Amicoumacins from a desert bacterium: quorum sensing inhibitor against Chromobacterium violaceum.

In our study, the anti-quorum sensing (QS) activity of fermentation broth from TRM B-02, a bacterium isolated from Taklimakan desert, was investigated using the biosensor bioassay on Chromobacterium violaceum ATCC12472. TRM B-02 was 100% similar to Bacillus subtilis subsp. Inaquosorum KCTC 13429(T) by genotypic and phenotypic analyses. Based on anti-QS activity tracking, six known amicoumacins, named as AI-77-H (1), AI-77-F (2), amicoumacin B (3), amicoumacin C (4), AI-77-C (5) and bacilosarcins D (6), were isolated and identified. Among them, compounds 1-3 exhibited a better inhibitory effect on C. violaceum ATCC12472. Further research suggested that compounds 1-3 could significantly down-regulate the expressions of violacein operon A (vioA), vioB, vioD and vioE and up-regulate vioC. Docking experiments indicated that compounds 1-3 may act as an inhibitor of violacein biosynthetic pathway competitively inhibiting the binding of flavin adenine dinucleotide (FAD) with the vioD enzyme.[Figure: see text].

Rapid identification and quantitative analysis of chemical constituents of Gentiana veitchiorum by UHPLC-PDA-QTOF-MS

ABSTRACT Gentiana veitchiorum Hemsl., Gentianaceae, a traditional Tibetan medicine, was used for the treatment of liver jaundice with damp-heat pathogen, as well as for headache and chronic pharyngitis. A rapid ultra-performance liquid chromatography, photodiode array detector, quadrupole time-of-flight mass spectrometry method was developed for the fast and accurate identification and quantification of the chemical constituents of G. veitchiorum. In fact, eighteen compounds were detected and identified on the basis of their mass spectra, fragment characteristics and comparison with published data. Especially, the MS fragmentation pathways of iridoid glycosides and flavone C-glycosides were illustrated. Five compounds among them were quantified by UHPLC-PDA, including swertiamarin, gentiopicroside, sweroside, isoorientin, and isovitexin. The proposed method was then validated based on the analyses of linearity, accuracy, precision, and recovery. The overall recoveries for the five analytes ranged from 96.54% to 100.81%, with RSD from 1.05% to 1.82%. In addition, ten batches of G. veitchiorum from different areas were also analyzed. The developed method was rapid and reliable for both identification and quantification of the chemical constituents of G. veitchiorum, especially for simultaneous qualitative and quantitative analysis of iridoid glycosides and flavone C-glycosides.

Anti-neuroinflammatory effect of Sophoraflavanone G from Sophora alopecuroides in LPS-activated BV2 microglia by MAPK, JAK/STAT and Nrf2/HO-1 signaling pathways.

BACKGROUND: Neuroinflammation plays a vital role in Alzheimer's disease (AD) and other neurodegenerative conditions. Sophora alopecuroides is widely used in traditional Uighur's medicine for the treatment of inflammation. Sophoraflavanone G (SG), a major flavonoid found in the S. alopecuroides, has also been reported to exhibit anti-inflammatory activity both in vitro and in vivo. However, the effect of S. alopecuroides and SG on microglia-mediated neuroinflammation has not been investigated. PURPOSE: The present study was designed to evaluate the anti-neuroinflammatory effect of S. alopecuroides and SG against lipopolysaccharide (LPS)-activated BV2 microglial cells and to explore the underlying mechanisms. METHODS: We measured the production of pro-inflammatory mediators and cytokines, and analyzed relevant mRNA and protein expressions by qRT-PCR and Western Blot. RESULTS: S. alopecuroides extract (SAE) and SG inhibited the LPS-induced release of nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1ß (IL-1ß). Additionally, SG reduced gene expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), TNF-α, IL-6 and IL-1ß, and further decreased the protein expressions of iNOS and COX-2. Mechanism studies found that SG down-regulated phosphorylated mitogen-activated protein kinases (MAPKs), phosphoinositide-3-kinase (PI3K)/AKT and Janus kinase/signal transducer and activator of transcription (JAK/STAT), and up-regulated heme oxygenase-1 (HO-1) expression via nuclear translocation of nuclear factor E2-related factor 2 (Nrf2). In addition, SG inhibited the cytotoxicity of conditioned medium prepared by LPS-activated BV2 microglia to neuronal PC12 cells and improved cell viability. CONCLUSION: S. alopecuroides and SG displayed anti-neuroinflammatory activity in LPS-activated BV2 microglia. SG was able to inhibit the neuroinflammation by MAPKs, PI3K/AKT, JAK/STAT and Nrf2/HO-1 signaling pathways and might act as a natural therapeutic agent to be further developed for the treatment of various neuroinflammatory conditions.

Interconverting flavonostilbenes with antibacterial activity from Sophora alopecuroides.

Five flavonostilbenes (alopecurones H, I, J, K and L) and five known ones were isolated from roots of Sophora alopecuroides, in addition to ten other phenolic compounds. A non-enzymatic interconversion of the lavandulyl-substituted flavonostilbenes was observed among alopecurones A, H, I, and K through a Wessely-Moser rearrangement reaction; this was proven by 1D and 2D NMR, HPLC-CD-PDA and HRMS analyses. Bioassay results suggested that flavonostilbenes exhibit significant antibacterial and anti-biofilm formation activities against Staphylococcus epidermidis with MIC values ranging from 3.1 to 12.5µg/mL.

Flavonostilbenes from Sophora alopecuroides L. as multidrug resistance associated protein 1 (MRP1) inhibitors.

Flavonoids have always attracted much attention due to their reversal activity on multidrug resistance (MDR). Eight flavonoids isolated from traditional Chinese medicine Sophora alopecuroides L. were applied to test their effect on MDR associated protein 1 (MRP1) through the established predicting assay. Three flavonostilbenes (alopecurone A, B and D) were first found exhibiting potent inhibitory activity on MRP1. All of them dramatically increased 6-carboxyfluorescein diacetate and doxorubicin accumulation in MRP1-transfected U-2 OS cells. The compounds significantly increased the cytotoxicity and decreased the IC50 value of doxorubicin on the MDR cells (12-, 5- and 8-fold, respectively) at a non-toxic concentration (20 µM). Besides, Q-PCR analysis reveals that the MRP1 mRNA level in U-2 OS/MRP1 was also markedly decreased by the three compounds. These findings indicate a new therapeutic role of the herb. The three flavonostilbenes may have the possibility for further development as novel therapeutic reversal agents against MDR.

Geranylated 2-arylbenzofurans from Morus alba var. tatarica and their α-glucosidase and protein tyrosine phosphatase 1B inhibitory activities.

Ten new geranylated 2-arylbenzofuran derivatives, including two monoterpenoid 2-arylbenzofurans (1 and 2), two geranylated 2-arylbenzofuran enantiomers (3a and 3b), and six geranylated 2-arylbenzofurans (4-9), along with four known 2-arylbenzofurans (10-13) were isolated from the root bark of Morus alba var. tatarica. Their structures and relative configurations were established on the basis of spectroscopic data analysis. Compounds 3-7 with one asymmetric carbon at C-7″ were supposed to be enantiomeric mixtures confirmed by chiral HPLC analysis, and the absolute configurations of each enantiomer in 3-7 were determined by Rh2(OCOCF3)4-induced CD and Snatzke's method. The enantiomers with the substituting group at C-2' exhibited better resolutions on a Chiralpak AD-H column than those with the substituting group at C-4'. Compounds 1-7, 10, 11 and 13, showed α-glucosidase inhibitory activities with IC50 values of 11.9-131.9 µM, and compounds 1 and 9-13 inhibited protein tyrosine phosphatase 1B (PTP1B) with IC50 values of 7.9-38.1 µM.

Characterisation of homoflavonoids from three Ophioglossum species using liquid chromatography with diode array detection and electrospray ionisation tandem mass spectrometry.

INTRODUCTION: Homoflavonoids, characterised by one more carbon atom directly added to C6 -C3 -C6 backbone of flavonoids, are rich in the species of genus Ophioglossum. Up to now we have little knowledge about their MS fragmentation patterns. It is therefore necessary to investigate their MS fragmentation pathways so as to distinguish them from other types of flavonoids. OBJECTIVE: To develop a rapid method for identifying homoflavonoids from Ophioglossum based on their characteristic MS fragmentation. METHODS: Mass spectrometry fragmentation pathways and qualitative analysis of homoflavonoids in three ferns of Ophioglosssum were investigated by using high-performance liquid chromatography coupled with diode-array detection and electrospray ionisation tandem mass spectrometry (HPLC-DAD-ESI/MS(n) ). RESULTS: The analyses of the MS(n) spectra of the homoflavonoids allowed us to classify them into two types according to their fragmentation characteristics. The type I homoflavonoids, with an attached additional carbon atom to the C-3 position of the C-ring, presented the initial competing loss of H2 O and CH2 O from their aglycone ions, compared to the initial removal of H2 O or CO in the case of the type II homoflavonoids, which bear the additional carbon atom at the C-2' site of the B-ring and forming ring D. The above characteristic fragmentations of homoflavonoids were quite different from those of other flavonoids, and were successfully applied to identify homoflavonoids in the crude extracts of three Ophioglossum species. CONCLUSION: The HPLC-DAD-ESI/MS(n) method obtained in the present study provided a powerful tool for identifying homoflavonoids from ferns in the genus Ophioglossum.

Two new homoflavonoids from the fern Ophioglossum pedunculosum.

Two new homoflavonoids (1 and 2) were isolated from the fern Ophioglossum pedunculosum Desv. Their structures were elucidated on the basis of spectroscopic data to be 6-(3-methyl-2-buten-1-yl) ophioglonin (1) and ophioglonin 4'-O-ß-D-glucopyranoside (2), respectively. In addition, the possible biogenetic pathway to compounds 1 and 2 was discussed.

Homoflavonoid glucosides from Ophioglossum pedunculosum and their anti-HBV activity.

Chemical investigation of the ethanolic extracts of the whole plant of Ophioglossum pedunculosum afforded seven new homoflavonoid glucosides, pedunculosumosides A-G (1-7). Pedunculosumosides A and C exhibit modest activity of blocking HBsAg secretion with IC(50) values of 238.0 and 70.5 µM, respectively.