Risk assessment of skin lightening cosmetics containing hydroquinone

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.

Hydroquinone Ecotoxicity: Unveiling Risks in Soil and River Ecosystems with Insights into Microbial Resilience

Despite widespread industrial use, the environmental safety of hydroquinone (HQ), a benzene compound from plants used in processes like cosmetics, remains uncertain. This study evaluated the ecotoxicological impact of HQ on soil and river environments, utilizing non-target indicator organisms from diverse trophic levels: Daphnia magna, Aliivibrio fischeri, Allium cepa, and Eisenia fetida. For a more environmentally realistic assessment, microbial communities from a river and untreated soil underwent 16S rRNA gene sequencing, with growth and changes in community-level physiological profiling assessed using Biolog EcoPlate™ assays. The water indicator D. magna exhibited the highest sensitivity to HQ (EC50 = 0.142 µg/mL), followed by A. fischeri (EC50 = 1.446 µg/mL), and A. cepa (LC50 = 7.631 µg/mL), while E. fetida showed the highest resistance (EC50 = 234 mg/Kg). Remarkably, microbial communities mitigated HQ impact in both aquatic and terrestrial environments. River microorganisms displayed minimal inhibition, except for a significant reduction in polymer metabolism at the highest concentration (100 µg/mL). Soil communities demonstrated resilience up to 100 µg/mL, beyond which there was a significant decrease in population growth and the capacity to metabolize carbohydrates and polymers. Despite microbial mitigation, HQ remains highly toxic to various trophic levels, emphasizing the necessity for environmental regulations.

Recent Advances on Electrochemical Sensors for Detection of Contaminants of Emerging Concern (CECs)

Contaminants of Emerging Concern (CECs), a new category of contaminants currently in the limelight, are a major issue of global concern. The pervasive nature of CECs and their harmful effects, such as cancer, reproductive disorders, neurotoxicity, etc., make the situation alarming. The perilous nature of CECs lies in the fact that even very small concentrations of CECs can cause great impacts on living beings. They also have a nature of bioaccumulation. Thus, there is a great need to have efficient sensors for the detection of CECs to ensure a safe living environment. Electrochemical sensors are an efficient platform for CEC detection as they are highly selective, sensitive, stable, reproducible, and prompt, and can detect very low concentrations of the analyte. Major classes of CECs are pharmaceuticals, illicit drugs, personal care products, endocrine disruptors, newly registered pesticides, and disinfection by-products. This review focusses on CECs, including their sources and pathways, health effects caused by them, and electrochemical sensors as reported in the literature under each category for the detection of major CECs.

Quality assessment of hydroquinone, mercury, and arsenic in skin-lightening cosmetics marketed in Ilorin, Nigeria

Hydroquinone, Mercury (Hg), and Arsenic (As) are hazardous to health upon long-term exposure. Hydroquinone, Hg, and As were analysed in skin-lightening cosmetics randomly purchased from different cosmetic outlets within the Ilorin metropolis, Nigeria. The amount of hydroquinone in the samples was determined using a UV-spectrophotometry method at 290 nm. Hg and As were quantified using atomic absorption spectrophotometry (AAS). UV-spectrophotometry method validation showed excellent linearity (r2 = 0.9993), with limits of detection (0.75 µg/mL), limits of quantification (2.28 µg/mL), relative standard deviation (0.01-0.35%), and recovery (95.85-103.56%) in the concentration range of 5-50 µg/mL. Similarly, r2, LOD, and LOQ for Hg and As were 0.9983 and 0.9991, (0.5 and 1.0 µg/L) and 1.65 and 3.3 µg/L) respectively. All the samples contained hydroquinone, Hg and As in varying amounts. The amounts of hydroquinone, Hg and As present were in the ranges of 1.9-3.3%, 0.08-2.52 µg/g and 0.07-5.30 µg/g respectively. Only three of the analysed samples contained hydroquinone within the permissible limit of 2.0% w/w in cosmetic products. All the samples analysed contained mercury and arsenic in varying amounts. The need to periodically monitor the levels of hydroquinone, mercury, and arsenic in skin-lightening cosmetics marketed in Nigeria is recommended.

Characterization and screening of anti-melanogenesis and anti-photoaging activity of different enzyme-assisted polysaccharide extracts from Portulaca oleracea L

BACKGROUND

The flavonoids and polysaccharides in Portulaca oleracea L. (PO) have significant antibacterial and antioxidant effects, which can inhibit common bacteria and remove free radicals in the body. However, there was little research on the use of PO to alleviate hyperpigmentation and photoaging damage.

PURPOSE

This study was to investigate the anti-photoaging and whitening activity mechanism of polysaccharide of PO (POP) in vitro and in vivo.

METHOD

In this study, 16 fractions obtained by four enzyme-assisted extraction from PO and their scavenging capabilities against 2,2-diphenyl-1-picrylhydrazyl and hydroxyl radicals were evaluated. Among these fractions, a polysaccharide fraction (VPOP3) showed the strongest biological activity. VPOP3 was characterized by Fourier-transform infrared spectroscopy, molecular weight (MW), and monosaccharide composition analysis, and the protective effect of VPOP3 on photoaging and hyperpigmentation was researched.

RESULTS

VPOP3 is a low-MW acidic heteropolysaccharide with MW mainly distributed around 0.71KDa, arabinose as its main monosaccharide component. VPOP3 reliably reduced the reactive oxygen species levels in cells and zebrafish and the level of lipid peroxidation in zebrafish. In addition, VPOP3 inhibited UVB-induced apoptotic body formation and apoptosis by downregulating caspase-3 and Bax and upregulating Bcl-2 in mitochondrion-mediated signaling pathways. On the other hand, VPOP3 at high concentrations significantly downregulated the expression of microphthalmia-associated transcription factor, tyrosinase (TYR), and TYR-related protein-1 and TYR-related protein-2 in the melanogenic signaling pathway to achieve a whitening effect.

CONCLUSION

The above results showed that VPOP3 has superior activities of anti-photoaging and anti-melanogenesis and can be utilized as a safe resource in the manufacture of cosmetics.

Determination of hydroquinone and benzoquinone in pharmaceutical formulations: critical considerations on quantitative analysis of easily oxidized compounds

Hydroquinone is a skin-lightening agent used as an active ingredient in topical dermatological formulations prescribed for treating cutaneous diseases caused by hyperpigmentation. Despite being widely used, some toxicological aspects have been associated with these products, mainly due to overdosage and long-term use combined with the easy oxidation of hydroquinone. In this work, an investigative study has been done to gather enough data for selecting a quantitative analytical method for quality control purposes that considers the ease of oxidation not only within the product but also during the experimental procedures. After studying the influence of pH, reversibility, sampling, and standard solution preparation on the redox reaction between hydroquinone and benzoquinone by using spectroscopic, electrophoretic, and electroanalytical measurements, a reliable, fast, and selective chronoamperometric method was achieved. The optimized method was used for the analysis of samples, previously diluted in Britton-Robinson (BR) buffer (pH 5.5) and methanol (1 : 9, v/v), by applying a potential fixed at 0.4 V. A glassy-carbon working electrode, lab-made Ag/AgCl_(sat) and platinum wire as a reference electrode and auxiliary electrodes, respectively, and BR buffer (pH 5.5) as supporting electrolyte were the additional experimental conditions used. Analytical performance parameters were verified to confirm the applicability of the new method (LOD 4.22 μmol L^-1 and LOQ 14.1 μmol L^-1; recovery mean value of 100% with 0.22% RSD). A gel topical formulation containing 4% (w/w) hydroquinone was analyzed through the developed method for determination of dosage and oxidation traces, and a content of 3.53 ± 0.095% (w/w) was found with no indications of degradation.

Preparation of Zr/Y co-doped TiO2 photocatalyst and degradation performance of hydroquinone

In this paper, Y-ZrO₂-TiO₂ photocatalyst was prepared by sol-gel method, the titanium source was tetrabutyl titanate, and the precursors were zirconium nitrate pentahydrate and yttrium nitrate hexahydrate. For the photocatalytic effect of Y-ZrO₂-TiO₂ to hydroquinone, these effects were investigated: doping ratios of Zr/Y, calcination conditions, pH, etc. And the materials were characterized by XRD, TEM-EDS, XPS, PL, ESR, etc. The results showed that the optimum preparation conditions of Y-ZrO₂-TiO₂ photocatalyst were as follows: the molar ratio of doping was Ti: Zr: Y = 100:6:0.5, the calcination temperature was 500 °C, and the calcination time was 2 h; the optimum reaction conditions were as follows: the dosage of Y-ZrO₂-TiO₂ was 1 g/L, and pH value was 6.96. The degradation rate of hydroquinone under 365-nm UV lamp for 50 min could reach 96.58%, while the degradation rates of pure TiO₂, Y-TiO₂, and ZrO₂-TiO₂ under the same conditions were 33.95%, 79.55%, and 90.30%, respectively. It can be seen that the addition of elements Zr and Y improves the photocatalytic performance of TiO₂.

Barium titanate nanoparticle-based disposable sensor for nanomolar level detection of the haematotoxic pollutant quinol in aquatic systems

Barium titanate nanoparticles synthesized by a simple co-precipitation method and applied for the electrochemical detection of quinol.

Analytical method development and percutaneous absorption of propylidene phthalide, a cosmetic ingredient

Propylidene phthalide (PP) is a cosmetic ingredient used in the fragrance industry and regulated for the limited content of 0.01% in cosmetic products in Korea. The aim of this study was to determine PP dermal absorption rate according to the Korea Ministry of Food and Drug Safety (MFDS) guidelines using in vitro Franz diffusion system. An analytical method in assessing PP was developed through method validation using LC-MS/MS. Linearity, precision, and accuracy were acceptable based upon MFDS guidelines. The stability of PP in receptor fluid (50% ethanol) at 32°C was sufficient up to 24 hr. Cream formulation (o/w) was topically applied to excised rat skin at a dose of 113 mg/cm² containing 0.7% PP. The time points for receptor fluid collection were set at 0, 1, 2, 4, 8, 12, and 24 hr. After 24 hr, the remaining formulation on the skin and stratum corneum (SC) were collected through swabbing with an alcohol cotton and tape stripping, respectively. The collected samples (swabbed-remained formulation, SC, and skin) were extracted using acetonitrile for 24 hr. Total dermal absorption rate of PP was approximately 24% in cream formulation. These findings may be used for further exposure evaluation of PP in human consumers.

Simultaneous determination of dihydroxybenzene isomers in cosmetics by synthesis of nitrogen-doped nickel carbide spheres and construction of ultrasensitive electrochemical sensor

N-doped nickel carbide spheres (N-NiCSs) were synthesised for the first time by controlling the type of surfactant, surfactant-to-Ni molar ratio, reaction temperature, and reaction time. The morphology, composition, and electrochemical behaviour of the synthesised spheres revealed that the spheres presented a large specific surface area, abundant pores, and good conductivity, with excellent electrocatalytic performance. A glassy carbon electrode-modified with N-NiCSs was used for the simultaneous identification of hydroquinone (HQ), catechol (CC), and resorcinol (RS) utilising differential pulse voltammetry. The oxidation peaks of HQ, CC, and RS were observed at 9.8, 119, and 470 mV, respectively (vs. SCE). Under optimal conditions, the oxidation peak currents of HQ, CC, and RS were linear in the concentration ranges of 0.005-100 μM, 0.05-200 μM, and 5-500 μM, respectively. The detection limits of HQ, CC, and RS were 0.00152 μM, 0.015 μM, and 0.24 μM (S/N = 3), respectively. The sensitivities of HQ, CC, and RS were 4.635, 2.069, and 0.985 μA μM^-1 cm^-2 (S/N = 3), respectively. The fabricated sensor was successfully used to detect HQ, CC, and RS in hair dye, whitening cream, and local tap water samples. Moreover, the sensor presented a good repeatability, reproducibility, and stability during cosmetic testing and a relatively wide linear range, an ultralow detection limit, and an ultrahigh sensitivity.

Size-dependent whitening activity of enzyme-degraded fucoidan from Laminaria japonica

Fucoidan from Laminaria japonica is a kind of sulfate polysaccharide with high molecular weight (MW) and broad bioactivities. This study was performed to investigate the relationship between MW and whitening activity of fucoidan and to exploit a novel functional ingredient for whitening cosmetics. High sulfate content fucoidan was enzymic degraded by Flavobacterium RC2-3 produced fucoidanase. Two hours were enough for the enzyme degradation to achieve degraded fucoidan with favorable tyrosinase inhibitory ability. The whitening activity of different MW fucoidan fractions were evaluated by their tyrosinase inhibitory ability, antioxidant activity and cellular melanogenesis inhibitory ability. Results showed that in the MW range above 5 kDa, the smaller MW of fucoidan were related to the better whitening activity. The fucoidan fraction with the MW between 5-10 kDa, presented the best tyrosinase inhibitory activity (62.0%), antioxidant activity (48.3%) and excellent anti-melanogenesis ability in B16 cells, which could be applied as the whitening factor in cosmetics development.

Consistent production of kojic acid from Aspergillus sojae SSC-3 isolated from rice husk

A consistent kojic acid producing fungal strain has been isolated from rice husk using glucose-peptone medium. The isolate was identified as Aspergillus sojae SSC-3 on 18S rDNA analysis. A. sojae was capable of producing substantially good amount of kojic acid, however the production was varying from batch to batch. In order to obtain consistent, repeated and high levels of kojic acid, monospore isolation procedures was adopted. The highest production of kojic acid obtained was 12 ± 2 g/L in 120 h with sucrose (10%) and yeast extract (0.5%) as carbon and nitrogen source respectively. The process was scale up to 10 L fermenter size which repeatedly resulted in the production of 18 ± 2 g/L of kojic acid in 96 h. Kojic acid was recovered (> 82%) from the fermentation broth with > 99% purity. Best to our knowledge this is the first report were kojic acid production is reported from Aspergillus sojae strain.

Halal Cosmetics: A Review on Ingredients, Production, and Testing Methods

The demand for halal cosmetic products among the 2.4 billion Muslim consumers worldwide is increasing. However, the demand for halal cosmetics remains unmet because cosmetics production is dominated by non-halal cosmetic manufacturers, whose production methods may not conform with the requirements of halal science. The development of halal cosmetics and the assessment of their product performance is still in its infancy. The integration of halal science in the manufacture of most cosmetic products remains inadequate. Moreover, there is a global dearth of guiding documents on the development and assessment techniques in the production of comprehensively halal cosmetics. This paper aims to abridge existing literature and knowledge of halal and cosmetic science in order to provide essential technical guidance in the manufacture of halal cosmetics. In addition, the adoption of these methods addresses the unique ethical issues associated with conformance of cosmetics’ product performance to religious practices and halal science. It highlights the applicability of established methods in skin science in the assessment of halal cosmetics.

Tuning the Transdermal Delivery of Hydroquinone upon Formulation with Novel Permeation Enhancers

Hydroquinone (HQ) is an anti-hyperpigmentation agent with poor physicochemical stability. HQ formulations are currently elaborated by compounding in local pharmacies. Variability in the characteristics of HQ topical formulations can lead to remarkable differences in terms of their stability, efficacy, and toxicity. Four different semisolid O/W formulations with 5% HQ were prepared using: (i) Beeler´s base plus antioxidants (F1), (ii) Beeler´s base and dimethyl isosorbide (DMI) as solubiliser (F2), (iii) olive oil and DMI (F3), and (iv) Nourivan^®, a skin-moisturising and antioxidant base, along with DMI (F4). Amongst the four formulations, F3 showed the greatest physicochemical stability with less tendency to coalescence but with marked chromatic aberrations. An inverse correlation was established by multivariate analysis between the mean droplet size in volume and the steady-state flux, which explains why F3, with the smallest droplet size and the most hydrophobic excipients, exhibited the highest permeation across both types of membranes with enhancement ratios of 2.26 and 5.67-fold across Strat-M^® and mouse skin, respectively, compared to F1. It is crucial to understand how the HQ is formulated, bearing in mind that the use of different excipients can tune the transdermal delivery of HQ significantly.

Assessment of the cytotoxicity, antioxidant activity and chemical composition of extracts from the cyanobacterium Fischerella major Gomont

Cyanoprokaryotes (Cyanobacteria/Cyanophyta) are ancient photosynthetic prokaryotic organisms with cosmopolitan distribution. They are producers of a number of biologically active substances with antitumor and antifungal activity, vitamins, antibiotics, algaecides, insecticides, repellents, hormones, immunosuppressants and toxins. So far, the cyanobacterium Fischerella major Gomont has not been studied regarding its impact on the environment and human health. In this study, the cytotoxic, antioxidant and antitumor activities of four extracts prepared from Fischerella major were evaluated in vitro. In addition, the total phenolic content and the potential for production of cyanotoxins were also analyzed. The conducted GC/MS analysis identified 45 compounds with different chemical nature and biological activity. Presence of microcystins and saxitoxins was detected in all Fischerella major extracts. In vitro testing on cell cultures showed a significant concentration- and time-dependent cytotoxic effect on all cell lines (HeLa, SK-Hep-1 and FL) treated at three exposure times (24, 48 and 72 h) with four extracts. A selective antitumor effect was not observed. This is the first study demonstrating biological activity of extracts from Fischerella major, which makes it an interesting subject for further research, including environmental risk assessments (as producer of cyanotoxins) or as a potential source of pharmaceuticals.

Restoration of cutaneous pigmentation by transplantation to mice of isogeneic human melanocytes in dermal-epidermal engineered skin substitutes

Autologous engineered skin substitutes (ESS) containing melanocytes (hM) may restore pigmentation and photoprotection after grafting to full-thickness skin wounds. In this study, normal hM were isolated from discard skin, propagated with or without tyrosinase inhibitors, cryopreserved, recovered into culture, and added to ESS (ESS-P) before transplantation. ESS-P were incubated in either UCMC160/161 or UCDM1 medium, scored for hM densities, and grafted to mice. The results showed that sufficient hM can be propagated to expand donor tissue by 100-fold; incubation of hM in tyrosinase inhibitors reduced pigment levels but did not change hM recovery after cryopreservation; hM densities in ESS-P were greater after incubation in UCDM1 than UCMC160 medium; hM were localized to the dermal-epidermal junction of ESS-P; and UCDM1 medium promoted earlier pigment distribution and density. These results indicate that hM can be incorporated into ESS-P efficiently to restore cutaneous pigmentation and UV photoprotection after full-thickness skin loss conditions.