6,7-Dihydroxycoumarin

The peel of Aesculus hippocastanum L.

Esculetin suppresses proteoglycan metabolism by inhibiting the production of matrix metalloproteinases in rabbit chondrocytes.[Pubmed:10334506]

Eur J Pharmacol. 1999 Apr 16;370(3):297-305.

The possible mechanism of the chondroprotective effect of 6,7-Dihydroxycoumarin (esculetin) was investigated using primary cultures of rabbit articular chondrocytes. Esculetin (EST) significantly suppressed the proteoglycan depletion and the release of pulse-labeled [35S]proteoglycan from the matrix layer of rabbit chondrocytes treated with recombinant human interleukin-1alpha. The matrix metalloproteinase inhibitor, 1,10-phenanthroline, also blocked the proteoglycan depletion and [35S]proteoglycan release. From these results, it is likely that recombinant human interleukin-1alpha-induced proteoglycan depletion is mediated by matrix metalloproteinases. Although esculetin did not directly inhibit collagenolytic activity in the culture media, it significantly suppressed the production of pro-matrix metalloproteinase-1/interstitial procollagenase and pro-matrix metalloproteinase-3/prostromelysin 1, accompanied by a decrease in the steady-state levels of their mRNAs. These results suggest that esculetin is a therapeutically effective candidate for inhibition of cartilage destruction in osteoarthritis and rheumatoid arthritis.

Esculetin (6,7-dihydroxycoumarin): a potential cancer chemopreventive agent through suppression of Sp1 in oral squamous cancer cells.[Pubmed:25310400]

Int J Oncol. 2015 Jan;46(1):265-71.

Esculetin (6,7-Dihydroxycoumarin), a coumarin compound, is known to inhibit proliferation and induce apoptosis in several types of human cancer cells and is regarded as a promising chemotherapeutic agent. The purpose of the present study was to investigate the anti-proliferative effects of esculetin on two oral squamous cell carcinoma (OSCC) cell lines, HN22 and HSC4, through regulation of specificity protein 1 (Sp1). We examined the apoptotic effects of esculetin were measured by MTS assay, DAPI staining, Annexin V, PI staining, RT-PCR, western blot analysis and immunocytochemistry in HN22 and HSC4 cells. Taken together, the results of the present study indicate that esculetin had anti-proliferative effect on the growth of OSCC cells (HN22 and HSC4) in a dose- and time-dependent manner. The treatment of HN22 and HSC4 cells with esculetin led to a significant reduction in growth and induced apoptosis, followed by the regulation of Sp1 and Sp1 regulatory protein. This indicates that esculetin inhibited cell growth and induced apoptosis by suppressing Sp1 in HN22 and HSC4 cells, suggesting it to be a potent anticancer drug candidate for oral cancer.

Esculetin inhibits the inflammatory response by inducing heme oxygenase-1 in cocultured macrophages and adipocytes.[Pubmed:25088305]

Food Funct. 2014 Sep;5(9):2371-7.

Obesity is associated with chronic low-grade inflammation of adipose tissue. In this study, we investigated the anti-inflammatory effects of esculetin (ECT) through up-regulation of heme oxygenase-1 (HO-1) in cocultured macrophages and adipocytes. RAW264.7 macrophages and differentiated 3T3-L1 adipocytes were cocultured in serum-free Dulbecco's modified Eagle's medium with or without ECT for 24 h. Nitric oxide (NO), tumor necrosis factor-alpha (TNF-alpha), and monocyte chemoattractant protein-1 (MCP-1) production was measured in the coculture supernatant. ECT decreased the secretion of NO, TNF-alpha, and MCP-1. The expression of adipogenic proteins, including peroxisome proliferator-activated receptors gamma (PPARgamma) and CCAAT/enhancer binding protein alpha (C/EBPalpha) in cocultured adipocytes and inducible nitric oxide synthase (iNOS) in cocultured macrophages, was inhibited by ECT. Additionally, HO-1 expression was induced in cocultured macrophages and adipocytes. Silencing of HO-1 expression increased the production of NO, TNF-alpha, and MCP-1 in cocultured cells, in spite of the presence of ECT. This study demonstrated that ECT exhibited anti-inflammatory properties by inhibiting the production of proinflammatory cytokines in the interaction between adipocytes and macrophages through HO-1 expression. ECT may have the potential to improve chronic inflammation in obesity.

Esculetin inhibits Ras-mediated cell proliferation and attenuates vascular restenosis following angioplasty in rats.[Pubmed:12781342]

Biochem Pharmacol. 2003 Jun 1;65(11):1897-905.

The proliferation of vascular smooth muscle cells (VSMCs) induced by injury to the intima of arteries is an important etiologic factor in vascular proliferative disorders such as atherosclerosis and restenosis. Esculetin, derived from the Chinese herb Artemisia scoparia, is well known as a lipoxygenase inhibitor. We have investigated the inhibitory effects of esculetin on VSMC proliferation and intimal hyperplasia by balloon angioplasty in the rat. We determined, using [3H]thymidine incorporation and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, that esculetin inhibited the proliferation of VSMCs via a lipoxygenase-independent pathway. Three predominant signaling pathways were identified to be inhibited by esculetin: (a) the activation of p42/44 mitogen-activated protein kinase (MAPK) and the downstream effectors of c-fos and c-jun immediate early genes by means of western and reverse transcription-polymerase chain reaction (RT-PCR) analyses; (b) the activation of nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1), using the electrophoretic mobility shift assay; and (c) the activation of phosphoinositide 3-kinase (PI 3-kinase) and cell cycle progression, by western blot analysis and flow cytometric detection. Furthermore, esculetin also profoundly inhibited Ras activation, a shared upstream event of the above signaling cascades. In vascular injury studies, intraperitoneal administration of esculetin significantly suppressed intimal hyperplasia induced by balloon angioplasty. We conclude that esculetin blocks cell proliferation via the inhibition of an upstream effector of Ras and downstream events including p42/44 MAPK activation, PI 3-kinase activation, immediate early gene expression, as well as NF-kappaB and AP-1 activation. It also inhibits intimal hyperplasia after balloon vascular injury in the rat, indicating the therapeutic potential for treating restenosis after arterial injury.

Esculetin induces apoptosis and inhibits adipogenesis in 3T3-L1 cells.[Pubmed:17062797]

Obesity (Silver Spring). 2006 Oct;14(10):1691-9.

OBJECTIVE: To determine the effects of esculetin, a plant phenolic compound with apoptotic activity in cancer cells, on 3T3-L1 adipocyte apoptosis and adipogenesis. RESEARCH METHODS AND PROCEDURES: 3T3-L1 pre-confluent preadipocytes and lipid-filled adipocytes were incubated with esculetin (0 to 800 microM) for up to 48 hours. Viability was determined using the Cell Titer 96 Aqueous One Solution cell proliferation assay; apoptosis was quantified by measurement of single-stranded DNA. Post-confluent preadipocytes were incubated with esculetin for up to 6 days during maturation. Adipogenesis was quantified by measuring lipid content using Nile Red dye; cells were also stained with Oil Red O for visual confirmation of effects on lipid accumulation. RESULTS: In mature adipocytes, esculetin caused a time- and dose-related increase in adipocyte apoptosis and a decrease in viability. Apoptosis was increased after only 6 hours by 400 and 800 microM esculetin (p < 0.05), and after 48 hours, as little as 50 microM esculetin increased apoptosis (p < 0.05). In preadipocytes, apoptosis was detectable only after 48 hours (p < 0.05) with 200 microM esculetin and higher concentrations. However, results of the cell viability assay indicated a reduction in preadipocyte number in a time- and dose-related manner, beginning as early as 6 hours with 400 and 800 microM esculetin (p < 0.05). Esculetin also inhibited adipogenesis of 3T3-L1 preadipocytes. Esculetin-mediated inhibition of adipocyte differentiation occurred during the early, intermediate, and late stages of the differentiation process. In addition, esculetin induced apoptosis during the late stage of differentiation. DISCUSSION: These findings suggest that esculetin can alter fat cell number by direct effects on cell viability, adipogenesis, and apoptosis in 3T3-L1 cells.

Inhibitory effect of esculetin on oxidative damage induced by t-butyl hydroperoxide in rat liver.[Pubmed:11097384]

Arch Toxicol. 2000 Oct;74(8):467-72.

Increasing evidence regarding free radical-generating agents and inflammatory processes suggests that accumulation of reactive oxygen species can cause hepatotoxicity. A short-chain analog of lipid hydroperoxide, t-butyl hydroperoxide (t-BHP), can be metabolized to free radical intermediates by cytochrome P-450 in hepatocytes, which in turn can initiate lipid peroxidation, affect cell integrity and result in cell injury. In this study, we used t-BHP to induce hepatotoxicity in vitro and in vivo and determined the antioxidative bioactivity of esculetin, a coumarin compound. Our investigations showed that pretreatment with esculetin (5-20 microg/ml) significantly decreased the leakage of lactate dehydrogenase (LDH) and alanine transaminase (ALT), and also decreased the formation of malondialdehyde (MDA) in primary cultured rat hepatocytes induced by a 30-min treatment with t-BHP. An in vivo study in rats showed that pretreatment with esculetin (i.p.) at concentrations of 0.5 and 5 mg/kg for 5 days before a single i.p. dose of t-BHP (0.1 mmol/kg) significantly lowered the serum levels of the hepatic enzyme markers (ALT and AST) and reduced oxidative stress in the liver. Histopathological evaluation of the rat livers revealed that esculetin reduced the incidence of liver lesions induced by t-BHP, including hepatocyte swelling, leukocyte infiltration, and necrosis. Based on the results described above, we speculate that esculetin may play a chemopreventive role via reducing oxidative stress in living systems.

Mushroom tyrosinase inhibitory activity of esculetin isolated from seeds of Euphorbia lathyris L.[Pubmed:12723615]

Biosci Biotechnol Biochem. 2003 Mar;67(3):631-4.

A tyrosinase inhibitor was isolated from the seeds of Euphorbia lathyris L. by bioassay-guided fractionation and purification, using silica gel column chromatography. It was identified as esculetin by comparing its physical properties and spectral data with those of an authentic sample. The IC50 value of esculetin in the mushroom tyrosinase activity test was 43 microM. The kinetic study indicates that esculetin exhibited competitive inhibition against the oxidation of 3-(3,4-dihydroxyphenyl)-alanine by mushroom tyrosinase. The structure-activity relationships among five esculetin analogs suggest that hydroxyl groups at the C6 and C7 positions of the coumarin skeleton played an important role in the expression of tyrosinase inhibitory activity.

Esculetin is an active ingredient extracted mainly from the bark of Fraxinus rhynchophylla. Esculetin inhibits platelet-derived growth factor (PDGF)-induced airway smooth muscle cells (ASMCs) phenotype switching through inhibition of PI3K/Akt pathway. Esculetin has antioxidant, antiinflammatory, and antitumor activities.

6,7-Dihydroxycoumarin,305-01-1,Aesculetin; Cichorigenin; Cichoriin aglycone; 6,7-Dihydroxycoumarin; Esculetol; Esculin aglycone,Natural Products, buy 6,7-Dihydroxycoumarin , 6,7-Dihydroxycoumarin supplier , purchase 6,7-Dihydroxycoumarin , 6,7-Dihydroxycoumarin cost , 6,7-Dihydroxycoumarin manufacturer , order 6,7-Dihydroxycoumarin , high purity 6,7-Dihydroxycoumarin