Mechanism of XiJiaQi in the treatment of chronic heart failure: Integrated analysis by pharmacoinformatics, molecular dynamics simulation, and SPR validation.

OBJECTIVE: Chronic heart failure (CHF) is a complicated clinical syndrome with a high mortality rate. XiJiaQi (XJQ) is a traditional Chinese medicine used in the clinical treatment of CHF, but its bioactive components and their modes of action remain unknown. This study was designed to unravel the molecular mechanism of XJQ in the treatment of CHF using multiple computer-assisted and experimental methods. METHODS: Pharmacoinformatics-based methods were used to explore the active components and targets of XJQ in the treatment of CHF. ADMETlab was then utilized to evaluate the pharmacokinetic and toxicological properties of core components. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were to explore the underlying mechanism of XJQ treatment. Molecular docking, surface plasmon resonance (SPR), and molecular dynamics (MD) were employed to evaluate the binding of active components to putative targets. RESULTS: Astragaloside IV, formononetin, kirenol, darutoside, periplocin and periplocymarin were identified as core XJQ-related components, and IL6 and STAT3 were identified as core XJQ targets. ADME/T results indicated that periplocin and periplocymarin may have potential toxicity. GO and KEGG pathway analyses revealed that XJQ mainly intervenes in inflammation, apoptosis, diabetes, and atherosclerosis-related biological pathways. Molecular docking and SPR revealed that formononetin had a high affinity with IL6 and STAT3. Furthermore, MD simulation confirmed that formononetin could firmly bind to the site 2 region of IL6 and the DNA binding domain of STAT3. CONCLUSION: This study provides a mechanistic rationale for the clinical application of XJQ. Modulation of STAT3 and IL-6 by XJQ can impact CHF, further guiding research efforts into the molecular underpinnings of CHF.

Chemical constituents from the linseed meal.

One megastigmane derivative 1, one methyl jasmonate glycoside derivative 2, and two C-28 steroids with 3ß,5ß-cis-dihydroxyl conformation 3 and 4, together with eight known compounds 5-12 were isolated from the 70% ethanol extract of linseed meal (Linum usitatissimum L). Structures of 1-4 were elucidated by spectroscopic methods including NMR, HRESIMS, and Mo2(OAc)4-induced CD. The absolute configuration of 1 and 3 was determined by observing their induced circular dichroism after addition of Mo2(OAc)4 in DMSO. The absolute configuration of 2 was determined by NOESY experiment together with conformational analysis. The structure of 4a was corrected as 4 by an extensive analysis of its 1D and 2D NMR, in combination with the Mo2(OAc)4-induced CD in DMSO. The effect of all the isolates on nitric oxide (NO) generation by stimulated macrophages was evaluated, and none of them showed active.

Application of quantitative 1H NMR for the calibration of protoberberine alkaloid reference standards.

Quantitative nuclear magnetic resonance spectroscopy (qNMR) has been developed into an important tool in the drug analysis, biomacromolecule detection, and metabolism study. Compared with mass balance method, qNMR method bears some advantages in the calibration of reference standard (RS): it determines the absolute amount of a sample; other chemical compound and its certified reference material (CRM) can be used as internal standard (IS) to obtain the purity of the sample. Protoberberine alkaloids have many biological activities and have been used as reference standards for the control of many herbal drugs. In present study, the qNMR methods were developed for the calibration of berberine hydrochloride, palmatine hydrochloride, tetrahydropalmatine, and phellodendrine hydrochloride with potassium hydrogen phthalate as IS. Method validation was carried out according to the guidelines for the method validation of Chinese Pharmacopoeia. The results of qNMR were compared with those of mass balance method and the differences between the results of two methods were acceptable based on the analysis of estimated measurement uncertainties. Therefore, qNMR is an effective and reliable analysis method for the calibration of RS and can be used as a good complementarity to the mass balance method.

Simultaneous structural identification of natural products in fractions of crude extract of the rare endangered plant Anoectochilus roxburghii using H NMR/RRLC-MS parallel dynamic spectroscopy.

Nuclear magnetic resonance/liquid chromatography-mass spectroscopy parallel dynamic spectroscopy (NMR/LC-MS PDS) is a method aimed at the simultaneous structural identification of natural products in complex mixtures. In this study, the method is illustrated with respect to (1)H NMR and rapid resolution liquid chromatography-mass spectroscopy (RRLC-MS) data, acquired from the crude extract of Anoectochilus roxburghii, which was separated into a series of fractions with the concentration of constituent dynamic variation using reversed-phase preparative chromatography. Through fraction ranges and intensity changing profiles in (1)H NMR/RRLC-MS PDS spectrum, (1)H NMR and the extracted ion chromatogram (XIC) signals deriving from the same individual constituent, were correlated due to the signal amplitude co-variation resulting from the concentration variation of constituents in a series of incompletely separated fractions. 1H NMR/RRLC-MS PDS was then successfully used to identify three types of natural products, including eight flavonoids, four organic acids and p-hydroxybenzaldehyde, five of which have not previously been reported in Anoectochilus roxburghii. In addition, two groups of co-eluted compounds were successfully identified. The results prove that this approach should be of benefit in the unequivocal structural determination of a variety of classes of compounds from extremely complex mixtures, such as herbs and biological samples, which will lead to improved efficiency in the identification of new potential lead compounds.

Dynamic selection of novel vancomycin N-terminal derivatives by resin-bound reversed D-Ala-D-Ala.

The most attractive advantage of dynamic combinatorial chemistry (DCC) is that it can screen the compound library as soon as compounds are synthesized. However, it is very difficult to analyze a dynamic combinatorial library with free probes using the state-of-the art analysis technologies. We report herein a method that uses a resin-immobilizing reversed peptide probe to screen vancomycin derivatives and provides a solution to this problem.

Glycosides from the stem bark of Fraxinus sieboldiana.

A norditerpene glucopyranoside with a novel carbon skeleton (1), eight new aromatic glycosides (2-9), and 25 known glycosides have been isolated from a H2O-soluble portion of an ethanolic extract of the stem bark of Fraxinus sieboldiana. Their structures were determined by spectroscopic and chemical methods. Based on analysis of the NMR data of threo- and erythro-arylglycerols in different solvents, an application of Delta delta C8-C7 values to distinguish threo-arylglycerol and erythro-arylglycerol isomers was proposed. In the in vitro assays, compound 5 displayed TNF-alpha secretion inhibitory activity with an IC50 value of 1.6 microM, compound 6 showed antioxidative activity inhibiting Fe+2-cystine-induced rat liver microsomal lipid peroxidation with an IC50 value of 0.9 microM, and plantasioside (10) showed selective activity against the human colon cancer cell line (HCT-8) with an IC50 value of 3.4 microM.

[Study on chemical constituents of Orobanche coerulescens].

Six compounds were isolated and purified from Orobanche coerulescens by extraction and different kinds of column chromatography. The structures were determined on the basis of spectral analysis. The structures were elucidated as D-mannitol(I), beta-sitosterol(II), succinic acid(III), caffeic acid(IV), protocatechuic aldehyde(V) and daucosterol(VI). All compounds are obtained from this plant for the first time.

New Diels-Alder type adducts from Morus macroura and their anti-oxidant activities.

Fractionation of the ethanolic extract of the stem bark of Morus macroura resulted in the isolation of four new Diels-Alder type adducts, named guangsangons K--N (1, 2, 5, 6), together with two known compounds, mulberrofuran G (3) and K (4). Their structures were determined on the basis of spectroscopic analyses and chemical methods. Furthermore, by means of (1)H-NMR variable temperature experiments and the Cotton curves in the circular dichroism (CD) spectra, the stereochemistry of four new compounds was elucidated. The isolated new compounds showed good activity on anti-oxidant in vitro, with the inhibitory rates of MDA being from 91.8 to 100.0% at concentrations of 10(-5) mol/l.

On-line identification of phenanthroindolizidine alkaloids in a crude extract from Tylophora atrofolliculata by liquid chromatography combined with tandem mass spectrometry.

Electrospray ionization multi-stage tandem mass spectrometry (ESI-MS(n)) and liquid chromatography coupled with sequential mass spectrometry (LC/MS(n)) were applied to identify trace-level phenanthroindolizidine alkaloids in crude extracts from Tylophora atrofolliculata. Based on the relationship between the characteristic fragmentation reactions and the structural features of related compounds of known structure from this plant, the bioactive crude extract was analyzed in detail by positive and negative ion ESI-MS(n), LC/UV-MS and LC/MS(n) techniques. A total of nine constituents in the crude extract were identified rapidly, including several isomers; seven of these constituents are new and two are known compounds. The structures of four of these constituents were subsequently confirmed by nuclear magnetic resonance (NMR) and accurate mass measurements using high-resolution fast-atom bombardment mass spectrometry (FAB-HRMS).