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DNA methylation controls the expression of tanshinone synthesis genes and the tanshinone accumulation in Salvia miltiorrhiza and Salvia bowleyana.

DNA methylation plays pivotal roles in regulating gene expression and the secondary metabolism in plants. Salvia miltiorrhiza and Salvia bowleyana are traditional Chinese medicinal plants with roots enriched with tanshinone components. However, the regulatory mechanism of DNA methylation on tanshinone production remains elusive. Here, we analyzed 30-day-old hairy roots of S. miltiorrhiza and S. bowleyana using targeted high-performance liquid chromatography analysis and found significantly higher tanshinone content in S. miltiorrhiza. Whole-genome bisulfite sequencing revealed elevated DNA methylation levels in S. miltiorrhiza, potentially due to the upregulation of methylation-related genes, including DOMAINS REARRANGED METHYLTRANSFERASE 1 (DRM1), DECREASE IN DNA METHYLATION 1 (DDM1), CHROMOMETHYLASE 2 (CMT1), and CHROMOMETHYLASE 3 (CMT3), alongside the low expression of the demethylase gene REPRESSOR OF SILENCING 1 (ROS1) in S. miltiorrhiza. Additionally, four genes that are involved in tanshinone biosynthesis, including 1-DEOXY-D-XYLULOSE-5-PHOSPHATE REDUCTASE (DXS1), GERANYLGERANYL DIPHOSPHATE SYNTHASE (GGPPS2), 4-HYDROXY-3-METHYLBUT-2-ENYL PYROPHOSPHATE REDUCTASE (HDR2), and COPALYL PYROPHOSPHATE SYNTHASE (CPS3), showed lower methylation levels in the promoters of DXS1, GGPPS2, and CPS3 and a higher DNA methylation level in the gene body of HDR2 in S. miltiorrhiza, which may lead to their high expression and the accumulation of tanshinones. Consistently, overexpression of the SmCMT3 in S. miltiorrhiza significantly reduced the contents of cryptotanshinone, tanshinone I, and tanshinone IIA. Transcriptomic and methylome analyses confirmed that the expression levels of the tanshinone biosynthesis-related genes, including SmMK, SmCPS1, SmDXS2, and SmAACT1, were correlated with their promoter or gene body DNA methylation levels. Our findings reveal that DNA methylation critically regulates tanshinone biosynthesis in S. miltiorrhiza and S. bowleyana, offering valuable insights for breeding.

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Simultaneous determination of cryptotanshinone, tanshinone I and tanshinone IIA in traditional Chinese medicinal preparations containing Radix salvia miltiorrhiza by HPLC.

A reversed-phase high performance liquid chromatographic method was established for the simultaneous determination of tanshinones in five kinds of traditional Chinese medicinal preparations (TCMPs) containing Radix salvia miltiorrhiza (Chinese herbal name: Danshen). Tanshinones including cryptotanshinone, tanshinone I and tanshinone IIA were successfully separated on a Diamonsil C18 column (150 mm x 4.6 mm i.d., 5 microm). The mobile phase was a mixture of methanol, tetrahydrofuran, water and glacial acetic acid (20:35:44:1, v/v/v/v), employing isocratic elution at a flow rate of 1.0 mL/min. Detection was accomplished at 254 nm. The compounds were identified by comparing their retention times and UV spectra in the 200-400 nm range with authentic standards. Regression equations revealed good linear relationship between the peak areas of the constituents and their concentrations (correlation coefficients: 0.9998 for cryptotanshinone, 0.9999 for tanshinone I and 1.0000 for tanshinone IIA). The relative standard deviations (n=6) of retention time and peak area were less than 0.25% and 1.00%, respectively. The recoveries were between 96.2% and 102.5%. The proposed method has been successfully applied to the simultaneous determination of the tanshinones in five kinds of Chinese herbal preparations containing Danshen within 20 min.

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Selection of a high tanshinone-producing crown gall strain and production of tanshinone in the strain.

Crown galls were induced by direct infection of sterile seedlings of Salvia miltiorrhiza with Agrobacterium tumefaciens C58 and subcultured on a 67-V hormone-free medium by successively selecting red cell aggregates. A high tanshinone-producing crown gall strain C1 was obtained after 12 months in a subculture. It grows well and retains its high tanshinone-producing characteristic in liquid stationary cultures. It is obvious that the yeast extract and fermentation extract of Armillaria mellea as elicitors promote strain C1 to produce tanshinone. Tanshinone content of strain C1 cultures was over three times higher than that of the crude drugs. The results indicated that the crown gall tissue and elicitor technique could provide some new clues for the production of tanshinone under the condition of a liquid stationary culture.

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Studies on the spectroscopic behavior of cryptotanshinone, tanshinone IIA, and tanshinone I.

A comparative study on the spectroscopic behavior of cryptotanshinone (CTan), tanshinone IIA (Tan IIA), and tanshinone I (Tan I) has been investigated, including UV-Vis absorption, low temperature phosphorescence (LTP), low temperature fluorescence (LTF), paper substrate-room temperature phosphorescence (PS-RTP), paper substrate-room temperature fluorescence (PS-RTF) and fluorescence in liquid (LF). The effect of pH on the luminescence intensity is discussed. Lifetime and polarization of the LTP and RTP have been examined with phosphorescence lifetime in the range of 0.6-0.9s and polarization in the range of 0.10-0.27. Analytical characteristics of LF, PS-RTF and PS-RTP of CTan, Tan IIA, and Tan I have been studied.

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Efficient production and recovery of diterpenoid tanshinones in Salvia miltiorrhiza hairy root cultures with in situ adsorption, elicitation and semi-continuous operation.

In Salvia miltiorrhiza hairy root cultures, the desired secondary metabolites diterpenoid tanshinones are normally produced at low yields and stored within the roots. To enhance tanshinone production and the secondary product recovery, we employed three means, elicitation with a yeast elicitor (YE), in situ adsorption of tanshinones with a hydrophobic polymeric resin (X-5) and semi-continuous mode of operation. YE treatment stimulated the tanshinone biosynthesis, increasing the total tanshinone (TT) content of root by about two-fold, from 0.46 to 1.37 mg/g dry weight (dw) (TT content=total content of three major tanshinones, cryptotanshinone, tanshinone I and tanshinone IIA). The addition of X-5 resins to the culture only increased the tanshinone yield slightly, but recovered more than 80% of tanshinones from the roots. With the application of a semi-continuous culture process involving repeated medium renewal, elicitor addition and resin replacement, starting at the late exponential growth phase, the root biomass was increased to 30.5g dw/l (versus 8-10g dw/l in batch mode) and the volumetric tanshinone yield to 87.5mg/l (about 15-fold increase), with 76.5% adsorbed to the resin. The volumetric productivity of total tanshinone reached 1.46 mg/lday, more than 7.4 times that of the batch culture. The results demonstrate that the integration of multiple elicitation, in situ adsorption and semi-continuous operation can synergistically enhance tanshinone production in S. miltiorrhiza hairy root cultures.

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Diterpene quinone tanshinone IIA selectively inhibits mouse and human cytochrome p4501A2.

1. Tanshinone IIA is the main active diterpene quinone in the herbal medicine Salvia miltiorrhiza. In untreated mouse liver microsomes, tanshinone IIA selectively inhibited 7-ethoxyresorufin O-deethylation (EROD) and 7-methoxyresorufin O-demethylation (MROD) activities without affecting the oxidation of benzo(a)pyrene, tolbutamide, N-nitrosodimethylamine and nifedipine. Tanshinone IIA was a competitive inhibitor of MROD activity with a K(i) of 7.2 +/- 0.7 nM. 2. In 3-methylcholanthrene-treated mouse liver microsomes, tanshinone IIA and two minor tanshinones, tanshinone I and cryptotanshinone, inhibited liver microsomal MROD activity without affecting EROD and benzo(a)pyrene hydroxylation activities at the concentrations up to 1 microM. Tanshinone IIA induced a type I binding spectrum with a spectral dissociation constant K(s) of 2.3 +/-0.8 microM without cooperativity. 3. In human liver microsomes, tanshinone IIA decreased EROD and MROD activities without affecting the oxidation of benzo(a)pyrene, tolbutamide, chlorzoxazone and nifedipine. 4. In Escherichia coli membranes expressing bicistronic human CYP1A enzymes, tanshinone IIA inhibited EROD activity of CYP1A1 with an IC(50) 48 times higher than that for CYP1A2. Tanshinone I and cryptotanshinone had the same IC(50) ratio (1A1/1A2) of 4. 5. The results indicate that tanshinone represents a new group of CYP1A inhibitors, and tanshinone IIA had the highest selectivity in inhibition of CYP1A2.

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[Anti-inflammatory constituents, aloesin and aloemannan in Aloe species and effects of tanshinon VI in Salvia miltiorrhiza on heart].

Cinnamoyl, p-coumaroyl, feruloyl, caffeoyl aloesin, and related compounds were isolated from Aloe species. The antiinflammatory and antioxidative activities of these compounds were examined based on the structure-activity relationship. It was suggested that the bioactivities may link to acyl ester groups in aloesin, together with those of aloesin-related compounds. However, investigations using the contact hypersensitivity response indicated a preventive effect of aloesin on the UV-B-induced immune suppression. Furthermore, aloesin inhibited tyrosine hydroxylase and dihydroxyphenylalanine (DOPA) oxidase activities of tyrosinase from normal human melanocyte cell lysates. These results show that aloesin prevents not only UV-B-induced immune suppression, but also could be a positive pigment-altering agent for cosmetic application. In preclinical study, aloe extract was investigated using phagocytosis and nitroblue tetrazolium chloride (NBT) reduction in adult bronchial asthma, and high molecular-weight materials, such as polysaccharide and glycoprotein fractions, were identified as active ingredients. The neutral polysaccharides, aloemannan and acemannan showed antitumor, antiinflammatory and immunosuppressive activities, and glycoprotein fractions with bradykinindegrading and cell proliferation-stimulating activities were identified from the nondialysate fraction of the gel part of Aloe species. Verectin fractionated from Aloe vera gel was examined biochemically and immunochemically, and verectin antibody was used in the appraisal of commercial Aloe vera gel products. It was reported that aloesin stimulates the proliferation of cultured human hepatoma SK-Hep 1 cells. Thus aloesin, related compounds, and high molecular-weight materials, such as aloemannan and verectin, may act in concert to exert therapeutic properties for wounds, burns and inflammation. The biodisposition of fluoresceinylisothiocyanate (FITC)--labeled aloemannan (FITC-AM) with the homogenate from some organs in mice was demonstrated, and FITC-AM was metabolized to a smaller molecule (MW 3000) by the large intestinal microflora in feces. The modified aloe polysaccharide (MW: 80000) with cellulase under restricted conditions, immunologically stimulated the recovery of UV-B-induced tissue in jury. Thus the modified polysaccharides of aloemannan, together with acemannan (MW: about 600000), are expected to participate in biological activity following oral administration. The effects of tanshinone VI, a diterpenoid isolated from Salvia miltiorrhiza, on the heart are reviewed. First, the effects on the posthypoxic recovery of contractile function of perfused rat hearts were examined. Hypoxia/reoxygenation induced a release of purine nucleosides and bases (ATP metabolites) and resulted in little recovery of contractile force of reoxygenated hearts. Pretreatment of the perfused heart with 42 nM tanshinone VI under hypoxic conditions attenuated the release of ATP metabolites during hypoxia/reoxygenation. Treatment with tanshinone VI enhanced the posthypoxic recovery of myocardial contractility. These results show that tanshinone VI may protect the heart against hypoxia/reoxygenation injury and improve the posthypoxic cardiac function. Second, the effects of tanshinone VI on in vitro myocardial remodeling were examined. Cardiomyocytes and cardiac fibroblasts were isolated from neonatal rat hearts, and simultaneously prepared insulin-like growth factor-1 (IGF-1) induced the hypertrophy of cardiomyocytes. IGF-1 increased the collagen synthesis of cardiac fibroblasts, that is, in vitro fibrosis. The hypertrophy of cardiomyocytes was attenuated in the presence of tanshinone VI in the culture medium. The fibrosis of cardiac fibroblasts was decreased by treatment with tanshinone VI. When tanshinone VI was added to cardiac fibroblast-conditioned medium, the medium-mediated hypertrophy of cardiomyocytes was also attenuated. These results show that tanshinone VI may attenuate in vitro cardiac remodeling. The series of studies has shown that tanshinone VI protects the myocardium against hypoxia/reoxygenation injury and attenuates progression of in vitro myocardial remodeling, suggesting that tanshinone VI is a possible agent for the treatment of cardiac disease with contractile failure.

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Characterization of tanshinones in the roots of Salvia miltiorrhiza (Dan-shen) by high-performance liquid chromatography with electrospray ionization tandem mass spectrometry.

The qualitative analysis of tanshinones in the roots of Salvia miltiorrhiza (Dan-shen in Chinese) was performed using high-performance liquid chromatography with electrospray ionization tandem mass spectrometry (ESI-MS(n)). Tanshinones are the major bioactive constituents of Dan-shen, which is used in China for the treatment of haematological abnormalities and cardiovascular diseases. The ESI-MS(n) fragmentation behavior of tanshinones was investigated. For tanshinones with the tanshinone I nucleus, the fragmentation was triggered by loss of a molecule of CO except bearing a substituent at C17 or C18, followed by sequential eliminations of CO. If C(15-16) was a saturated bond, the fragmentation was triggered by elimination of a molecule of H2O. For tanshinones with the tanshinone IIA nucleus, the fragmentation was triggered by loss of a molecule of H2O, followed by successive eliminations of CO. Ions corresponding to loss of a molecule of propylene (Delta m = 42) were also observed. Moreover, when C(15-16) was a saturated bond, ions corresponding to losses of CH3, H2O and propylene were more abundant. If no D-ring existed, the presence of isopropyl resulted in an elimination of a molecule of H2O with an adjacent CO or OH. In addition, the extension of the pi-conjugation in the A-ring (especially at C(1-2)) induced the fragmentation by loss of a molecule of CO. These fragmentation rules were applied to the identification of tanshinones in a chloroform/methanol (3:7) extract of Dan-shen, which was separated on a C18 column with gradient elution. A total of 27 tanshinones were identified, including five new constituents. The established method could be used for the sensitive and rapid identification of tanshinones in the Dan-shen drug and its pharmaceutical preparations.

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[Inhibition of proliferation and induction of apoptosis by tanshinone II A in NCI-H460 cell].

OBJECTIVE: To investigate the inhibition of tanshinone II A in NCI-H460 cell line and its mechanism. METHODS: MTT was used to measure the levels of the proliferation of NCI-H460 cultured with tanshinone II A in different concentrations. The effects of tanshinone II A on cell cycle of NCI-H460 were observed by FCM. After treated with tanshinone II A for 48h, the level of mRNA of bcl-2 and C-myc in NCI-H460 was tested by RT-PCR method. RESULT: The proliferation of NCI-H460 was obviously inhibited by tanshinone II A in a dose dependent manner. The outcome of FCM showed that the apoptotic cell rate was 1.2%, 3.4%, 7.7% respectively, when cultured with tanshinone II A at 0.5 microg/ml for 24, 48, 72 h. The apoptotic cell rate was 2.6%, 5.9%, 13.4%, when cultured with tanshinone II A at 1.0 microg/ml for 24, 48, 72 h. The apoptotic cell rate was 4.1%, 8.7%, 37.6%, when cultured with tanshinone II A at 2.0 microg/ml for 24, 48, 72 h. The outcome of RT-PCR showed that the expression of proto-onco gene bcl-2 and C-myc was notably decrease, after cultured with tanshinone II A for 48 h. CONCLUSION: Tanshinone IIA can inhibit the proliferation of NCI-H460 and induce the apoptosis of the cell.

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Induction and potentiation of diterpenoid tanshinone accumulation in Salvia miltiorrhiza hairy roots by beta-aminobutyric acid.

The non-protein amino acid beta-aminobutyric acid (BABA) is a proven inducer of plant defense against pathogens. This work examines its effect on the production of diterpenoid tanshinones in Salvia miltiorrhiza hairy root cultures, both separately and in combination with a yeast elicitor (YE, the carbohydrate fraction of yeast extract). In the absence of YE, BABA at 0.1, 1 and 2 mM caused a dose-dependent enhancement of tanshinone accumulation, with up to a 4.5-fold increase (from 0.24 to 1.09 mg/g DW) in total content of three major tanshinones (cryptotanshinone, tanshinone I and tanshinone IIA) in the hairy roots. The combination of BABA with YE treatment further enhanced tanshinone production, but only when the BABA treatment was applied to the culture a few days before the YE treatment. Compared with methyl jasmonate, BABA was more effective in enhancing tanshinone production. A 3-day pretreatment with 1 mM BABA followed by YE-treatment, increased the total tanshinone content of roots by 9.4 times to 2.26 mg/g cells, and the volumetric tanshinone yield of culture by 6.3 times (from 3.2 to 20.1 mg/l). The results suggest that BABA can strongly potentiate elicitor-induced secondary metabolism in plant tissue cultures.

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Identification of tanshinone IIA metabolites in rat liver microsomes by liquid chromatography-tandem mass spectrometry.

Tanshinone IIA, the major component extracted from Radix salvia miltiorrhiza, has been observed to possess various kinds of pharmacological activities including antioxidant, prevention of angina pectoris and myocardial infarction and anticancer. Tanshinone IIA was incubated with rat liver microsomes and the resulting metabolites were identified by liquid chromatography/tandem mass spectrometry. The results showed the formation of three main hydroxyl metabolites. The three hydroxyl metabolites of tanshinone IIA were proved to be tanshinone IIB, hydroxytanshinone IIA and przewaquinone A by comparing the tandem mass spectra and the chromatographic retention time with that of the respective authentic compounds. Tanshinone IIB, hydroxytanshinone IIA and przewaquinone A are all the chemical components of total tanshinones. It was reasonable to presume that the three hydroxy metabolites of tanshinone IIA were pharmacologically active the same as tanshinone IIA and the total tanshinones.

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Inhibition of interleukin-12 and interferon-gamma production in immune cells by tanshinones from Salvia miltiorrhiza.

Pharmacological control of interleukin-12 (IL-12) and interferon-gamma (IFN-gamma) production may be a key therapeutic strategy for modulating immunological diseases dominated by Th1-derived cytokine responses. In this study, we investigated the effects of three different tanshinone pigments from Salvia miltiorrhiza (tanshinone I, dihydrotanshinone, and cryptotanshinone) on IL-12 production in mouse macrophages and on IFN-gamma production in lymph node cells. All tested tanshinones significantly inhibited IL-12 production in lipopolysaccharide (LPS)-activated macrophages and also IFN-gamma production in keyhole limpet hemocyanin (KLH)-primed lymph node cells in a dose-dependent manner. Dihydrotanshinone was more effective than tanshinone I or cryptotanshinone. Tanshinones significantly inhibited the expression of IL-12 p40 gene at the mRNA level. Furthermore, tanshinones potently inhibited the promoter activation of IL-12 p40 gene and nuclear factor (NF)-kappaB binding to the kappaB site, suggesting that tanshinones may negatively regulate IL-12 production at the transcription level. These results may explain some known biological activities of tanshinones including their anti-inflammatory effect, and suggest a possible use of tanshinones in the treatment of immunological diseases dominated by Th1-derived cytokine responses.

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Pharmacokinetics, absorption and tissue distribution of tanshinone IIA solid dispersion.

This study was designed to elucidate the pharmacokinetics, absorption, tissue distribution and plasma protein binding properties of tanshinone IIA, a highly lipophilic compound isolated from Salvia miltiorrhiza. Tanshinone IIA was isolated using a previously well developed LC-MS/MS method. Its pharmacokinetic characteristics, absolute bioavailability, tissue distribution and plasma protein binding properties were determined. The membrane permeability was evaluated using Caco-2 cells in monolayer. The pharmacokinetic plasma profile of tanshinone IIA after a single intravenous dosing exhibited a triexponential pattern consisting of rapid distribution (t1/2 alpha, 0.024 h), slow redistribution (t1/2 beta, 0.34 h) and terminal elimination phase (t1/2 gamma, 7.5 h). Tanshinone IIA preferentially distributed into the reticuloendothelial system, especially into liver and lung, after either intravenous or oral doses. Tanshinone IIA (99.2 %) bound highly to plasma proteins, among which lipoprotein played an important role (77.5 %). Tanshinone IIA absorption was extremely poor with an absolute bioavailability below 3.5 %. Absorptive saturation was deduced from the fact that the AUC and Cmax increased less proportionally to dose and Tmax was significantly prolonged. The poor absorption of tanshinone IIA may be caused by its low aqueous solubility and limited membrane permeability. There were no significant differences of the apparent permeability coefficient for all tested concentrations and for the apical to basolateral and reverse direction transport, suggesting a passive transport mode and no involvement of an efflux protein. In conclusion, tanshinone IIA has a suitable pharmacokinetic behavior except for its poor absorption. A pharmaceutical strategy for promoting its absorption should be designed to develop tanshinone IIA as a new drug candidate.

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Partial neuroprotective effect of pretreatment with tanshinone IIA on neonatal hypoxia-ischemia brain damage.

Tanshinone IIA is a compound purified from the Chinese herb Danshen (Radix Salviae Miltiorrhiza Bge). The neuroprotective effect of tanshinone IIA was investigated in a neonatal rat model of hypoxia-ischemia brain damage. Hypoxia-ischemia encephalopathy was induced in rats at day 7 of postnatal age by ligation of the right common carotid artery, followed by 2 h of hypoxia. Tanshinone IIA (10 mg/kg, i.p.) was injected daily from day 2 before surgery for 9 or 16 d. Our results demonstrated significant and sustained brain damage in the hypoxia-ischemia- and vehicle-treated groups at 1 and 3 wk after surgery. Treatment with tanshinone IIA significantly reduced the severity of brain injury, as indicated by the increase in ipsilateral brain weight and neuron density, compared with those of sham-operated animals. The recovery of sensorimotor function and histology was observed in animals that received tanshinone IIA. The plasma of tanshinone IIA-treated rats exhibited higher antioxidant activities, as reflected by the oxygen radical absorbance capacity assay, compared with the vehicle-treated rats. In the neural progenitor cell line C17.2 that was subjected to 2,2'-azobis (2-amidino propane hydrochloride)-induced oxidative stress, tanshinone IIA increased cell viability and protected against mitochondrial damage (JC-1 assay). Our results suggest that tanshinone IIA has antioxidative activities and that treatment that is started before a hypoxic-ischemic insult is partially neuroprotective. Further studies are required to elucidate whether rescue treatment with tanshinone IIA is effective and to determine whether its protective effect is also associated with secondary cooling of the brain.

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[Study on improving the dissolution rate of tanshinone in vitro by solvent deposition method].

OBJECTIVE: To improve the dissolution rate of a poorly watersoluble drug, tanshinone. METHOD: Using pregeletinged starch as carrier, to prepare solvent deposition systems of tanshinone solvent method. The dissolution rate of tanshinone, solvent deposition systems and physical mixture were detected, and the physico-chemical properties of these study forms were investigated with scanning electron microscopy and infrared spectroscopy. RESULT: The dissolution rate of tanshinone from the solvent deposition systems in vitro was significantly higher than that from physical mixtures and tanshinone powered alone. Tanshinone deposited on the surface of the carrier in crystal form, and the size was obviously reduced. A lot of acerose crystals of tanshinone on the surface of the carrier occurred. No chemical reaction acted between tanshinone and carrier. CONCLUSION: The dissolution rate of tanshinone in vitro can be improved with solvent deposition method.

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Characterization of metabolites of tanshinone IIA in rats by liquid chromatography/tandem mass spectrometry.

The metabolism of tanshinone IIA was studied in rats after a single-dose intravenous administration. In the present study, 12 metabolites of tanshinone IIA were identified in rat bile, urine and feces with two LC gradients using LC-MS/MS. Seven phase I metabolites and five phase II metabolites of tanshinone IIA were characterized and their molecular structures proposed on the basis of the characteristics of their precursor ions, product ions and chromatographic retention time. The seven phase I metabolites were formed, through two main metabolic routes, which were hydroxylation and dehydrogenation metabolism. M1, M4, M5 and M6 were supposedly tanshinone IIB, hydroxytanshinone IIA, przewaquinone A and dehydrotanshinone IIA, respectively, by comparing their HPLC retention times and mass spectral patterns with those of the standard compounds. The five phase II metabolites identified in this research were all glucuronide conjugates, all of which showed a neutral loss of 176 Da. M9 and M12 were more abundant than other identified metabolites in the bile, which was the main excretion path of tanshinone IIA and the metabolites. M12 was the main metabolite of tanshinone IIA. M9 and M12 were proposed to be the glucuronide conjugates of two different semiquinones and these semiquinones were the hydrogenation products of dehydrotanshinone IIA and tanshinone IIA, respectively. This hydrogenized reaction may be catalyzed by the NAD(P)H: quinone acceptor oxidoreductase (NQO). The biotransformation pathways of tanshinone IIA were proposed on the basis of this research.

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Molecular mechanisms of inhibitory activities of tanshinones on lipopolysaccharide-induced nitric oxide generation in RAW 264.7 cells.

The effects of four tanshinones isolated from Tanshen (the root of Salvia miltiorrhiza Bunge, Labiatae) were tested for their inhibition of nitric oxide production in macrophage cells, and the underlying molecular mechanisms studied. Of the four tanshinones used, 15, 16-dihydrotanshinone-I, tanshinone-IIA and cryptotanshinone, but not tanshinone I, demonstrated significant inhibition of the LPS-induced nitric oxide production in RAW 264.7 cells, with calculated IC50 values of 5, 8, and 1.5 microM, respectively. Tanshinones exerted inhibitory activities on the LPS-induced nitric oxide production only when applied concurrently with LPS, and tanshinone-IIA and cryptotanshinone were found to inhibit LPS-induced NF-kappaB mobilization and extracellular-regulated kinase (ERK) activation, respectively. These results suggest that tanshinones inhibit LPS-induced nitric oxide generation by interfering with the initial stage of LPS-induced expression of certain genes. NF-kappaB and ERK could be the molecular targets for tanshinones for the inhibition of LPS-induced nitric oxide production in macrophage cells.

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