OBJECTIVE: To explore the inhibitory effects of Nardostachys Jatamansi DC. volatile oil (NJVO) on psychological factors substance P (SP)/cortisol (CORT)-induced hyperpigmentation. METHODS: The model of psychologically-induced hyperpigmentation of B16F10 cells was created using SP (10 nmol/L) + CORT (10 µmol/L) for 72 h. The levels of melanin content, tyrosinase (TYR) activity using NaOH lysis and L-dihydroxyphenylalanine (L-DOPA) oxidation methods were assessed, respectively. The effect of NJVO on SP/CORT-induced normal human skin tissue pigmentation was detected by Masson staining. Protein expressions of tyrosinase-related protein 1 (TRP-1), tyrosinase-relative protein 2 (DCT), and microphthalmia-associated transcription factor were determined using Western blot. The melanosome number, maturation, and melanosomal structure changes were detected through transmission electron microscopy and immunofluorescence experiments. In vivo, zebrafish pigment content was evaluated in SP/CORT-induced zebrafish hyperpigmentation model. RESULTS: NJVO significantly reduced the melanin content (P<0.01) and inhibited tyrosinase activity (P<0.01), the pigmentation of the normal skin tissue in the NJVO group was significantly lower than that in the SP/CORT group (P<0.05). And NJVO considerably downregulated expressions of melanogenesis-related proteins (TYR, TRP-1, DCT) in cells (P<0.01). In addition, the number of melanosomes was decreased and the dentrites formation of B16F10 cells was inhibited after NJVO treatment (P<0.01). In vivo, NJVO significantly reduced the pigment content in the zebrafish body (P<0.01). CONCLUSION NJVO effectively reversed SP/CORT-induced hyperpigmentation by suppressing the activity and expression of TYR and TRPs and inhibiting melanosome maturation in mouse B16F10 melanoma cells.
Animals ; Hyperpigmentation/psychology* ; Zebrafish ; Oils, Volatile/therapeutic use* ; Melanins/metabolism* ; Humans ; Monophenol Monooxygenase/metabolism* ; Mice ; Nardostachys/chemistry* ; Substance P ; Hydrocortisone ; Skin Pigmentation/drug effects* ; Cell Line, Tumor ; Melanosomes/ultrastructure* ; Microphthalmia-Associated Transcription Factor/metabolism* ; Melanoma, Experimental ; Oxidoreductases/metabolism* ; Intramolecular Oxidoreductases/metabolism*

Nigella sativa L. seeds have been traditionally utilized in Chinese folk medicine for centuries to treat vitiligo. This study revealed that the ethanolic extract of Nigella sativa L. (HZC) enhances melanogenesis and mitigates oxidative stress-induced cellular senescence and dysfunction in melanocytes. In accordance with established protocols, the ethanol fraction from Nigella sativa L. seeds was extracted, concentrated, and lyophilized to evaluate its herbal effects via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays, tyrosinase activity evaluation, measurement of cellular melanin contents, scratch assays, senescence-associated β-galactosidase (SA-β-gal) staining, enzyme-linked immunosorbent assay (ELISA), and Western blot analysis for expression profiling of experimentally relevant proteins. The results indicated that HZC significantly enhanced tyrosinase activity and melanin content while notably increasing the protein expression levels of Tyr, Mitf, and gp100 in B16F10 cells. Furthermore, HZC effectively mitigated oxidative stress-induced cellular senescence, improved melanocyte condition, and rectified various functional impairments associated with melanocyte dysfunction. These findings suggest that HZC increases melanin synthesis in melanocytes through the activation of the MAPK, PKA, and Wnt signaling pathways. In addition, HZC attenuates oxidative damage induced by H₂O₂ therapy by activating the nuclear factor E2-related factor 2-antioxidant response element (Nrf2-ARE) pathway and enhancing the activity of downstream antioxidant enzymes, thus preventing premature senescence and dysfunction in melanocytes.
Oxidative Stress/drug effects* ; Melanocytes/cytology* ; Cellular Senescence/drug effects* ; Nigella sativa/chemistry* ; Plant Extracts/pharmacology* ; Seeds/chemistry* ; Mice ; Animals ; Melanins/metabolism* ; Monophenol Monooxygenase/metabolism* ; Humans

OBJECTIVE: To explore the genetic basis of a patient with suspected Oculocutaneous albinism (OCA). METHODS: An OCA patient presented at the West China Second Hospital of Sichuan University and his mother were selected as the study subjects. Peripheral blood samples were collected for the extraction of, genomic DNA, and whole exome sequencing (WES) was carried out. Candidate variants were verified through specific primer amplification, Sanger sequencing, and agarose gel electrophoresis. Bioinformatic analysis and pathogenicity rating were conducted on the candidate variants. This study has been approved by the Medical Ethics Committee of West China Second Hospital (No. 2024-228). RESULTS: Genetic testing revealed that the patient had harbored variants in exon 1 of the TYR gene, including a c.157G>T (p.G53C) missense variant and a c.609dup (p.A204fs) frameshifting variant. Specific primer amplification and Sanger sequencing, combined with agarose gel electrophoresis, confirmed that these are compound heterozygous variants. Based on the guidelines from the ACMG, the c.157G>T was rated as likely pathogenic, and c.609dup was rated as pathogenic. Alphafold3 predicted that the variant proteins had significant structural changes. CONCLUSION The patient was diagnosed with OCA due to compound heterozygous variants of the TYR gene. Discovery of the c.609dup variant has enriched the mutational spectrum of OCA and provided a basis for genetic counseling and prenatal diagnosis for this patient.
Humans ; Albinism, Oculocutaneous/enzymology* ; Male ; Female ; Monophenol Monooxygenase/chemistry* ; Base Sequence ; Mutation, Missense

Twelve flavonoids were isolated and purified from the ethyl acetate fraction of 95% ethanol extract of Dalbergia odorifera by heat reflux extraction, solvent extraction, recrystallization, normal phase silica gel, Sephadex LH-20, MCI gel and HPLC methods. The structures were identified with multiple spectroscopic methods, including 1 D-NMR, 2 D-NMR and MS. The compounds were identified as 6,7,8-trimethoxy-5,4'-dihydroxy isoflavone(1), medicarpin(2), 7,2'-dihydroxy-4'-methoxy-isoflavanol(3), biochanin A(4), prunetin(5), genistein(6), pratensein(7), 3-(4-hydroxyphenyl)-6-isopentenyl-7-methoxy-4H-chromen-4-one(8), tectorigenin(9), irisolidone(10), vestitol(11), and formononetin(12). Compound 1 was a new isoflavone, and compound 8 was isolated from D. odorifera for the first time. The results showed that compounds 1-3 had inhibitory effects on tyrosinase, with inhibition rates of 35.58%, 38.63% and 51.34% at the concentration of 1.0 mmol·L~(-1), respectively.
Dalbergia/chemistry* ; Ethanol ; Flavonoids/chemistry* ; Genistein ; Isoflavones/pharmacology* ; Monophenol Monooxygenase ; Plant Extracts/pharmacology* ; Silica Gel ; Solvents

Several chemical compounds can restore pigmentation in vitiligo through mechanisms that vary according to disease etiology. In the present study, we investigated the melanogenic activity of six structurally distinct compounds, namely, scopoletin, kaempferol, chrysin, vitamin D, piperine, and 6-benzylaminopurine. We determined their effectiveness, toxicity, and mechanism of action for stimulating pigmentation in B16F10 melanoma cells and in a zebrafish model. The melanogenic activity of 6-benzylaminopurine, the compound identified as the most potent, was further verified by measuring green fluorescent protein concentration in tyrp1 a: eGFP (tyrosinase-related protein 1) zebrafish and mitfa: eGFP (microphthalmia associated transcription factor) zebrafish and antioxidative activity. All the tested compounds were found to enhance melanogenesis responses both in vivo and in vitro at their respective optimal concentration by increasing melanin content and expression of TYR and MITF. 6-Benzyamino-purine showed the strongest re-pigmentation action at a concentration of 20 μmol·Lin vivo and 100 μmol·Lin vitro, and up-regulated the strong fluorescence expression of green fluorescent protein in tyrp1a: eGFP and mitfa: eGFP zebrafish in vitro. However, its relative anti-oxidative activity was found to be very low. Overall, our results indicated that 6-benzylaminopurine stimulated pigmentation through a direct mechanism, by increasing melanin content via positive regulation of tyrosinase activity in vitro, as well as up-regulating the expression of the green fluorescent protein in transgenic zebrafish in vivo.
Alkaloids ; chemistry ; pharmacology ; Animals ; Benzodioxoles ; chemistry ; pharmacology ; Benzyl Compounds ; chemistry ; pharmacology ; Cholecalciferol ; chemistry ; pharmacology ; Flavonoids ; chemistry ; pharmacology ; Humans ; Kaempferols ; chemistry ; pharmacology ; Melanins ; genetics ; metabolism ; Monophenol Monooxygenase ; genetics ; metabolism ; Pigmentation ; drug effects ; Piperidines ; chemistry ; pharmacology ; Polyunsaturated Alkamides ; chemistry ; pharmacology ; Purines ; chemistry ; pharmacology ; Scopoletin ; chemistry ; pharmacology ; Vitiligo ; drug therapy ; enzymology ; metabolism ; Zebrafish

Tea contains polyphenols and is one of the most popular beverages consumed worldwide. Because most tyrosinase inhibitors that regulate melanogenesis are phenol/catechol derivatives, this study investigated the inhibitory effects of Camellia sinensis water extracts (CSWEs), including black tea, green tea, and white tea extracts, on melanogenesis using immortalized melanocytes. CSWEs inhibited melanin accumulation and melanin synthesis along with tyrosinase activity in a concentration-dependent manner. These inhibitory effects were superior to those of arbutin, a well-known depigmenting agent. The anti-melanogenic activity of black (fermented) tea was higher than that of a predominant tea catecholamine, epigallocatechin gallate. CSWEs, especially black tea extract, decreased tyrosinase protein levels in a concentration-dependent manner. These results suggest that the anti-melanogenic effect of CSWEs is mediated by a decrease in both tyrosinase activity and protein expression, and may be augmented by fermentation. Thus, CSWEs could be useful skin-whitening agents in the cosmetic industry.
Animals ; Catechin/analogs & derivatives/metabolism ; Cell Line ; Melanins/*metabolism ; Melanocytes/enzymology/*metabolism ; Mice ; Monophenol Monooxygenase/*metabolism ; Plant Extracts/*pharmacology ; Plant Leaves/chemistry ; Tea/*chemistry

The present paper intends to discuss the antioxidant and tyrosinase inhibition effect of solanesol from three aspects of ultraviolet radiation and free radical scavenging. The paper makes a survey on diurnal variation rule of the minimum ultraviolet transmittance and ultraviolet transmittance of solanesol, hydroxyl (OH) free radical scavenging method of Smirnoff reaction system model, superoxide anion O2- free radical scavenging method of pyrogallol autoxidation, and the inhibitory effect of solanesol on tyrosinase activity by enzyme kinetic method. The experiment results showed that solanesol could effectively scavenge lipid radicals to block lipid peroxidation, and inhibit effects on tyrosinase. Solanesol is a natural extract which could be used to prevent senile atrophy of human skin and senile plaque.
Enzyme Inhibitors ; chemistry ; Free Radical Scavengers ; chemistry ; Humans ; Hydroxyl Radical ; chemistry ; Lipid Peroxidation ; Monophenol Monooxygenase ; antagonists & inhibitors ; Terpenes ; chemistry ; Ultraviolet Rays

The anti-melanogenesis effect of glyceollins was examined by melanin synthesis, tyrosinase activity assay in zebrafish embryos and in B16F10 melanoma cells. When developing zebrafish embryos were treated with glyceollins, pigmentation of the embryos, melanin synthesis and tyrosinase activity were all decreased compared with control zebrafish embryos. In situ expression of a pigment cell-specific gene, Sox10, was dramatically decreased by glyceollin treatment in the neural tubes of the trunk region of the embryos. Stem cell factor (SCF)/c-kit signaling pathways as well as expression of microphthalmia-associated transcription factor (MITF) were determined by western blot analysis. Glyceollins inhibited melanin synthesis, as well as the expression and activity of tyrosinase induced by SCF, in a dose-dependent manner in B16F10 melanoma cells. Pretreatment of B16F10 cells with glyceollins dose-dependently inhibited SCF-induced c-kit and Akt phosphorylation. Glyceollins significantly impaired the expression and activity of MITF. An additional inhibitory function of glyceollins was to effectively downregulate intracellular cyclic AMP levels stimulated by SCF in B16F10 cells. Glyceollins have a depigmentation/whitening activity in vitro and in vivo, and that this effect may be due to the inhibition of SCF-induced c-kit and tyrosinase activity through the blockade of downstream signaling pathway.
Animals ; Embryo, Nonmammalian/drug effects ; Melanins/*biosynthesis ; Melanoma, Experimental/metabolism/pathology ; Mice ; Monophenol Monooxygenase/metabolism ; Phosphorylation/drug effects ; Pigmentation/drug effects ; Proto-Oncogene Proteins c-kit/*metabolism ; Pterocarpans/chemistry/*pharmacology ; SOXE Transcription Factors/metabolism ; Sesquiterpenes/chemistry/*pharmacology ; Signal Transduction/*drug effects ; Soybeans/*chemistry ; Stem Cell Factor/*pharmacology ; Zebrafish/embryology/metabolism

In this study, lyophilized and methanolic extracts of aloe gel from different germplasms were evaluated for their potential to inhibit mushroom tyrosinase activity. The results showed potent inhibitory effect of Aloe vera gel extracts on L-dihydroxyphenylalanine (L-DOPA) oxidation catalyzed by tyrosinase in a dose-dependent manner. Significant differences in % inhibition of tyrosinase among the extraction methods and the germplasms were observed. The relative performance of the germplasms was evaluated with the help of posthoc multicomparison test. The methanolic extract was more effective than the lyophilized crude gel in all the germplasms. The inhibitory effect of the lyophilized gel and methanolic extract tested from five germplasms followed the order: RM > TN > S24 > OR > RJN. The germplasm RM showed the highest tyrosinase inhibition, and the maximum % inhibition noted was 26.04% and 41.18%, respectively for the lyophilized and methanolic extracts at 6 mg · mL(-1) concentration. Lineweaver-Burk plots of the different concentrations of L-DOPA in the absence and presence of lyophilized gel extract showed competitive inhibition of mushroom tyrosinase in all the germplasms. This study suggests that the germplasm RM could potentially be used for the isolation and identification of the effective tyrosinase inhibitory component, and ascertains the critical role of selecting the best source of germplasm for natural product isolation and characterization.
Agaricales ; enzymology ; Aloe ; chemistry ; Enzyme Inhibitors ; chemistry ; Fungal Proteins ; antagonists & inhibitors ; chemistry ; Gels ; chemistry ; Kinetics ; Monophenol Monooxygenase ; antagonists & inhibitors ; chemistry ; Plant Extracts ; chemistry

Tyrosinase is a key enzyme related to skin pigmentation disorders of elderly people, while self-aggregation of the amyloid-beta peptide, Abeta42, has been considered as a key event in the pathogenesis of Alzheimer's disease (AD). The present study was undertaken to investigate the inhibitory effects of 20 samples from Rhodiola species on tyrosinase and Abeta42 aggregation, and to isolate their corresponding bioactive components. The results demonstrated that the oligomeric proanthocyanidins (OPCs) commonly found in Rhodiola species were the major bioactive components corresponding to their anti-tyrosinase and anti-Abeta42 aggregation bioactivities. Salidroside, a representative compound of Rhodiola plants, proved not to be active in the present studies.
Amyloid beta-Peptides ; antagonists & inhibitors ; metabolism ; Drugs, Chinese Herbal ; isolation & purification ; pharmacology ; Glucosides ; isolation & purification ; pharmacology ; Monophenol Monooxygenase ; antagonists & inhibitors ; metabolism ; Peptide Fragments ; antagonists & inhibitors ; metabolism ; Phenols ; isolation & purification ; pharmacology ; Plant Roots ; chemistry ; Plants, Medicinal ; chemistry ; Proanthocyanidins ; isolation & purification ; pharmacology ; Rhodiola ; chemistry