Tyrosinase Inhibitory Activity Research Articles

Elucidation of chemical compounds in different extracts of two Lavandula taxa and their biological potentials: Walking with versatile agents on the road from nature to functional applications

Due to their health-promoting and nutraceutical properties, lavenders are frequently employed in the food and pharmaceutical industries. Here, we focused on investigate the chemical profile of hexane, MeOH, and water extracts of leaf, flower, and root of L. pedunculata and L. stoechas and to assess their antioxidant, enzyme inhibitory, and antibacterial properties. The highest total polyphenolic and flavonoids contents were recorded from the water and MeOH extracts of the leaf and flower of L. stoechas, respectively. Our HPLC/MS/MS analysis detected over 90 secondary metabolites, consisting of both known and novel terpenoids, polyphenols, flavonoids, and their derivative. Water leaf extract of L. stoechas displayed significantly (p < 0.05) the highest antiradical, Cu2+ and Fe3+ reducing capacity while hexane extract of the leaf and MeOH extract of the flower of L. pedunculata revealed the best metal chelating ability and total antioxidant activity respectively. The hexane extract of the leaf of L. pedunculata exerted the highest acetylcholinesterase and tyrosinase inhibition activity, whereas the hexane extracts from L. stoechas leaf and L. pedunculata root recorded the highest ability to inhibit the butyrylcholinesterase and ⍺-amylase enzymes respectively. The water extracts of the leaf of the two species, besides the hexane extract of the leaf of L. pedunculata exerted the best inhibition effect against the α-glucosidase. The sensitivities of Gram-positive and Gram-negative bacteria species against different extracts at two different concentrations were tested based on agar well diffusion assay. According to the result, we found that the n-hexane extract of L. stoechas-flowers showed the highest antibacterial activity. In conclusion, the results suggest that both Lavandula species have promising potential as sources of bioactive agents for various industrial applications.

Extraction and purification of narirutin and hesperidin from green yuzu (Citrus junos) and evaluating their biological activities

This study examines how to obtain high levels of two major flavonoids, hesperidin and narirutin, from GY (green yuzu) powder and investigate their biological properties. We selected solvent extraction and enzyme treatment conditions before purification with an HP-20 Diaion column. We determined the appropriate extracted condition as 5 % GY with a 50 % ethanol solvent, and the enzyme treatment condition as 0.05 % RF enzyme for 24 h. Purification using 50 % ethanol as an eluent resulted in highly-enriched narirutin and hesperidin (50.78 % and 42.43 %, respectively). We also investigated the biological activities of extracts from each step, including the assessment of MMP-1 and tyrosinase inhibition activities, antibacterial properties, cytotoxicity, and anti-inflammatory activities. The extracts exhibited desirable properties such as skin elasticity, whitening effects, and anti-inflammatory effects in LPS-simulated RAW 264.7 cells. Highly purified extracts showed better antibacterial activity against food and dermatological pathogens. The results suggested that narirutin and hesperidin concentration and purity may influence the extracts’ biological effects. Overall, this study provides valuable insights into the improved extraction and purification of narirutin and hesperidin from GY powder and their biological activities, highlighting their potential as a functional food and health product ingredients.

Fractionation of Simulated Digestive Products of Bird’s Nest In Vitro: Skin Whitening Activity of Fractions

Edible bird’s nest (EBN) has been proven to exhibit whitening activity. In spite of this, the relationship between the digestive products of EBN and the whitening activity is still unclear. Hence, the B16-F10 cell model was used in this study to study the whitening activity of simulated EBN digestion products in vitro. The simulated digestive juices showed significant inhibition of tyrosinase (TYR) ( P &lt; 0.05), and the release rate of free sialic acid was 21.87% in EBN digestive juices. After simulated gastrointestinal digestion, the relative contents of &lt;1 kDa components, 1–3 kDa components, and &gt;3 kDa components were 42.63%, 15.05%, and 42.32%, respectively. EBN digestive products were further fractionated, and the fraction of &lt;1 kDa (EPP-1) exhibited the highest tyrosinase inhibitory activity with 83.12% and its peptides content was 92.44%. The EPP-1 significantly inhibited tyrosinase activity and decreased melanin content ( P &gt; 0.05) by regulating the cAMP/MITF/TRP-1/TRP-2 tyrosinase signaling pathways in the B16-F10 cell experiment. Based on these findings, our data suggest that the digestive products of EBN may potentially be fit for developing a new generation of natural whitening health products.

Comparative Study of Binding Behaviors of Cyanidin, Cyanidin-3-Galactoside, Peonidin with Tyrosinase.

Cyanidin, peonidin and cyanidin-3-galactoside are the common anthocyanins with a variety of biological activities. Tyrosinase is a speed-limiting enzyme associated with melanin production. The inhibition of tyrosinase activity can prevent melanin disease while contributing to whitening. The interaction behaviors of the three anthocyanins against tyrosinase have been discussed in this paper. Cyanidin has strongest inhibitory effect on tyrosinase, and then peonidin, cyanidin-3-galactoside. Furthermore, the inhibition of tyrosinase by the three anthocyanins is mixed modes. The three anthocyanins can induce the static fluorescence quenching of tyrosinase. Cyanidin exhibits strongest binding affinity on tyrosinase, and then peonidin, cyanidin-3-galactoside based on Ka values obtain by fluorescence analysis. The binding of all anthocyanin to tyrosinase induce its conformation changes. According to molecular docking and fluorescence studies, they bind to tyrosinase by hydrogen bond and van der Waals force. In addition, the optimal modes of the three anthocyanins with tyrosinase are predicated by molecular docking. This work emphasizes that cyanidin, peonidin and cyanidin-3-galactoside may be potential drugs for the treatment of diseases caused by melanin.

Characterization of tea (Camellia sinensis L.) flower extract and insights into its antifungal susceptibilities of Aspergillus flavus

BackgroundTea (Camellia sinensis L.) flowers will compete with tea leaves in nutrition and are abandoned as an undesirable by-product. In this study, the biological efficacy of tea flowers was investigated. Further exploration of its antifungal activity was explained.MethodsTea flowers harvested from China were characterized in term of component, antioxidant ability, tyrosinase inhibition, and antifungal ability. Chemical compounds of tea flowers were analyzed by LC-MS. Disinfectant compounds were identified in tea flowers, and 2-ketobutyric acid exhibited antifungal activity against Aspergillus flavusCCTCC AF 2023038. The antifungal mechanism of 2-ketobutyric acid was further investigated by RNA-seq.ResultsWater-soluble tea flower extracts (TFEs) exhibited free radical scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2, 2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS) as well as a high ferric-reducing ability. However, no inhibition of tyrosinase activity was observed. In the antifungal test, 6.4 mg/mL TFE reached 71.5% antifungal rate and the electrical conductivity of the culture broth increased with increasing concentration of TFE, implying that it damaged the fungal cell membrane by the TFE. Several disinfectants were identified in TFE by LC-MS, and 2-ketobutyric acid was also confirmed to be capable of fungal inhibition. Propidium iodide (PI) staining indicated that 2-ketobutyric acid caused damage to the cell membrane. RNA-seq analysis revealed that 3,808 differentially expressed genes (DEGs) were found in A. flavus CCTCC AF 2023038 treated by 2-ketobutyric acid, and more than 1,000 DEGs involved in the integral and intrinsic component of membrane were affected. Moreover, 2-ketobutyric acid downregulated aflatoxin biosynthesis genes and decreased the aflatoxin production.ConclusionsOverall, TFE exhibited excellent antioxidant ability and fungal inhibition against A. flavus CCTCC AF 2023038 due to its abundant disinfectant compounds. As a recognized food additive, 2-ketobutyric acid is safe to use in the food industry and can be utilized as the basis for the research and development of strong fungicides.

Synthesis, Anti-Tyrosinase Activity, and Spectroscopic Inhibition Mechanism of Cinnamic Acid-Eugenol Esters.

Tyrosinase plays crucial roles in mediating the production of melanin pigment; thus, its inhibitors could be useful in preventing melanin-related diseases. To find potential tyrosinase inhibitors, a series of cinnamic acid-eugenol esters (c1~c29) was synthesized and their chemical structures were confirmed by 1H NMR, 13C NMR, HRMS, and FT-IR, respectively. The biological evaluation results showed that all compounds c1~c29 exhibited definite tyrosinase inhibitory activity; especially, compound c27 was the strongest tyrosinase inhibitor (IC50: 3.07 ± 0.26 μM), being ~4.6-fold stronger than the positive control, kojic acid (IC50: 14.15 ± 0.46 μM). Inhibition kinetic studies validated compound c27 as a reversible mixed-type inhibitor against tyrosinase. Three-dimensional fluorescence and circular dichroism (CD) spectra results indicated that compound c27 could change the conformation and secondary structure of tyrosinase. Fluorescence-quenching results showed that compound c27 quenched tyrosinase fluorescence in the static manner with one binding site. Molecular docking results also revealed the binding interactions between compound c27 and tyrosinase. Therefore, cinnamic acid-eugenol esters, especially c27, could be used as lead compounds to find potential tyrosinase inhibitors.

Antioxidant and Tyrosinase Inhibitory Activities of Athamanta sicula L. Aqueous Extract

Introduction: Overexpression of tyrosinase in humans causes an increase in melanin production in the skin, which can result in hyperpigmentation consequences such as freckles, melasma, age spots, and melanoma. Free radicals also play a significant role in the increase of the biosynthesis of melanin. Tyrosinase inhibitors capable of inhibiting the biosynthesis of melanin are currently used in various hyperpigmentation and cosmetic agents to control the formation of freckles. Several synthetic tyrosinase inhibitors have been associated with several serious side effects. Also, synthetic antioxidants have many toxicological side effects, including carcinogenicity. There is an increasing interest in the search for natural tyrosinase inhibitors and antioxidant agents. Aims: The objective of this study is to evaluate total polyphenol and flavonoid contents as well as examine the antioxidative and tyrosinase inhibitory effects of A. sicula L. aqueous extract. Methods: Antioxidant activities were evaluated using superoxide radical scavenging and reducing power methods. Moreover, a tyrosinase inhibitory assay was used to determine anti-hyperpigmentation. Results: The results showed that this extract was rich in total polyphenols (58.01 ± 1.18 micrograms of gallic acid equivalents per milligrams of extract) and flavonoids (17.91 ± 1.81 micrograms quercetin equivalents per milligram of extract). A. sicula L. aqueous extract was capable of scavenging free radicals (IC50 = 11.87 ± 0.13 μg/mL) and acting as a strong reducing agent (A 0.5= 6.37 ± 0.42 μg/mL). A. sicula L. had a potent tyrosinase inhibitory potential (IC50= 12.63 ± 1.15 μg/mL), which was higher compared to kojic acid used as a standard (IC50= 25,23 ± 0,78 μg/mL, p &lt;0.001). Conclusion: These results support that A. sicula L. could be a new source of antioxidant and cosmetic use. Further studies focusing on the isolation and characterization of active principles of antioxidant and tyrosinase inhibitory activities are needed.

In vitro Examination of Antioxidant and Anti-cholinesterase Effects of Athamanta sicula L. Aqueous and Methanolic Extracts

Introduction: Oxidative stress plays a critical role in the pathological process of Alzheimer’s disease (AD). There is a growing interest in natural anti-oxidants and cholinesterase inhibitors from medicinal plants that may aid in the prevention of oxidative injury and treatment of AD. Considering this, Athamanta sicula L. is found to be an important medicinal plant. Aims: The aim of the current study was to investigate the total phenolic content, antioxidant, and anticholinesterase properties of aqueous (AqE) and methanolic extracts (MethE) from Athamanta sicula L. (A. sicula L.). Methods: The phenanthroline, ABTS free radical scavenging, and β-carotene bleaching methods were utilized to assess the antioxidant capacity. Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory methods were used to determine the anti-cholinesterase effect. Results: These extracts were found to be rich in phenolic contents. They were capable of scavenging free radicals, inhibiting lipid peroxidation, and reducing agents. A. sicula L. had a remarkable cholinesterase inhibitory effect. Conclusion: These results support that A. sicula L. could be a new source of anti-oxidant and anticholinesterase natural drugs. Further studies on the isolation and characterization of active principles of anti-oxidant and tyrosinase inhibitory activities are needed.

Pyracantha as a promising functional food: A comprehensive review on bioactive characteristics, pharmacological activity, and industrial applications

AbstractPyracantha is a plant with edible and medicinal value and widely distributed from eastern Asia to southern Europe but is underutilized and has great potential. As scientists gradually study its properties, it was found that Pyracantha contains various phytochemical components such as pigments and phospholipids. Meanwhile, Pyracantha is also rich in phenolic substances, such as flavonoids. The extract of Pyracantha shows strong biological properties, such as inhibition of tyrosinase activity, anti‐oxidative, and tumor‐preventive effects. Pyracantha bioavailability releases quantities of compounds in the food matrix from the digestive process that are important for its health‐promoting properties. The extraction of biologically active substances in Pyracantha would be applied in various aspects. Their extracts can also be used as health food, food additives, and cosmetics. As the interaction of phytochemicals, proteins, and phenolic compounds can affect the pharmacological activity and bioavailability of Pyracantha, it is important to understand the mechanism of effect, which can further allow consumers to choose a healthier Pyracantha dietary culture. This review aims to prove the nutritional components and pharmacological activities of Pyracantha and to make consumers better aware of the benefits of Pyracantha in connection with their bioavailability and application, in order to provide a reference for further research and development of Pyracantha resources.

Identification and molecular mechanism of novel 5-alkenyl-2-benzylaminothiazol-4(5H)-one analogs as anti-melanogenic and antioxidant agents

Mushroom tyrosinase is a tetramer, whereas mammalian tyrosinase is a monomeric glycoprotein. In addition, the amino acid sequence of mushroom tyrosinases differs from that of mammalian tyrosinases. MHY2081 exhibits potent inhibitory activity against both mushroom and mammalian tyrosinases. Accordingly, based on the MHY2081 structure, 5-alkenyl-2-benzylaminothiazol-4(5H)-one analogs were designed as a novel anti-tyrosinase agent and synthesized using 2-((3,4-dimethoxybenzyl)amino)thiazol-4(5H)-one (16), a key intermediate obtained via the rearrangement of a benzylamino group. Compounds 6 and 9 (IC50 = 1.5–4.6 µM) exhibited higher mushroom tyrosinase inhibitory activity than kojic acid (IC50 = 20–21 µM) in the presence of l-tyrosine and/or l-dopa. Based on kinetic analysis using Lineweaver-Burk plots, 6 was a mixed inhibitor, whereas 9 was a competitive inhibitor, and docking simulation results supported that these compounds could bind to the active site of mushroom tyrosinase. Using B16F10 mammalian cells, we demonstrated that these compounds inhibited melanogenesis more potently than kojic acid, and their anti-melanogenic effects could be attributed to tyrosinase inhibition. All synthesized compounds could scavenge reactive oxygen species (ROS), with five compounds exhibiting mild-to-strong ABTS+ and DPPH radical-scavenging abilities. Compounds 6 and 9 were potent tyrosinase inhibitors with strong antioxidant activities against ROS, ABTS+, and DPPH radicals. Moreover, the compounds significantly suppressed tyrosinase expression in a dose-dependent manner. Collectively, these results suggest that the novel 5-alkenyl-2-benzylaminothiazol-4(5H)-one analogs, especially 6 and 9, are potential anti-melanogenic agents with antioxidant activity.

Chemical Composition and In Vitro Antimicrobial, Antioxidant, and Tyrosinase-Inhibiting Activity of Essential Oils Extracted From the Leaves and Twigs of Calocedrus macrolepis var. formosana

In this study, we focused on evaluating the antimicrobial, antioxidant, and tyrosinase-inhibiting properties of leaf and twig essential oils from Calocedrus macrolepis var. formosana. Additionally, we determined the major components associated with these effects. The findings revealed that α-pinene (36.4%) and limonene (23.6%) were the dominant components in the leaf essential oil, while α-pinene (36.2%), ferruginol (22.5%), and limonene (13.1%) were the major constituents in the twig essential oil. However, when comparing the biological activities of the 2 essential oils, the twig essential oil demonstrated excellent inhibitory effects against skin pathogens, as well as strong antioxidant and tyrosinase-inhibiting activities, in contrast to the leaf essential oil. The twig essential oil also exhibited excellent antimicrobial activity against 5 skin pathogenic strains, with the strongest inhibitory effect being that against Staphylococcus aureus, S epidermidis, and Candida albicans, which was accompanied by an inhibition zone of 46 to 48 mm, a minimum inhibitory concentration (MIC) of 125 μg/mL, and a minimum bactericidal concentration (MBC) of 250 μg/mL. The inhibitory activity of the twig essential oil against lipid peroxidation was found to be potent, as evidenced by an IC50 value of 216 ± 1.9 μg/mL. It also exhibited strong scavenging activity against free radicals, including 2,2-diphenyl-1-picrylhydrazyl (DPPH) (IC50 = 121.6 ± 0.5 μg/mL) and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) (IC50 = 136.8 ± 1.6 μg/mL) cation radicals. In addition, it exhibited a high cupric ion reducing–antioxidant capacity (CUPRAC), with the A0.50 value determined to be 186.28 ± 0.5 μg/mL. It also exhibited adequate activity in terms of inhibiting in vitro tyrosinase activity, as evidenced by an IC50 value of 168.5 ± 0.6 μg/mL. Further analysis revealed that ferruginol was the active component responsible for the antimicrobial, antioxidative, and tyrosinase-inhibiting activities observed in twig oil. These findings suggest that the twig oil is a promising candidate for further research because of its favorable antimicrobial, antioxidative, and tyrosinase-inhibiting activity.

GC-MS Analysis and Bioactivity Screening of Leaves and Fruits of Zanthoxylum armatum DC.

Zanthoxylum armatum DC. is a plant that has been homologated for medicine and food by the Chinese for three thousand years. In this study, the essential oils of fresh leaves and fruits were extracted by hydrodistillation, the aromas of fresh leaves and fruits were extracted by headspace solid-phase microextraction and their chemical compositions were analyzed by gas chromatography mass spectrometry. The main components of the leaf essential oils were linalool (62.01%), 2-undecanone (9.83%) and 2-tridecanone (5.47%); the fruit essential oils were linalool (72.17%), limonene (8.05%) and sabinene (6.77%); the leaf aromas were limonene (39.15%), β-myrcene (15.8%), sabinene (8.17%) and linalool (5.25%); the fruit aromas were limonene (28.43%), sabinene (13.56%), linalool (11.47%) and β-myrcene (8.64%). By comparison, it was found that the composition of leaf essential oils and fruit essential oils were dominated by oxygenated monoterpenes, while the composition of their aromas were both dominated by monoterpenes; the relative content of non-terpene components in leaf essential oil and leaf aroma is second only to oxygenated monoterpenes, while their content in fruits is low; the chemical composition of leaf aromas and fruit aromas were richer than those of essential oils. In this study, we reported for the first time that the antitumor, tyrosinase inhibition, HMGR inhibition and nitric oxide production inhibition activity of leaf essential oils were stronger than those of fruit essential oils in in vitro tests. The results of the study can provide a reference for the recycling and green low-carbon transformation of the leaves, and also help to deepen the understanding of the value of the volatile chemical constituents of this plant in “forest medicine” or “aromatherapy”, and provide new ideas for the transformation of the value of the plant in the secondary and tertiary industry chain.

Synthesis and Evaluation of Some Sulfonamide-Substituted of 1,3,5-Triphenyl Pyrazoline Derivatives as Tyrosinase Enzyme Inhibitors

Pyrazoline is well-known as heterocycles compound that can exhibit many biological effects. In this work, we synthesized a series of sulfonamide-substituted 1,3,5-triphenyl pyrazoline compounds as a promising tyrosinase inhibitor agent. These compounds prepared by multicomponent reaction of corresponding aldehyde, ketone, and hydrazine using seal-vessel reactor. Pyrazolines compound were tested for their tyrosinase inhibitor activity through in vitro assay. The test result found that compound 4c, 4d, and 4e possessed better tyrosinase inhibitory activity compared to the reference drug, kojic acid. Compound 4c exhibited the strongest tyrosinase inhibitory effect with an IC50 value of 30.14 µM. The results suggested that hydroxyl and methoxy substituent at para position are preferable. Furthermore, molecular docking studies result match the pattern of in vitro assay where the compound will provide a stronger binding interaction and lower binding free energies.

Ginsenoside Re inhibits melanogenesis and melanoma growth by downregulating microphthalmia-associated transcription factor

Panax ginseng, also known as Korean ginseng, is a traditional remedy widely used in Asian countries. Its major active compounds are ginsenosides, specifically triterpenoid saponins. Among them, one notable ginsenoside called Re has shown various biological effects, including anti-cancer and anti-inflammatory properties. However, the potential beneficial effects of Re on melanogenesis and skin cancer remain poorly understood. To investigate this, we conducted a comprehensive study using biochemical assays, cell-based models, a zebrafish pigment formation model, and a tumor xenograft model. Our results revealed that Re effectively inhibited melanin biosynthesis in a dose-dependent manner by competitively inhibiting the activity of tyrosinase, an enzyme involved in melanin production. Moreover, Re significantly reduced the mRNA expression levels of microphthalmia-associated transcription factor (MITF), a key regulator of melanin biosynthesis and melanoma growth. Furthermore, Re decreased the protein expression of MITF and its target genes, including tyrosinase, TRP-1, and TRP-2, through a partially ubiquitin-dependent proteasomal degradation mechanism, mediated by the AKT and ERK signaling pathways. These findings indicate that Re exerts its hypopigmentary effects by directly inhibiting tyrosinase activity and suppressing its expression via MITF. Additionally, Re demonstrated inhibitory effects on skin melanoma growth and induced tumor vascular normalization in our in vivo experiments. This study represents the first evidence of Re-mediated inhibition of melanogenesis and skin melanoma, shedding light on the underlying mechanisms. These promising preclinical findings warrant further investigation to determine the suitability of Re as a natural agent for treating hyperpigmentation disorders and skin cancer.

Optimization the Mixing Ratio of Leaf and Seed Extracts of Brassica juncea L. Czern. as a Cosmetic Material

Purpose: This study aimed to investigate the physiological activity of mustard (Brassica juncea L. Czern.) leaf and seed extracts as a cosmetic material, and optimization the mixing ratio using response surface methodology (RSM).Methods: Optimal conditions for RSM were determined the ratio of mustard leaf (X1) and seed (X2) extracts as the independent variable, and total polyphenol content, total flavonoid content, DPPH radical scavenging activity, ABTS radical scavenging activity, tyrosinase inhibitory activity and elastase inhibitory activity was determined as the dependent variable.Results: Optimal mixing ratio with maximum antioxidant, whitening, and anti-wrinkle effects was determined as 3.28 (4.10 mg/mL) for leaves and 4.21 (5.26 mg/mL) for seeds. The DPPH radical and ABTS radical scavenging activities, tyrosinase and elastase inhibitory activities was predicted to be 80.01%, 58.50%, 22.11%, 53.88%, respectively. In addition, when the mixture was treated in LPS-induced RAW264.7 cells, NO production was inhibited by about 41% compared to the control group, and no cytotoxicity was observed.Conclusion: In this study, the physiological activity of optimal mixture of mustard leaf and seed extracts with antioxidant, whitening, anti-wrinkle and anti-inflammatory effects has been confirmed, this finding suggest that can use as a cosmetic material.

Comprehensive Phytochemical Analysis and Bioactivity Evaluation of Padina boergesenii: Unveiling Its Prospects as a Promising Cosmetic Component.

Marine macroalgae, such as Padina boergesenii, are gaining recognition in the cosmetics industry as valuable sources of natural bioactive compounds. This study aimed to investigate the biochemical profile of P. boergesenii and evaluate its potential as a cosmetic ingredient. Fourier-transform infrared (FTIR), gas chromatography-mass spectrometry (GCMS), and high-resolution liquid chromatography-mass spectrometry quadrupole time-of-flight (HRLCMS QTOF) analyses were employed to assess the functional groups, phycocompounds, and beneficial compounds present in P. boergesenii. Pigment estimation, total phenol and protein content determination, DPPH antioxidant analysis, and tyrosinase inhibition assay were conducted to evaluate the extracts' ability to counteract oxidative stress and address hyperpigmentation concerns. Elemental composition and amino acid quantification were determined using inductively coupled plasma atomic emission spectrometry (ICP-AES) and HRLCMS, respectively. FTIR spectroscopy confirmed diverse functional groups, including halo compounds, alcohols, esters, amines, and acids. GCMS analysis identified moisturizing, conditioning, and anti-aging compounds such as long-chain fatty alcohols, fatty esters, fatty acids, and hydrocarbon derivatives. HRLCMS QTOF analysis revealed phenolic compounds, fatty acid derivatives, peptides, terpenoids, and amino acids with antioxidant, anti-inflammatory, and skin-nourishing properties. Elemental analysis indicated varying concentrations of elements, with silicon (Si) being the most abundant and copper (Cu) being the least abundant. The total phenol content was 86.50 µg/mL, suggesting the presence of antioxidants. The total protein content was 113.72 µg/mL, indicating nourishing and rejuvenating effects. The ethanolic extract exhibited an IC50 value of 36.75 μg/mL in the DPPH assay, indicating significant antioxidant activity. The methanolic extract showed an IC50 value of 42.784 μg/mL. Furthermore, P. boergesenii extracts demonstrated 62.14% inhibition of tyrosinase activity. This comprehensive analysis underscores the potential of P. boergesenii as an effective cosmetic ingredient for enhancing skin health. Given the increasing use of seaweed-based bioactive components in cosmetics, further exploration of P. boergesenii's potential in the cosmetics industry is warranted to leverage its valuable properties.

Fluorometric Assay of Tyrosinase and Atrazine Based on the Use of Carbon Dots and the Inhibition of Tyrosinase Activity.

Sensitive and convenient strategy of tyrosinase (TYR) and its inhibitor atrazine is in pressing demand for essential research as well as pragmatic application. In this work, an exquisite label-free fluorometric assay with high sensitivity, convenience and efficiency was described for detecting TYR and the herbicide atrazine on the basis of fluorescent nitrogen-doped carbon dots (CDs). The CDs were prepared via one-pot hydrothermal reaction starting from citric acid and diethylenetriamine. TYR catalyzed the oxidation of dopamine to dopaquinone derivative which could quench the fluorescence of CDs through a fluorescence resonance energy transfer (FRET) process. Thus, a sensitive and selective quantitative evaluation of TYR can be constructed on the basis of the relationship between the fluorescence of CDs and TYR activity. Atrazine, a typical inhibitor of TYR, inhibited the catalytic activity of TYR, leading to the reduced dopaquinone and the fluorescence was retained. The strategy covered a broad linear range of 0.1-150 U/mL and 4.0-80.0 nM for TYR and atrazine respectively with a low detection limit of 0.02 U/mL and 2.4 nM/mL. It is also demonstrated that the assay can be applied to detect TYR and atrazine in spiked complex real samples, which provides infinite potential in application of disease monitoring along with environmental analysis.

Secondary Metabolites from the Cultures of Medicinal Mushroom Vanderbylia robiniophila and Their Tyrosinase Inhibitory Activities.

Vanderbylia robiniophila (Huaier in Chinese) has been used as a traditional herbal medicine in China for over 1600 years. However, the secondary metabolites of V. robiniophila have not been systematically examined. Corresponding chemical investigation in this study led to the discovery of two new compounds, (22E, 24R)-6β, 7α-dimethoxyergosta-8(14), 22-diene-3β, 5α-diol (1) and vanderbyliolide A (8), along with eight known ones (2-7, 9-10). Their structures were determined by extensive spectroscopic analyses and electronic circular dichroism (ECD) calculations. The tyrosinase inhibitory activity of all isolated compounds was evaluated, and compound 10 showed a potential tyrosinase inhibitory effect with an IC50 value of 60.47 ± 2.63 μM. Kinetic studies of the inhibition reactions suggested that 10 provides the inhibitory ability on tyrosinase in an uncompetitive way.

Synthesis and tyrosinase inhibitory activities of novel isopropylquinazolinones

To find new anti-browning and whitening agents in this study, new series of isopropylquinazolinone derivatives were designed and synthesized. All derivatives were evaluated as possible tyrosinase inhibitors and compound 9q bearing 4-fluorobenzyl moieties at the R position exhibited the best potencies with an IC50 value of 34.67 ± 3.68 µM. The kinetic evaluations of 9q as the most potent derivatives recorded mix-type inhibition. Compounds 9o and 9q also exhibited potent antioxidant capacity with IC50 values of 38.81 and 40.73 µM, respectively confirming their antioxidant potential. Molecular docking studies of 9q as the most potent derivative were exacuated and it was shown that quinazolinone and acetamide moieties of compound 9q participated in interaction with critical His residues of the binding site. The obtained results demonstrated that the 9q can be considered a suitable pharmacophore to develop potent tyrosinase inhibitors.

Biotransformation of ginsenoside Rb1 and Rd to four rare ginsenosides and evaluation of their anti-melanogenic effects.

Improving physiological activity of primary ginsenosides through biotransformation is of great significance for food applications. In this study, gynostapenoside XVII, gynostapenoside LXXV, ginsenoside F2, and ginsenoside CK were obtained by enzymolysis of an accessible extract composed of ginsenoside Rb1 and Rd. Their effects on melanin content and tyrosinase activity were compared in vitro, and molecular docking simulation was employed to elucidate the interaction between tyrosinase and individual saponin. The results indicated that four rare ginsenosides decreased tyrosinase activity, melanin content and microphthalmia-associated transcription factor (MITF) expression level, more greatly than their primary ginsenosides, and they were more readily to bind with ASP10 and GLY68 at active site of tyrosinase to inhibit tyrosinase activity as well. These findings suggested that the rare ginsenosides obtained by enzymolysis had excellent anti-melanogenic effect, which could expand the application of ginsenosides in the field of functional foods and health supplements.