Search Results (295)

Prickly pear (Opuntia ficus-indica (L.) Mill.) generates substantial agro-industrial by-products, such as press cake, seed, and oil, that remain underexploited despite their recognized phytochemical richness. This study reports the systematic optimization, characterization, and bioactivity profiling of flavonoid-rich extracts recovered from these three matrices. A Box–Behnken design (BBD) coupled with response surface methodology (RSM) was applied to optimize the ultrasound-assisted extraction (UAE) of total flavonoid content (TFC) from press cake using a natural deep eutectic solvent (NADES: fructose–glycerol–sorbitol–water and FGSH), selected through an initial screening of fifteen solvent systems. The quadratic polynomial model showed excellent fit (R² = 0.9852; R²adj = 0.9687; MAPE = 1.31%; Durbin–Watson = 1.857), and optimal extraction conditions were established at 37.6 min extraction time, 35.6% ultrasonic power, and 29.4 °C, yielding a maximum predicted TFC of 54.78 ± 0.49 mg quercetin equivalents (QE)/mL. HPLC-DAD analysis of the press cake extract revealed five isorhamnetin derivatives as the dominant flavonoids, with isorhamnetin-3-O-glucoside (23.18 ± 0.12 mg/g DW) and isorhamnetin-3-O-rutinoside (13.80 ± 0.28 mg/g DW) as the most abundant. Comprehensive bioactivity assessment demonstrated significant antioxidant capacities (CUPRAC: 191.35 ± 3.22 µM AAE; ORAC: 184.44 ± 3.44 µM TE; DPPH: 103.47 ± 9.98 µM TE for press cake extract), potent in cellulo ROS/RNS suppression in a yeast UV-stress model (85.9 ± 1.0% inhibition for press cake), and differential tyrosinase inhibition across fractions (press cake: 32.8%; seed: 57.5%; oil: 83.8%), highlighting the oil as a potent anti-melanogenic ingredient. In silico safety prediction (ProTox-II/pkCSM) confirmed the favorable toxicity profiles of all identified isorhamnetin derivatives (LD₅₀ > 5000 mg/kg; Toxicity Class V). These results collectively position Opuntia ficus-indica by-products as high-value natural sources of bioactive flavonoids with applications in cosmetic, nutraceutical, and dermatological formulations. Full article

Tyrosinase is a pivotal therapeutic target for hyperpigmentation disorders, yet current inhibitors frequently exhibit limited potency and suboptimal safety. Here, we employed structure-based virtual screening of an FDA-approved drug library against a refined human tyrosinase homology model, identifying methotrexate and selinexor as potent anti-melanogenic candidates. Both compounds markedly suppressed cellular tyrosinase activity and melanin synthesis (IC₅₀ < 1 µM) in MNT-1 melanoma cells. Mechanistically, they orchestrate a multi-pronged downregulation of microphthalmia-associated transcription factor (MITF) by attenuating cAMP/PKA/CREB signaling, promoting β-catenin degradation, and accelerating MITF proteolysis via AKT/ERK activation. Additionally, they bolster the intracellular antioxidant defense system. These findings unveil a sophisticated regulatory network and suggest that with strict control of systemic exposure through optimized topical formulations, these FDA-approved agents could be further investigated as potential localized treatments for pigmentary disorders. Full article

Background: Baeckea frutescens L. (BF) has been reported as a potential natural source for skin-whitening agents. However, its antimelanogenic activity and mechanisms remain unclear. Methods: The antimelanogenic effects of BF were evaluated in α-melanocyte-stimulating hormone (α-MSH)-stimulated B16F10 cells and in zebrafish embryos. Cell viability, intracellular tyrosinase activity and melanin content were measured. Western blot (WB) analysis was used to examine melanogenesis-related proteins. Network pharmacology and molecular docking were performed to predict potential targets and interactions of BF-derived metabolites. Results: The ethanolic extract of BF reduced intracellular tyrosinase activity and melanin content in cells without cytotoxicity. Western blot analysis showed decreased expression of microphthalmia-associated transcription factor (MITF) and its downstream melanogenic enzymes, including tyrosinase (TYR), tyrosinase-related protein-1 (TRP-1), and dopachrome tautomerase (DCT). In addition, BF reduced phosphorylation of protein kinase A (PKA), cAMP responsive element-binding protein (CREB) and extracellular signal-regulated kinase (ERK), suggesting potential suppression of PKA/CREB and ERK signaling pathways. These regulatory effects may contribute to MITF downregulation and subsequent inhibition of melanogenesis. BF reduced melanin accumulation in zebrafish embryos. Network pharmacology and molecular docking analyses further suggested that BF-derived metabolites, particularly bayogenin, may interact with multiple melanogenesis-related targets. Conclusions: BF may inhibit melanogenesis through coordinated modulation of multiple signaling pathways and may represent a promising skin-whitening candidate. Full article

The aim of this study was to investigate the anti-melanogenic effects and underlying mechanisms of PFRMY (Pro-Phe-Arg-Met-Tyr), a pentapeptide derived from tilapia skin (Oreochromis niloticus), using B16F10 murine melanoma cells. Treatment with PFRMY (1.0 mg/mL) significantly reduced intracellular melanin content and tyrosinase (TYR) activity by 39.55 ± 1.51% and 32.46 ± 1.31%, respectively. RT-PCR and Western blotting analyses revealed that PFRMY suppressed melanogenesis through the α-MSH/PKA/CREB signaling pathway. Notably, PFRMY reversed α-MSH-induced upregulation of key downstream factors including PKA, CREB, MITF, and TYR, while showing minimal effects on the protein expression of MC1R or α-MSH. Molecular docking further suggested that PFRMY binds to MC1R with higher affinity than α-MSH, potentially occupying the ligand-binding site and thereby interfering with downstream signaling. Collectively, these findings demonstrate that PFRMY effectively inhibits melanogenesis by competitively antagonizing the α-MSH/MC1R axis, highlighting its potential as a safe and efficacious ingredient for hyperpigmentation treatment and cosmetic applications. Full article

Ultraviolet (UV) irradiation induces complex skin damage, including hyperpigmentation, oxidative stress, and alterations in proteins related to keratinocyte differentiation and epidermal barrier-associated status. This study investigated the multifunctional protective effects of Padina arborescens ethanolic extract (PAEE) against skin damage in melanocytes, keratinocytes, and zebrafish. In alpha-melanocyte-stimulating hormone (α-MSH)-stimulated B16F10 cells, PAEE effectively suppressed the protein kinase A (PKA)/cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB) signaling pathway, which was associated with reduced expression of microphthalmia-associated transcription factor (MITF) and tyrosinase, leading to decreased melanin synthesis. PAEE also exhibited photoprotective properties by reducing reactive oxygen species (ROS), inhibiting interleukin-1 beta (IL-1β), and attenuating matrix metalloproteinase-1 (MMP-1) upregulation associated with UVB (ultraviolet B)-induced photodamage in HaCaT keratinocytes. Notably, PAEE restored the UVB-reduced expression of filaggrin and involucrin, representative markers of keratinocyte differentiation and epidermal barrier-associated status, in HaCaT keratinocytes. In zebrafish embryos, PAEE suppressed α-MSH-induced melanin accumulation and UVB-induced ROS generation at non-toxic concentrations. Taken together, these results suggest that PAEE exerts anti-melanogenic and photoprotective effects in cellular and zebrasfish models and may serve as a promising marine-derived ingredient for cosmeceutical applications targeting UVB-related skin damage. Full article

Background/Objectives: Psychological stress triggers excessive melanin deposition via neuroendocrine pathways, yet targeted interventions for stress-induced hyperpigmentation remain limited. Salidroside (SAL) exhibits established depigmenting effects in UV-induced models and possesses neuroprotective properties. This study investigated SAL’s efficacy in psychological stress-induced hyperpigmentation and elucidated its underlying mechanisms. Methods: B16F10 melanocytes, C57BL/6J mice, zebrafish, and human foreskin organ cultures were subjected to stress factor (Substance P/cortisol) or α-MSH/IBMX stimulation to model psychological stress-induced and canonical cAMP-driven hyperpigmentation, respectively. Melanin content, tyrosinase activity, melanosome maturation (transmission electron microscopy/HMB45 staining), and melanogenic protein/mRNA expression were assessed. Drug Affinity Responsive Target Stability (DARTS) assays, molecular docking, and SEC23A siRNA knockdown were employed to identify and validate SAL’s molecular target and downstream signaling pathways. Results: SAL dose-dependently reduced melanin content, tyrosinase activity, and TYR/TRP-1/DCT expression in SP/Cort-stimulated melanocytes, exhibiting greater potency (200 μM) than in IBMX-induced models (400 μM). SAL reversed SP/Cort-induced hyperpigmentation in human skin explants, zebrafish, and C57BL/6J mice, and normalized melanosome number/maturation. DARTS and molecular docking identified SEC23A as a direct SAL-binding target. SP/Cort specifically upregulated SEC23A, which SAL suppressed. SAL concurrently activated the SEC23A-p-ERK-MITF axis and inhibited the NK1R-p38-MITF axis in the stress model. SEC23A knockdown potentiated SAL’s anti-melanogenic effects specifically in SP/Cort-stimulated cells. Conversely, in IBMX-induced models, SEC23A remained unchanged, and SAL acted via PKA/CREB, PI3K/AKT, and Wnt/β-catenin pathways. Conclusions: SEC23A is a novel core target in psychological stress-induced hyperpigmentation. SAL selectively binds SEC23A to inhibit stress-induced melanogenesis via dual ERK and p38 MAPK signaling axes, demonstrating etiological specificity distinct from canonical cAMP pathway inhibition. Full article

Background: Glabridin, a natural compound derived from Glycyrrhiza glabra L., possesses skin-lightening effects. This study aims to further elucidate the depigmentation mechanism of glabridin by investigating its effects on melanogenesis and melanin transfer. Methods: We initially confirmed the anti-melanogenic effects of glabridin in MNT-1 human melanoma cells. Then, we investigated the mechanism of its anti-melanogenic effect by evaluating the protein expression of β-catenin and MITF via Western blot. To investigate melanin transfer, we compared glabridin’s efficacy with that of niacinamide, a recognized inhibitor of melanosome transfer and employed two complementary experimental models: (1) α-melanocyte-stimulating hormone (α-MSH)-stimulated MNT-1 cells to analyze dendrite formation, and (2) a UVB-irradiated co-culture system of MNT-1 cells and HaCaT keratinocytes to evaluate melanin transfer. Results: By measuring glabridin’s effects on melanin content, tyrosinase activity, and melanogenesis-related protein expression confirmed its inhibition of melanin synthesis. Further investigation demonstrated that glabridin suppresses melanogenesis by downregulating β-catenin and MITF, indicating inhibition of the Wnt/β-catenin pathway. Furthermore, in α-MSH-treated MNT-1 cells, both glabridin and niacinamide were found to suppress dendrite formation and elongation. In a UVB-exposed co-culture system, both glabridin and niacinamide inhibited melanin transfer to keratinocytes. Mechanistically, these effects were linked to the regulation of Rho GTPases (Rac1, RhoA, Cdc42) and suppression of F-actin reorganization. Conclusions: This study provides, for the first time, evidence that the skin-lightening effect of glabridin involves two complementary mechanisms: inhibition of melanogenesis through suppression of the Wnt/β-catenin pathway, and attenuation of both dendricity and melanin transfer via the influence of Rho family GTPases expression. Full article

Pomegranate (Punica granatum L.) is a potent source of bioactive compounds with antioxidant and anti-inflammatory properties, offering therapeutic potential against cancer, Alzheimer’s disease, hypertension, diabetes, hepatic disorders, and obesity. This review highlights the capacity of pomegranate leaves, flowers, arils, juice, seeds, and peel to modulate or inhibit key enzymes involved in inflammatory, metabolic, neurodegenerative, cardiovascular, hepatic, and melanogenic pathways. Additionally, pomegranate enhances endogenous antioxidant defenses (CAT, SOD, GPx, GR, and GST) and regulates caspase activity, further contributing to its health-promoting effects. While preclinical evidence underscores its multifaceted enzymatic and therapeutic benefits, positioning pomegranate as a promising natural adjunct for the prevention and management of enzyme-related diseases, further research is needed to elucidate mechanisms and validate clinical efficacy. Full article

Background: Hyperpigmentation disorders lack effective therapies due to efficacy and safety limitations. Spirulina-derived peptides (SPs) show promises as anti-melanogenic agents, but their mechanisms remain unclear. Methods: SPs (<1 kDa, 3–6 amino acids) were isolated and assessed for tyrosinase inhibition, antioxidant, and anti-glycation activities. In vitro effects were tested in B16F10 cells; transcriptomic profiling used RNA sequencing. In vivo efficacy was evaluated in UVB-induced hyperpigmentation mouse models. Results: SPs exhibited mixed-type kinetic inhibition of tyrosinase along with strong antioxidant and anti-glycation activities. In vitro, SP suppressed melanin synthesis by directly inhibiting tyrosinase, downregulating the cAMP/PKA/CREB cascade, and activating the PI3K/Akt/GSK-3β pathway, resulting in reduced MITF and tyrosinase expression. Transcriptomic analysis revealed broad regulation of melanogenesis and inflammatory pathways. In vivo, topical SP treatment significantly reduced UVB-induced hyperpigmentation and skin inflammation, correlating with decreased CREB phosphorylation and tyrosinase expression. Conclusions: SP acts as a dual anti-melanogenic/anti-inflammatory agent through enzyme inhibition and signaling modulation, offering a novel therapeutic strategy for inflammation-associated hyperpigmentation. Full article

Postharvest processing conditions critically influence the phytochemical composition and functional quality of medicinal plants. Emerging evidence suggests that light quality acts as an active regulatory signal capable of modulating secondary metabolism even after harvest. In this study, we examined the effects of light quality during postharvest drying on flavonoid accumulation and associated bioactivities in Adenophora triphylla leaves. Blue light treatment for 24 h significantly enhanced anti-inflammatory and anti-melanogenic activities compared with red or white light, without inducing cytotoxicity. These functional improvements correlated strongly with increased total flavonoid and anthocyanin contents. Gene expression analyses further demonstrated that blue light significantly induced key flavonoid biosynthetic genes, including CHS1, CHS2, DFR, and LDOX, indicating that harvested leaves retain light-responsive transcriptional capacity. Taken together, these results suggest that postharvest blue light exposure can upregulate flavonoid metabolism during drying, thereby improving the pharmaceutical properties of A. triphylla leaves. This study highlights light quality-guided postharvest drying as an effective and scalable approach for enhancing the value and quality consistency of medicinal plant materials. Full article

Melanin produced in melanocytes contributes to photoprotection, oxidative stress reduction, immune regulation, and epidermal homeostasis, while its dysregulation underlies diverse pigmentary disorders. Natural products modulate melanogenesis by regulating tyrosinase activity, intracellular signaling pathways such as extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) and cyclicAMP/protein kinase A/cAMP response element-binding protein (cAMP/PKA/CREB), and cellular redox balance. Anti-melanogenic effects have been reported for various fruit-derived phytochemicals, ginseng-based metabolites, and plant polyphenols, which act through direct enzymatic inhibition, suppression of melanoenic signaling, modulation of melanosome dynamics, and antioxidant or anti-inflammatory activities. Advances in delivery systems, including nano- and microencapsulation platforms, further enhance the stability and topical bioavailability of these compounds. In contrast, certain methoxylated flavonoids and phenolic constituents can stimulate pigmentation by sustaining melanogenic signaling and promoting microphthalmia-associated transcription factor (MITF)-driven transcription, emphasizing the context-dependent and bidirectional influence of natural substances on pigmentation outcomes. Collectively, these findings highlight the therapeutic potential of natural product-based modulators of melanogenesis while underscoring the need for mechanistic clarification, safety evaluation, and translational studies to ensure effective and controlled pigmentation management. This review summarizes the biological functions of melanin and examines natural strategies for regulating pigmentation. Full article

Marine plants are a rich source of bioactive compounds with unique properties. The Mediterranean seagrass Posidonia oceanica is particularly abundant in phenolics and flavonoids, which exhibit antioxidant and anti-inflammatory activities. In this study, a phenolic-rich extract (POS) was obtained from beach-cast P. oceanica leaves using supercritical fluid extraction (SFE), an eco-friendly technique that preserves thermolabile compounds and avoids organic solvents. POS was incorporated into a base cream (POS-enriched cream) to evaluate its bioactive potential in topical applications. The antioxidant capacity of POS and the cream formulation was firstly evaluated using the DPPH radical scavenging assay, confirming strong radical scavenging activity for the POS (IC₅₀ = 2.32 ± 0.33 mg/mL) and significant activity for the POS-enriched cream (IC₅₀ = 16.76 ± 0.58 mg/mL) compared to a base cream as control (IC₅₀ = 37.62 ± 1.27 mg/mL). The antioxidant and photoprotective effects of POS were investigated in human skin fibroblasts (HS-68) exposed to oxidative stress and UV-induced damage, while anti-melanogenic activity was assessed in human epidermal melanocytes (HEM) by measuring tyrosinase activity and melanin content. POS significantly reduced ROS accumulation and modulated key molecular pathways involved in apoptosis (p-JNK), inflammation (NF-κB), energy balance (p-AMPK), and collagen synthesis (Col1A1) in fibroblasts. In melanocytes, both POS pure extract and POS-enriched cream effectively inhibited tyrosinase activity while maintaining unaltered basal melanin levels, indicating a modulatory rather than fully suppressive effect. These findings highlight the potential of P. oceanica SFE extracts as sustainable natural marine-derived products for photoprotection and anti-melanogenesis, thereby bridging the gap between marine waste stream management and applications in skin health and anti-aging strategies. Full article

N-Benzylthiocarbamate (NBTC) analogs 1–10 were synthesized as potential Cu²⁺-chelating tyrosinase inhibitors. Most analogs exhibited strong Cu²⁺-chelating activity, but none inhibited mushroom tyrosinase (mTYR) activity better than kojic acid (KA). However, owing to their potent cellular TYR inhibitory activity, all analogs, except 8, inhibited melanin formation in B16F10 cells more than KA. Analogs 3, 4, and 9 exhibited stronger antimelanogenic properties than N-phenylthiourea. The TYR inhibitory activity of the analogs of mTYR and B16F10 TYR was probably different because mTYR and mammalian TYR have different structural characteristics. All analogs had a potency to significantly scavenge reactive oxygen species (ROS). Analog 1 was very effective in reducing browning in potato juice. Furthermore, analog 3 inhibited zebrafish larval pigmentation 2000 times more potently than KA and was more effective than N-phenylthiourea. It is believed that their capacity to scavenge ROS amplifies their antimelanogenic effects. Exogenously added CuSO₄ attenuated the inhibitions of cellular TYR activity and melanin formation in B16F10 cells caused by analog 9. This result might have been due to the externally added Cu²⁺ ions forming chelates with 9. The differential TYR inhibitory activity of NBTC analogs appeared to be due to their high sensitivity to interactions with TYRs of different origins. Full article

Acne vulgaris is a common chronic inflammatory skin condition. Conventional acne treatments are often limited by adverse effects, driving interest in alternative therapies. This study explored the multifunctional bioactivities of a lyophilized cell-free supernatant (LCFS) derived from Lacticaseibacillus paracasei T0901, isolated from fermented palm sap, with a focus on its antimicrobial, antibiofilm, and antimelanogenic potential for dermatological applications. Antimicrobial activity was evaluated using agar well diffusion and broth microdilution assays against acne-associated pathogens, while antibiofilm effects were quantified via crystal violet staining. Antimelanogenic activity was assessed in α-melanocyte-stimulating hormone (α-MSH)-stimulated B16F10 melanoma cells by measuring melanin content and tyrosinase activity. Whole-genome sequencing was performed to identify genes linked to observed bioactivities, and molecular docking was used to predict metabolite–protein interactions. The LCFS exhibited strong inhibitory activity against acne-associated bacteria, with inhibition zones of C. acnes (10.67 ± 0.58 mm), S. epidermidis (21.00 ± 0.00 mm), and S. aureus (20.00 ± 0.00 mm), and a minimum inhibitory concentration of 25 mg/mL. Biofilm formation was significantly reduced by 62.98 ± 3.54%. In α-MSH-stimulated B16F10 cells, LCFS treatment (10 mg/mL) significantly decreased melanin content (73.23 ± 2.36%) and intracellular tyrosinase activity (68.19 ± 6.29%) relative to control. Genomic analysis revealed antioxidant-related genes (sodA, trxB, nox), pigmentation regulators (mco, fcbD), and buk (butyrate kinase), supporting the observed bioactivities. Molecular docking further demonstrated strong binding affinities of LCFS-derived metabolites to tyrosinase and MITF, suggesting modulation of melanogenic pathways. Collectively, these results indicate that L. paracasei T0901 produces safe postbiotic compounds with potent antimicrobial, antibiofilm, and antimelanogenic activities, highlighting its promise as a multifunctional ingredient in probiotic-based skincare formulations. Full article

Excessive melanin production causes hyperpigmentation disorders such as freckles, melasma, and age spots, affecting appearance and quality of life. Tyrosinase is the key enzyme controlling melanin synthesis, and natural compounds are being explored as effective tyrosinase inhibitors. Fisetin, a dietary flavonoid found in fruits and vegetables like grapes and onions, is known for its anti-inflammatory and anticancer properties, but its anti-melanogenic activity remains unclear. This study demonstrated that fisetin, up to 60 μM, is non-toxic and significantly decreases tyrosinase activity and melanin content in human melanoma cells. Mechanistically, fisetin activates PKCα, leading to phosphorylation and degradation of β-catenin, thereby downregulating MITF expression. Additionally, it activates ERK and AKT/GSK3β pathways, promoting ubiquitination and proteasomal degradation of MITF, resulting in reduced levels of tyrosinase, TRP-1, and TRP-2. The proteasome inhibitor MG132 confirmed that fisetin accelerates β-catenin and MITF degradation. Additionally, inhibition of the PI3K/AKT pathway by LY294002 or the ERK pathway by PD98059 reversed fisetin’s reduction of tyrosinase activity and melanin synthesis, further verifying the participation of these pathways. Computational docking integrated with deep learning-based CNN scoring revealed that fisetin interacts with PKCα, β-catenin, tyrosinase, and TYRP1. Collectively, these findings suggest that fisetin exerts multi-targeted inhibitory effects on melanogenesis, highlighting its potential as a therapeutic and cosmetic agent for hyperpigmentation. Full article