Tyrosinase Inhibitory Activity Research Articles

Potential skincare benefits and self-healing properties of Lignosus rhinocerotis polysaccharides as affected by ultrasound-assisted H2O2/Vc treatment

Natural polysaccharides have been recognized as major bioactive components in skincare and wound care products. In this study, the skincare benefits and self-healing properties of Lignosus rhinocerotis polysaccharides (LRP) and its degraded products (DLRP-1, DLRP-2 and DLRP-3) by ultrasound assisted H2O2/Vc treatment (U-H/V) at different ultrasonic intensity (28.14, 70.35, and 112.56 W/cm2) were investigated. U-H/V altered the internal crystalline structure and microstructure of LRP, and enhanced the thermal stability. Due to the breakage of molecular chains after U-H/V, the moisture absorption of LRP was enhanced but the moisturizing property showed a different degree of reduction. U-H/V significantly improved the antioxidant, anti-tyrosinase and anti-inflammatory activities of LRP. Furthermore, the results of enzyme kinetic studies showed a mixed competitive-noncompetitive inhibition of tyrosinase activity by DLRP-3 and the inhibition constant of DLRP-3 on tyrosinase was 2.97 mg/mL. The apparent viscosity of LRP dispersions showed a first increasing followed by decreasing trend as ultrasonic intensity rose. U-H/V enhanced the viscoelastic properties of LRP gels without destroying their self-healing properties. This findings reveal that U-H/V is beneficial for improving the skincare efficacy of LRP, providing a theoretical foundation for the applicability of LRP in wound dressings.

Multi-functional tyrosinase inhibitors derived from kojic acid and hydroquinone-like diphenols for treatment of hyperpigmentation: Synthesis and in vitro biological evaluation.

A series of multi-functional tyrosinase inhibitors derived from kojic acid (KA) and hydroquinone-like diphenols were designed and synthesized using click chemistry. The in vitro enzymatic assay revealed that all compounds containing a free enolic structure showed excellent activity against tyrosinase (IC50 = 0.14-3.7 µM), being significantly more potent than KA. The most active compounds were catechol (6c) and α-naphthol (6i) analogs with 138- and 96-fold higher potency than KA. On the other hand, all free phenolic compounds (6a-c and 6g-j) derived from aromatic diols showed outstanding free radical scavenging activities superior to KA. Certainly, the α-naphthol derivative 6i with IC50 = 10.1 µM was the most active anti-oxidant, being as potent as quercetin. The SAR analysis indicated that the enolic head of the conjugate molecules mainly contributes to the anti-tyrosinase activity, and the free phenolic part of the molecules can offer anti-oxidant potency. The anti-melanogenic assay of the most promising derivative, 6i, against melanoma (B16F10) cells demonstrated that the prototype compound 6i can significantly reduce the melanin content, more effectively than KA. By using a conjugation strategy, we have improved the tyrosinase inhibitory and radical scavenging activity in the multi-functional agents such as 6i over the parent compound KA, being potentially useful in the treatment of hyperpigmentation and other skin disorders.

Insights into Citrus limon (L.) Osbeck peel essential oil from NE India: A study of its pharmacological properties and chemical composition

Citrus limon (L.) Osbeck is considered as one of the most significant horticultural as well as essential oil crop. However, the significance of the fruit peels left after the utilization of the sour fruit find limited importance and these leftover peels are rich in essential oil. Lemon peel essential oil (LPEO) finds used in the fragrance, food, cosmetic, and pharmaceutical industries. In this study lemon peel were used for isolation of essential oil by hydro-distillation, analyzed by GC-FID and GC-MS and was further subjected to in vitro anti-oxidant (DPPH, ABTS), anti-inflammatory, anti-tyrosinase, genotoxicity and anti-diabetic assays. The essential oil analysis has revealed limonene as major compound (38.08%) along with other minor compounds namely, α-citral (12.02%), decanal (8.14%) and neral (7.36%). The total amount of citral (α-citral and neral) was found to be 19.38%, comparatively higher compared to previous reports. LPEO was found to exhibit very strong tyrosinase inhibition activity along with good alpha-amylase inhibition. The results from this study further strengthen the immense potential of LPEO as an anti-diabetic and skin whitening agent. The results framed from this study will further strengthen the position of earlier works on biological activities of C. limon besides providing a descriptive work on the potential of Assam LPEO.

Eco-friendly Synthesis of Gold Nanoparticles of Methanolic Extract of Bauhinia vahlii Leaves and Evaluation of Tyrosinase Inhibitory Activity

Background: The green synthesis of gold nanoparticles (AuNPs) using natural materials has gained significant attention in recent years due to their eco-friendliness and potential applications in various fields. Methods: The present study aimed at the green synthesis and anti-hyperpigmentation potential of gold nanoparticles (AuNPs) using a methanolic extract of Bauhinia vahlii. Furthermore, the green synthesis of the AuNPs was confirmed by UV-visible, FT-IR, XRD, and EMDEX analysis. The size and surface topological significance of green synthesized AuNPs were evaluated through Scanning Electron Microscope and Field Emission Scanning Electron Microscopy. Results: The size of the synthesized AuNPs was found to be in the range of 100-1000 nm. The tyrosinase inhibitory activity of AuNPs was evaluated through the mushroom tyrosinase inhibitory assay method. The tyrosinase inhibitory activities of crude extract, AuNPs, and Kojic acid were found to be 98.7 ±0.7, 75±1.3 and 41±1.1 μg/ml, respectively. Conclusion: Hence, green synthesized AuNPs of B. vahlii leaf extract may be used as a potent antihyperpigmentation agent in the market of nano cosmeceuticals.

Gigantolevisins A–C, tyrosinase inhibitory benzylidenes from the shoots of Gigantochloa levis

The excessive tyrosinase activity has been linked to the overproduction of melanin which can lead to hyperpigmentation, oxidative stress, browning, and an increased risk of melanoma. Due to these detrimental effects associated with the overexpression of tyrosinase, research efforts are focused on finding bioactive compounds that can inhibit this enzyme efficiently. This study, conducted to find tyrosinase inhibitors utilizing the shoots of Gigantochloa levis (G. levis), produced three previously undescribed benzylidene derivatives (1–3) and two known compounds, with promising anti-tyrosinase activity. The new compounds were designated as gigantolevisins A–C, and the two known compounds as (E)-3-(4-hydroxyphenyl)-2-phenylacrylaldehyde (4) and (E)-2,3-bis(4-hydroxyphenyl)acrylaldehyde (5), respectively, based on the spectroscopic data and X-ray crystallographic analysis. The isolated compounds showed inhibition effects against tyrosinase, ranging from 42 % to 58 % (IC50 values of >400–286 ± 15 μM) in comparison to the positive control Kojic acid with 100 % inhibition (IC50 value of 43 ± 3 μM). The findings suggest that, while the isolated compounds are less potent than Kojic acid, they can be effective in inhibiting tyrosinase activity. Thus, the study highlights the therapeutic potential of G. levis shoots for treating melanin-related conditions.

Ethanolic Extract of Bergenia purpurascens Exhibits Antimelanogenic Effects in B16F10 Cells through Multiple Mechanisms That Suppress Tyrosinase.

Bergenia purpurascens, renowned for its antibacterial and antioxidant properties, remains relatively unexplored in its impact on melanogenesis. This study delves into the antimelanogenic potential of the ethanol extract derived from B. purpurascens (BPE). Our investigations reveal the robust antioxidant capabilities of the BPE, along with its effective inhibition of mushroom tyrosinase activity. Remarkably, these effects were significantly stronger than those observed with arbutin, the positive control. In vitro assays demonstrate the BPE's efficacy in reducing the melanin content and tyrosinase activity in α-MSH-stimulated B16F10 cells. Immunofluorescence and qPCR analyses further reveal the BPE's ability to inhibit MITF-mediated gene expression levels associated with melanogenesis, including Trp-1, Trp-2, and tyrosinase. These findings suggest that the extract operates through dual mechanisms, suppressing both tyrosinase activity and key transcription factor-mediated downstream signaling. Utilizing UPLC-MS/MS analysis, we identified six key compounds implicated in tyrosinase activity inhibition and melanogenesis suppression. Docking simulations confirm moderate binding affinities between these compounds and tyrosinase. This study highlights the potential of B. purpurascens as a novel natural agent for depigmentation in medicinal and cosmetic applications, elucidating its dual mechanism of action in melanogenesis inhibition.

Synthesis of newly designed hydrazones, in vitro and in silico studies, and structure-activity relationship

Herein, new N'-(substituted benzylidene)-3,5-dihydroxybenzohydrazide (1–13) series were synthesized, and their antioxidant, anticholinesterase, anti-tyrosinase, anti-urease, and antidiabetic activities were investigated together with in silico studies. The synthesized derivates were characterized using molecular spectroscopy, and the structure-activity relationships (SAR) were discussed for all tested biological assays. According to activity results, compound 3 exhibited excellent antioxidant activity in all tests, while compound 1 demonstrated the best acetylcholinesterase (AChE) inhibitory and butyrylcholinesterase (BChE) inhibitory activities. On the other hand, compound 11 showed excellent tyrosinase inhibitory (IC50:3.02±0.10 mM) and urease inhibitory (IC50:9.21±0.27 µM) activity. Moreover, among the synthesized compounds, compound 6 was detected as the best antidiabetic compound by inhibiting α-amylase (IC50:30.68±0.94 µM) and α-glycosidase (IC50:41.35±0.03 µM) enzymes, which were related with the antidiabetic activity. Molecular docking analysis confirmed AChE, BChE, tyrosinase, urease, α-amylase, and α-glucosidase inhibitory activities. In line with the findings obtained from in vitro bioactivity results and molecular docking analysis, hydrazone compounds are a suitable class of organic compounds for developing acetylcholinesterase, butyrylcholinesterase, urease, α-amylase, and α-glucosidase inhibitors.

Inhibitory potential of 7-hydroxycoumarin-3-carboxylic acid against tyrosinase and its effect on the preservation of fresh-sliced apples

Excessive tyrosinase expression leads to pigmented diseases in humans and browning in plants, necessitating effective tyrosinase inhibitors. This study investigated the inhibitory effect and mechanism of 7-hydroxycoumarin-3-carboxylic acid (7-HC-3-CA) on tyrosinase. Using UV–visible absorption spectroscopy, we found that 7-HC-3-CA effectively inhibited tyrosinase activity, with an IC50 value of 364 ± 1.3 μM. Enzyme kinetics, fluorescence methods and molecular simulation techniques revealed that 7-HC-3-CA acted as a reversible and competitive inhibitor, forming a stable complex with tyrosinase through hydrophobic interactions and hydrogen bonding. This altered the microenvironment of Tyr and Trp residues, causing the structural stretching and conformational changes that diminish catalytic activity.Preservation experiments demonstrated that 0.5 mM 7-HC-3-CA significantly reduced mass loss and decreased browning of fresh-sliced apples. It also lowered polyphenol oxidase activity from 0.22 to 0.18 and delayed phenolic oxidation, enhancing total phenolic content from 0.34 to 0.54, thereby controlling browning and extending storage life. Cell assays indicated that 0.5 mM 7-HC-3-CA had no significant impact on cell proliferation, with viability over 80 %. Acute toxicity tests proved that 0.5 mM of 7-HC-3-CA is completely non-lethal to KM mice. In conclusion, this study confirmed 7-HC-3-CA was a viable and safe antibrowning agent and revealed its potential application in the field of food preservation.

New Phytol Derivatives with Increased Cosmeceutical Potential.

Natural compounds are widely incorporated into cosmetic products for many purposes. Diterpenes often function as fragrances, enhancing the sensory experience of these formulations. However, current trends in cosmetic science aim to develop multifunctional products, where compounds traditionally used for texture or fragrance also possess biological activities that contribute to the product's efficacy. In this context, this study focuses on synthesizing derivatives of phytol-a compound already presents in cosmetic formulations-to enhance its anti-aging properties. The derivatives were synthesized through esterification with substituted benzoic and cinnamic acids, known for their antioxidant and enzyme inhibition properties. Reaction yields ranged from 91.0% to 5.2%, depending on the substituents in acid derivatives. The structures of the synthesized compounds were confirmed through NMR and MS techniques. Both the natural and newly synthesized derivatives were evaluated for their cosmeceutical potential using antioxidant assays and inhibition assays for tyrosinase, elastase, collagenase, and hyaluronidase. This work presents the first report of the synthesis and cosmetic evaluation of several of these derivatives. Comparing with phytol (1), which presented an IC50 of 77.47 µM, four of the derivatives presented improved tyrosinase inhibitory activity, with phytyl 4-methoxybenzoate being the most active (IC50 = 27.9 µM), followed by phytyl benzoate with an IC50 of 34.73 µM. Substitutions at other positions on the aromatic ring were less effective. Molecular docking studies confirmed that the modifications potentiated a stronger interaction between the synthesized compounds and tyrosinase.

Design, Synthesis, and Anti-Melanogenic Activity of 2-Mercaptomethylbenzo[d]imidazole Derivatives Serving as Tyrosinase Inhibitors: An In Silico, In Vitro, and In Vivo Exploration.

2-Mercaptomethylbenzo[d]imidazole (2-MMBI) derivatives were designed and synthesized as tyrosinase (TYR) chelators using 2-mercaptomethylimidazole scaffolds. Seven of the ten 2-MMBI derivatives exhibited stronger inhibition of mushroom TYR activity than kojic acid. Their ability to chelate copper ions was demonstrated through experiments using the copper chelator pyrocatechol violet and assays measuring TYR activity in the presence or absence of exogenous CuSO4. The inhibition mechanisms of derivatives 1, 3, 8, and 9, which showed excellent TYR inhibitory activity, were elucidated through kinetic studies and supported by the docking simulation results. Derivatives 3, 7, 8, and 10 significantly inhibited cellular TYR activity and melanin production in B16F10 cells in a dose-dependent manner, with stronger potency than kojic acid. Furthermore, in situ, derivatives 7 and 10 showed stronger inhibitory effects on B16F10 cell TYR activity than kojic acid. Six derivatives, including 8, showed highly potent depigmentation in zebrafish larvae, outpacing kojic acid even at 200-670 times lower concentrations. Additionally, all derivatives could scavenge for reactive oxygen species without causing cytotoxicity in epidermal cells. These results suggested that 2-MMBI derivatives are promising anti-melanogenic agents.

Phenolic content, antioxidant activity, and tyrosinase inhibitor potential for both skin and physical health: test of extract, skin content and content of Garcinia Cowa fruit

Skin aging leads to reduced structural integrity and reduced skin function. Medicinal plant extracts that have antioxidant properties and are able to inhibit tyrosinase have become a trend in various uses for anti-aging. One of the commonly used plants in traditional medicine that grows in many Asian countries is garcinia cowa. Currently, no one has studied the fruit from two different aspects, namely for the skin and to help in physical improvement. The purpose of this study is to test the phenolic content, antioxidants, and tyrosinase inhibition activity of the extract from the skin and pulp of garcinia cowa as well as its effectiveness on the physical ability and function of the skin. The stages carried out start from the collection of garcina cowa fruits, the determination of total phenolic levels, the determination of antioxidant activity, and the determination of tyrosinase inhibition activity. The total phenolic content was determined by the folin-ciocalteu method. The phenolic content of garcinia cowa fruit peel extract is 17.789 mg of gallic acid equivalent extract (GAE)/g, while the meat extract is 12.078 mg GAE/g extract. Furthermore, the flesh of garcinia cowa showed weak antioxidant activity with an IC50 value of 490.2 μg/mL, but the fruit peel extract showed moderate antioxidant activity at 243.3 μg/mL. The skin of garcinia cowa fruit shows tyrosinase inhibition activity in vitro, which is more significant than the pulp. Garcinia cowa peel and pulp extracts both contain phenolic compounds and show the antioxidant activity, but it was found that the fruit peel extract has a higher content. This means that with its antioxidant content, it can ward off free radicals, prevent cell damage, and reduce the risk of chronic diseases. The combination of phenolic content, antioxidant activity, and tyrosinase inhibitor potential provides significant benefits for skin health and overall physical health.

Tyrosinase Inhibitory Activity of Crude Procyanidin Extract from Green Soybean Seed and the Stability of Bioactive Compounds in an Anti-Aging Skin Care Formulation

Green soybean (Glycine max L.) seed contains a high procyanidin content and high antioxidant activity. Moreover, ultrasound-assisted extraction (UAE) has proved to be advantageous in providing high extraction efficiency. Hence, this study aimed to extract procyanidins from green soybean seeds (GSSs) using UAE. This study also evaluated the inhibitory activities of tyrosinase and the cytotoxic effects of crude procyanidin extract. The extract exhibited maximum levels of bioactive components and antioxidant capacity when subjected to a temperature of 15 °C and an extraction time of 20 min. The crude procyanidin extract at a concentration of 10 mg/mL inhibited the tyrosinase enzyme by more than 60%, and the half-maximal inhibitory concentration (IC50) value obtained for the extract was 6.85 ± 0.81 mg/mL. This result was much greater than the IC50 value obtained for kojic acid (0.089 ± 0.08 mg/mL), which was used as a positive control. For the cytotoxicity assessment, the results indicated that the crude procyanidin extract showed no cytotoxicity and actually stimulated the growth of human skin fibroblast cells. More than 80% of the bioactive compounds (total phenolic content (TPC), total flavonoid content (TFC), procyanidin content (PC)) and antioxidant activities (DPPH and FRAP) of the crude extract powder were retained at 38.68 ± 0.01 mg GAE/g, 16.07 ± 0.01 mg CAE/g, 9.24 ± 0.01 mg PC/g, 359.8 ± 0.72 μM Trolox eq/g, and 1640 ± 2.86 μM Trolox eq/g, respectively, after 12 weeks of storage at 25 °C. The crude procyanidin extract powder was then included in a facial serum formulation and tested for pH value and physical evaluation. The stability of the crude procyanidin extract facial serum was shown to be greater for bioactive compounds and antioxidant activity when stored at a temperature of 4 °C than when stored at a temperature of 25 °C. These results suggest that the GSS extracts obtained via ultrasonication show promise for use in cosmeceutical formulations for whitening skincare products.

Metabolomics of Withania somnifera L. extracts by an integrated LC-MS and NMR approach and evaluation of their tyrosinase inhibitory activity

Metabolomics of Withania somnifera L. extracts by an integrated LC-MS and NMR approach and evaluation of their tyrosinase inhibitory activity

Nanoencapsulation of citrus essential oils in systematic modified chitosan‐based nanofibers

AbstractIn this study, chitosan (CH)/polyvinyl alcohol (PVA) hybrid nanofibers incorporating three distinct essential oils lemon, lime, and grapefruit were successfully obtained via the innovative electrospinning technique. Characteristics of the electrospinning polymeric mixture loaded with essential oils using variable ratios of CH/PVA were evaluated. The nanoencapsulation process of citrus essential oils was achieved with 47.67%–88.16% encapsulation efficiency. Notably, the thermal stability of the encapsulated essential oils experienced a significant enhancement after encapsulation. Scanning electron microscopy analysis revealed valuable insights, revealing that an increased amount of incorporated essential oil within the polymeric mixture solutions led to a reduction in the average fiber diameters. The resulting nanofibers demonstrated notable attributes such as antioxidant, tyrosinase inhibitory, and antibacterial activities. The present research demonstrates the ability of CH/PVA hybrid nanofibers obtained through an electrospinning process to preserve citrus essential oils properties quality and reveals a high potential application of nonencapsulated citrus essential oils in biomaterials, food packaging, and advanced cosmetic application.

Investigation of Antioxidant and Enzyme Inhibitory Activities of Echinophora chrysantha: Microwave-assisted Hydrodistillation and SPME Analysis of its Essential Oils.

Echinophora genus is represented by six species in Türkiye, including three endemics. The objective of this study was to ascertain the antioxidant, tyrosinase, and collagenase inhibitory activities and to analyse the volatile oil and extracts derived from E. chrysantha using GC/MS/SPME. The antioxidant and enzyme inhibition activities were evaluated using spectrophotometric methods. The findings indicated that the methanol extract of E. chrysantha exhibited the highest antioxidant activity. Furthermore, both the methanol extract and volatile oil of the plant demonstrated potent inhibitory effects on tyrosinase and collagenase. A total of 84 volatile compounds were identified from the hydrodistilled oil obtained using a microwave oven, and 23 compounds were detected by the solid-phase microextraction (SPME) method. The most frequently occurring volatile components were α-Phellandrene, o-Cymene, p-Cymene, E-β-Farnesene, Carotol, trans-Caryophyllene, and β-Phellandrene. The results of this study indicate that E. chrysantha has the potential to be developed for the treatment of hyperpigmentation issues and anti-aging applications. Furthermore, it may also have applications in pharmacology, cosmetics and the food industry.

Synthesis of Carbazole-Thiazole Dyes via One-Pot Tricomponent Reaction: Exploring Photophysical Properties, Tyrosinase Inhibition, and Molecular Docking.

Carbazole is an aromatic heterocyclic organic compound consisting of two fused benzene rings and a pyrrole ring and is a very valuable building structure for the design of many compounds for use in various fields of chemistry and medicine. This study presents three new carbazole-based thiazole derivatives that differ in the presence of a different halogen atom: chlorine, bromine, and fluorine. Experimental studies and quantum-chemical simulations show the effect of changing a halogen atom on the physicochemical, biological, and linear and nonlinear optical properties. We have also found that carbazoles C-Cl, C-Br, and C-F exhibit high tyrosinase inhibitory activity, with IC50 values in the range of 68-105 µM with mixed mechanism of action. Finally, molecular docking to the active site of Concanavalin A (ConA) and bioavailability for all compounds were evaluated.

Tyrosinase Inhibitory Activity of The Extracts from Garcinia lateriflora Blume var. Javanica Boerl, Garcinia fruticosa Lauterb, and Garcinia xanthochymus

Tyrosinase overexpression in humans increases melanin production in the skin, which may have hyperpigmentation-causing effects. In this study, various extracts from the Garcinia lateriflora Blume var. Javanica Boerl, Garcinia fruticosa Lauterb, and Garcinia xanthochymus plants were tested for their ability to inhibit the tyrosinase enzyme. The results showed that the G. fruticosa Lauterb stem bark hexane extract had the highest activity followed succesively by the G. lateriflora Blume var javanica Boerl leaf methanol extract, G xanthochymus mesocarp hexane extract, G. xanthochymus mesocarp methanol extract. The results show that the G. fruticosa Lauterb stem bark hexane extract has the highest tyrosinase inhibitory activity (45.61 ± 1.58%) among the four extracts and the tyrosinase inhibitory activity of kojic acid (65.07 0.86%).

α-Arbutin ameliorates UVA-induced photoaging through regulation of the SIRT3/PGC-1α pathway.

Owing to its tyrosinase inhibitory activity, α-arbutin has been added to several skin care products as a skin-lightening agent. However, the protective effect of α-arbutin against ultraviolet A (UVA)-induced photoaging has not been well investigated. The present study was designed to investigate the photoprotective effect and mechanism of α-arbutin against UVA-induced photoaging. In vitro experiments, HaCaT cells were treated with UVA at a dose of 3J/cm2 to evaluate the anti-photoaging effect of α-arbutin. α-Arbutin was found to exhibit a strong antioxidant effect by increasing glutathione (GSH) level and inhibiting reactive oxygen species (ROS) production. Meanwhile, α-arbutin markedly improved the expression of sirtuin 3 (SIRT3) and peroxisome proliferator-activated receptor γ coactivator 1 α (PGC-1α) proteins, initiating downstream signaling to increase mitochondrial membrane potential and mediate mitochondrial biogenesis, and improve mitochondrial structure significantly. In vivo analysis, the mice with shaved back hair were irradiated with a cumulative UVA dose of 10J/cm2 and a cumulative ultraviolet B (UVB) dose of 0.63J/cm2. The animal experiments demonstrated that α-arbutin increased the expression of SIRT3 and PGC-1α proteins in the back skin of mice, thereby reducing UV-induced skin damage. In conclusion, α-arbutin protects HaCaT cells and mice from UVA damage by regulating SIRT3/PGC-1α signaling pathway.

Comparative Analysis of Chemical Profiles and Biological Activities of Essential Oils Derived from Torreya grandis Arils and Leaves: In Vitro and In Silico Studies.

Torreya grandis (T. grandis, Taxaceae) is a well-known nut tree species. Its fruit aril and leaves possess a unique aroma, making it an ideal natural raw material for extracting essential oils (EOs). This study aims to comprehensively compare the composition, biological activities, and pharmacological mechanism of EOs extracted from the arils (AEO) and leaves (LEO) of T. grandis. The results revealed that the chemical composition of the two EOs was highly consistent, with α-pinene and D-limonene as the main components. Both EOs significantly reduced cellular melanin production and inhibited tyrosinase activity in α-MSH-stimulated B16 cells (p < 0.05). AEO and LEO suppressed inflammatory responses in LPS-stimulated RAW 264.7 macrophages, significantly inhibiting cellular NO production and proinflammatory cytokines such as TNF-α and IL-6 (p < 0.05). A network pharmacology analysis reveals that AEO and LEO share similar molecular mechanisms and pharmacological pathways for treating skin pigmentation and inflammation. Regulating inflammatory cytokines may be a critical pathway for AEO and LEO in treating skin pigmentation. These findings suggest that AEO and LEO have potential for cosmetic applications. The leaves of T. grandis could be a valuable source of supplementary materials for producing T. grandis aril EO.

Inhibitory mechanism on tyrosinase activity of flavonoids from flower buds of Sophora japonica L

The flower buds of Sophora japonica L. (FBSJ) have long been applied as Traditional Chinese Medicine (TCM) and functional food in East Asia. In this study, extracts of FBSJ from 11 different locations were analyzed using the HPLC method to establish their HPLC fingerprints. By determining the IC50 on tyrosinase activity, it was discovered that the extract from Kunming, Yunnan Province exhibited the strongest inhibitory activity. Further analysis, including partial least squares regression coefficient analysis and grey correlation analysis, regarded kaempferol, isorhamnetin, and quercetin as the compounds with significant tyrosinase inhibitory activities. To understand the inhibition mechanism of tyrosinase activity, various analytical techniques such as enzymatic kinetic analysis, fluorescence quenching, circular dichroism (CD), molecular docking, and molecular dynamics simulation were employed. The results revealed that quercetin, isorhamnetin, and kaempferol exhibited higher inhibitory activity and binding energy compared with kojic acid, indicating their potential value as natural tyrosinase inhibitors. This research provides a solid theoretical foundation for studying the application and mechanism of flavonoids against tyrosinase in FBSJ.