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PubMed2004

Hypolipidemic effects and absorption of citrus polymethoxylated flavones in hamsters with diet-induced hypercholesterolemia.

Formulations containing citrus polymethoxylated flavones (PMFs), mainly tangeretin, or citrus flavanone glucosides, hesperidin and naringin, were evaluated for cholesterol-lowering potential in hamsters with diet-induced hypercholesterolemia. PMF metabolites were also investigated. Diets containing 1% PMFs significantly reduced serum total and very low-density lipoprotein (VLDL) + LDL cholesterol (by 19-27 and 32-40%, respectively) and either reduced or tended to reduce serum triacylglycerols. Comparable reductions were achieved by feeding a 3% mixture of hesperidin and naringin (1:1, w/w), implying lower hypolipidemic potency of the hesperidin/naringin vs PMFs. HPLC-MS analysis identified high serum, liver, and urine concentrations of tangeretin metabolites including dihydroxytrimethoxyflavone and monohydroxytetramethoxyflavone glucuronides and aglycones. Total liver concentrations of tangeretin derivatives corresponded to hypolipidemic concentrations of intact tangeretin in earlier experiments in vitro. This suggests that PMFs are novel flavonoids with cholesterol- and triacylglycerol-lowering potential and that elevated levels of PMF metabolites in the liver might be directly responsible for their hypolipidemic effects in vivo.

Absorption↗
PubMed2006

Fourier transform infrared spectroscopic analysis of the polymethoxylated flavone content of orange oil residues.

Preliminary studies have shown that orange peel polymethoxylated flavones (PMFs) exhibit beneficial biological properties in animals. These properties have increased the demands for these compounds as candidate nutraceuticals and specialty food ingredients. Orange oil residues are a likely commercial source of the PMFs, and a rapid, solvent-free method for the analysis of the PMFs in orange oil residues has been developed based on Fourier transform infrared (FTIR) spectroscopy. The intensities of the FTIR vibrations of the phenyl ring nu(C=C) stretch at 1515 cm(-1) of the PMFs can be used, relative to the intensity of the carbonyl stretch at 1733 cm(-1) of the non-PMF orange oil residue components, to measure PMF content. Excellent correlations for the ratios of the intensities of these vibrations and the total PMF content were observed irrespective of the source, viscosity, and presence of particulate material. The detection limit by this method is approximately 0.1% PMF.

Citrus sinensis↗
PubMed2006

Lead optimization providing a series of flavone derivatives as potent nonsteroidal inhibitors of the cytochrome P450 aromatase enzyme.

Following our SAR studies on aromatase inhibitors, new compounds were designed by appropriately modifying the structure of flavone 1 using our previously reported CoMFA model. While the introduction of substituents on the 2-phenyl ring alone did not cause improvement in potency, these modifications and the removal of the 7-methoxy group led to compounds showing inhibitory activity in the nanomolar range, comparable to the marketed drug fadrozole.

Aromatase↗
PubMed2005

Solvent-free synthesis of functionalized flavones under microwave irradiation.

[reaction: see text] Eco-friendly direct solvent-free synthesis of flavones is achieved by microwave irradiation of phloroglucinol and beta-ketoesters. Heating with microwaves versus under classical conditions was shown to be higher yielding, cleaner, and faster. The reaction goes through a cycloaddition of an alpha-oxo ketene intermediate followed by an uncatalyzed thermal Fries rearrangement.

Flavones↗
PubMed2005

Pd-catalyzed copper-free carbonylative Sonogashira reaction of aryl iodides with alkynes for the synthesis of alkynyl ketones and flavones by using water as a solvent.

The Pd-catalyzed copper-free carbonylative Sonogashira coupling reaction to synthesize alkynyl ketones from terminal alkynes and aryl iodides was achieved by using water as a solvent. The reaction was carried out at room temperature under balloon pressure of CO with Et(3)N as a base. The developed method was successfully applied to the synthesis of flavones.

Alkynes↗
PubMed2004

The flavone hispidulin, a benzodiazepine receptor ligand with positive allosteric properties, traverses the blood-brain barrier and exhibits anticonvulsive effects.

The functional characterization of hispidulin (4',5,7-trihydroxy-6-methoxyflavone), a potent benzodiazepine (BZD) receptor ligand, was initiated to determine its potential as a modulator of central nervous system activity. After chemical synthesis, hispidulin was investigated at recombinant GABA(A)/BZD receptors expressed by Xenopus laevis oocytes. Concentrations of 50 nm and higher stimulated the GABA-induced chloride currents at tested receptor subtypes (alpha(1-3,5,6)beta(2)gamma(2)S) indicating positive allosteric properties. Maximal stimulation at alpha(1)beta(2)gamma(2)S was observed with 10 microm hispidulin. In contrast to diazepam, hispidulin modulated the alpha(6)beta(2)gamma(2)S-GABA(A) receptor subtype. When fed to seizure-prone Mongolian gerbils (Meriones unguiculatus) in a model of epilepsy, hispidulin (10 mg kg(-1) body weight (BW) per day) and diazepam (2 mg kg(-1) BW per day) markedly reduced the number of animals suffering from seizures after 7 days of treatment (30 and 25% of animals in the respective treatment groups, vs 80% in the vehicle group). Permeability across the blood-brain barrier for the chemically synthesized, (14)C-labelled hispidulin was confirmed by a rat in situ perfusion model. With an uptake rate (K(in)) of 1.14 ml min(-1) g(-1), measurements approached the values obtained with highly penetrating compounds such as diazepam. Experiments with Caco-2 cells predict that orally administered hispidulin enters circulation in its intact form. At a concentration of 30 microm, the flavone crossed the monolayer without degradation as verified by the absence of glucuronidated metabolites.

Animals↗
PubMed2004

A new flavone from Hypericum wightianum.

A new flavone, wightianin (1), along with five known compounds, n-triacontanol (2), betulinic acid (3), oleanolic acid (4), 3,4-O-isopropylidene-shikimic acid (5), and isoquercitrin (6), were isolated from the whole plants of Hypericum wightianum Wall ex Wight et Arn. Their structures were elucidated on the basis of spectral data, including 2D NMR techniques.

Flavones↗
PubMed2005

A new bioactive flavone glycoside from the seeds of Melilotus indica All.

Melilotus indica All. [Chopra, R.N., Nayar, S.L. and Chopra, I.C. (1956) Glossary Indian Med. Plants, 164 C.S.I.R. Publication New-Delhi; Kirtikar, K.R. and Basu, B.D. (1935) Indian Medicinal Plants, 2nd Ed., Vol. I, pp. 703-704 Lalit Mohan Basuan Co. Allahabad. The Wealth of India (1962) A Dictionary of Raw Materials and Industrial Products, Vol. VI, pp. 329-331 (C.S.I.R. Publication: New-Delhi)] belongs to family Leguminosae, which is commonly known as 'Banmethi' in Hindi. It is found in North India, extending into S. Persia, S. Europe and the Tropical zone of India. The seeds are used as an anthelmintic, an antipyretic, for curing heart diseases, bronchitis, leprosy, bowel complaints and infantile diarrhea. The plant has also been used as a discutient, emollient, and as a fomentation. It is also useful in a plaster for swelling. It is considered astringent and narcotic. Earlier workers have reported the presence of C-glycosides [Sayed, E.L., Ishak, M.S. and Mabry, T.J. (1997) Asian J. Chem., 9, 551], methylene-dioxypterocarpan (MIS6) [Saxena, V.K. and Nigam, S. (1997) Fitoterapia, 68, 343-345], pterocarpane (MIS2) [Saxena, V.K. and Nigam, S. (1996) J. Institution Chem. 68, 122-125] and prenylated pterocarpan [Saxena, V.K. and Nigam, S. (1997) Fitoterapia, 68, 403-407] from this plant. Here, we report the isolation of the new flavone glycoside 5,7,4'-trihydroxy-6,3'-dimethoxyflavone-7-O-alpha-L-arabinopyranosyl(1-->6)-O-beta-D-galactopyranoside (1) from the seeds of this plant.

Flavones↗
PubMed2006

Inhibition of intestinal carcinogenesis by a new flavone derivative, chafuroside, in oolong tea.

A new flavone derivative, chafuroside, has been isolated as a strong anti-inflammatory compound from oolong tea leaves, and its structure determined to be (2R,3S,4S,4aS,11bS)-3,4,11-trihydroxy-2-(hydroxymethyl)-8-(4-hydroxyphenyl)-3,4,4a,11b-tetrahydro-2H,10H-pyrano[2',3':4,5]furo[3,2-g]chromen-10-one. To assess its potential to inhibit intestinal carcinogenesis, 2.5, 5 and 10 p.p.m. chafuroside was given in the diet to Apc-deficient Min mice for 14 weeks from 6 weeks of age. Total numbers of polyps were reduced to 83, 73 and 56% of the control value, respectively. Moreover, dietary administration at 10 and 20 p.p.m. reduced azoxymethane (AOM)-induced colon aberrant crypt foci (ACF) development in rats to 69% of the AOM-treated control value with the higher dose. Chafuroside-associated toxicity was not observed at 2.5-10 p.p.m. in Min mice and 10-20 p.p.m. in AOM-treated rats. These results suggest that chafuroside might be a good chemopreventive agent for colon cancer.

Animals↗
PubMed2005

Effect of Oenanthe javanica flavone on human and duck hepatitis B virus infection.

AIM: To study the antiviral effect of Oenanthe javanica flavones (OjF) on human hepatoma HepG2.2.15 culture system and duck hepatitis B virus (DHBV) infection. METHODS: (1) After incubation for 24 h, the 2.2.15 cells were treated with different concentrations of OjF for 12 d. The cell alteration was observed by microscope. The presence of HBsAg and HBeAg were measured using the enzyme immunoassay kit after 2.2.15 cells were treated with OjF for 9 d. (2) Ducklings infected with DHBV intravenously were divided into 5 groups and treated with OjF, acyclovir (ACV), and normal saline respectively for 10 d. All the ducklings were bled before, during, and after treatments at different times, and serum levels of DHBV-DNA were detected by a dot-blot hybridization assay. RESULTS: (1) The 50% toxic concentration (TC50) of OjF was 2.28 g/L. The maximum nontoxic concentration (TC0) was 1.00 g/L. In nontoxic concentrations, OjF significantly inhibited HBsAg and HBeAg in 2.2.15 cells after 9 d of treatment (P<0.05, P<0.01). (2) The DHBV-DNA levels decreased significantly after the treatment with 0.50 and 1.00 g/kg of OjF (P<0.01). The inhibition of the peak of viremia was maximum at a dose of 1.00 g/kg and reached 54.3% on d 5 and 64.5% on d 10, respectively. CONCLUSION: The results demonstrate that OjF is a strong inhibitor of HBsAg and HBeAg secretion in 2.2.15 cells and DHBV-DNA levels in the HBV-infected duck model.

Animals↗
PubMed2006

Protective effect of total flavones of rhododendra on ischemic myocardial injury in rabbits.

This study was to investigate the effect of total flavones of rhododendra (TFR) on ischemic myocardial injury in rabbits. Rabbit ischemic myocardial injury was induced by occluding the anterior descent of the left artery (LAD). The ECG was recorded; the plasma creatine kinase (CK), nitric oxide (NO) and endothelin-1 (ET-1) levels were measured using spectrophotometry, Griess method and radioimmunoassay, respectively. The myocardial ischemic size and infarction size were determined by dual staining with Evan's blue and Nitroblue tetrazolium reductionest (N-BT). A typical ECG S-T segment elevation and an increase of plasma CK activity were observed 6 and 24 hours after the induction of ischemia. These changes were inhibited in rabbits treated with either TFR (30, 60 mg/kg) or ginkgo biloba extract (EGB) for 7 days, indicating a protective effect of TFR on ischemic myocardial injury. The myocardial ischemic size and infarction size were 40.7 +/- 3.6% and 36.8 +/- 3.6% respectively in the control group, while TFR (60 mg/kg) pretreatment for 7 days significantly reduced both myocardial ischemic size (32.40 +/- 5.38%, p < 0.05) and infarction size (28.7 +/- 5.8%, p < 0.05). In addition, the occlusion of LAD resulted in an increase of ET-1 and a decrease of NO levels in the plasma, effects that were inhibited by TFR treatment, suggesting a possible mechanism for the protective effect of TFR against myocardial ischemic injury.

Animals↗
PubMed2005

Total flavones from Elsholtzia blanda reduce infarct size and improve heart function during acute myocardial infarction by inhibiting myocardial apoptosis in canines.

OBJECTIVE: The current study tests the hypothesis that inhibition of apoptotic cell death with total flavones from Elsholtzia blanda (TFEB), a traditional Chinese medicine, reduces infarct size and improves heart function during myocardial ischaemia induced by coronary occlusion in canines. METHODS AND RESULTS: Myocardial apoptosis was detected by the TdT-mediated dUTP nick end labelling (TUNEL) method and DNA laddering. Infarct size of the left ventricle, serum level of CK-MB, haemodynamic parameters including rate of rise and decline of left ventricular pressure (+/- dp/dtmax), left ventricular systolic pressure (LVSP), main arterial pressure (MAP), coronary blood flow (CBF), coronary vascular resistance (CVR) were measured in this study. TUNEL positive cells were markedly reduced from 27.83 +/- 8.15% in the control dogs to 7.74 +/- 3.50% in the TFEB-treated ones (P < 0.01), consistent with the absence of DNA laddering. TFEB significantly reduced infarct size from 19.30 +/- 6.66% in the control dogs to 8.87 +/- 1.66% (P < 0.01), confirmed by lower serum CK-MB activity. TFEB significantly reduced MAP and CVR. The decrease in +/- dp/dtmax, LVSP and CBF also tended to be much smaller in the TFEB treated group. CONCLUSION: These data suggest that the inhibitory effect of TFEB on apoptosis during coronary occlusion is associated with reduction in infarct size and improvement in heart function.

Animals↗
PubMed2006

Molecular interactions between human cytochrome P450 1A2 and flavone derivatives.

Activation by human cytochrome P450 1A2 (hCYP1A2) of heterocyclic amines is assumed to trigger of a number of carcinogenic processes. In this work, a group of natural inhibitors of human cytochrome P450 1A2 reported in literature has been theoretically analysed. These consist of flavone hydroxylated derivatives, natural compounds that exist in plants and associated products. Different theoretical/computational tools were used to describe the specific molecular interactions between these compounds and hCYP1A2. Based on this analysis, a method is proposed for helping the selection of specific molecular features that enhance protein-inhibitor interaction.

Binding Sites↗
PubMed2006

[Effects of Pollen Typhae total flavone on glucose and lipid metabolism in 3T3-L1 adipocytes].

OBJECTIVE: To observe the effects of Pollen Typhae total flavone (PTF) on glucose and lipid metabolism in 3T3-L1 adipocytes. METHODS: The content of glucose which disappeared from the culture medium after incubation with drugs for 24 hours was determined as glucose consumption of the cells. The activity of cells was detected by XTT method. The transport of glucose was observed by (3)H-glucose uptake method. The efflux of free fatty acid (FFA) from adipocytes was observed by the concentration of FFA in the culture medium. RESULTS: The glucose concentration in culture medium was significantly decreased with a concentration-dependent effect, when PTF concentrations were from 0.025 g/L to 0.4 g/L. The toxic effect on cells appeared while PTF concentration was 0.4 g/L, and the MTT value decreased. PTF also significantly increased glucose transportation in the 3T3-L1 adipocytes as rosiglitazone (ROS) did. At the same time, FFA concentration in culture medium was significantly decreased as compared to the normal control group, while ROS-treated group did not show any difference. CONCLUSION: PTF can increase insulin sensitivity by increasing glucose transportation and consumption in the 3T3-L1 adipocytes as well as decreasing the FFA efflux from the cells.

3T3-L1 Cells↗
PubMed2006

[Purification of total flavones from Morus alba L.by macroporous adsorbents and kinetic model for the process].

OBJECTIVE: To establish the separation and purification technology for the total flavones from Morus alba L.(MTF), and present a kinetic model for this process. METHODS: Three types of macroporous adsorbents were tested to separate and purify MTF, and to evaluated by adsorption capacity, elution ratio and product purity. The curves of dynamic adsorption-elution process was plotted and the kinetic equations were presented. RESULT: Among three types of macroporous adsorbents, the NKA-9 type showed better property with the adsorption capacity of 43.4 mg.g(-1)and the elution ratio of 98.2%. The purity of MTF product reached to 58.2 % in the technological conditions following: extract sample concentration of 20 mg.ml(-1), 6 times washing water and elution reagent of 70% ethanol. The adsorbent could be used for 4 times repeatedly. The kinetic equation was y=u(1 - e(-kx)). CONCLUSION: The NKA-9 type of macroporous absorbent is suitable to purify the MTF.

Adsorption↗
PubMed2004

[Protective effects of total flavones of metasequosia on cerebral ischemia-reperfusion injury in rats].

OBJECTIVE: To observe the protective effects of total flavones of metasequosia (TFM) on cerebral ischemia-reperfusion injury in rats. METHOD: The bilateral vertebral arteries of rats were occluded under anesthesia, and 4-5 h later the carotid arteries of rats in the conscious condition were occluded for 30 min followed by reperfusion for 90 min. The effects of TFM on the contents of water, Na+, Ca2+ in cortex, malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in brain hemispheres, as well as the EEG activities were observed. RESULT: After 30 min ischemia and 90 min reperfusion, the contents of water, Na+ , Ca2+ and MDA were increased, and the SOD activity was reduced with abnormal EEG activity and ischemic injury in the brain tissues. TFM 25-100 mg x kg(-1) ip 30 min before the carotid arteries were occluded, decreased the elevated water, Na+, Ca2+ and MDA contents, increased the SOD activity, reduced the ischemic injury of brain tissue, and promoted the recovery of EEG activities. CONCLUSION: TFM has a protective effect on cerebral ischemia-reperfusion injury in rats.

Animals↗
PubMed2005

A new flavone glycoside and other constituents from Carduus crispus.

A new flavone glycoside, chrysoeriol 7-O-(2"-O-6'''-O-acetyl-beta-D-glucopyranosyl-beta-D-glucopyranoside (1), along with fourteen known compounds 2-15 were isolated from the whole plant of Carduus crispus Linn. Their structures were established on the basis of spectroscopic methods and chemical evidences. The antitumour activity of compound 1, 4 and 5 was tested. Compound 4 exhibited significant antitumour activity against HO-8901 (human ovarian neoplasm) cells.

Antineoplastic Agents, Phytogenic↗