Tyrosinase Activity Research Articles

Green synthesis of silver nanoparticles using food supplement from Avena sativa L., and their antioxidant, antiglycation, and anti-aging activities: In vitro and in silico studies

Food supplement of Avena sativa L. dry extract (AsDE) is produced with green leaves of wild oats and it is commonly used in patients with cognitive disorders and muscle deficits. These symptoms and pathologies can be promoted and/or aggravated by oxidative stress and protein glycation. In order to prevent or treat these disorders, new formulations that could enhance and benefit AsDE have been developed and the formation of metallic nanoparticles by green synthesis has shown to be an alternative. Thus, this study aimed to prepare silver nanoparticles (AgNPs) by green synthesis using AsDE and characterize these AgNPs. Besides, it aimed to evaluate in vitro antioxidant and antiglycation activities of AsDE and AgNPS, and analyze in vitro and in silico inhibitory action on aging enzymes (collagenase, elastase, and tyrosinase). UV–visible spectroscopy, Zeta potential and scanning transmission electron microscopy were used to characterize AgNPs. Antioxidant activity was determined by DPPH free radical scavenging, ferric ion reducing power (FRAP), lipid peroxidation inhibition, ABTS radical scavenging, and oxygen radical absorption capacity (ORAC). Molecular docking analyses were performed to evaluate interactions between the major compounds of AsDE and aging enzymes or DNA. Antioxidant tests demonstrated antioxidant activity of 19.67 % for AsDE and 42.98 % for AgNPs in DPPH test; and 115.67 µM Trolox Equivalent (TE)/g for AsDE and 554.33 µM TE/g for AgNPs in FRAP test. In addition, AsDE and AgNPs inhibited 25.40 % and 11.33 % of lipid peroxidation, respectively, and presented 255.22 µM TE/g for AsDE and 317.44 µM TE/g for AgNPs in ABTS test. AsDE and AgNPs exhibited antioxidant potential observed in ORAC assay. In addition, AsDE presented inhibitory action on collagenase, elastase and tyrosinase activities (78.23 %, 68.14 % and 62.27 % inhibition, respectively). Antiglycation tests demonstrated that bovine serum albumin exposed to ribose and treated with AsDE at 0.5 mg/mL exhibited the highest percentage of free amino groups (45.21 %), while samples treated with AgNPs showed 35.41 % free amino groups. On the other hand, AgNPs exhibited the highest percentage of inhibition of advanced glycation end-products formation (85.75 %), which did not differ from aminoguanidine, a known antiglycation agent. Besides, relative electrophoretic mobility assay demonstrated that samples treated with AsDE at 0.1 mg/mL or AgNPs showed antiglycation activity comparable to aminoguanidine. The in silico assays showed interactions between the major compounds of AsDE and aging enzymes or DNA. Therefore, results represent an important indicator for the development and discovery of new nanostructured pharmaceutical and cosmetic formulations using plants and their bioactive compounds.

Design, synthesis, and anti-melanogenic efficacy of 2-mercaptobenzoxazoles with nanomolar tyrosinase activity inhibition

Tyrosinase is a metalloenzyme that contains copper(II) ions. We designed and synthesized eight known low-molecular-weight 2-mercaptobenzoxazole (2-MBO) analogs as tyrosinase inhibitors. Our focus was on the mercapto functional group, which interacts with copper ions. Analogs 1–3 exhibited mushroom tyrosinase inhibitory activity at the nanomolar level and demonstrated strong potency with extremely low half-maximal inhibitory concentration (IC50) values of 80–90 nM for l-dopa and 100–240 nM for l-tyrosine. Analogs 2, 4, and 5 showed the most potent anti-melanogenic effects in B16F10 cells, and their mode of action was demonstrated by kinetic analysis. Their anti-melanogenic effects were similar to the tyrosinase inhibition results, suggesting that their anti-melanogenic effects could be attributed to their tyrosinase inhibitory ability. Experiments using copper-chelating activity assays and changes in tyrosinase inhibitory activity with and without CuSO4 demonstrated that 2-MBO analogs inhibit tyrosinase activity by chelating the copper ions of tyrosinase. In conclusion, the 2-MBO analogs show potential as anti-melanogenic agents with potent tyrosinase inhibitory activity.

In Vitro Biological Activities and Relative Chemicals in Different Extracts of Licorice and Fermenting Licorice

Purpose: This paper aims to qualitatively and quantitatively analyze the differences between the main chemicals in different licorice and fermented licorice (FL) extracts and their <i>in vitro</i> skin care activities and active ingredients. To evaluate the effect of fermentation on the efficacy of licorice.Methods: The DPPH free radical scavenging activity, mushroom tyrosinase activity, tyrosinase activity of B16F10 cells, and melanin synthesis inhibition activity of different extracts treated by fermentation and different extracts without fermentation treatment were evaluated. The effects of ethyl acetate components (EaF) including glycyrrhizin, isoglycyrrhizin, liquiritoside, isoliquiritigenin and glycyrrhizin ketone A on melanin synthesis were tested in vitro. Further assessment of FL at stromal metalloproteinase-1 (MMP-1) levels in human dermal fibroblasts (HDF).Results: Glycyrrhizin, isoglycyrrhizin, liquiritoside, isoliquiritigenin were improved in FL, and the antioxidant and MMP-1 inhibitory activities of FL controls were significantly increased.Conclusion: After fermentation, the anti-aging effect of licorice was greatly improved, indicating that the fermentation process had a good effect on improving the efficacy of licorice.

Plectranthus scutellarioides (L.) R.Br. Leaf Extract as Sunscreen, Skin Lightening, and Antiaging

Plectranthus scutellaroides is a plant with attractive colored leaves. It contains secondary metabolite compounds such as flavonoids and phenolics, which provide skin protection against ultraviolet rays from the sun. The research aims to investigate the activity of P. scutellarioides leaf extract from various variants and different solvents on sunscreen, skin lightening, and anti aging activities. The best extract is formulated in gel dosage form. Each P. scutellaroides leaf was extracted using ethanol, ethyl acetate, and hexane as solvents. The obtained extract was assessed for Sun Protecting Factor (SPF), UVA Protection grade (PA), antioxidant activity, and inhibition of tyrosinase, collagenase, elastase, and hyaluronidase. Determination was conducted in vitro using spectrophotometric methods. The highest sunscreen activity was observed in the ethanol extract Va (Va-ET), which exhibited SPF and PA values of 25.618±0.265, and 0.681±0.007 (star 3), respectively at a concentration of 100 ug/mL. The most significant skin-lightening activity was observed in the ethanol extract Vc (Vc-ET), with an IC50 value inhibiting tyrosinase of 39.059 ug/mL. Regarding the anti-aging activity of the extracts, as determined by their antioxidant activity and inhibition of collagenase, elastase, and hyaluronidase, the most promising extracts were obtained from ethanol extract Va (Va-ET) and ethyl acetate extract Va (Va-EA), with IC50 values of 79.734, 76.838, 143.384, and 122.467 ug/ mL, respectively. The Va-ET was formulated into a gel dosage form, and there was a significant effect of the gelling agent on the SPF value of the extract after formulation (p < 0.05). All extracts exhibit activity as sunscreen, skin lightening, and anti-aging, with the Va-ET showing the highest efficacy. Gelling agents significantly influence the SPF value of extracts after formulation into the gel dosage form. Among them, F3, formulated from the Va-ET of P. scutellaroides using Carbopol-940 as a gelling agent, exhibits the highest efficacy.

Effects of Vitamin C and SH-Polypeptide-10 Cosmetic Ingredients on Wrinkle Improvement and Skin Whitening

In this study, 20 female subjects in their 30s to 50s used cosmetics containing the main ingredients vitamin C and SH-Polypeptide-10 in an environment exposed to ultraviolet rays, and underwent clinical trials to determine the effects of improving wrinkles, brightness, and whitening of the skin. Efficacy evaluation was performed. Wrinkles around the eyes significantly decreased from 0.0592 to 0.0507(p<0.001), and the wrinkle improvement effect decreased by 16.78%(p<0.05). Skin brightness significantly decreased from 65.44 to 67.04 in the experimental group(p<0.001), and skin brightness increased by 2.45%(p<0.05). Additionally, the skin whitening effect significantly decreased from 66.38 to 55.51(p<0.001), and melanin pigment decreased by 19.57%(p<0.05). The cosmetics used in this experiment were shown to have antioxidant effects that protect cells from oxidative stress, increase transdermal permeability, promote epidermal cell growth and cell regeneration, inhibit tyrosinase activity and promote collagen formation. Overall, the use of cosmetics containing vitamin C and SH-Polypeptide-10 as main ingredients resulted in significant improvement in the experimental group, which can be seen as having a positive effect on improving wrinkles around the eyes and skin whitening.

Antioxidant, Anti-Inflammation, and Melanogenesis Inhibition of Sang 5 CMU Rice (Oryza sativa) Byproduct for Cosmetic Applications.

Prolonged exposure to environmental oxidative stress can result in visible signs of skin aging such as wrinkles, hyperpigmentation, and thinning of the skin. Oryza sativa variety Sang 5 CMU, an inbred rice cultivar from northern Thailand, contains phenolic and flavonoid compounds in its bran and husk portions that are known for their natural antioxidant properties. In this study, we evaluated the cosmetic properties of crude extracts from rice bran and husk of Sang 5 CMU, focusing on antioxidant, anti-inflammatory, anti-melanogenesis, and collagen-regulating properties. Our findings suggest that both extracts possess antioxidant potential against DPPH, ABTS radicals, and metal ions. Additionally, they could downregulate TBARS levels from 125% to 100% of the control, approximately, while increasing the expression of genes related to the NRF2-mediated antioxidant pathway, such as NRF2 and HO-1, in H2O2-induced human fibroblast cells. Notably, rice bran and husk extracts could increase mRNA levels of HO-1 more greatly than the standard L-ascorbic acid, by about 1.29 and 1.07 times, respectively. Furthermore, the crude extracts exhibited anti-inflammatory activity by suppressing nitric oxide production in both mouse macrophage and human fibroblast cells. Specifically, the bran and husk extracts inhibited the gene expression of the inflammatory cytokine IL-6 in LPS-induced inflammation in fibroblasts. Moreover, both extracts demonstrated potential for inhibiting melanin production and intracellular tyrosinase activity in human melanoma cells by decreasing the expression of the transcription factor MITF and the pigmentary genes TYR, TRP-1, and DCT. They also exhibit collagen-stimulating effects by reducing MMP-2 expression in H2O2-induced fibroblasts from 135% to 80% of the control, approximately, and increasing the gene associated with type I collagen production, COL1A1. Overall, the rice bran and husk extracts of Sang 5 CMU showed promise as effective natural ingredients for cosmetic applications.

Methylsulfonylmethane promotes melanogenesis via activation of JNK in Mel-Ab cells.

Methylsulfonylmethane (MSM), which contains organic sulphur, has been used for a long time as a medicinal ingredient because of its benefits to human health. MSM is reported to be protective against certain skin disorders, but it is unknown whether it affects melanin synthesis. Therefore, in our current research, we examined the possibility of MSM controlling the production of melanin in Mel-Ab melanocytes. In Mel-Ab cells, melanin contents and tyrosinase activities were assessed and quantified. The expression of microphthalmia-associated transcription factor (MITF) and tyrosinase was evaluated using western blot analysis, while MSM-induced signalling pathways were investigated. The MSM treatment significantly resulted in a dose-dependent increase in melanin production. Furthermore, MSM elevated melanin-related proteins, including MITF and tyrosinase. However, the rate-limiting enzyme of melanin production, tyrosinase, was not directly influenced by it. Therefore, we investigated potential melanogenesis-related signalling pathways that may have been triggered by MSM. Our findings showed that MSM did not influence the signalling pathways associated with glycogen synthase kinase 3β, cAMP response-element binding protein, extracellular signal-regulated kinase, or p38 mitogen-activated protein kinase. However, MSM phosphorylated c-Jun N-terminal kinases/stress-activated protein kinase (JNK/SAPK), which is known to induce melanogenesis. SP600125, a specific JNK inhibitor, inhibited MSM-induced melanogenesis. Taken together, our study indicates that MSM induces melanin synthesis and may serve as a therapeutic option for hypopigmentary skin disorders such as vitiligo.

Molecular Docking Studies of Ortho-Substituted Phenols to Tyrosinase Helps Discern If a Molecule Can Be an Enzyme Substrate.

Phenolic compounds with a position ortho to the free phenolic hydroxyl group occupied can be tyrosinase substrates. However, ortho-substituted compounds are usually described as inhibitors. The mechanism of action of tyrosinase on monophenols is complex, and if they are ortho-substituted, it is more complicated. It can be shown that many of these molecules can become substrates of the enzyme in the presence of catalytic o-diphenol, MBTH, or in the presence of hydrogen peroxide. Docking studies can help discern whether a molecule can behave as a substrate or inhibitor of the enzyme. Specifically, phenols such as thymol, carvacrol, guaiacol, eugenol, isoeugenol, and ferulic acid are substrates of tyrosinase, and docking simulations to the active center of the enzyme predict this since the distance of the peroxide oxygen from the oxy-tyrosinase form to the ortho position of the phenolic hydroxyl is adequate for the electrophilic attack reaction that gives rise to hydroxylation occurring.

Chemical constituents and bioactivities of fermented rose (from Yunnan) extract

Natural plant extracts have gained significant attention in research due to their low toxicity, and potent antioxidant, and anti-aging properties. The present study investigated the phytochemical composition of a fermented rose extract (FRE), and evaluated its antioxidant, skin whitening, and anti-aging activities in vitro. The results showed that the FRE was rich in polyphenols and flavonoids. A total of 13 major compounds were identified by Liquid Chromatography-Mass Spectrometry (LC-MS), with astragalin as the primary component. In vitro, analysis of antioxidant activity showed that FRE effectively eliminated 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals and dose-dependent reduced intracellular reactive oxygen species (ROS) levels. The FRE dose-dependent inhibited tyrosinase, collagenase, and hyaluronidase activity, reduced intracellular melanin synthesis, up-regulated the expression of collagen type I alpha 1 (COL1A1) and collagen type III alpha 1 (COL3A1), and down-regulated matrix metalloproteinases (MMPs) expression. Additionally, treatment with FRE significantly downregulated the expression of mitogen-activated protein kinase 1 (MAPK1), suggesting that FRE may modulate MAPK signaling pathways for skin anti-aging.

Relationships between degree of polymerization and activities: A study on condensed tannins from the bark of Ficus altissima

Condensed tannins were isolated from the bark of Ficus altissima and fractionated into four subcomponents on a Sephadex LH-20 column with 60 %, 80 %, 100 % methanol, and 70 % acetone, separately. Their structures were characterized by MALDI-TOF MS coupled with HPLC-ESI-MS and confirmed to be polymers of B-type procyanidin glucosides, procyanidins, and prodelphinidin glucosides. The degree of polymerization (DP) of these polymers was as high as 21, and the mDPs of the four subcomponents were calculated as 2.4, 6.6, 10.5 and 13.4, respectively. They competitively or noncompetitively suppressed the activities of tyrosinase and α-glucosidase through hydrogen bonding and hydrophobic interaction. And they also showed a powerful antioxidative activity. Correlation analyses verified that the anti-tyrosinase capacity exhibited a significant positive correlation (R2monophenolase = 0.9167 and R2diphenolase = 0.9302) with mDP within the methanol-water system, and the anti-α-glucosidase activity also showed a significant positive correlation with the mDP (R2 = 0.9187). In contrast, the antioxidant capability showed a significant negative correlation with the mDP (R2DPPH = 0.9258, R2ABTS = 0.9372). This study confirmed that condensed tannins from the bark of F. altissima were desirable anti-tyrosinase, anti-α-glucosidase, and antioxidant agents, and elucidated the relationships of their mDP (molecular weight) and activities, which provided a scientific basis for the comprehensive utilization of these polymers in the food, cosmetics, medicine and other fields.

Preparation of Rubra (Paeonia lactiflora Pall.) extract and studies in activity and skin penetration

The inhibition rate of tyrosinase activity was used to determine extraction solvent of Paeoniae Radix Rubra extract (PRRE), which was established quality control standards by HPLC and verified the antioxidant activity. Ternary phase diagram was used to screen the best formulation of PRRE nanoemulsion, the skin permeability of PRRE and nanoemulsion were compared. The results show that 70% ethanol as the extraction solvent were highest (88.89%) and the contents of catechin (CC) and paeoniflorin (PF) in PRRE were 0.145 ± 0.0006 μg/mg and 21.783 ± 0.0247 μg/mg, respectively. The inhibition rate of PRRE on pyrogallol autoxidation was 6.94% ± 0.53%. The optimal formulation is Isopropyl myristate (IPM) as oil phase, Ethoxylated hydrogenated castor oil (RH40) as emulsifier, glycerine as coemulsifier, Km 3:1. The skin penetration of CC in PRRE nanoemulsion (0.79 ± 0.04 μg·cm−2) was significantly higher than that PRRE (0.17 ± 0.09 μg·cm−2) after 12 h.

Investigation of the Efficacy of Benzylidene-3-methyl-2-thioxothiazolidin-4-one Analogs with Antioxidant Activities on the Inhibition of Mushroom and Mammal Tyrosinases.

Based on the fact that substances with a β-phenyl-α,β-unsaturated carbonyl (PUSC) motif confer strong tyrosinase inhibitory activity, benzylidene-3-methyl-2-thioxothiazolidin-4-one (BMTTZD) analogs 1-8 were prepared as potential tyrosinase inhibitors. Four analogs (1-3 and 5) inhibited mushroom tyrosinase strongly. Especially, analog 3 showed an inhibitory effect that was 220 and 22 times more powerful than kojic acid in the presence of l-tyrosine and l-dopa, respectively. A kinetic study utilizing mushroom tyrosinase showed that analogs 1 and 3 competitively inhibited tyrosinase, whereas analogs 2 and 5 inhibited tyrosinase in a mixed manner. A docking simulation study indicated that analogs 2 and 5 could bind to both the tyrosinase active and allosteric sites with high binding affinities. In cell-based experiments using B16F10 cells, analogs 1, 3, and 5 effectively inhibited melanin production; their anti-melanogenic effects were attributed to their ability to inhibit intracellular tyrosinase activity. Moreover, analogs 1, 3, and 5 inhibited in situ B16F10 cellular tyrosinase activity. In three antioxidant experiments, analogs 2 and 3 exhibited strong antioxidant efficacy, similar to that of the positive controls. These results suggest that the BMTTZD analogs are promising tyrosinase inhibitors for the treatment of hyperpigmentation-related disorders.

Impact of herbal treatments for Vitiligo disease

Vitiligo is a common skin disorder resulting from the breakdown of functional epidermal melanocytes. The global prevalence of vitiligo ranges from 0.5% to 2%, with higher rates reported in certain populations. Melanocytes, responsible for skin color, are destroyed in vitiligo condition leading to the appearance of smooth, white patches on the skin. The progression of vitiligo is influenced by various factors, including genetics, autoimmunity, psychosis, melanocyte self-destruction, trace element deficiency, oxidative stress, and other biochemical and environmental variables. Recent research has identified herbal plant extractions as potential agents for re-pigmentation and regeneration of normal skin color. Specific components of these herbal plants, such as furocoumarin, thymoquinone, flavonoids, curcuminoids, and glycyrrhizin, play crucial roles in promoting re-pigmentation. Combination therapies involving these herbal compounds have shown promise in increasing tyrosinase activity and reducing oxidative stress, which are two important aspects of vitiligo treatment. The review aims to comprehensively evaluate the efficacy of herbal plant therapies for melanocyte re-pigmentation in vitiligo patients. By analyzing the effectiveness of various herbal extracts and their active components, this study seeks to advance the understanding and potential application of herbal treatments for vitiligo. The findings from this review may contribute to the current knowledge on therapeutic options available for vitiligo patients.

Cyclocurcumin, a Minor Curcuminoid, Is a Novel Candidate for Hypopigmentary Skin Disorders with Melanogenesis-Stimulating Capacity

Effective therapies to treat skin hypopigmentation disorders caused by diminished melanin synthesis or export are limited due to potential side effects. In this work, we explored if cyclocurcumin (CYC), a curcuminoid found in minor amounts in turmeric rhizomes, might enhance the process of melanogenesis. CYC did not demonstrate antioxidant activity as evaluated by the DPPH assay. At noncytotoxic concentrations, CYC robustly enhanced melanin synthesis and melanin export in B16F10 mouse melanoma cells, which was correlated to increased cellular tyrosinase activity. The melanogenesis-stimulating efficacy of CYC was enhanced in B16F10 cocultures with HaCaT cells. Next, our results in MNT-1 human melanoma cells confirmed that CYC is a stimulator of both melanin synthesis and melanin export and acts by upregulating microphthalmia transcription factor (MITF) protein, although CYC did not alter tyrosinase protein or tyrosinase activity in MNT-1 cells. Moreover, the examination of CYC in MNT-1:HaCaT cocultures continued to show a more potent effect on stimulating melanin synthesis, as well as its export to recipient keratinocytes. Finally, CYC was shown to demonstrate a potent capacity to stimulate melanin production in primary human melanocytes from a Caucasian donor (HEMn-LP cells), although the effects on cellular tyrosinase activity were biphasic. Taken together, this is the first study to report the novel finding that CYC is a potent promelanogenic candidate that exhibits potential utility in the therapeutic management of skin disorders arising due to hypopigmentation in humans. Future studies that examine the molecular mechanisms and elucidate the promelanogenic efficacy of CYC in vivo are necessary.

Phenolic profile, fatty acid and mineral composition with antioxidant, antibacterial, and enzyme inhibitor activities of different extracts from Erodium Cicutarium (L.) L’Hér. consumed as a vegetable in Kilis, Turkey

This study aimed to explore the antioxidant activities, phenolic profile, fatty acid and mineral composition of the different extracts of Erodium cicutarium (L.) L’Hér. consumed as a vegetable in Kilis, Turkey. While catechine hydrate was the most abundant phenolic compounds in methanol, ethanol and diethyl ether extracts, it was chlorogenic acid in the water extract. Looking at the fatty acid profile, the amount of palmitic acid, one of the saturated fatty acids, was found to be high (34.30%), followed by stearic acid (5.10%). Total monounsaturated fatty acids are the second highest fatty acids. Total polyunsaturated fatty acids were determined as the third rank fatty acids. While the amount of linoleic acid, one of the total polyunsaturated fatty acids, was determined as 17.62%, the ratio of linolenic acid was determined as 9.60%. While the most calcium, magnesium and potassium were found among the 9 different mineral substances determined, respectively; the lowest element was found to be nitrogen. Looking at the results, it was determined that the plant is a high source of calcium (1078.503 mg/kg). Inhibitory effects against Pseudomonas aeruginosa ATCC 9027 were observed, with a zone diameter of 5.5 mm and 11 mm in methanol extract and diethyl ether extract, respectively. Ethanol and water extracts of E. cicutarium (L.) L.‘Hér. may be preferred as an alternative natural agent due to their amylase and tyrosinase activities. The results suggested that the E. cicutarium (L.) L.‘Hér. extracts may be useful for food and medicinal applications.

Anti-Melanogenic and Anti-Inflammatory Effects of 2'-Hydroxy-4',6'-dimethoxychalcone in B16F10 and RAW264.7 Cells.

Chalcone is a type of flavonoid compound that is widely biosynthesized in plants. Studies have shown that consuming flavonoids from fruits and vegetables or applying individual ingredients reduces the risk of skin disease. However, the effects of chalcone on melanogenesis and inflammation have not been fully investigated. The aim of this study was to evaluate the anti-melanogenic and anti-inflammatory effects of 2'-hydroxy-3,4'-dimethoxychalcone (3,4'-DMC), 2'-hydroxy-4,4'-dimethoxychalcone (4,4'-DMC), 2'-hydroxy-3',4'-dimethoxychalcone (3',4'-DMC), and 2'-hydroxy-4',6'-dimethoxychalcone (4',6'-DMC). Among the derivatives of 2'-hydroxy-4'-methoxychalcone, 4',6'-DMC demonstrated the most potent melanogenesis-inhibitory and anti-inflammatory effects. As evidenced by various biological assays, 4',6'-DMC showed no cytotoxicity and notably decreased the expression of tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2 enzymes. Furthermore, it reduced cellular melanin content and intracellular tyrosinase activity in B16F10 melanoma cells by downregulating microphthalmia-associated transcription factor (MITF), cAMP-dependent protein kinase (PKA), cAMP response element-binding protein (CREB), p38, c-Jun N-terminal kinase (JNK), β-catenin, glycogen synthase kinase-3β (GSK3β), and protein kinase B (AKT) proteins, while upregulating extracellular signal-regulated kinase (ERK) and p-β-catenin. Additionally, treatment with 4',6'-DMC significantly mitigated the lipopolysaccharide (LPS)-induced expression of NO, PGE2, inflammatory cytokines, COX-2, and iNOS proteins. Overall, 4',6'-DMC treatment notably alleviated LPS-induced damage by reducing nuclear factor kappa B (NF-κB), p38, JNK protein levels, and NF-kB/p65 nuclear translocation. Finally, the topical applicability of 4',6'-DMC was evaluated in a preliminary human skin irritation test and no adverse effects were found. These findings suggest that 4',6'-DMC may offer new possibilities for use as functional ingredients in cosmeceuticals and ointments.

Establishment of an invitro cell coculture model for investigating the whitening mechanism of Paeonia lactiflora Pall seeds oil.

In vitro single-cell experiments may yield inconsistent results compared to clinical trials. To enhance the reliability of cosmetic active ingredient screening, a coculture model of B16F10-HaCaT cells was established invitro based on the structural characteristics of human skin, thereby improving the credibility of experimental outcomes. Currently, most cosmetic whitening additives primarily target simple efficacy goals such as inhibiting tyrosinase activity or melanin transfer. Therefore, investigating novel and efficient whitening additives has become a prominent research focus. The aim is to establish an invitro cell coculture model for more reliable experimental results and investigate the mechanism by which Paeonia lactiflora Pall seeds oil inhibits melanin production and transfer. The impact of different concentrations of Paeonia lactiflora Pall seeds oil on cocultured cell proliferation rate was assessed using cck8 assay. Tyrosinase inhibition ability in cocultured cells was tested using levodopa as a substrate. Melanin production inhibition ability in coculture cells was evaluated by lysing cells with sodium hydroxide. The effect of Paeonia lactiflora Pall seeds oil on dendrite-related gene expression levels was examined through qPCR analysis. Additionally, Western blotting was employed to study the effect of Paeonia lactiflora Pall seeds oil on dendrite-related protein expression levels. Different concentrations of Paeonia lactiflora Pall seeds oil did not affect the proliferation activity of cocultured cells. A specific concentration of α-MSH increased cell tyrosinase activity, cellular melanin content, as well as Rac1, Cdc42, and PAR-2 gene and protein expression related to dendritic formation. Treatment with a certain concentration of Paeonia lactiflora Pall seeds oil resulted in decreased tyrosinase activity and melanin content in cells along with downregulated expression levels of Rac1, Cdc42, and PAR-2 genes and proteins associated with dendritic formation. Paeonia lactiflora Pall seeds oil at specific concentrations exhibits the ability to inhibit tyrosinase activity, decrease melanin content, and possesses the potential to impede melanin transfer.

Anti-Melanogenic Activity of Ethanolic Extract from Garcinia atroviridis Fruits Using In Vitro Experiments, Network Pharmacology, Molecular Docking, and Molecular Dynamics Simulation.

Melanin, the pigment responsible for human skin color, increases susceptibility to UV radiation, leading to excessive melanin production and hyperpigmentation disorders. This study investigated the ethanolic extract of Garcinia atroviridis fruits for its phenolic and flavonoid contents, antioxidant activity, and impact on melanogenesis pathways using qRT-PCR and Western blot analysis. Utilizing network pharmacology, molecular docking, and dynamics simulations, researchers explored G. atroviridis fruit extract's active compounds, targets, and pharmacological effects on hyperpigmentation. G. atroviridis fruit extract exhibited antioxidant properties, scavenging DPPH• and ABTS•+ radicals radicals and chelating copper. It inhibited cellular tyrosinase activity and melanin content in stimulated B16F10 cells, downregulating TYR, TRP-1, phosphorylated CREB, CREB, and MITF proteins along with transcription levels of MITF, TYR, and TRP-2. LC-MS analysis identified thirty-three metabolites, with seventeen compounds selected for further investigation. Network pharmacology revealed 41 hyperpigmentation-associated genes and identified significant GO terms and KEGG pathways, including cancer-related pathways. Kaempferol-3-O-α-L-rhamnoside exhibited high binding affinity against MAPK3/ERK1, potentially regulating melanogenesis by inhibiting tyrosinase activity. Stable ligand-protein interactions in molecular dynamics simulations supported these findings. Overall, this study suggests that the ethanolic extract of G. atroviridis fruits possesses significant antioxidant, tyrosinase inhibitory, and anti-melanogenic properties mediated through key molecular targets and pathways.

Exploring the Phytochemical Composition and the Bioactive Properties of Malbec and Torrontés Wine Pomaces from the Calchaquíes Valleys (Argentina) for Their Sustainable Exploitation.

Hydroalcoholic extracts from Malbec and Torrontés wine pomaces (Vitis vinifera L.) originating from the high-altitude vineyards of Argentina's Calchaquí Valleys were characterized. Total phenolics, hydroxycinnamic acids, orthodiphenols, anthocyanins, non-flavonoid phenolics, total flavonoids, flavones/flavonols, flavanones/dihydroflavonols, and tannins were quantified through spectrophotometric methods, with the Malbec extract exhibiting higher concentrations in most of phytochemical groups when compared to Torrontés. HPLC-DAD identified more than 30 phenolic compounds in both extracts. Malbec displayed superior antiradical activity (ABTS cation, nitric oxide, and superoxide anion radicals), reduction power (iron, copper, and phosphomolybdenum), hypochlorite scavenging, and iron chelating ability compared to Torrontés. The cytotoxicity assessments revealed that Torrontés affected the viability of HT29-MTX and Caco-2 colon cancer cells by 70% and 50%, respectively, at the highest tested concentration (1 mg/mL). At the same time, both extracts did not demonstrate acute toxicity in Artemia salina or in red blood cell assays at 500 µg/mL. Both extracts inhibited the lipoxygenase enzyme (IC50: 154.7 and 784.7 µg/mL for Malbec and Torrontés), with Malbec also reducing the tyrosinase activity (IC50: 89.9 µg/mL), and neither inhibited the xanthine oxidase. The substantial phenolic content and diverse biological activities in the Calchaquí Valleys' pomaces underline their potentialities to be valorized for pharmaceutical, cosmetic, and food industries.

Examination of wnt signaling mediated melanin transport and shell color formation in Pacific oyster (Crassostrea gigas)

Mollusca exhibit remarkable diversity in shell coloration, attributed to the presence of melanin, a widely distributed pigment with various essential roles, such as mechanical strengthening, antioxidation and thermoregulation. However, the regulatory network governing melanogenesis and melanin transport in molluscs remains poorly understood. In this study, we conducted a systematic analysis of melanin distribution and transport in the Pacific oyster, utilizing light microscopy and high-resolution transmission electron microscopy. In addition, we characterized CgWnt1 and CgWnt2b-a in Crassostrea gigas, and analyzed Wnt signaling in melanocyte formation. Expression analysis revealed that these genes were predominantly expressed in the mantle of black-shelled individuals, particularly in the outer fold of the mantle. Furthermore, we employed RNA interference and inhibitors to specifically inhibit Wnt signaling in both in vivo and in vitro. The results revealed impaired melanogenesis and diminished tyrosinase activity upon Wnt signaling inhibition. These findings suggest the crucial role of Wnt ligands and downstream factors in melanogenesis. In summary, our study provides valuable insights into the regulatory mechanism of shell pigmentation in C. gigas. By demonstrating the promotion of melanogenesis through Wnt signaling modulation, we contribute to a better understanding of the complex processes underlying molluscan melanin production and shell coloration.