Difference analysis of different parts of chicory based on HPLC fingerprint and multi-component content determination / 中草药·英文版

Objective: To establish HPLC fingerprints of different parts of chicory stems, leaves, roots, flowers and seeds, and compare the similarities and differences of chemical components in different parts, so as to provide a scientific basis for the comprehensive utilization of chicory. Methods: To establish the HPLC fingerprint of chicory, the chromatographic column was chosen with Agilent ZORBAX Eclipse XDB-C

Esculetin protects against early sepsis via attenuating inflammation by inhibiting NF-κB and STAT1/STAT3 signaling / 中国天然药物

Esculetin, a natural derivative from the traditional and widely-used Chinese medicinal herb Cortex Fraxini, has a variety of pharmacological effects, especially in anti-inflammation. However, it is not clear whether esculetin has a therapeutic effect on sepsis. This study aimed to investigate the anti-inflammatory and protective effects of esculetin on early sepsis. The results showed that the lung injury was significantly relieved with the treatment of esculetin, accompanied with the restrained production of inflammatory factors including IL-1β, IL-6, TNF-α, CCL2 and iNOS during the early phase of E.coli-induced sepsis. Of note, activation of NF-κB and STAT1/STAT3 signals, the main upstream signals of many inflammatory factors, were attenuated by esculetin in both lung tissues from septic mice and LPS-stimulated macrophage. These findings suggested that the protection of esculetin against early sepsis should be related to its anti-inflammatory effect, which was at least partly due to its inhibition on NF-κB and STAT1/STAT3 signaling pathway in macrophage. Thus, esculetin could serve as a potential therapeutic agent by rebalancing innate immune response in macrophage for the treatment of early sepsis.

Esculetin as bioactive marker: towards a rational scientific approach for the treatment of hyperuricemia using Traditional Chinese Medicine

Traditional Chinese Herbal Medicine has been used to prevent and cure disease in China for thousands of years and has gained global interest in recent decades. The Erding formula is a Chinese Pharmacopeia (ChP)-listed herbal preparation used for treating sore throat, carbuncles and boils. Esculetin is a ChP quality control (QC) marker for these indications. A previous study found that a new indication, hyperuricemia, can be added to the Erding formula. Therefore, this study aimed to evaluate whether the traditionally used marker, esculetin, still has bioactivity for hyperuricemia, which is substantially different from the original indications. The study analyzed the quantity of esculetin by high-performance liquid chromatography, assessed the therapeutic effect of esculetin using animal model, and then characterized esculetin and its metabolites in serum via ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. The results showed that the esculetin content in the aqueous Erding extract was 0.26±0.05% (w/w). Both the Erding extract and esculetin significantly reduced uric acid levels. Six metabolites of esculetin were identified in mice serum. This study revealed a rational scientific approach to prove esculetin is a reliable bioactive and QC marker for Erding formula in hyperuricemia treatment which contributed to ensure product quality and therapeutic efficacy.

A new norlignan from fruiting bodies of Amauroderma rude / 中草药

Objective For the purpose of finding new bioactive compounds from natural resources, the phytochemical investigation on the fruiting bodies of Amauroderma rude was carried out. Methods The chemical constituents from A. rude were isolated by various technologies, such as silica gel, Sephadex LH-20, MCI-gel resin, and high performance liquid chromatography. The isolated compounds were elucidated by spectroscopic methods, including extensive 1D, 2D NMR, and ESI-MS techniques. Results Three compounds (1-3) including a new norlignan, were isolated from this mushroom. Their structures were identified as 4-ethyoyl-E-3-(3,4-dihydroxybenzylidene)-5-(3,4-dihydroxyphenyl)furan-2-one (1), esculetin (2), and caffeic acid (3). Conclusion Compound 1 is a new compound isolated from this fungus, which is identified as amauroderin A.

Isolation and Identification of Antioxidant Activity Constituents from Elephantopus scaber / 中国实验方剂学杂志

Objective:To study the chemical constituents of 95% ethanol extract of the whole plant of Elephantopus scaber and investigate its antioxidant activity. Method:The chemical constituents were isolated and purified by silica gel column chromatography,Sephadex LH-20 column chromatography,ODS column chromatography,semi-preparative high performance liquid chromatography (HPLC) and recrystallization methods,while their structures were identified on the basis of nuclear magnetic resonance (NMR), mass spectrometry and comparison of their spectral data with those reported in the literature. Result:Fourteen compounds were isolated and their structures were identified as:(E)-3-(3,4-dihydroxybenzylidene)-5-(3,4-dihydroxyphenyl)-2(3H)-furanone (1),esculetin (2),dihydrosyringenin (3),(+)-isololiolide (4),caffic acid (5),luteolin-7-O-β-D-glucuronide (6),luteolin-7-O-β-D-glucuronide methyl ester (7),chlorogenic acid methyl ester (8),blumenol A (9),(6R,9R)-3-oxo-α-ionol-β-D-glucopyranoside (10),byzantionoside B (11),3,5-O-dicaffeoyl quinic acid methyl ester (12),3,4-O-dicaffeoyl quinic acid methyl ester (13) and 4,5-O-dicaffeoyl quinic acid methyl ester (14). Conclusion:Compounds 1-4 and 8-10 were isolated from the genus Elephantopus for the first time. Compound 11 was isolated from E. scaber for the first time. The DPPH radical and ABTS+ radical scavenging experiments on twelve of these compounds showed that compounds 1,2,5,6,12 and 13 had significant antioxidant activity.

Esculetin Prevents the Induction of Matrix Metalloproteinase-1 by Hydrogen Peroxide in Skin Keratinocytes

BACKGROUND: Reactive oxygen species (ROS) are involved in various cellular diseases. Excessive ROS can cause intracellular oxidative stress, resulting in a calcium imbalance and even aging. In this study, we evaluated the protective effect of esculetin on oxidative stress-induced aging in human HaCaT keratinocytes. METHODS: Human keratinocytes were pretreated with esculetin for 30 minutes and treated with H₂O₂. Then, the protective effects on oxidative stress-induced matrix metalloproteinase (MMP)-1 were detected by Flou-4-AM staining, reverse transcription-PCR, Western blotting, and quantitative fluorescence assay. RESULTS: Esculetin prevented H₂O₂-induced aging by inhibiting MMP-1 mRNA, protein, and activity levels. In addition, esculetin decreased abnormal levels of phospho-MEK1, phospho-ERK1/2, phospho-SEK1, phospho-JNK1/2, c-Fos, and phospho-c-Jun and inhibited activator protein 1 binding activity. CONCLUSIONS: Esculetin prevented excessive levels of intracellular calcium and reduced the expression levels of aging-related proteins.

Esculetin Inhibits the Survival of Human Prostate Cancer Cells by Inducing Apoptosis and Arresting the Cell Cycle

BACKGROUND: Prostate cancer (PCa) is one of the most important causes of death in men and thus new therapeutic approaches are needed. In this study, antiproliferative and anti-migration properties of a coumarin derivative esculetin were evaluated. METHODS: Human PCa cell lines PC3, DU145, and LNCaP were treated with various concentrations of esculetin for 24 to 72 hours, and cell viability was determined by the MTT test. Cell cycle and apoptosis were analyzed by using cell-based cytometer. Gene expression levels were assessed by reverse transcription and quantitative real-time PCR, cell migration was determined by the wound healing assay. The protein expression was measured by Western blotting. RESULTS: Esculetin inhibited cell proliferation in a dose- and time-dependent manner. Cell migration was inhibited by esculetin treatment. Administration of esculetin significantly reduced the cells survival, induced apoptosis and caused the G1 phase cell cycle arrest shown by image-based cytometer. The induced expression of cytochrome c, p53, p21 and p27, and down-regulated CDK2 and CDK4 may be the underlying molecular mechanisms of esculetin effect. Esculetin suppressed phosphorylation of Akt and enhanced protein expression of tumor-suppressor phosphatase and tensin homologue. CONCLUSIONS: Our findings showed that the coumarin derivative esculetin could be used in the management of PCa. However, further in vivo research is needed.

Study on chemical fingerprint of Wuwei Xiaoduyin Oral Liquid and simultaneous determination of six characteristic components / 中草药

Objective: To establish the HPLC chemical fingerprints of Wuwei Xiaoduyin Oral Liquid (WXOL) and simultaneous determination method for six major characteristic components in this herbal preparation, i.e. chlorgenic acid, luteoloside, luteolin, linarin, caffeic acid, and esculetin. Methods: Both chemical fingerprint analysis and quantitative determination were implemented by Agilent 1260 high performance liquid chromatography system with an Agilent 5 TC-C18 column (250 mm × 4.6 mm, 5 μm). A gradient elution program, with the mobile phase of 0.5% glacial acetic acid aqueous solution (A) and methanol (B), was employed as following: 0—10 min, 10%—32% B; 10—20 min, 32% B; 20—25 min, 32%—46% B; 25—31 min, 46%—48% B; 31—41 min, 48%—80% B at the flow rate of 1.0 mL/min. The detection wavelength and column temperature were set at 320 nm and 30 ℃, respectively. Additionally, fingerprint similarity of 10 batches of WXOL was evaluated by software “Similarity Evaluation System for Chromatographic Fingerprint of TCM” published by GPC (Version 2012). The amounts of six characteristic components in WXOL were also simultaneously determined. Results: The common fingerprint pattern derived from 10 batches of samples was obtained with the similarity over 0.98 and 17 common peaks defined. Meanwhile, some common peaks were identified via peak pattern match with standard substances, showing that the peak No.5, No.7, No.8, No.12, No.16, and No.17 was chlorgenic acid, esculetin, caffeic acid, luteoloside, linarin, and lutelin, respectively. Chlorgenic acid content range of 54.038 3—105.551 1 μg/mL, esculetin content range of 4.122 1—31.359 9 μg/mL, caffeic acid content range of 2.413 0—4.420 7 μg/mL, luteoloside content range of 4.042 8—11.312 8 μg/mL, linarin content range of 3.866 3—46.271 9 μg/mL, and luteolin content range of 0.990 8—2.126 8 μg/mL. In combination with the non-significant difference of multiple characteristic components content among 10 batches of samples, the quality of home-made WXOL would be stable. Conclusion: A novel quality control method, which is HPLC fingerprint in combination with simultaneous quantitative analysis of multiple components, was established in this study, with high repeatability and reliability. Therefore, this method provides an applicable approach for the quality control of WXOL.

Anti-Alzheimer's disease potential of coumarins from Angelica decursiva and Artemisia capillaris and structure-activity analysis

Objective: To use structure-activity analysis to study the anti-Alzheimer's disease (anti-AD) activity of natural coumarins isolated from Angelica decursiva and Artemisia capillaris, along with one purchased coumarin (daphnetin). Methods: Umbelliferone, umbelliferone 6-carboxylic acid, scopoletin, isoscopoletin, 7-methoxy coumarin, scoparone, scopolin, and esculetin have been previously isolated; however 2'-isopropyl psoralene was isolated from Angelica decursiva for the first time to evaluate their inhibitory effects against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and β-site amyloid precursor protein cleaving enzyme 1 (BACE1) enzyme activity. We scrutinized the potentials of coumarins as cholinesterase and BACE1 inhibitors via enzyme kinetics and molecular docking simulation. Results: Among the test compounds, umbelliferone 6-carboxylic acid, esculetin and daphnetin exhibited potent inhibitory activity against AChE, BChE and BACE1. Both esculetin and daphnetin have a catechol group and exhibit significant anti-AD activity against AChE and BChE. In contrast, presence of a sugar moiety and methoxylation markedly reduced the anti-AD activity of the coumarins investigated in this study. With respect to BACE1 inhibition, umbelliferone 6-carboxylic acid, esculetin and daphnetin contained carboxyl or catechol groups, which significantly contributed to their anti-AD activities. To further investigate these results, we generated a 3D structure of BACE1 using Autodock 4.2 and simulated binding of umbelliferone 6-carboxylic acid, esculetin and daphnetin. Docking simulations showed that different residues of BACE1 interacted with hydroxyl and carboxylic groups, and the binding energies of umbelliferone 6-carboxylic acid, esculetin and daphnetin were negative (-4.58, -6.25 and -6.37 kcal/mol respectively). Conclusions: Taken together, our results suggest that umbelliferone 6-carboxylic acid, esculetin and daphnetin have anti-AD effects by inhibiting AChE, BChE and BACE1, which might be useful against AD.

Chemical constituents from leaves of Perilla frutescens / 中草药

Objective: To investigate the chemical constituents from the aqueous extract of leaves of Perilla frutescens. Methods: The compounds were isolated and purified by chromatography on macroporous resin, silica gel, ODS, and preparative HPLC. Their structures were elucidated on the basis of chemical and spectroscopic methods, including MS, 1D and 2D NMR spectral techniques. Results: Seventeen compounds were isolated from the aqueous extract of leaves of P. frutescens, and were identified as (+)- isololiolide (1), dehydrovomifoliol (2), (-)-loliolide (3), scutellarin (4), p-hydroxybenzaldehyde (5), p-hydroxyacetophenone (6), 3-formylindole (7), trans-p-hydroxycinnamic acid (8), apigenin (9), luteolin (10), esculetin (11), caffeic acid (12), rosmarinic acid (13), methyl rosmarinate (14), sericoside (15), caffeic acid vinyl ester (16), and negletein (17). Conclusion: Compounds 1-2, 6-8, and 15 are firstly isolated from the plants of Perilla Linn.

Anti-Alzheimer's disease potential of coumarins from Angelica decursiva and Artemisia capillaris and structure-activity analysis

OBJECTIVE@#To use structure-activity analysis to study the anti-Alzheimer's disease (anti-AD) activity of natural coumarins isolated from Angelica decursiva and Artemisia capillaris, along with one purchased coumarin (daphnetin).@*METHODS@#Umbelliferone, umbelliferone 6-carboxylic acid, scopoletin, isoscopoletin, 7-methoxy coumarin, scoparone, scopolin, and esculetin have been previously isolated; however 2'-isopropyl psoralene was isolated from Angelica decursiva for the first time to evaluate their inhibitory effects against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and β-site amyloid precursor protein cleaving enzyme 1 (BACE1) enzyme activity. We scrutinized the potentials of coumarins as cholinesterase and BACE1 inhibitors via enzyme kinetics and molecular docking simulation.@*RESULTS@#Among the test compounds, umbelliferone 6-carboxylic acid, esculetin and daphnetin exhibited potent inhibitory activity against AChE, BChE and BACE1. Both esculetin and daphnetin have a catechol group and exhibit significant anti-AD activity against AChE and BChE. In contrast, presence of a sugar moiety and methoxylation markedly reduced the anti-AD activity of the coumarins investigated in this study. With respect to BACE1 inhibition, umbelliferone 6-carboxylic acid, esculetin and daphnetin contained carboxyl or catechol groups, which significantly contributed to their anti-AD activities. To further investigate these results, we generated a 3D structure of BACE1 using Autodock 4.2 and simulated binding of umbelliferone 6-carboxylic acid, esculetin and daphnetin. Docking simulations showed that different residues of BACE1 interacted with hydroxyl and carboxylic groups, and the binding energies of umbelliferone 6-carboxylic acid, esculetin and daphnetin were negative (-4.58, -6.25 and -6.37 kcal/mol respectively).@*CONCLUSIONS@#Taken together, our results suggest that umbelliferone 6-carboxylic acid, esculetin and daphnetin have anti-AD effects by inhibiting AChE, BChE and BACE1, which might be useful against AD.

Esculetin, a Coumarin Derivative, Inhibits Aldose Reductase Activity in vitro and Cataractogenesis in Galactose-Fed Rats

Naturally occurring coumarin compounds have received substantial attention due to their pharmaceutical effects. Esculetin is a coumarin derivative and a polyphenol compound that is used in a variety of therapeutic and pharmacological strategies. However, its effect on aldose reductase activity remains poorly understood. In this study, the potential beneficial effects of esculetin on lenticular aldose reductase were investigated in galactose-fed (GAL) rats, an animal model of sugar cataracts. Cataracts were induced in Sprague-Dawley (SD) rats via a 50% galactose diet for 2 weeks, and groups of GAL rats were orally treated with esculetin (10 or 50 mg/kg body weight). In vehicle-treated GAL rats, lens opacification was observed, and swelling and membrane rupture of the lens fiber cells were increased. Additionally, aldose reductase was highly expressed in the lens epithelium and superficial cortical fibers during cataract development in the GAL rats. Esculetin reduced rat lens aldose reductase (RLAR) activity in vitro, and esculetin treatment significantly inhibited lens opacity, as well as morphological alterations, such as swelling, vacuolation and liquefaction of lens fibers, via the inhibition of aldose reductase in the GAL rats. These results indicate that esculetin is a useful treatment for galactose-induced cataracts.

Esculetin, a coumarin derivative, exerts in vitro and in vivo antiproliferative activity against hepatocellular carcinoma by initiating a mitochondrial-dependent apoptosis pathway

This study investigated the in vitro and in vivo antiproliferative activity of esculetin against hepatocellular carcinoma, and clarified its potential molecular mechanisms. Cell viability was determined by the MTT (tetrazolium) colorimetric assay. In vivo antitumor activity of esculetin was evaluated in a hepatocellular carcinoma mouse model. Seventy-five C57BL/6J mice were implanted with Hepa1-6 cells and randomized into five groups (n=15 each) given daily intraperitoneal injections of vehicle (physiological saline), esculetin (200, 400, or 700 mg·kg-1·day-1), or 5-Fu (200 mg·kg-1·day-1) for 15 days. Esculetin significantly decreased tumor growth in mice bearing Hepa1-6 cells. Tumor weight was decreased by 20.33, 40.37, and 55.42% with increasing doses of esculetin. Esculetin significantly inhibited proliferation of HCC cells in a concentration- and time-dependent manner and with an IC50 value of 2.24 mM. It blocked the cell cycle at S phase and induced apoptosis in SMMC-7721 cells with significant elevation of caspase-3 and caspase-9 activity, but did not affect caspase-8 activity. Moreover, esculetin treatment resulted in the collapse of mitochondrial membrane potential in vitro and in vivo accompanied by increased Bax expression and decreased Bcl-2 expression at both transcriptional and translational levels. Thus, esculetin exerted in vitro and in vivo antiproliferative activity in hepatocellular carcinoma, and its mechanisms involved initiation of a mitochondrial-mediated, caspase-dependent apoptosis pathway.

Chemical constituents of Carthamus tinctorius / 中草药

Objective: To investigate the chemical constituents of Carthamus tinctorius. Methods: Compounds were isolated by a combination of various column chromatography over silica gel, Sephadex LH-20, and pre-HPLC and their structures were identified by spectral analytical methods of MS and NMR and/or comparison with literature data. Results: Twenty compounds were isolated from the ethanol extract of C. tinctorius. Their structures were identified as kaempferol-3-O-β-D-glucosyl-(1→2)-β-D-glucoside (1), scutellarein (2), hexacosanoic acid (3), (2S)-1-O-heptatriacontanoyl glycerol (4), 4,4-dimethyl heptanedioic (5), 5,7,4'-trihydroxy-6- methoxyflavone-3-O-β-D-rutinoside (6), n-tetratriacont-20,23-dienoic acid (7), vanillic acid (8), gallic acid (9), tetrephthalic acid mono-[2-(4-carboxy-phenoxycarbonyl)-vinyl] ester (10), esculetin (11), 6-hydroxyapigenin-6-O-β-D-glucoside-7-O-β-D-glucuronide (12), quercetin-3,7-di-O-β-D-glucoside (13), 6-methoxykaempferol (14), syringing (15), E-1-(4'-hydroxypheny)-but-1-en-3-one (16), ursolic acid (17), 1-hexadecanoyl propan-2,3-diol (18), citrostadienol (19), and scopoletin (20). Conclusion: Compounds 1, 5, 7, 10, 18, and 19 are isolated from the plants of Carthamus L. for the first time, and compounds 2-4, 6, 8, 9, 11, 17, and 20 are obtained from C. tinctorius for the first time.

Content Comparison of Esculetin in Different Parts of Viola Philippica from Different Habitats / 中国药师

To determine the content of esculetin in the different parts of Viola philippica from various habitats by HPLC to provide the basis for the reasonable application and the quality assessment of the herb. Methods:The content of esculetin in roots, leaf stems and leaves of Viola philippica was determined by HPLC, and the proportion of various parts in the total grass was calculated, and the content of esculetin in Viola philippica from different habitats was compared. Results:The index ingredient esculetin was de-tected out in the roots, leaf stems and leaves, the content in leaf blades was the highest followed by leaf stalks, and that in root was the lowest. There were notable differences in the quality of Viola philippica from different habitats. Conclusion:The content of esculetin in the leaves of Viola philippica is the highest proportion, and that in Viola philippica from Hebei is the higher. The difference among the other habitats is relatively small. The results can provide reference for the harvest and reasonable application of Viola philippica.

Esculetin, a Coumarin Derivative, Exhibits Anti-proliferative and Pro-apoptotic Activity in G361 Human Malignant Melanoma

BACKGROUND: Although esculetin, a coumarin compound, is known to induce apoptosis in human cancer cells, the effects and molecular mechanisms on the apoptosis in human malignant melanoma (HMM) cells are not well understood yet. In this study, we investigated the anti-proliferative effects of esculetin on the G361 HMM cells. METHODS: We analyzed the anti-proliferative effects and molecular mechanisms of esculetin on G361 cells by a 3-(4,5-dimethylthiazol- 2-yl)-5-(3-carboxymethoxy phenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay, 4\',6-diamidino-2-phenylindole staining and Western blotting. RESULTS: Esculetin exhibited significant anti-proliferative effects on the HMM cells in a dose-dependent manner. Interestingly, we found that esculetin induced nuclear shrinkage and fragmentation, typical apoptosis markers, by suppression of Sp1 transcription factor (Sp1). Notably, esculetin modulated Sp1 downstream target genes including p27, p21 and cyclin D1, resulted in activation of apoptosis signaling molecules such as caspase-3 and PARP in G361 HMM cells. CONCLUSIONS: Our results clearly demonstrated that esculetin induced apoptosis in the HMM cells by downregulating Sp1 protein levels. Thus, we suggest that esculetin may be a potential anti-proliferative agent that induces apoptotic cell death in G361 HMM cells.

Comparison on HPLC fingerprints between fraxini cortex and its eye drop / 中草药·英文版

Objective: To compare the HPLC fingerprints of Fraxini Cortex and its eye drop. Methods: Using esculin and esculetin as reference substances, HPLC method was established for fingerprint chromatography of Fraxini Cortex and its eye drop. The similarity was analyzed by similarity evaluation and system cluster analysis. Results: For Fraxini Cortex, eight peaks were separated, among which four common peaks were obtained; for eye drop, eleven peaks were separated including six common peaks. Similarities of both fingerprints were good. Cluster analysis further showed that different sources resulted in the variance of ingredients in crude drug. Both materials and eye drop had some common peaks such as esculin and esculetin, on the other hand, they had some different peaks which might be caused by extracting process. Conclusion: HPLC fingerprint chromatogram could be applied for the quality control of Fraxini Cortex and its preparations; the pharmaceutical process may be responsible for the variance of ingredients. © 2013 Tianjin Press of Chinese Herbal Medicines.

Chemical constituents in ethyl acetate extract from aerial part of Gynura divaricata / 中草药

Objective: To study the chemical constituents of ethyl acetate fraction in 80% ethanol reflux extract from the aerial part of Gynura divaricata. Methods: Column chromatographic techniques were applied to isolate and purify the chemical constituents. The chemical structures of the constituents were elucidated on the basis of mass properties and NMR spectral data. Results: Fourteen compounds were isolated and their structures were determined spectroscopically as succinic acid (1), methyl succinate (2), ethyl succinate (3), ethyl methyl succinate (4), 4-hydroxybenzoic acid (5), salicylic acid (6), isovanillic acid (7), p-coumaric acid (8), esculetin (9), quercetin (10), kaempferol (11), isoquercitrin (12), astragalin (13), and rutin (14). Conclusion: Compounds 1-4 and 6-9 are isolated from this plant for the first time.

Chemical constituents from Cardamine leucantha / 中草药

Objective: To investigate the chemical constituents in the whole herbs of Cardamine leucantha. Methods: The chemical constituents were isolated and purified via silica gel, polyamide, D-101 macroperous resin, and Sephadex LH-20 column chromatography. Their structures were determined on the basis of spectral analysis and physicochemical properties. Results: Fourteen compounds were isolated and identified, covering three simple indoles: indole-3-carboxylic acid (1), 6-hydroxyindole-3-carboxylic acid (2), and 6-hydroxyindole-3-carboxylic acid-6-O-β-D-glucopyranoside (3); two coumarins: esculetin (4) and esculin (5); seven steroids: 3-O-(p-coumaroyl)-β-sitosterol (6), β-sitosterol (7), 5α, 8α-epidioxyergosta-6, 22-dien-3β-ol (8), 5α, 8α-epidioxyergosta-6, 9 (11), 22-trien-3β-ol (9), sitost-5-ene-3β, 7α-diol (10), β-sitosteryl-3β-glucopyranoside-6'-O-palmitate (11), and daucosterol (12); and two phenolic compounds: p-hydroxybenzoic acid (13) and vanillic acid (14). Conclusion: All the compounds are isolated from the plants in Cardamine L. for the first time.

Esculetin inhibits N-methyl-D-aspartate neurotoxicity via glutathione preservation in primary cortical cultures / 한국실험동물학회지

Recently, loss of endogenous glutathione during N-methyl-D-aspartate (NMDA) receptor-mediated excitotoxic injury, and the resultant overproduction of reactive oxygen species (ROS) through an arachidonic acid cascade process in brain, have been implicated in neuronal damage in various neurodegenerative diseases. Glutathione depletion induced by L-buthionine-(S,R)-sulfoximine (BSO), an inhibitor of glutathione synthesis, is known to cause arachidonic acid-mediated excitotoxicity in primary mixed cortical cultures. The aim of this study was to investigate whether esculetin (6,7-dihydroxycoumarin), an inhibitor of lipoxygenase, protects against neurotoxicity induced by NMDA or BSO. We observed that neurotoxicity induced by NMDA but not kainic acid was attenuated by esculetin. At the same concentration (100 microM), esculetin attenuated the 45Ca2+ uptake elevation induced by NMDA. Free radical-mediated neuronal injury induced by H2O2 and xanthine/xanthine oxidase was concentration-dependently blocked by esculetin. Esculetin (1-30 microM) dose-dependently inhibited BSO-induced neuronal injury. In addition, arachidonate-induced neurotoxicity was completely blocked by esculetin. BSO also reduced glutathione peroxidase (GPx) activity, but did not change glutathione reductase (GR) activity 24 h after treatment. Esculetin dose-dependently increased GR activity, but did not alter GPx activity. These findings suggest that esculetin can contribute to the rescue of neuronal cells from NMDA neurotoxicity and that this protective effect occurs partly through NMDA receptor modulation and the sparing of glutathione depletion.