Denigrins and Dactylpyrroles, Arylpyrrole Alkaloids from a Dactylia sp. Marine Sponge.

Seven new arylpyrrole alkaloids (1-7), along with four known compounds, were isolated from an extract of a Dactylia sp. nov. marine sponge, and their structures were elucidated by interpretation of NMR and MS spectroscopic data. Denigrins D-G (1-4) have highly substituted pyrrole or pyrrolone rings in their core structures, while dactylpyrroles A-C (5-7) have tricyclic phenanthrene cores. Due to the proton-deficient nature of these scaffolds, key heteronuclear correlations from 1H-15N HMBC and LR-HSQMBC NMR experiments were used in the structure assignment of denigrin D (1). Dictyodendrin F (8), a previously described co-metabolite, inhibited transcription driven by the oncogenic PAX3-FOXO1 fusion gene with an IC50 value of 13 µM.

National Cancer Institute (NCI) Program for Natural Products Discovery: Rapid Isolation and Identification of Biologically Active Natural Products from the NCI Prefractionated Library.

An automated, high-capacity, and high-throughput procedure for the rapid isolation and identification of biologically active natural products from a prefractionated library is presented. The semipreparative HPLC method uses 1 mg of the primary hit fraction and produces 22 subfractions in an assay-ready format. Following screening, all active fractions are analyzed by NMR, LCMS, and FTIR, and the active principle structural classes are elucidated. In the proof-of-concept study, we show the processes involved in generating the subfractions, the throughput of the structural elucidation work, as well as the ability to rapidly isolate and identify new and biologically active natural products. Overall, the rapid second-stage purification conserves extract mass, requires much less chemist time, and introduces knowledge of structure early in the isolation workflow.

Dehydrocostus lactone, a sesquiterpene from Saussurea lappa Clarke, suppresses allergic airway inflammation by binding to dimerized translationally controlled tumor protein.

BACKGROUND: We previously reported that the biologically active form of histamine releasing factor (HRF) is dimerized translationally controlled tumor protein (dTCTP) which is involved in a number of allergic diseases. HYPOTHESIS/PURPOSE: Hoping that agents that modulate dTCTP may provide new therapeutic targets to allergic inflammatory diseases, we screened a library of natural products for substances that inhibit dTCTP. One such inhibitor we found was dehydrocostus lactone (DCL), a natural sesquiterpene present in rhizome of Saussurea lappa Clarke, the subject of this study. METHODS: We evaluated the therapeutic efficacy of DCL in a mouse model of ovalbumin (OVA)-induced allergic airway inflammation, employing the ELISA system using BEAS-2B cells and splenocytes, and confirmed that DCL interacts with dTCTP using SPR assay. RESULTS: DCL inhibited dTCTP-induced secretion of IL-8 in BEAS-2B cells. From kinetic analysis of dTCTP and DCL, we found that KD value was 5.33 ±â€¯0.03 µM between dTCTP and DCL. DCL also significantly reduced inflammatory lung eosinophilia, type 2 cytokines in BALF, as well as OVA specific IgE and mucus production in a mouse model of ovalbumin induced allergy. Moreover, DCL suppressed NF-κB activation. CONCLUSION: DCL's therapeutic potential in allergic airway inflammation is based on its anti-inflammatory activity of suppressing the function of dTCTP.

Tussilagonone-induced Nrf2 pathway activation protects HepG2 cells from oxidative injury.

Tussilagonone is a compound derived from the medicinal plant Tussilago farfara L., which is used as a traditional medicine for respiratory diseases, including asthma and pneumonia. Recent reports suggest that tussilagonone exhibits anti-inflammatory effects; however, the scope of protective functions has not been elucidated yet. In this study, we demonstrate that tussilagonone enhances cellular detoxification by increasing quinone reductase activity in Hepa1c1c7 cells. In addition, tussilagonone decreased tert-butyl hydroperoxide(t-BHP)-induced ROS production and cell death, suggesting that it also acts as a potent antioxidant. To verify the molecular mechanism underlying tussilagonone activity, we examined the expression of nuclear factor erythroid 2-related factor 2(Nrf2)-a transcription factor that regulates antioxidant protein expression-in HepG2 cells. Significantly, these results showed that tussilagonone induces Nrf2 activation and nuclear accumulation, resulting in the upregulation of the detoxifying enzymes NAD(P)H quinone dehydrogenase 1(NQO1) and heme oxygenase-1(HO-1) that protect cells from oxidative stress. Further molecular analyses revealed that tussilagonone-induced Nrf2 activation was mediated by ERK1/2 in HepG2 cells. Collectively, these data indicate that tussilagonone attenuates t-BHP-induced ROS and activates quinone reductase activity via Nrf2 pathway activation and target gene expression, and thereby acts as an antioxidant that protects HepG2 cells from oxidative stress and associated damage.

Heme oxygenase-1-mediated anti-inflammatory effects of tussilagonone on macrophages and 12-O-tetradecanoylphorbol-13-acetate-induced skin inflammation in mice.

The dried flower buds of Tussilago farfara L. have been used in traditional medicine, mainly as an antitussive in the treatment of cough and other respiratory problems. In the present study, we investigated the anti-inflammatory signaling pathway via the upregulation of heme oxygenase-1 (HO-1) in response to tussilagonone (TGN), a sesquiterpene compound isolated from T. farfara. TGN induced HO-1 expression and nuclear factor-E2-related factor 2 (Nrf2) activation in RAW 264.7 cells. Nuclear translocation of Nrf2 by TGN also increased in a time- and dose-dependent manner, indicating that TGN induced HO-1 via the Nrf2 pathway. Consistent with the notion that HO-1 has anti-inflammatory properties, TGN suppressed inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression and reduced the mRNA expression of proinflammatory cytokines, as well as nitric oxide (NO) and prostaglandin E2 (PGE2) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. TGN inhibited the phosphorylation and degradation of inhibitory κB-α (IκB-α) and the nuclear translocation of nuclear factor (NF)-κB. However, a specific inhibitor of HO-1 reversed the TGN-mediated suppression of NO production and knockdown of HO-1 by small interfering RNA abrogated inhibitory effects of TGN on iNOS and COX-2 protein expression and NF-κB nuclear translocation. Furthermore, TGN reduced iNOS and COX-2 expression in a 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced skin inflammation mouse model. Taken together, these findings suggest an important role for TGN-induced HO-1 activation in regulating inflammatory responses. Moreover, TGN is a potent therapeutic candidate for targeting the crosstalk between Nrf2/HO-1 and the NF-κB signaling pathway in the prevention or treatment of inflammation-associated diseases.

A comparative study on hulled adlay and unhulled adlay through evaluation of their LPS-induced anti-inflammatory effects, and isolation of pure compounds.

Coicis semen (=the hulled seed of Coix lacryma-jobi L. var. ma-yuen (Rom.Caill.) Stapf; Gramineae), commonly known as adlay and Job's tears, is widely used in traditional medicine and as a nutritious food. Bioassay-guided fractionation of the AcOEt fraction of unhulled adlays, using measurement of nitric oxide (NO) production on lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells, led to the isolation and identification of two new stereoisomers, (+)-(7'S,8'R,7″S,8″R)-guaiacylglycerol ß-O-4'-dihydrodisinapyl ether (1) and (+)-(7'S,8'R,7″R,8″R)-guaiacylglycerol ß-O-4'-dihydrodisinapyl ether (2), together with six known compounds, 3-8. Compounds 3 and 4 exhibited inhibitory activities on LPS-induced NO production with IC50 values of 1.4 and 3.7 µM, respectively, and suppressed inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein expressions in RAW 264.7 macrophage cells. Simple high-performance liquid chromatography with ultraviolet detection (HPLC/UV) was used to compare the AcOEt fraction of unhulled adlays responsible for the anti-inflammatory activity in RAW 264.7 cells and the inactive AcOEt fraction of hulled adlays.