Evaluation of in vivo mutagenicity of hydroquinone in Muta™ mice

Topical isoniazid as a novel treatment for melasma: A randomized, double-blind, vehicle-controlled clinical trial

INTRODUCTION

Melasma is a chronic hyperpigmentation disorder, and its treatment poses a challenge to dermatologists due to its chronicity and resistance to conventional therapies. Oral isoniazid is used for the treatment of tuberculosis. One of us had previously showed that topical isoniazid exerts a strong depigmenting action in animal models. In this clinical trial, we assessed the therapeutic effect of topical isoniazid on melasma.

METHODS

Twenty female patients suffering from epidermal melasma were enrolled and divided equally into two groups. The treatment group received topical isoniazid 10%, and the control group received the cold cream vehicle as the placebo. All participants were advised to avoid sunlight and used SPF 50 sunscreen. Patients applied topical agents once daily at night for 3 months. The melanin and erythema indices were measured by colorimetric evaluations at baseline and after 4, 8, and 12 weeks of treatment. At these time points, the (mMASI) score was also determined, as was the subjective evaluation through Melasma Quality of Life Scale (MELASQOL) scores. Blood tests were performed to evaluate CBC and the liver enzymes.

RESULTS

All patients completed the 12-week study. In the treatment group, a significant decrease in melanin index from 63.77 ± 6.27 at baseline to 55.92 ± 5.79 was recorded (p = 0.001). Very minimal clinical changes were also seen in the control group and melanin index was decreased from 62.65 ± 2.23 to 61.25 ± 2.34 (p = 0.004). Clinically significant differences were observed in the rate of changes between both groups. These findings indicate that topical isoniazid has significant depigmenting effects compared to the placebo (p = 0.001). The erythema index remained unchanged in both groups. In the treatment group, the mMASI score was 5.63 ± 3.28 at baseline and 2.13 ± 1.71 at the last follow-up, significantly reduced compared to the control group (p = 0.002). The MELASQOL score indicated a significant improvement in the quality of life in the treatment group.

CONCLUSION

This clinical trial shows for the first time that topical isoniazid is effective in treating melasma. Further clinical trials are necessary to confirm the efficacy and tolerability of topical isoniazid in comparison with other skin-depigmenting compounds.

Fabrication of an Extremely Cheap Poly(3,4-ethylenedioxythiophene) Modified Pencil Lead Electrode for Effective Hydroquinone Sensing

Hydroquinone (HQ) is one of the major deleterious metabolites of benzene in the human body, which has been implicated to cause various human diseases. In order to fabricate a feasible sensor for the accurate detection of HQ, we attempted to electrochemically modify a piece of common 2B pencil lead (PL) with the conductive poly(3,4-ethylenedioxythiophene) or PEDOT film to construct a PEDOT/PL electrode. We then examined the performance of PEDOT/PL in the detection of hydroquinone with different voltammetry methods. Our results have demonstrated that PEDOT film was able to dramatically enhance the electrochemical response of pencil lead electrode to hydroquinone and exhibited a good linear correlation between anodic peak current and the concentration of hydroquinone by either cyclic voltammetry or linear sweep voltammetry. The influences of PEDOT film thickness, sample pH, voltammetry scan rate, and possible chemical interferences on the measurement of hydroquinone have been discussed. The PEDOT film was further characterized by SEM with EDS and FTIR spectrum, as well as for stability with multiple measurements. Our results have demonstrated that the PEDOT modified PL electrode could be an attractive option to easily fabricate an economical sensor and provide an accurate and stable approach to monitoring various chemicals and biomolecules.

Hvdroquinone: Assessment of genotoxic potential in the in vivo alkaline comet assay

Hydroquinone (HQ) exposure is common as it is a natural component of plant-based foods and is used in some fingernail polishes, hair dyes, and skin lighteners. Industrially it is used as an antioxidant, polymerization inhibitor, and reducing agent. The current study was undertaken to determine whether HQ may cause DNA damage in an in vivo comet assay in F344 rats. DNA strand breaks were assessed in the duodenum as a direct tissue contact site, the testes, and the liver and kidneys, which were tumor sites in bioassays. Rats were exposed to HQ by gavage at 0, 105, 210, or 420 mg/kg/day. At all dose levels, mean % tail intensity and tail moment values for all tissues in animals given HQ were similar to the control. There were no statistically significant increases in tail intensity in any tissue following HQ treatment of male and female rat and data for all animals fell within the available historical control ranges for each tissue. There was no evidence of induction of DNA damage in cells isolated from duodenum, kidney or liver of male and female rats or in the testes of male rats following exposure to HQ at a dose levels up to 420 mg/kg/day, which caused acute renal necrosis.

A systematic review on the skin whitening products and their ingredients for safety, health risk, and the halal status

BACKGROUND

Skin-whitening products are in the high trend of demand for skin beautifying and lightening. Sources of ingredients for cosmetics could be natural, semi-synthetic, and synthetic that may affect the halal status of a product. The lack of scientific evidence on the safety and risks of such ingredients is a major concern to many consumers.

OBJECTIVE

This review paper aimed to shed light on the skin-whitening ingredients and their issues related to safety, health risk, and halal status.

METHODOLOGY

Based on the reviews scientific publications published from January 2015 to July 2020 using Web of Science and Scopus engines.

FINDINGS

Based on the review, most of the common ingredients in the skin-whitening products are originated from plants, animals, microbes, and heavy metals. Health risk of the ingredients was evaluated based on the usage, chronic or acute adverse effect, frequency of incidence, and the hazardous chemical contents of a halal cosmetics. The halal status of the ingredients was investigated based on the sources of origin, safety evaluation, and associated health risk of the ingredients.

ORIGINALITY

This review shows that ingredients play a vital role in the halal status decision-making of a cosmetic product. Therefore, the categories of Halal-Safe, Haram-Prohibited, and Critical-Need further evaluation were suggested to integrate the sources of ingredients with safety.

Selective electrochemical detection of hydroquinone and catechol at a one-step synthesised pine needle-like nano-CePO4 modified carbon paste electrode

A pine needle-like nano-CePO₄ modified carbon paste electrode was successfully constructed for simultaneous detection of hydroquinone and catechol sensitively and selectively.

Evaluation of the in vivo genotoxicity of Allura Red AC (Food Red No. 40)

Allura Red AC (Food Red No. 40) is a red azo dye that is used for food coloring in beverage and confectionary products. However, its genotoxic properties remain controversial. To clarify the in vivo genotoxicity, we treated mice with Allura Red AC and investigated the induction of DNA damage (liver, glandular stomach), clastogenicity/anuegenicity (bone marrow), and mutagenicity (liver, glandular stomach) using Comet assays, micronucleus tests, and transgenic gene mutation assays, respectively. All studies were conducted in accordance with the Organization for Economic Co-operation and Development (OECD) guideline. Although Allura Red AC was administered up to the maximum doses recommended by the OECD guideline, no genotoxic effect was observed in any of the genotoxic endpoints. These data clearly show no evidence of in vivo genotoxic potential of Allura Red AC administered up to the maximum doses in mice.