical and oral glutathione as a skin-whitening agent: a double-blind randomized controlled clinical trial

BACKGROUND

The antimelanogenesis effect of topical and oral glutathione has been shown in several in vitro and clinical studies. However, whether combination of topical and oral glutathione is superior to topical or oral monotherapy is unknown. This study aimed to compare the skin-whitening effect of topical and oral glutathione combination therapy against topical and oral monotherapy.

METHODS

This double-blind randomized controlled study was done on 46 participants who were divided into two equal groups. Each group received oral placebo and oral glutathione, respectively. All participants were also instructed to apply topical placebo and glutathione to each facial side, respectively. Colorimeter examination was done biweekly using mexameter and chromameter for 8 weeks. One-way ANOVA test was used to compare the results of all groups.

RESULTS

The combination group showed significantly lower melanin index (MI) and L* score to placebo (P < 0.05). The mean MI and L* score of the combination group were the highest of all groups. Statistical significance of difference in L* score was reached when the combination group was compared to the oral placebo and topical glutathione group (P < 0.05).

CONCLUSION

This study showed that topical and oral glutathione were effective skin-lightening agents. Furthermore, combination of topical and oral glutathione might be superior to monotherapy.

The dark side of skin lightening: An international collaboration and review of a public health issue affecting dermatology

Skin lightening (SL) for cosmetic reasons is associated with profound negative impacts on well-being and adverse effects on the skin, resulting in immense challenges for dermatologists. Despite current regulations, lightening agents continue to dominate the cosmetic industry. In this review, our international team of dermatologists tackles the topic of SL as a global public health issue, one of great concern for both women's health and racial implications. We have examined SL in Africa, Asia, the Middle East, and the Americas. We aim to inspire a global discourse on how modern dermatologists can utilize scientific evidence and cultural competency to serve and protect patients of diverse skin types and backgrounds. In doing so, we hope to promote healthy skin and inclusive concepts of beauty in our patients and society.

The dark side of occupation within the context of modern-day beauty pageants

BACKGROUND

The desire to be physically beautiful is inherent among human beings. In particular, some women who participate in modern-day beauty pageants tend to spend more time, energy, money and emotional resources to alter their natural body and looks to fit socially and culturally constructed standards of beauty.

OBJECTIVE

The authors frame beauty pageants as the context where diverse occupations are at play with the purpose of becoming a 'beauty queen'. This commentary aims to discuss the origins and culture of beauty pageants, the different perspectives on pageantry work, and essential and hidden occupations performed within the context of this form of performing art.

APPROACH

Using the conceptual lens of the dark side of occupation, hidden occupations are characterised by the doings of pageant hopefuls that are less explored and acknowledged because they are perceived as health-compromising, risky, dishonest, illicit, and socially or personally undesirable.

CONCLUSION

Furthermore, this commentary calls for the exploration of occupations beyond the conventional scope of its understanding and the acknowledgment of hidden occupations intertwined into people's everyday doings specifically in the context of desiring to be 'beautiful'.

Cosmetic skin lightening use and side effects

Cosmetic skin lightening is a growing dermatologic public health problem that affects communities of color worldwide. Despite well-documented adverse health effects, cosmetic skin lightening continues to be a popular practice among patients of color. Given the US's changing demographics, it is critical for dermatologists to be knowledgeable about the medical impact as well as social and cultural implications of this practice. This review article aims to serve as a primer for the dermatologist on the medical and sociocultural aspects of cosmetic skin lightening, as well as an approach to discuss the issue of cosmetic skin lightening with patients. We conducted a comprehensive PubMed search using the terms 'skin lightening agents,' 'skin bleaching,' and 'depigmenting agents,' and reviewed the literature on cosmetic skin lightening products, active ingredients, and adverse side effects. Herein, we review the prevalence, ingredients, and health implications of cosmetic skin lightening products. We also provide recommendations for counseling patients who practice cosmetic skin lightening in a culturally sensitive manner.

Safety and efficacy of parenteral glutathione as a promising skin lightening agent: A controlled assessor blinded pharmacohistologic and ultrastructural study in an animal model

Hyperpigmentation was induced in the skin of experimental animals using UVB at 6 J/cm² three times a week for three consecutive weeks. Subsequently, glutathione was injected intraperitoneally in the experimental animals at doses of 10, 20, and 40 mg/kg body weight three times a week for three consecutive weeks. At the end of the experiment, blood samples and lung, kidney, liver, and skin tissue specimens were collected from animals for hematological, biochemical, histological, and electron microscopy examination. Glutathione at 40 mg/kg body weight/day reduced skin hyperpigmentation significantly, except at low doses. The skin lightening effect assessed by a chromameter was dose-dependent. There were no statistically significant differences among the mean values of AST, ALT, creatinine, BUN, and CBC counts across the four groups. Lung, kidney, and liver tissue specimens did not show any histological toxic changes. The number of melanin granules was significantly lower in the group treated with the highest dose of glutathione compared to that in the control. Electron microscopy proved that glutathione at 20 and 40 mg/kg body weight/day was able to reduce the number of melanized cells significantly compared to that in the control. Parenteral glutathione was effective as a skin lightening agent and did not provoke any toxic effects in the employed animal model. The limitation of the study was conducted in guinea pigs and was of short-term duration.

Can reducing cosmetic substances help prevent chromate contact allergy?

BACKGROUND

Allergic contact dermatitis caused by Cr(VI) is often severe and difficult to treat. Therefore, primary prevention is a main goal but, secondary prevention can be valuable to ease the symptoms or prevent relapse of Cr(VI) dermatitis when sensitization has occurred. Barrier creams have been tried for many chemical substances, but until now there is no successful barrier cream against Cr(VI).

OBJECTIVES

To investigate the ability of reducing agents to transform Cr(VI) into Cr(III) in an experimental situation, in order to find suitable chemicals to investigate for possible use in a barrier cream.

METHODS

The capacity to reduce the amount of Cr(VI) was analyzed in water solutions of acetylcysteine, cysteine, dihydroxyacetone, glutathione, and iron sulfate heptahydrate. Thereafter the reducing capacity of acetylcysteine, dihydroxyacetone, glutathione, and iron sulfate on the amount of Cr(VI) in cement extracts was investigated. The content of Cr(VI) in the test solutions and in the cement extracts was estimated by the diphenyl carbazide spot test.

RESULTS

All of the chosen chemicals reduced the amount of Cr(VI) in the test solutions and in the cement extracts to some extent. The reducing capacity was most prominent for iron sulfate.

CONCLUSION

A reducing capacity was found for all chosen chemicals.

[What's new in clinical dermatology?]

In this article, we performed a review of all new data of clinical relevance for the dermatologists that were published in the medical literature between September, 2017 and September, 2018. Besides advances that will be useful in day-to-day dermatological practice, we intended to give a more general perspective to this review by taking into account certain international health issues that might in final concern each of us in a globalized world. Focus were more particularly done on the following topics: infectious diseases (including sexually transmitted infections), neglected tropical diseases, adverse effects of drugs, bullous diseases, allergology, wound healing, dermatology on black skin, and public health dermatology.

In vitro effect of oxidized and reduced glutathione peptides on angiotensin converting enzyme purified from human plasma

Angiotensin converting enzyme (ACE, peptidyldipeptidase A, EC 3.4.15.1) plays an important role in the regulation of blood pressure. In this study, ACE was purified from human plasma by affinity chromatography in single step. The enzyme purified in 5367-fold from human plasma and specific activity was found to be 1208 EU/mg protein. The purity and molecular weight of ACE were determined by SDS-PAGE, which indicated two bands at around 60 kDa and 70 kDa on the gel. Effect of oxidized glutathione (GSSG) peptide and reduced glutathione (GSH) peptide on purified ACE activity were also investigated in which lisinopril was used as reference inhibitor. GSSG showed activation effect on ACE activity whereas GSH provided inhibition effect. In the lights of activity (%) versus activator graph for GSSG and activity (%) versus inhibitor graphs for GSH and lisinopril; IC₅₀ values for GSH and lisinopril were determined to be 16.2 μM and 0.781 nM, respectively. Type of inhibition for GSH and lisinopril from graph Lineweaver-Burk was found to be reversible non-competitive inhibition and K_i constants for GSH and lisinopril were calculated as 11.7 μM and 0.662 nM, respectively.