chrysin and baicalein

The incidence of nonalcoholic fatty liver disease (NAFLD), especially nonalcoholic steatohepatitis (NASH), has significantly increased in recent years and has become an important public health issue. However, no U.S. Food and Drug Administration (FDA)-approved first-line drug is currently available for the treatment of NAFLD and NASH; therefore, research on new drugs is currently a hot topic. Oroxylum indicum (Linn.) Kurz is extensively distributed in South China and South Asia and has many biological activities. However, its effects on NAFLD or even NASH and the corresponding mechanisms are still not clear.. To investigate the effect and mechanism of O. indicum seed extract (OISE) on preventing anti-inflammatory action in the progression from simple nonalcoholic fatty liver (NAFL) to NASH.. A network pharmacology method to construct ingredient-target networks and the protein-protein interaction (PPI) network of OISE in NASH were constructed for topological analyses and hub-target screening. Enrichment analyses were performed to identify the critical biological processes and signaling pathways. Simultaneously, in vitro and in vivo experiments investigated the effect and mechanism of OISE, baicalein, and chrysin on inflammation by biochemical indicator detection, luciferase reporters, pathological staining, and immunoblotting in oleic acid-stimulated HepG2 cells or in high-fat diet-fed rats.. The network pharmacology showed that OISE prevented the development and progression of NAFL into NASH through various pathways and targets and that the nuclear factor NF-κB (NF-κB) pathway regulated by baicalein and chrysin played an important role in the treatment of NASH. In in vitro experiments, we further showed that OISE and its ingredients, namely, baicalein and chrysin, all improved the inflammatory status in oleic acid-stimulated HepG2 cells, inhibited the nuclear transcriptional activities of NF-κB, increased the IκB level, and decreased the phosphorylation level of NF-κB. Furthermore, in a high-fat diet-induced NASH model in rats, we also showed that OISE prevented the development and progression of NASH by inhibiting the nuclear transcriptional activity of NF-κB.. OISE suppressed inflammatory responses and prevented the development and progression of NAFL into NASH through inhibition of the nuclear transcriptional activity of NF-κB. OISE may be used to treat NAFLD through many functions, including an increase in insulin sensitivity, a decrease in lipid accumulation in the liver, suppression of inflammation, and clearance of free radicals.

Topics: Animals; Bignoniaceae; Diet, High-Fat; Flavanones; Flavonoids; Hep G2 Cells; Humans; Lipid Metabolism; Liver Cirrhosis; Male; NF-kappa B; Non-alcoholic Fatty Liver Disease; Oleic Acid; Plant Extracts; Protein Interaction Maps; Rats, Sprague-Dawley; Seeds; Signal Transduction

A series of halogenated derivatives of natural flavonoids: baicalein and chrysin were designed and investigated as possible ligands for the catalytic subunit of tumor-associated human kinase CK2. Thermal shift assay method, in silico modeling, and high-performance liquid chromatography-derived hydrophobicity together with IC

Topics: Antineoplastic Agents; Casein Kinase II; Cell Line, Tumor; Drug Screening Assays, Antitumor; Flavanones; Flavonoids; Halogenation; Humans; Magnetic Resonance Spectroscopy; Models, Molecular; Protein Kinase Inhibitors; Structure-Activity Relationship

Baicalein and scutellarein are bioactive flavones found in the medicinal plant Scutellaria baicalensis Georgi, used in traditional Chinese medicine. Extensive previous work has demonstrated the broad biological activity of these flavonoids, such as antifibrotic, antiviral and anticancer properties. However, their supply from plant material is insufficient to meet demand. Here, to provide an alternative production source and increase production levels of these flavones, we engineered an artificial pathway in an Escherichia coli cell factory for the first time. By first reconstructing the plant flavonoid biosynthetic pathway genes from five different species: phenylalanine ammonia lyase from Rhodotorula toruloides (PAL), 4-coumarate-coenzyme A ligase from Petroselinum crispum (4CL), chalcone synthase from Petunia hybrida (CHS), chalcone isomerase from Medicago sativa (CHI) and an oxidoreductase flavone synthase I from P. crispum (FNSI), production of the intermediates chrysin and apigenin was achieved by feeding phenylalanine and tyrosine as precursors. By comparative analysis of various versions of P450s, a construction expressing 2B1 incorporated with a 22-aa N-terminal truncated flavone C-6 hydroxylase from S. baicalensis (F6H) and partner P450 reductase from Arabidopsis thaliana (AtCPR) was found most effective for production of both baicalein (8.5 mg/L) and scutellarein (47.1 mg/L) upon supplementation with 0.5 g/L phenylalanine and tyrosine in 48 h of fermentation. Finally, optimization of malonyl-CoA availability further increased the production of baicalein to 23.6 mg/L and scutellarein to 106.5 mg/L in a flask culture. This report presents a significant advancement of flavone synthetic production and provides foundation for production of other flavones in microbial hosts.

Topics: Apigenin; Biosynthetic Pathways; Escherichia coli; Flavanones; Flavonoids; Malonyl Coenzyme A; Metabolic Engineering; Phenylalanine; Plants; Scutellaria baicalensis; Tyrosine

Baicalein, wogonin, and their glycosides are major bioactive compounds found in the medicinal plant Scutellaria baicalensis Georgi. These flavones can induce apoptosis in a variety of cancer cell lines but have no effect on normal cells. Furthermore, they have many additional benefits for human health, such as anti-oxidant, antiviral, and liver-protective properties. Here, we report the isolation and characterization of two CYP450 enzymes, SbCYP82D1.1 and SbCYP82D2, which function as the flavone 6-hydroxylase (F6H) and flavone 8-hydroxylase (F8H), respectively, in S. baicalensis. SbCYP82D1.1 has broad substrate specificity for flavones such as chrysin and apigenin and is responsible for biosynthesis of baicalein and scutellarein in roots and aerial parts of S. baicalensis, respectively. When the expression of SbCYP82D1.1 is knocked down, baicalin and baicalein levels are reduced significantly while chrysin glycosides accumulate in hairy roots. SbCYP82D2 is an F8H with high substrate specificity, accepting only chrysin as its substrate to produce norwogonin, although minor 6-hydroxylation activity can also be detected. Phylogenetic analysis suggested that SbCYP82D2 might have evolved from SbCYP82D1.1 via gene duplication followed by neofunctionalization, whereby the ancestral F6H activity is partially retained in the derived SbCYP82D2.

Topics: Apigenin; Cytochrome P-450 Enzyme System; Flavanones; Flavones; Flavonoids; Humans; Phylogeny; Plant Roots; Saccharomyces cerevisiae; Scutellaria baicalensis

Topics: Andrographis; Antineoplastic Agents, Phytogenic; Apigenin; Apocynaceae; Asia, Southeastern; Biflavonoids; Bignoniaceae; Catechin; Diterpenes; Ethnopharmacology; Flavanones; Flavonoids; Hep G2 Cells; Humans; Lamiaceae; Liver Neoplasms; Metabolomics; Plants, Medicinal; Proanthocyanidins

Naturally occurring polyphenolic compounds are of medicinal importance because of their unique antioxidant, anticancer, and chemopreventive properties. Baicalein, a naturally occurring polyhydroxy flavonoid possessing a diverse range of pharmacological activities, has been used in traditional medicines for treatment of various ailments. Apart from its isolation from natural sources, its synthesis has been reported via multistep chemical approaches. Here, we report a preparative-scale biotransformation, using whole yeast cells stably expressing human cytochrome P450 1A1 (CYP1A1) enzyme that allows regioselective C6-hydroxylation of 5,7-dihydroxyflavone (chrysin) to form 5,6,7-trihydroxyflavone (baicalein). Molecular modeling reveals why chrysin undergoes such specific hydroxylation mediated by CYP1A1. More than 92% reaction completion was obtained using a shake-flask based process that mimics fed-batch fermentation. Such highly efficient selective hydroxylation, using recombinant yeast cells, has not been reported earlier. Similar CYP-expressing yeast cell based systems are likely to have wider applications in the syntheses of medicinally important polyphenolic compounds.

Topics: Biocatalysis; Biotransformation; Cytochrome P-450 CYP1A1; Flavanones; Flavonoids; Gene Expression; Humans; Hydroxylation; Saccharomyces cerevisiae

As an effort to identify newer anti-obesity lead(s) we have selected 13 plant materials from the six plant species which have been reported in Indian Ayurvedic medicine as remedy against complications affecting glucose and lipid homeostasis.. In vitro screening of six Indian Ayurvedic medicinal plants on anti-adipogenic and pancreatic lipase (PL) inhibition potential followed by bioactivity guided isolation from most active plant material.. In vitro anti-adipogenic assay using 3T3-L1 preadipocytes and pancreatic lipase (PL) inhibition assay were performed for hexanes, dichloromethane, ethyl acetate and methanolic extracts of all the plant materials. Bioactivity guided isolation approach was used to identify active constituent for anti-adipogenesis and PL inhibition assay. Inhibition of lipid accumulation and adipogenic transcription factor was measured by oil Red 'O' staining and quantitative real-time PCR method respectively.. Ethyl acetate extract of Oroxylum indicum bark was found to be most active in screening of anti-adipogenesis (59.12±1.66% lipid accumulation as compared to control at 50μg/mL dose) and PL inhibition (89.12±6.87% PL inhibition at 250μg/mL dose) assays. Further, three bioactive flavonoids were isolated and identified as oroxylin A, chrysin and baicalein from O. indicum bark. Oroxylin A, chrysin, and baicalein were inhibited lipid accumulation in 3T3-L1 preadipocytes (75.00±5.76%, 70.21±4.23% and 77.21±5.49% lipid accumulation respectively in comparison to control at 50μM dose) and PL enzyme (69.86±2.96%, 52.08±2.14% and 45.06±2.42% PL inhibition respectively at 250μg/mL dose). In addition, oroxylin A and chrysin also inhibited PPARγ and C/EBPα, major adipogenic transcription factors, in 3T3L-1 preadipocytes during adipogenesis process at 50μM dose.. The present study augurs the anti-obesity potential of well practiced Ayurvedic herb O. indicum and its flavonoids.

Topics: 3T3-L1 Cells; Adipocytes; Adipogenesis; Animals; Anti-Obesity Agents; Bignoniaceae; CCAAT-Enhancer-Binding Protein-alpha; Cell Line; Flavanones; Flavonoids; India; Lipase; Medicine, Ayurvedic; Mice; Obesity; Plant Bark; Plant Extracts; Plants, Medicinal; PPAR gamma

Topics: Carbon; Chitosan; Electrochemical Techniques; Electrodes; Flavanones; Flavonoids; Limit of Detection; Oxidation-Reduction; Oxides; Tantalum

The constitutive androstane receptor (CAR) is a crucial transcriptional regulator of key xenobiotic-metabolizing enzymes such as cytochrome P450 CYP3A4, CYP2C9 and CYP2B6. The flavonoids chrysin, baicalein and galangin have been reported to activate CAR and interfere with EGFR signaling. Nevertheless, it is not known if these flavonoids are direct CAR ligands or indirect phenobarbital-like CAR activators via the inhibition of epidermal growth factor receptor (EGFR) signaling. We analyze the interactions of chrysin, galangin and baicalein and its glycoside baicalin with human CAR. We have employed and validated methods that can study direct interaction with the CAR ligand binding pocket. Secondly, we determined if the compounds affect human EGFR signaling and interact with EGFR. Employing a TR-FRET coactivator assay with recombinant CAR or CAR assembly assay, a consistent activation of CAR with flavonoids and phenobarbital was not observed. It was determined, however, that galangin, chrysin, and baicalein may slightly repress EGFR-Tyr1068 autophosphorylation after EGF treatment, phosphorylation of downstream transcription factor ELK1 and stimulate EGFP-CAR nuclear translocation in primary human hepatocytes. These data suggest that flavonoids chrysin, galangin and baicalein are indirect human CAR activators. This study also demonstrates new approach how to test the direct CAR interaction with its ligands.

Topics: Binding Sites; Cell Line; Constitutive Androstane Receptor; Cytochrome P-450 CYP2B6; ErbB Receptors; ets-Domain Protein Elk-1; Flavanones; Flavonoids; Hepatocytes; Humans; Phenobarbital; Protein Transport; Receptors, Cytoplasmic and Nuclear

A simple and effective neuraminidase-immobilized capillary microreactor was fabricated by glutaraldehyde cross-linking technology for screening the neuraminidase inhibitors from traditional Chinese medicines. The substrate and product were separated by CE in short-end injection mode within 2 min. Dual-wavelength ultraviolet detection was employed to eliminate the interference from the screened compounds. The parameters relating to the separation efficiency and the activity of immobilized neuraminidase were systematically evaluated. The activity of the immobilized neuraminidase remained 90% after 30 days storage at 4°C. The immobilized NA microreactor could be continuously used for more than 200 runs. The Michaelis-Menten constant of neuraminidase was determined by the microreactor as 136.6 ± 10.8 μM. In addition, six in eighteen natural products were found as potent inhibitors and the inhibition potentials were ranked in the following order: bavachinin>bavachin>baicalein>baicalin>chrysin and vitexin. The half-maximal inhibitory concentrations were 59.52 ± 4.12, 65.28 ± 1.07, 44.79 ± 1.21 and 31.62 ± 2.04 for baicalein, baicalin, bavachin and bavachinin, respectively. The results demonstrated that the neuraminidase-immobilized capillary microreactor was a very effective tool for screening neuraminidase inhibitors from traditional Chinese medicines.

Topics: Drugs, Chinese Herbal; Electrophoresis, Capillary; Enzyme Inhibitors; Enzymes, Immobilized; Flavanones; Flavonoids; Neuraminidase

Flavone glucuronide isomers of five flavones (chrysin, apigenin, luteolin, baicalein, and scutellarein) were differentiated by collision-induced dissociation of [Co(II) (flavone-H) (4,7-diphenyl-1,10-phenanthroline)(2)](+) complexes. The complexes were generated via postcolumn addition of a metal-ligand solution after separation of the glucuronide products generated upon incubation of each flavone with an array of uridine 5'-diphosphate (UDP)-glucuronosyltransferase (UGT) isozymes. Elucidation of the glucuronide isomers allowed a systematic investigation of the regioselectivity of 12 human UGT isozymes, including 8 UGT1A and 4 UGT2B isozymes. Glucuronidation of the 7-OH position was the preferred site for all the flavones except for luteolin, which possessed adjacent hydroxyl groups on the B ring. For all flavones and UGT isozymes, glucuronidation of the 5-OH position was never observed. As confirmed by the metal complexation/MS/MS strategy, glucuronidation of the 6-OH position only occurred for baicalein and scutellarein when incubated with three of the UGT isozymes.

Topics: Apigenin; Biotransformation; Chromatography, High Pressure Liquid; Coordination Complexes; Flavanones; Flavonoids; Glucuronides; Glucuronosyltransferase; Isoenzymes; Isomerism; Luteolin; Tandem Mass Spectrometry

A liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous determination of baicalin, wogonoside, baicalein, wogonin, oroxylin A and chrysin in rat plasma, using naringin as an internal standard. After acidifying with HCl, plasma samples were pretreated by liquid-liquid extraction with acetone. Chromatographic separation was accomplished on a Hypersil Gold-C(18) analytical column (2.1×150 mm, 5 μm) utilizing a gradient elution profile and a mobile phase consisting of (A) 0.1% formic acid in water and (B) acetonitrile. Detection was performed by multiple reaction monitoring (MRM) mode using electrospray ionization in the positive ion mode. All analytes showed good linearity over the investigated concentration range (r>0.9900). The lower limit of quantification was 0.5 ng/ml for baicalin, wogonoside, wogonin and oroxylin A, and 1.0 ng/ml for baicalein and chrysin. Intra-day and inter-day precisions (RSD%) were less than 15% and accuracy (RE%) ranged from -6.7% to 5.8%. The validated method was successfully applied to investigate the pharmacokinetics of the major flavonoids of Radix scutellariae extract after oral administration to rats.

Topics: Administration, Oral; Animals; Area Under Curve; Chromatography, Liquid; Drugs, Chinese Herbal; Flavanones; Flavonoids; Glucosides; Half-Life; Limit of Detection; Male; Metabolic Clearance Rate; Plant Extracts; Rats; Rats, Wistar; Reference Standards; Reproducibility of Results; Scutellaria baicalensis; Sensitivity and Specificity; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry

Indoleamine dioxygenase (IDO) is a heme- containing enzyme that catalyzes the oxidation of tryptophan to N-formylkynurenine, kynurenine and the downstream quinolinic acid. Though IDO is physiologically important in maintaining tissue integrity, aberrant IDO expression represses T cell function and promotes regulatory T cells (Treg) in cancer. It additionally exacerbates Alzheimer, depression, Huntington and Parkinson diseases via quinolinic acid. Inhibition of IDO has thus been recently proposed as a strategy for treating cancer and neuronal disorders. In the present study, we have developed a cell-based assay to evaluate the suppressive effect of anti-inflammatory phytochemicals on the enzyme. When stimulated by INF-γ, profound high expressions of IDO-1 mRNA as well as the protein were detected in human neural stem cells (hNSC) and verified by real-time retro-transcribed PCR and western blot analysis, respectively. The protein activity was measured by kynurenine concentration and the assay was validated by dose-responsive inhibition of IDO-1 antagonists including 1-methyltryptaphan, indomethacin and acetylsalicylic acid. Among the tested compounds, apigenin, baicalein, chrysin, and wogonin exhibit a potent repressive activity with IC(50s) comparable to that of indomethacin. The inhibition was further found to be independent of gene expression and protein translation because of the unaltered levels of mRNA and protein expression. Although curcumin displayed a potent inhibitory activity to the enzyme, it appeared to be cytotoxic to hNSCs. Morphological examination of hNSC revealed that baicalein and wogonin at the inhibitory concentrations induced neurite outgrowth. In conclusion, our data shows that certain phytochemicals with 2-phenyl-1-benzopyran-4-one backbone (flavones) attenuate significantly the IDO-1 protein activity without harming hNSCs. The inhibitory activity might have partially contributed to the anti-cancer and neuro-protective property of the compounds.

Topics: Aromatic-L-Amino-Acid Decarboxylases; Cells, Cultured; Flavanones; Flavonoids; Humans; Indoleamine-Pyrrole 2,3,-Dioxygenase; Indomethacin; Interferon-gamma; Neural Stem Cells; RNA, Messenger

Four flavones (flavone, 7-hydroxyflavone, chrysin, and baicalein) sharing the same B- and C-ring structure but a different numbers of hydroxyl groups on the A-ring were studied for their affinities for BSA and HSA. The hydroxylation on ring A of flavones increased the binding constants (K(a)) and the number of binding sites (n) between flavones and serum albumins. The affinities of 7-hydroxyflavone for BSA and HSA were about 800 times and 40 times higher than that of flavone, respectively. It appears that the optimal number of hydroxyl groups introduced to the ring A of flavones is one. As more hydroxyl groups were introduced to positions at C-5, C-6, and/or C-7 of flavones, the affinities for serum albumins decrease. The critical energy transfer distances (R(0)) between the hydroxylated flavones (1-3 OH on the ring A) and serum albumins decreased with the increasing affinities for serum albumins.

Topics: Algorithms; Binding Sites; Flavanones; Flavones; Flavonoids; Glycoproteins; Hydrogen Bonding; Hydrogen-Ion Concentration; Hydroxylation; Kinetics; Protein Binding; Serum Albumin; Serum Albumin, Bovine; Serum Albumin, Human; Spectrometry, Fluorescence; Spectrophotometry; Structure-Activity Relationship

Pharmacologically motivated natural product investigations have yielded a large variety of structurally unique lead compounds with interesting biomedical properties, but the natural roles of these molecules often remain unknown. In the present investigation, a series of benzyl substituted-flavone derivatives have been synthesized from the lead compounds and were screened against 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and α-glucosidase inhibitory properties. The resulting activity profiles of these flavone derivatives were compared for degree of similarity to the profile of 1-3. Most of the synthesized derivatives displayed potent activities when compared to the parent compounds. Maximum potencies for DPPH free radical scavenging activity were observed only in compounds containing the 4-hydroxyl substitution and 3-methoxyl group on the phenyl ring. While the 2- and 4-hydroxyl group substitutions on the phenyl ring seem to be crucial for the intestinal α-glucosidase inhibitory activity.

Topics: Benzene Derivatives; Bignoniaceae; Biphenyl Compounds; Flavanones; Flavonoids; Free Radical Scavengers; Glycoside Hydrolase Inhibitors; Hypoglycemic Agents; India; Molecular Structure; Picrates; Plant Roots; Plants, Medicinal

To study the ethyl acetate soluble constituents from the water extractive of Huanglian Jiedutang decoction, which are composed of Rhizoma Coptidis, Radix Scutellariae, Cortex Phellodendri and Fructus Gardeniae, and provide substances foundation for its pharmacokinetic and pharmacodynamic investigation.. The chemical constituents were isolated by various column chromatographic methods and structurally elucidated by NMR and MS techniques.. Thirty-five compounds were isolated, among which twenty compounds have been identified as beta-sitosterol (1), oroxylin A (2), wogonin (3), ursolic acid (4), skullcapflavone I (5), tenaxin I (6), skullcapflavone II (7), limonin (8), 5, 2'-dihydroxy-6, 7, 8, 3'-tetramethoxyflavone (9), chrysin (12), baicalein (17), tenaxin II (19), 5, 7, 2'-trihydroxy-6, 8-dimethoxyflavone (21), shihulimonin A (22), 6, 2'-dihydroxy-5, 7, 8, 6'-tetramethoxyflavone (26), viscidulin II (28), 5, 7, 4'-trihydroxy-8-methoxyflavone (29), 5, 7, 2', 6'-tetrahydroxyflavone (30), wogonin-7-O-beta-D-glucuronide methyl ester (31) and daucosterol (34).. On the basis of reported results of the chemical constituents of Rhizoma Coptidis, Radix Scutellariae, Cortex Phellodendri and Fructus Gardeniae, it was estimated that all flavonoid compounds rised from the Radix Scutellariae, and compounds 8 and 22 rised from Cortex Phellodendri. Compound 22 was identified in the Cortex Phellodendri for the first time.

Topics: Acetates; Drugs, Chinese Herbal; Flavanones; Flavones; Flavonoids; Limonins; Magnetic Resonance Spectroscopy; Sitosterols; Spectrometry, Mass, Electrospray Ionization; Triterpenes; Ursolic Acid

In this paper, the molecular connectivity indices were applied to theoretically predict the direct chemiluminescence (CL) behavior of chrysin and baicalein with our recently proposed discriminant function. Then, combined with flow-injection analysis, a new CL system for determination of chrysin and baicalein was proposed. The method was based on the oxidation of chrysin and baicalein by acidic KMnO(4) in the presence of formaldehyde to produce strong CL emission. The present paper suggested a new model to discover new CL analytical system: first, to theoretical predict the CL behavior, and the second, to suggest analytical system.

Topics: Drug Combinations; Equipment Design; Flavanones; Flavonoids; Flow Injection Analysis; Hydrochloric Acid; Luminescence; Luminescent Measurements; Models, Chemical; Molecular Structure; Oils; Osmolar Concentration; Oxidants; Phenols; Potassium Permanganate

Baicalin and its aglycone baicalein are the major flavonoid components of the root of Scutellaria baicalensis. Recent studies have shown that they can attenuate oxidative stress in various in vitro models as they possess potent antioxidant activities. This study investigated alternative protective mechanisms of baicalein in a cardiomyocyte model.. Neonatal rat cardiomyocytes pretreated with the test compound were subjected to hypoxia/reoxygenation. The extent of cellular damage was accessed by the amount of released lactate dehydrogenase. Pretreatment with baicalein up to 10 microM reduced lactate dehydrogenase release significantly (P<0.001), while pretreatment with baicalin up to 100 microM was ineffective. The cardioprotective effect of baicalein is not due to its antioxidant effect, because an adverse effect rather than a protective effect was observed when baicalein was present during hypoxia. Cotreatment with N-acetylcysteine attenuated the protective effect of baicalein and concomitantly increased intracellular reactive oxygen species level and the cytotoxic effect of baicalein, but N-acetylcysteine alone did not have such effects. In addition, cotreatment with catalase, but not superoxide dismutase or mannitol, reversed the cardioprotective effect of baicalein, suggesting the involvement of hydrogen peroxide in the cardioprotective mechanism. The NAD(P)H:quinone oxidoreductase inhibitors dicoumarol and chrysin also abolished the cardioprotective effect of baicalein. While pretreatment with baicalein did not increase antioxidant enzyme activities, it alleviated calcium accumulation in cardiomyocytes undergoing simulated ischemia.. These results highlight the important role of hydrogen peroxide produced during the auto-oxidation of baicalein in the cardioprotective effect of baicalein.

Topics: Acetylcysteine; Animals; Antioxidants; Calcium; Catalase; Cells, Cultured; Dicumarol; Enzyme Inhibitors; Flavanones; Flavonoids; Hypoxia; L-Lactate Dehydrogenase; Myocytes, Cardiac; Rats

Twenty-six flavonoids were isolated from Scutellaria baicalensis. Their affinities for the benzodiazepine (BDZ) binding site of GABA A receptor have been studied using [ 3H]flunitrazepam binding to rat cortical membranes in vitro. The structure-activity relationships suggested that 2'-OH flavones exhibited the most potent binding affinity, which could lead to the design and discovery of new BDZ receptor ligands.

Topics: Animals; Apigenin; Binding Sites; Flavanones; Flavonoids; Flunitrazepam; GABA Modulators; Glucuronates; Molecular Structure; Plant Extracts; Quantitative Structure-Activity Relationship; Rats; Rats, Sprague-Dawley; Receptors, GABA-A; Scutellaria baicalensis