Targeting tyrosinase in hyperpigmentation: Current status, limitations and future promises.

Hyperpigmentation is a common and distressing dermatologic condition. Since tyrosinase (TYR) plays an essential role in melanogenesis, its inhibition is considered a logical approach along with other therapeutic methods to prevent the accumulation of melanin in the skin. Thus, TYR inhibitors are a tempting target as the medicinal and cosmetic active agents of hyperpigmentation disorder. Among TYR inhibitors, hydroquinone is a traditional lightening agent that is commonly used in clinical practice. However, despite good efficacy, prolonged use of hydroquinone is associated with side effects. To overcome these shortcomings, new approaches in targeting TYR and treating hyperpigmentation are desperately requiredessentialneeded. In line with this purpose, several non-hydroquinone lightening agents have been developed and suggested as hydroquinone alternatives. In addition to traditional approaches, nanomedicine and nanotheranostic platforms have been recently proposed in the treatment of hyperpigmentation. In this review, we discuss the available strategies for the management of hyperpigmentation with a focus on TYR inhibition. In addition, alternative treatment options to hydroquinone are discussed. Finally, we present nano-based strategies to improve the therapeutic effect of drugs prescribed to patients with skin disorders.

Functionalized chitosan nanoparticles for cutaneous delivery of a skin whitening agent: an approach to clinically augment the therapeutic efficacy for melasma treatment.

The increase in the production of melanin level inside the skin prompts a patient-inconvenient skin color disorder namely; melasma. This arouses the need to develop efficacious treatment modalities, among which are topical nano-delivery systems. This study aimed to formulate functionalized chitosan nanoparticles (CSNPs) in gel form for enhanced topical delivery of alpha-arbutin as a skin whitening agent to treat melasma. Ionic gelation method was employed to prepare α-arbutin-CSNPs utilizing a 24 full factorial design followed by In vitro, Ex vivo and clinical evaluation of the nano-dispersions and their gel forms. Results revealed that the obtained CSNPs were in the nanometer range with positive zeta potential, high entrapment efficiency, good stability characteristics and exhibited sustained release of α-arbutin over 24 h. Ex vivo deposition of CSNPs proved their superiority in accumulating the drug in deep skin layers with no transdermal delivery. DSC and FTIR studies revealed the successful amorphization of α-arbutin into the nanoparticulate system with no interaction between the drug and the carrier system. The comparative split-face clinical study revealed that α-arbutin loaded CSNPs hydrogels showed better therapeutic efficacy compared to the free drug hydrogel in melasma patients, as displayed by the decrease in: modified melasma area and severity index (mMASI) scores, epidermal melanin particle size surface area (MPSA) and the number of epidermal monoclonal mouse anti-melanoma antigen recognized by T cells-1 (MART-1) positive cells which proved that the aforementioned system is a promising modality for melasma treatment.

Systematic review of clinical studies assessing the needling for treatment of melasma: Focusing on efficacy, safety, and recurrence rate.

BACKGROUND AND OBJECTIVE: Melasma is common, chronic and treatment-challenging cosmetic concern and the aim of this study was to systematically evaluate clinical studies assessing the treatment of melasma through needling while focusing on efficiency, safety, and recurrence. METHOD: After e-search a total of 54 articles were reviewed and 12 published articles (February 2011-September 2020) in terms of content, topic, and purpose, were finalized. Articles were open pilot trials, case reports, case series, retrospective studies, quasi-experimental trials, randomized clinical trials, and split face comparative studies. RESULTS: The highest decrease in MASI score was 85.71% and allocated to microneedling method following only 3 sessions with an interval of 30 days. On the other hand, the lowest decrease in this score was 3.7% and allocated to microneedling treatment and its use for vitamin C delivery at the end of the fourth week of treatment. No side effects were reported in included studies, and the various needling methods used were safe. Recurrence after treatment was reported in none of these articles, and only one of them reported a 4% recurrence in the second phase of treatment, but no recurrence was reported in the last phase of that study. CONCLUSION: Non-aggressive microneedling with topical depigmenting agents was more effective than topical depigmenting agents alone, so that the mean MASI score was significantly higher than those who used lightening serum alone. So needling can be suggested as an effective and safe method with low recurrence rate for the treatment of melasma.

An open-label, investigator-initiated, single-center, prospective, pilot clinical study to evaluate the efficacy of a skin whitening serum applied twice daily combined with a spot-preventing SPF50+ sunscreen in healthy female subjects with melasma hyperpigmentation.

BACKGROUND: Melasma is a common skin disorder characterized by alterations in normal skin pigmentation. The objective was to evaluate the efficacy and safety of a skin whitening serum containing niacinamide, hydroxyphenoxy propionic acid, dipotassium glycyrrhizate, glycolic acid, and 4-n-butylresorcinol applied twice daily combined with a spot-preventing SPF50+ sunscreen for treatment of melasma. METHODS: Twelve healthy Caucasian women with melasma (Fitzpatrick skin types II-IV) were enrolled in this pilot clinical study. Efficacy evaluations were performed at baseline and weeks 4, 8, and 12 of treatment and included clinical and instrumental assessments. RESULTS: All endpoints for melasma hyperpigmentation showed a statistically significant improvement from baseline to the end of the study. There was only one dropout. No signs of irritation or discomfort were observed at baseline, w4, w8, or w12. An overall improvement in melasma was observed both clinically and on reflectance confocal microscopy (RCM). CONCLUSION: This topical skin whitening serum had favorable outcomes for the treatment of melasma hyperpigmentation in adult women, as demonstrated on investigator and instrumental assessments. The results of this pilot study need to be confirmed in randomized, controlled studies with a larger sample size.

Spherical Nucleic Acids for Topical Treatment of Hyperpigmentation.

Oligonucleotide-based materials such as spherical nucleic acid (SNA) have been reported to exhibit improved penetration through the epidermis and the dermis of the skin upon topical application. Herein, we report a self-assembled, skin-depigmenting SNA structure, which is based upon a bifunctional oligonucleotide amphiphile containing an antisense oligonucleotide and a tyrosinase inhibitor prodrug. The two components work synergistically to increase oligonucleotide cellular uptake, enhance drug solubility, and promote skin penetration. The particles were shown to reduce melanin content in B16F10 melanoma cells and exhibited a potent antimelanogenic effect in an ultraviolet B-induced hyperpigmentation mouse model.

Salidroside can target both P4HB-mediated inflammation and melanogenesis of the skin.

Rationale: Many external factors can induce the melanogenesis and inflammation of the skin. Salidroside (SAL) is the main active ingredient of Rhodiola, which is a perennial grass plant of the Family Crassulaceae. This study evaluated the effect and molecular mechanism of SAL on skin inflammation and melanin production. It then explored the molecular mechanism of melanin production under ultraviolet (UV) and inflammatory stimulation. Methods: VISIA skin analysis imaging system and DermaLab instruments were used to detect the melanin reduction and skin brightness improvement rate of the volunteers. UV-treated Kunming mice were used to detect the effect of SAL on skin inflammation and melanin production. Molecular docking and Biacore were used to verify the target of SAL. Immunofluorescence, luciferase reporter assay, CO-IP, pull-down, Western blot, proximity ligation assay (PLA), and qPCR were used to investigate the molecular mechanism by which SAL regulates skin inflammation and melanin production. Results: SAL can inhibit the inflammation and melanin production of the volunteers. SAL also exerted a protective effect on the UV-treated Kunming mice. SAL can inhibit the tyrosinase (TYR) activity and TYR mRNA expression in A375 cells. SAL can also regulate the ubiquitination degradation of interferon regulatory factor 1 (IRF1) by targeting prolyl 4-hydroxylase beta polypeptide (P4HB) to mediate inflammation and melanin production. This study also revealed that IRF1 and upstream stimulatory factor 1 (USF1) can form a transcription complex to regulate TYR mRNA expression. IRF1 also mediated inflammatory reaction and TYR expression under UV- and lipopolysaccharide-induced conditions. Moreover, SAL derivative SAL-plus (1-(3,5-dihydroxyphenyl) ethyl-ß-d-glucoside) showed better effect on inflammation and melanin production than SAL. Conclusion: SAL can inhibit the inflammation and melanogenesis of the skin by targeting P4HB and regulating the formation of the IRF1/USF1 transcription complex. In addition, SAL-plus may be a new melanin production and inflammatory inhibitor.

Algae Metabolites in Cosmeceutical: An Overview of Current Applications and Challenges.

Cosmetics are widely used by people around the world to protect the skin from external stimuli. Consumer preference towards natural cosmetic products has increased as the synthetic cosmetic products caused adverse side effects and resulted in low absorption rate due to the chemicals' larger molecular size. The cosmetic industry uses the term "cosmeceutical", referring to a cosmetic product that is claimed to have medicinal or drug-like benefits. Marine algae have gained tremendous attention in cosmeceuticals. They are one of the richest marine resources considered safe and possessed negligible cytotoxicity effects on humans. Marine algae are rich in bioactive substances that have shown to exhibit strong benefits to the skin, particularly in overcoming rashes, pigmentation, aging, and cancer. The current review provides a detailed survey of the literature on cosmeceutical potentials and applications of algae as skin whitening, anti-aging, anticancer, antioxidant, anti-inflammation, and antimicrobial agents. The biological functions of algae and the underlying mechanisms of all these activities are included in this review. In addition, the challenges of using algae in cosmeceutical applications, such as the effectiveness of different extraction methods and processing, quality assurance, and regulations concerning extracts of algae in this sector were also discussed.

Randomised, controlled, double-blind study of combination therapy of oral tranexamic acid and topical hydroquinone in the treatment of melasma.

BACKGROUND/OBJECTIVES: Melasma is a common pigmentary disorder for which oral tranexamic acid has shown some efficacy in previous studies. The aim of this study was to assess the effectiveness of oral tranexamic acid in combination with hydroquinone cream in the treatment of melasma. METHODS: Subjects with moderate-to-severe melasma were enrolled. Group A received hydroquinone 4% cream, sunscreen and oral tranexamic acid, while Group B received hydroquinone 4% cream, sunscreen and placebo capsules for 3 months. All subjects had an additional 3-month follow-up visit on sunscreen alone. The primary outcome measure was change in modified Melasma Area and Severity Index (mMASI) score. In addition, the melanin index was measured using a mexameter. RESULTS: Fifty subjects were enrolled, and all completed the study. There was a 55% reduction in mMASI after 3 months from mean 8.96 (SD 2.45) to 4.0 (SD 1.6) in Group A compared to 10.9% from mean 8.53 (SD 2.04) to 7.6 (SD 2.0) in Group B. Three months after oral and topical therapy was discontinued, there was a 42% decrease in mMASI compared to baseline in Group A (mean 5.1 SD 1.7) vs. 4.7% in Group B (mean 8.1 SD 2.0). No serious adverse events were observed. CONCLUSIONS: A combination of oral tranexamic acid and topical hydroquinone is more effective than hydroquinone alone in the treatment of melasma.

Formulation and clinical evaluation of the standardized Litchi chinensis extract for skin hyperpigmentation and aging treatments.

INTRODUCTION: The standardized litchi extract had been revealed on phytochemical actives, in vitro and cellular activities against aging and darkening of skin. However, a formulation containing the extract has never been developed as per clinical evaluated. MATERIALS AND METHODS: The litchi serum was developed, safety and efficacy were clinically evaluated in human volunteers. The stable and none irritated 0.05 and 0.1% litchi serums were randomized-single blind placebo control clinical applied on the inner forearm of 29 volunteers for a consecutive 112 days and monitored by Mexameter® MX18, Cutometer® MPA 580 and Visioscan® VC 98. RESULTS: Skin lightening efficacy of the 0.1% and 0.05% litchi serum was significantly (P<0.001 and P<0.05) higher than the placebo. Skin elasticity and wrinkle reduction was significantly (P<0.05 and P<0.005) achieved by the 0.1% litchi serum. The efficacy of litchi serums was confirmed by a split-face, randomized, single-blind controlled that the 0.1% litchi serum was significantly (P<0.05) better than the 0.05% one of all examined parameters. CONCLUSION: Safety and efficacy of litchi extract are clinically confirmed for hyperpigmentation and aging of skin treatments.

Melasma Treatment: An Evidence-Based Review.

BACKGROUND: Melasma is an acquired, chronic pigmentary disorder predominantly affecting women. It may significantly affect quality of life and self-esteem due to its disfiguring appearance. Multiple treatments for melasma are available, with mixed results. OBJECTIVE: The aim of this article was to conduct an evidence-based review of all available interventions for melasma. METHODS: A systematic literature search of the PubMed electronic database was performed using the keywords 'melasma' and/or 'chloasma' in the title, through October 2018. The search was then limited to 'randomized controlled trial' and 'controlled clinical trial' in English-language journals. The Cochrane database was also searched for systematic reviews. RESULTS: The electronic search yielded a total of 212 citations. Overall, 113 studies met the inclusion criteria and were included in this review, with a total of 6897 participants. Interventions included topical agents, chemical peels, laser- and light-based devices, and oral agents. Triple combination cream (hydroquinone, tretinoin, and corticosteroid) remains the most effective treatment for melasma, as well as hydroquinone alone. Chemical peels and laser- and light-based devices have mixed results. Oral tranexamic acid is a promising new treatment for moderate and severe recurrent melasma. Adverse events from all treatments tend to be mild, and mainly consist of skin irritation, dryness, burning, erythema, and post-inflammatory hyperpigmentation. CONCLUSIONS: Hydroquinone monotherapy and triple combination cream are the most effective and well-studied treatments for melasma, whereas chemical peels and laser- and light-based therapies are equal or inferior to topicals, but offer a higher risk of adverse effects. Oral tranexamic acid may be a safe, systemic adjunctive treatment for melasma, but more studies are needed to determine its long-term safety and efficacy. Limitations of the current evidence are heterogeneity of study design, small sample size, and lack of long-term follow-up, highlighting the need for larger, more rigorous studies in the treatment of this recalcitrant disorder.

A selection of eleven plants used as traditional Polynesian cosmetics and their development potential as anti-aging ingredients, hair growth promoters and whitening products.

ETHNOPHARMACOLOGICAL RELEVANCE: In French Polynesia, embellishment of the hair and skin is an important cultural and everyday practice. Yet, little research has focused on traditional preparations used for beautification in this region and their potential development as innovative cosmetic ingredients. AIM OF THE STUDY: In this present study we aim to assess and compile the ethnocosmetic potential of plants of French Polynesia to select and further study plants showing the most promise to be developed as anti-aging, anti-blemish and hair care products. MATERIALS AND METHODS: A literature analysis of plants of the IECIC list, present in French Polynesia was conducted. The most interesting plants from a cosmetic development standpoint were selected based on four main criteria, i.e. their traditional use in Polynesian cosmetic-related preparations, their biogeographical status, their phytochemistry of cosmetic interest, and lastly their availability and absence from the UICN list. Furthermore, a preliminary screening of antioxidant and anti-inflammatory activities was also performed on several extracts obtained. RESULTS: Eleven plants were chosen, and a compilation of multidisciplinary data emphasized each selected plant's potentiality. Traditional allegations showed uses ranging from dermatology such as wound healing or anti-inflammatory properties, to hair growth promoting preparations or even skin ligthening ones. Preliminary screenings were useful in narrowing the number of extracts to study. Literature-based data associated to traditional uses depicted how the remaining plants and plant parts could be developed for targeted cosmetic applications. CONCLUSIONS: A prospective approach of plants used traditionally for cosmetic purposes in French Polynesia gave insight on their development potential when paired with the appropriate multidisciplinary data. The eleven plants presented show promise in being developed sustainably as natural anti-aging or hair care products and as skin brightening agents.

Efficacy of D-pigment dermocosmetic lightening product for solar lentigo lesions of the hand: A randomized controlled trial.

Solar lentigo, benign lesions which mostly appear on chronically, sun-exposed surfaces, are associated with ageing. Patients are increasingly requesting a more uniform skin texture, especially for hands. Treatment options include dermoabrasion, intense pulsed light, cryotherapy, peelings, and laser therapy. Topical compounds can be employed, in alternative or associated with dermatologic procedures. The current study was designed to evaluate solar lentigo hyperpigmentation, skin architecture and clinician and patient assessments comparing a dermocosmetic lightening product (active) with a moisturizing product (control) according to clinical, digital and subjective analyses in 72 lesions over 12-month follow up period. Statistically significant differences were observed between the lesions treated with the active compared to the control in terms of papillary brightness (p = 0.03) and contrast (p = 0.03), and in the limitation of dermal-epidermal junction destructuring (p = 0.03) according to dermal-epidermal junction destructuring score at Reflectance Confocal Microscopy. Luminance (p = 0.04) and redness (p = 0.03) were improved at color analysis, and physician and patient evaluations favored the active in efficacy and patient satisfaction investigations. The dermocosmetic lightening product utilized in the current study proved to be more effective, according to clinical, digital and subjective analyses in reducing lesion hyperpigmentation, stabilizing the lesion skin architecture and increasing patient satisfaction compared to the control in a cohort of 36 subjects, over a 12-month period. Beside demonstrating the efficacy of this topical lightening product, we propose a "destructuring score", which improves the robustness of solar lentigo's evaluation, and can be used in future studies to standardize the quantitative comparisons of different treatment options.

What's New in Pigmentary Disorders.

Pigmentary disorders are common and can be very distressing to patients. There is a need for better, standardized therapies. The authors review the most recent data for topical, systemic, light, and laser treatments for vitiligo, melasma, and postinflammatory hyperpigmentation. There is a paucity of large-scale, well-designed, randomized, controlled trials for these treatments. Treatment options are often drawn from smaller trials and case series. The treatments described in this article are promising candidates for larger follow-up studies.

Hyperpigmentation Disorders in Hispanic Population in the United States

The Hispanic population is the third largest growing group in the United States and is projected to increase to 119 million by 2060. Skin of color populations including Hispanics are more susceptible to a variety of pigmentary disorders including melasma and post-inflammatory hyperpigmentation (PIH). Most previous treatment options for these disorders remain unsatisfactory. Current treatment options include topical therapies using skin lightening/bleaching agents, chemical peels, and physical therapies such as microdermabrasion, microneedling, radiofrequency, and lasers. Combination therapies using skin lighting agents, peels, and physical means are also commonly used. New trends include protection and prevention using sunscreens, physical blockers, and the use of new and effective anti-oxidants and anti-inflammatory agents. The choice of therapeutic agents involves assessment of the risk-benefit profile of each individual. As the pathophysiology of melasma and PIH are being intensely investigated and studied, the treatment options are also expanding. In this review, the current therapeutic options are summarized and new and emerging treatment options for PIH and melasma are discussed. J Drugs Dermatol. 2019;18(3 Suppl):s112-114.

Hyperpigmentation Disorders in Hispanic Population in the United States

The Hispanic population is the third largest growing group in the United States and is projected to increase to 119 million by 2060. Skin of color populations including Hispanics are more susceptible to a variety of pigmentary disorders including melasma and post-inflammatory hyperpigmentation (PIH). Most previous treatment options for these disorders remain unsatisfactory. Current treatment options include topical therapies using skin lightening/bleaching agents, chemical peels, and physical therapies such as microdermabrasion, microneedling, radiofrequency, and lasers. Combination therapies using skin lighting agents, peels, and physical means are also commonly used. New trends include protection and prevention using sunscreens, physical blockers, and the use of new and effective anti-oxidants and anti-inflammatory agents. The choice of therapeutic agents involves assessment of the risk-benefit profile of each individual. As the pathophysiology of melasma and PIH are being intensely investigated and studied, the treatment options are also expanding. In this review, the current therapeutic options are summarized and new and emerging treatment options for PIH and melasma are discussed. J Drugs Dermatol. 2019;18(3 Suppl):s112-114.

Discovery of new depigmenting compounds and their efficacy to treat hyperpigmentation: Evidence from in vitro study.

Human skin pigmentation is a result of constitutive and facultative pigmentation. Facultative pigmentation is frequently stimulated by UV radiation, pharmacologic drugs, and hormones whereby leads to the development of abnormal skin hyperpigmentation. To date, many state-of-art depigmenting compounds have been studied using in vitro model to treat hyperpigmentation problems for cosmetic dermatological applications; little attention has been made to compare the effectiveness of these depigmenting compounds and their mode of actions. In this present article, new and recent depigmenting compounds, their melanogenic pathway targets, and modes of action are reviewed. This article compares the effectiveness of these new depigmenting compounds to modulate several melanogenesis-regulatory enzymes and proteins such as tyrosinase (TYR), TYR-related protein-1 (TRP1), TYR-related protein-2 (TRP2), microphthalmia-associated transcription factor (MITF), extracellular signal-regulated kinase (ERK) and N-terminal kinases (JNK) and mitogen-activated protein kinase p38 (p38 MAPK). Other evidences from in vitro assays such as inhibition on melanosomal transfer, proteasomes, nitric oxide, and inflammation-induced melanogenesis are also highlighted. This article also reviews analytical techniques in different assays performed using in vitro model as well as their advantages and limitations. This article also provides an insight on recent finding and re-examination of some protocols as well as their effectiveness and reliability in the evaluation of depigmenting compounds. Evidence and support from related patents are also incorporated in this present article to give an overview on current patented technology, latest trends, and intellectual values of some depigmenting compounds and protocols, which are rarely highlighted in the literatures.

Azelaic acid-loaded nanoemulsion with hyaluronic acid - a new strategy to treat hyperpigmentary skin disorders.

OBJECTIVE: To develop an azelaic acid (AzA)-loaded nanoemulsion with hyaluronic acid (HA) as a double targeting strategy to increase drug retention and tyrosinase inhibition activity. SIGNIFICANCE: Dermic melasma is a recalcitrant disease. Therefore, the development of new technologies that allow a deeper penetration in the skin while enhancing the efficacy of a safe and well-known dermatological active, like AzA, is a very promising alternative to improve the treatment of this disease. METHODS: An oil-in-water nanoemulsion was developed and characterized according to its droplet size distribution, zeta potential, pH value, drug content, encapsulation efficiency, spectroscopic characteristics, morphology, and stability. In vitro mushroom tyrosinase inhibition assay, cytotoxicity, and permeation studies were performed. A descriptive sensory evaluation was also carried out. RESULTS: Drug content was 10 mg/ml, particle size 419 ± 23 nm with monomodal distribution, encapsulation efficiency was 84.65%, zeta potential -10.9 ± 0.44 mV and pH 5.01 ± 0.01. The nanoemulsion was stable for 30 days (30 °C/65% RH). The nanoemulsion decreased tyrosinase activity and permeated through the skin, reaching viable epidermis and dermis and did not show signs of cytotoxicity. Sensory evaluation profile showed a higher spreadability with lesser whitening residue. CONCLUSION: The nanoemulsion presented characteristics within the nanoscale and reached the deeper layers of the skin while improving in vitro tyrosinase inhibition; hence, it could be a promising treatment to dermic melasma.

The color of skin: psychiatric ramifications.

Skin color is one of the major attributes that defines both individual distinctiveness and differences between groups. There is a preference for lighter skin world-wide, among both light- and dark-skinned individuals, further leading to skin-color bias based upon skin-color hierarchy within certain ethnoracial groups. The psychiatric and psychosocial ramifications of skin color are important in several situations, including (1) disorders of skin discoloration (eg, vitiligo), which can significantly affect the psychosocial development of the patient especially when it has its first onset during adolescence; (2) widespread use of skin-lightening products, which are used despite knowledge about serious toxicity from inorganic mercury and potent corticosteroids that are some of their main constituents; (3) indoor tanning, which is a recognized carcinogen and practiced by over 50% of university-age adults and 20% of adolescents. Educating about photocarcinogenicity does not change tanning behaviors, which is strongly driven by peer pressure; and (4) when a psychiatric disorder, such as body dysmorphic disorder or major depressive disorder, is the primary basis for skin color dissatisfaction. Despite the role of complex sociocultural and psychiatric factors in clinical manifestations involving skin color, a supportive relation with the dermatologist can significantly aid the patient in managing their disease burden.