FITOTERAPIA
·
2024
·
IF 2.5
Jianjin Guo,Jing Gao,Yan Guo,Lu Bai,Chi-Tang Ho,Naisheng Bai
The bark of Fraxinus mandshurica is a traditional folk herb used to clear heat and dry dampness. To investigate the differences in coumarins content in the bark of F. mandshurica , 24 batches of samples from four origins were collected and analyzed. Eight coumarins were obtained by traditional natural product extraction, isolation and identification techniques and quantified by high performance liquid chromatography-photodiode array (HPLC-DAD). The quantitative results showed that the overall content of compound 30 (Fraxinol) was higher at 100.23 mg/g, while the overall content of compound 23 (Cichoriin) was lower, which may be related to environmental factors in different regions. The method validation showed that the linear range of the eight standards was between 10 and 2500 μg/mL with correlation coefficient ( R 2 ) values >0.9991; the relative standard deviation (RSD, %) values of intra-day precision were between 0.35 and 1.38, while the RSD values of inter-day precision were between 0. 29–1.78; the RSD (%) values for the reproducibility experiments ranged from 0.29 to 1.87, while the RSD (%) values for the stability experiments ranged from 0.22 to 2.33; the spiked recovery of the samples ranged from 98.65 to 101.34%, and the RSD (%) values ranged from 0.22 to 1.96. The method validation results showed that the instrument used for the analysis had good precision, the reproducibility and stability of the samples were good, and the accuracy of the experimental method was high. In addition, a total of 54 chemical components were identified from F. mandshurica bark by ultra performance liquid chromatography-electrospray quadrupole time-of-flight mass spectrometry (UPLC-ESI-Q-TOF-MS). Based on this, fingerprinting, heatmap and multivariate analysis, including principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA), were established for 24 batches of samples, and four marker compounds that could be used to distinguish different origins of F. mandshurica were screened. To further investigate the bioactivities of the eight coumarins, in vitro enzyme activity inhibition studies were performed, and the results showed that they all exhibited different degrees of inhibition of acetylcholinesterase, tyrosinase and α-glucosidase, thus having potential applications in the treatment of Alzheimer's disease, blemish whitening and anti-diabetes, and becoming a new source of natural enzyme activity inhibitors. This study established an identification and evaluation method applicable to plants of different origins, which provides a strong reference for quality control, origin evaluation and clinical application of traditional medicinal plants.
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ANALYTICAL CHEMISTRY
·
2017
·
IF 6.32
Huihui Li,Wei Liu,Fengyuan Zhang,Xinyue Zhu,Liqiu Huang,Haixia Zhang
The detection of tyrosinase, a biomarker for melanoma, is of great significance. Herein, a fluorescent tyrosinase probe, with resorufin as the fluorophore and m-tolylboronic acid pinacol ester as the receptor, is proposed. The response relies on the tyrosinase-catalyzed hydroxylation of phenylboronic acid pinacol ester at an adjacent position followed by 1,6-rearrangement elimination to release resorufin. This probe well quantifies tyrosinase in the range from 1 to 100 U mL–1 with a detection limit of 0.5 U mL–1. Importantly, the probe exhibits high selectivity for tyrosinase over other biological substances including reactive oxygen species. In addition, it is successfully applied to the imaging of tyrosinase in cells. This probe provides a novel platform for selective detection of tyrosinase in biosystems.
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FOOD CHEMISTRY
·
2024
·
IF 8.5
Jinfeng Zhang,Wei Yang,Min He,Zhiyun Peng,Guangcheng Wang
Tyrosinase (Polyphenol oxidase), a key enzyme in enzymatic browning, is an attractive target for developing new anti-browning agents in the food industry. In this work, twenty pyrazole-1,2,4-triazole derivatives ( 3a-3n, 4a-4f) were synthesized and tested in vitro, most of compounds showed potent anti-tyrosinase activity. Of these, 3c (IC 50 = 1.02 ± 0.08 μM) was found to be 14 folds stronger than kojic acid (IC 50 = 14.74 ± 1.23 μM) and behaved as a mixed type inhibitor. Besides, the disappeared peak of dopaquinone in the HPLC assay intuitively validated the inhibitory effect of 3c . Copper ions chelating, fluorescence quenching and molecular docking assays showed that coordination with copper is the key to play a role. Furthermore, 3c exhibited excellent anti-browning ability for the Rosa roxburghii Tratt, the non-enzymatic browning experiment showed that 3c could prevent browning in non-enzymatic ways. It is suggested that these derivatives could serve as the leading compounds to find more efficient anti-browning agents in the future.
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BIOMEDICAL CHROMATOGRAPHY
·
2024
·Vol. 38
·期 6
·e5861
·
IF 1.8
Jianjin Guo,Shaojing Liu,Yan Guo,Lu Bai,Chi-Tang Ho,Naisheng Bai
Fraxinus mandshurica (Oleaceae) is used as a traditional medicinal plant for the treatment of red eyes, menstrual disorders, excessive leucorrhea, chronic bronchitis and psoriasis. To perform chemical characterization of the secondary metabolites of F. mandshurica roots, bark, stems and leaves, 32 samples were collected from eight provinces in this study. A total of 64 chemical components were detected from four different parts of F. mandshurica by ultra-performance liquid chromatography–quadrupole time-of-flight mass spectrometry. Meanwhile, a total of nine secoiridoids were obtained by natural product chemical extraction, isolation and identification methods. Quantitative analysis by high-performance liquid chromatography–diode array detection–mass spectrometry showed the highest total content of secoiridoids in the bark, which is also consistent with the traditional medicinal parts. The results of methodological validation showed that the correlation coefficient ( R 2 ) values were all >0.9993, indicating a good linear range of the standard curve, while the relative standard deviations of precision, reproducibility and stability were <3%, and the spiked recoveries ranged from 98.22 to 102.27%, indicating that the experimental method was reliable and stable. In addition, fingerprinting and a heatmap were established to demonstrate the content trends of F. mandshurica more visually from different origins. Multivariate analysis, including principal component analysis and partial least squares discriminant analysis, was performed to determine the chemical characteristics of different parts of F. mandshurica , and six characteristic secoiridoids that could be used to distinguish different origins were screened. Finally, the inhibition of tyrosinase, α -glucosidase, acetylcholinesterase and pancreatic lipase activities by the nine characteristic compounds and extracts from different parts were investigated, and the results showed that they all exhibited different degrees of enzyme activity inhibition and thus have potential applications in whitening and blemish removal, hypoglycemia, anti-Alzheimer's disease and anti-obesity as a new source of natural enzyme activity inhibitors. This study establishes an identification and evaluation method applicable to phytochemistry of different origins, which is a guideline for quality control, origin evaluation and clinical application of traditional medicinal plants. This is also an unprecedented study on the identification of the chemical composition of different parts of F. mandshurica , characteristic compounds and the inhibition of enzyme activity of extracts from different parts.
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Food Bioscience
·
2024
·
IF 4.8
Zhengming Xu,Xi Zhu,Jiayi Lian,Yuan Guan,Zhengang Zhao
Exploiting efficient tyrosinase inhibitors and utilizing the inhibition mechanism are of great significance to avoid enzymatic browning in food and skin melanogenesis. Polydatin had excellent tyrosinase inhibitory activity in vitro with IC 50 value of 24.90 μM; however, it exhibited unsatisfactory inhibitory activity intracellularly, which was associated with poor cellular uptake. Fortunately, 6″- O -lauryl polydatin was green-efficiently synthesized by lipase-catalyzed acylation under microwave irradiation. 6″- O -lauryl polydatin exhibited superior mono-/diphenolase inhibitory activity within 100 μM than kojic acid, which had IC 50 of 221 μM. Neither polydatin nor 6″- O -lauryl polydatin bound to the catalytic site, but rather bound noncovalently to the allosteric site 2 of tyrosinase through hydrogen bonds and hydrophobic interactions according to molecular simulations, thereby inducing secondary structure unfolding and reducing tyrosinase activity. 6″- O -lauryl polydatin showed stronger anti-browning effects than polydatin in the natural storage of potato and apple pieces. Polydatin and kojic acid did not induce apoptosis, but 6″- O -lauryl polydatin inhibited human melanin A375 cell proliferation by stimulating ROS overproduction and regulating cell cycle and apoptotic pathways. In addition, lipophilic 6″- O -lauryl polydatin had greater cellular uptake though suffered from intracellular hydrolysis, and exerted better tyrosinase and melanogenesis inhibitory activity than polydatin and kojic acid based on mouse B16F10 melanoma cell model. The results suggested polydatin and 6″- O -lauryl polydatin were promising tyrosinase inhibitors for anti-browning in foods or cosmetics fields.
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Journal of Materials Chemistry B
·
2025
·
IF 5.7
Zhenyuan Wang,Tie Dong,Jin Yang,Yiyu Wang,Mi Wang,Jiaheng Zhang
Due to its rich bioactivities, tranexamic acid (TA) has garnered significant attention in the biomedical and cosmetic fields. However, TA's hydrophilic nature impedes its penetration through the skin's stratum corneum. This limitation is addressed in the current study by designing a supramolecular TA, i.e., GATA, based on the non-covalent interactions between TA and glycolic acid (GA). The structure and formation mechanism of GATA are explored using multidimensional characterization techniques, including single crystal analysis and computer-aided simulations. In vitro, the supramolecular interactions within GATA facilitate deeper TA penetration into the skin, achieving >2.5 times improved transdermal permeability than pure TA. Notably, GATA does not damage the skin barrier, with the associated irritation and cytotoxicity significantly lower than that caused by GA. Moreover, compared with TA, GATA has comparable or superior thermal stability, water solubility, anti-glycation, antioxidant, and anti-inflammatory properties. GATA also exhibits excellent skin whitening efficacy. Hence, GATA is a promising alternative to TA, with enhanced permeability, bioactivity, and biosafety, as well as considerable application prospects in transdermal delivery.
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PLANTA MEDICA
·
2017
·Vol. 84
·期 05
·336-343
·
IF 2.342
Yifan Wang,Liangjin Xu,Wen Gao,Lixin Niu,Chunyue Huang,Peiming Yang,Xiao Hu
Three new Diels-Alder adducts, macrourins E – G (1–3), one new 2-arylbenzofuran, macrourin H (4), and eight known Diels-Alder adducts (5–12) were isolated from Morus macroura. Their structures were elucidated through extensive analysis of spectroscopic data. The 1H NMR and ECD trends in the determination of the configurations of these Diels-Alder adducts were summarized. The tyrosinase inhibitory activities of all compounds isolated were evaluated, and the new compounds (1–4) as well as the eight known compounds (5–12) were found to be potent with IC50 values ranging from 0.39 to 4.54 µM. Among them, 1 showed the best tyrosinase inhibitory activity with an IC50 value of 0.39 µM, approximately 50 times stronger than the positive control, kojic acid.
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EXPERIMENTAL AND MOLECULAR PATHOLOGY
·
2025
·
IF 3.7
Jinpeng Lv,Kun Zou,Chuanwei Yin,Wenhui Xu,Duo Meng,Huansha Zhang,Wenhao Yu,Peiwen Jiang,Changjun Yun,Hui Xue,Nan Hu,Rongyin Gao
Daidzin, a prominent isoflavone found in soybeans, Pueraria lobata , and various legumes, has been extensively investigated for its diverse pharmacological activities, which include anticancer, antioxidant, anti-inflammatory, antiepileptic, and alcohol detoxification properties. Previous studies have shown that the dichloromethane fraction of Pueraria lobata stem (DCM-PLS) exhibits significant anti-melanogenic activity, with daidzin identified as the principal active compound. However, the precise role of daidzin in pigmentation remains incompletely understood. This study aimed to investigate the effects of daidzin on pigmentation and to elucidate the underlying mechanisms. Our findings revealed that daidzin not only inhibited basal melanin production but also reduced melanin synthesis induced by α-MSH, ACTH, and UV exposure. The effects of daidzin were primarily mediated through the activation of the extracellular signal-regulated protein kinase (ERK) and protein kinase B (AKT) pathways. Upon activation, these pathways facilitated the ubiquitination and degradation of Melanocytes Inducing Transcription Factor (MITF), resulting in decreased expression of tyrosinase, TRP-1, and TRP-2, ultimately inhibiting melanogenesis. Importantly, our research further demonstrated that daidzin reduced pigmentation in both zebrafish and human skin explants, highlighting its potential application as a therapeutic approach for disorders related to skin pigmentation.
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ACS Omega
·
2025
·
IF 4.3
Wenqingqing Kang,Henry H. Y. Tong,Shu Li
Tyrosinase, a copper-dependent oxidase, plays a critical role in melanin biosynthesis and is a target in skin-whitening cosmetics. Conventional inhibitors like arbutin and kojic acid are widely used but suffer from cytotoxicity, instability, and inconsistent efficacy, highlighting the need for safer, more effective alternatives. In this study, two ligand-based machine learning models were developed: one to predict the biological activity of compounds and the other to estimate specific pIC50 values. These models were employed to screen potential tyrosinase inhibitors from natural product libraries and FDA-approved drug databases. Subsequently, the molecules identified through machine learning screening were subjected to more precise multi tyrosinase-like structures molecular docking to refine the selection. We identified three top-ranking inhibitors, rhodanine-3-propionic acid, lodoxamide, and cytidine 5′-(dihydrogen phosphate), with strong binding affinities mediated by metal ion coordination and π–π interactions at the enzyme’s active site. In vitro assays revealed that all three compounds exhibited higher inhibitory activity against mushroom tyrosinase compared to arbutin (IC50 = 38.37 mM), with rhodanine-3-propionic acid displaying the most potent inhibition (IC50 = 0.7349 mM). Furthermore, transdermal permeation experimental results confirmed that these compounds achieved markedly better skin permeability than commercial arbutin-based formulations, highlighting their potential as next-generation agents for inhibiting melanin production in cosmetic applications.
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FOOD CHEMISTRY
·
2025
·
IF 9.8
Guangcheng Wang,Jinfeng Zhang,Zhiyun Peng
The tyrosinase inhibitory activity and inhibition mechanism of pyrimidine-2-thiol (PT) and pyrimidine-2,4-dithiol (PDT) were investigated. In the anti-tyrosinase activity evaluation assay, PT exhibited 2-fold stronger activity than kojic acid in the presence of L-Tyrosine and L-Dopa, and PDT showed 13 times higher activity than kojic acid, respectively. Kinetic analysis revealed PT and PDT acted as mixed inhibitors. Copper ions chelation, fluorescence quenching, 1 H NMR titration, and molecular docking assays manifested PT and PDT could participate in chelation with copper ions in the tyrosinase. Furthermore, UV and CD assay results suggested that PT or PDT could induce conformational changes in tyrosinase. Critically, both compounds delayed fresh-cut apple browning and did not exhibit appreciable toxicity on normal cells. These findings demonstrate that PT and PDT are highly potent, safe, and promising tyrosinase inhibitors, with significant potential as novel anti-browning agents for extending the shelf life of fresh-cut fruits in the food industry.
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Separation Science Plus
·
2025
·Vol. 8
·期 4
·e70035
·
IF 1.6
Bingqian Zhou,Yuncan Chen,Minghui Yu,Jie Tang,Lijun Zhu,Shaomin Liu,Yangyang Xue,Changguo Wang,Rui Yang
A new method utilizing magnetic molecularly imprinted solid-phase extraction (SPE) with ultraviolet–visible (UV–vis) spectrophotometry was developed to selectively extract, preconcentrate, and detect nicotinamide (NAM) in human plasma samples. To selectively adsorb NAM, novel magnetic molecularly imprinted polymers (Fe 3 O 4 @MIPs) were synthesized. The as-prepared Fe 3 O 4 @MIPs exhibited a uniform core–shell structure with a polymer layer thickness of approximately 20 nm. The magnetic susceptibility of Fe 3 O 4 @MIPs was 7.7 emu/g, which can meet the need for rapid separation. Fe 3 O 4 @MIPs had an adsorption capacity of 411.8 mg/g, which was 232.7 mg/g larger than that of Fe 3 O 4 @NIPs. Moreover, Fe 3 O 4 @MIPs can achieve adsorption equilibrium within 15 min and exhibit good selectivity for NAM. On the basis of the above results, Fe 3 O 4 @MIPs were chosen as magnetic SPE adsorbent to selectively extract NAM from human plasma samples under the optimal experimental conditions, followed by concentration analysis using a UV–vis spectrophotometer. The validation experiment demonstrated that the proposed method had a broad linear range (50 ng/mL to 30 µg/mL), a low detection limit (8.2 ng/mL), and good recovery (92.8%–103.2%). Besides, the recovery of NAM by Fe 3 O 4 @MIPs remained above 85.2% even after five adsorption–desorption cycles. These results indicate that the proposed method, with its simplicity, rapidness, and low cost provides a potential prospect for extraction and accurate detection of targets in complicated samples.
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JOURNAL OF SEPARATION SCIENCE
·
2015
·Vol. 38
·期 16
·2887-2892
·
IF 2.737
Lilin Tang,Wenpeng Zhang,Haiyan Zhao,Zilin Chen
A capillary-electrophoresis-based method for the screening of tyrosinase inhibitors in traditional Chinese medicines was developed. The method integrated electrophoretically mediated microanalysis with sandwich mode injection, partial filling, and rapid polarity switching techniques, and carried out on-column enzyme reaction and the separation of substrate and product. The conditions were optimized including the background electrolyte, mixing voltage, and the incubation time. Finally, the screening of nine standard natural compounds of traditional Chinese medicines was carried out. The inhibitors can be directly identified from the reduced peak area of the product compared to that obtained without any inhibitor. Chlorogenic acid (100 μM) showed inhibitory activity with the inhibitory percentage of 19.8%, while the other compounds showed no inhibitory activity. This method has great application potential in drug discovery from traditional Chinese medicines.
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危险品化学品经营许可证（带存储）