Chrysoeriol

J Pharmacol Sci. 2009 May;110(1):105-10.

An inhibitory effect of chrysoeriol on platelet-derived growth factor (PDGF)-induced proliferation and PDGF receptor signaling in human aortic smooth muscle cells.[Pubmed: 19423953]

Platelet-derived growth factor (PDGF)-BB is one of the most potent factors in the development and progression of various vascular disorders such as restenosis and atherosclerosis. Chrysoeriol is a flavonoid with antioxidant and anti-inflammatory activities.
METHODS AND RESULTS:
In this study, we investigated the effect of Chrysoeriol on the proliferation of human aortic smooth muscle cells (HASMC). Chrysoeriol significantly inhibited PDGF (20 ng/mL)-induced migration and [(3)H]-thymidine incorporation into DNA at concentrations of 5 and 10 microM without any cytotoxicity. Chrysoeriol also blocked PDGF-stimulated dissociation of actin filament and inhibited PDGF beta-receptor (Rbeta) phosphorylation in a concentration-dependent manner. As a result, the downstream signal transduction pathways of PDGF-Rbeta, including ERK1/2, p38, and Akt phosphorylation, were also inhibited by Chrysoeriol in the same pattern.
CONCLUSIONS:
These findings suggest that in addition to its antioxidant and anti-inflammatory activities, Chrysoeriol may be used for the prevention and treatment of vascular diseases and during restenosis after coronary angioplasty.

Toxicology. 2010 Jul-Aug;274(1-3):42-8.

Inhibitory effects of chrysoeriol on DNA adduct formation with benzo[a]pyrene in MCF-7 breast cancer cells.[Pubmed: 20553787]

Cytochrome P450 (CYP) 1 families including CYP1A1, 1A2 and 1B1 are well known to be deeply involved in the initiation of several cancers, due to the fact that they activate environmental pro-carcinogens to form ultimate carcinogens. Benzo[a]pyrene (BaP) is one of the major classes of prototypical pro-carcinogen. It is activated by the CYP1 family to its ultimate carcinogenic forms, mainly BaP-7,8-diol-9,10-epoxide (BPDE), and it forms adducts with DNA. This has been recognized to be a major initiation pathway for cancer. Our previous study demonstrated that Chrysoeriol, which is a dietary methoxyflavonoid, selectively inhibited CYP1B1 enzymatic activity and might protect the CYP1B1 related-diseases such as breast cancer.
METHODS AND RESULTS:
In the present study, we further examined the effects of Chrysoeriol on the other initiation pathway of cancer relating to the CYP1 family with BaP in human breast cancer MCF-7 cells. The effects of Chrysoeriol on the formation of BPDE-DNA adducts were analyzed specifically using the liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. When MCF-7 cells were incubated with 2 microM BaP for 24h, three types of BPDE-dG adducts, especially (+)-trans-BPDE-dG as the dominant adduct, were detected. Co-treatment of MCF-7 cells with 10 microM Chrysoeriol and BaP remarkably reduced (+)-trans-BPDE-dG formation. Chrysoeriol (1-10 microM) dose-dependently inhibited both EROD activity and the gene expressions of CYP1A1, 1B1 and 1A2 stimulated by treatment with BaP. In addition, the same amounts of Chrysoeriol significantly inhibited the binding of BaP to the aryl hydrocarbon receptor (AhR), which is the key factor concerning the induction of the CYP1 families.
CONCLUSIONS:
In conclusion, our results clearly indicate that Chrysoeriol inhibited the formation of BPDE-DNA adducts via regulation of the AhR pathway stimulated by BaP. As a consequence Chrysoeriol may be involved in the chemoprevention of environmental pro-carcinogens such as BaP.

J Biomed Sci. 2005 Dec;12(6):949-59.

Chrysoeriol potently inhibits the induction of nitric oxide synthase by blocking AP-1 activation.[Pubmed: 16228289 ]

Chrysoeriol is a flavonoid with antioxidant and anti-inflammatory activities. Despite the large number of studies performed on its biological activities, no clear picture of its mode of action has emerged.
METHODS AND RESULTS:
In the present study, we isolated Chrysoeriol from the leaves of Digitalis purpurea (foxglove), and studied its effect on the induction of the inducible nitric oxide synthase (iNOS) gene, and the mechanism of this induction in Raw264.7 macrophages. Chrysoeriol pretreatment potently inhibited the release of NO in the cells treated with lipopolysaccharide (LPS), and Western blot and RT-PCR analyses revealed that Chrysoeriol inhibited the LPS-induced inductions of iNOS gene. Moreover, it is known that the activations of nuclear factor-kappaB (NF-kappaB) and activator protein 1 (AP-1) are crucial steps in the transcriptional activation of the iNOS gene. Here, we found that Chrysoeriol selectively suppressed AP-1 activation, and that activation of AP-1 is likely to be essential for iNOS induction in LPS-treated macrophages.
CONCLUSIONS:
This presumed inhibitory effect on AP-1 activation by Chrysoeriol may be associated with its potent NO blocking and anti-inflammatory effects.

Eur J Nutr. 2006 Dec;45(8):463-9.

Selective bronchodilatory effect of Rooibos tea (Aspalathus linearis) and its flavonoid, chrysoeriol.[Pubmed: 17080260]

Rooibos tea (Aspalathus linearis) is commonly used for hyperactive gastrointestinal, respiratory and cardiovascular disorders. The aqueous extract of Rooibos tea (RT) was studied for the possible bronchodilator, antispasmodic and blood pressure lowering activities in an attempt to rationalize some of its medicinal uses.
METHODS AND RESULTS:
Isolated tissue preparations, such as rabbit jejunum, aorta and guinea-pig trachea and atria were set up in appropriate physiological salt solutions and aerated with carbogen. For in vivo studies rats were anesthetized with pentothal sodium and blood pressure was measured through carotid artery cannulation.In jejunum, RT caused a concentration-dependent relaxation of low K(+) (25 mM)-induced contractions, with mild effect on the contractions induced by high K(+) (80 mM). In presence of glibenclamide, the relaxation of low K(+)-induced contractions was prevented. Similarly, cromakalim caused glibenclamide-sensitive inhibition of low K(+), but not of high K(+), while verapamil did not differentiate in its inhibitory effect on contractions produced by the two concentrations of K(+). Like in jejunum, RT caused glibenclamide-sensitive relaxation of low K(+)-induced contractions in trachea and aorta, but with a 20 times higher potency in trachea. In atria, RT was least potent with weak inhibitory effect on atrial force and rate of contractions. RT caused a dose-dependent fall in arterial blood pressure in rats under anesthesia. Among the tested pure compounds of Rooibos, Chrysoeriol showed selective bronchodilator effect.
CONCLUSIONS:
Chrysoeriol (luteolin 3'-methyl ether) is a bioactive flavonoid known for antioxidant, antiinflammatory, antitumor, antimicrobial, antiviral, and free radical scavenging activities.

J Huazhong Univ Sci Technolog Med Sci. 2010 Dec;30(6):734-40.

Discovery of chrysoeriol, a PI3K-AKT-mTOR pathway inhibitor with potent antitumor activity against human multiple myeloma cells in vitro.[Pubmed: 21181363]

This study was designed to determine the impact of Chrysoeriol on proliferation and cell cycle progression in the human multiple myeloma cell lines RPMI 8226 and KM3, and its related molecular mechanisms.
METHODS AND RESULTS:
Chryseoriol was identified by using the phosphorylated AKT-specific cytoblot high throughput assay. CCK-8 assay was employed to examine the growth inhibition rate and IC(50) (48 h) in peripheral blood mononuclear cells (PBMNCs), RPMI 8226 and KM3 cells treated with Chrysoeriol at various concentrations. Cells were labeled with 5-6-carboxyfluorescein diacetate succinimidyl ester (CFSE), and the proliferation dynamics was detected by flow cytometry and analyzed with ModFit software. The cell cycles of RPMI 8226 and KM3 cells were measured by flow cytometry when the IC(50) concentration of Chrysoeriol was adopted. The alterations in cell-cycle related proteins (Cyclin B1, Cyclin D1, p21) and proteins in PI3K-AKT-mTOR pathway were determined by Western blot analysis. The results showed the proliferation of multiple myeloma cells was significantly inhibited by Chrysoeriol, resulting in cell cycle arrest in G(2)/M phase. Chrysoeriol could significantly reduce the expression of p-AKT (s473) and p-4eBP1 (t37/46) protein, meanwhile enhanced Cyclin B1 and p21 protein expression. Similar effects were not observed in PBMNCs from normal donors.
CONCLUSIONS:
It was concluded that Chrysoeriol was a selective PI3K-AKT-mTOR pathway inhibitor. It restrained the proliferation of human multiple myeloma cells, but didn't affect proliferation of PBMNCs from normal donors. It might exhibit the cell cycle regulatory effect via the inhibition of PI3K-AKT-mTOR signal pathway.

J Appl Toxicol. 2010 Oct;30(7):666-73.

Chrysoeriol isolated from Eurya cilliata leaves protects MC3T3-E1 cells against hydrogen peroxide-induced inhibition of osteoblastic differentiation.[Pubmed: 20981859]

Chrysoeriol is a flavonoid compound found in several tropical medicinal plants.
METHODS AND RESULTS:
To elucidate the protective effects of Chrysoeriol isolated from Eurya cilliata on the response of osteoblasts to oxidative stress, osteoblastic MC3T3-E1 cells were incubated with Chrysoeriol and/or H₂O₂, and markers of osteoblast function and oxidative damage were examined. Chrysoeriol treatment significantly (P < 0.05) reversed the cytotoxic effect of H₂O₂ and increased collagen content, alkaline phosphatase activity and calcium deposition of osteoblasts in the presence of H₂O₂. These effects were blocked by ICI182780, suggesting that Chrysoeriol's effect might be partly involved in estrogen action. Moreover, H₂O₂-induced reduction of osteocalcin was recovered in the presence of Chrysoeriol. Chrysoeriol significantly (P < 0.05) decreased the production of receptor activator of nuclear factor-κB ligand, interleukin-6, protein carbonyl and malondialdehyde of MC3T3-E1 cells in the presence of H₂O₂.
CONCLUSIONS:
These results demonstrate that Chrysoeriol isolated from E. cilliata can protect osteoblasts from oxidative stress-induced toxicity.

Chin Med J (Engl). 2009 Nov 5;122(21):2652-6.

Protective effect of chrysoeriol against doxorubicin-induced cardiotoxicity in vitro.[Pubmed: 19951587]

The use of doxorubicin (DOX) is limited by its dose-dependent cardiotoxicity. Reactive oxygen species (ROSs) play an important role in the pathological process of DOX-induced cardiotoxicity. The aim of this study was to evaluate the protective effect of Chrysoeriol, a flavone compound, against DOX-induced apoptosis and death in H9c2 cells and to find out its preliminary mechanism.
METHODS AND RESULTS:
We used 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, Hoechst33258 staining and measurement of lactate dehydrogenase (LDH) release to evaluate the protective effect of Chrysoeriol against DOX-induced apoptosis and death in H9c2 cells. To find out the mechanism of this protective effect, we observed the immunofluorescence of intracellular ROS and measured the activities of malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GPx). Furthermore, we evaluated the effect of Chrysoeriol on the antitumor activity of DOX in HeLa cells with MTT assay. The results of MTT assay, Hoechst 33258 staining and measurement of LDH release showed that Chrysoeriol significantly reduced doxorubicin-induced apoptosis and cell death. Chrysoeriol at a dose of 20 microg/ml notably reduced intracellular ROS, decreased the concentration of MDA in the supernatant of DOX-treated H9c2 cells and increased SOD and GPx activities to their normal levels. Further study showed that the addition of Chrysoeriol did not affect the antitumor activity of DOX.
CONCLUSIONS:
Chrysoeriol could potentially serve as a novel cardioprotective agent against DOX-induced cardiotoxicity without affecting the antitumor activity of DOX.