In silico design and synthesis of N-arylalkanyl 2-naphthamides as a new class of non-purine xanthine oxidase inhibitors.

A series of N-arylalkanyl 2-naphthamides (Xa~e), which were predicted from virtual molecular docking on a built xanthine oxidase template as potential inhibitors, were synthesized. Their inhibitory activity against xanthine oxidase was assayed. Among these prepared, compounds Xb (IC50 13.6 µM), Xc (IC50 13.1 µM), and Xd (IC50 12.5 µM) showed comparable inhibitory activity to allopurinol (IC50 22.1 µM). The in vitro assay result correlated well with molecular docking scores, ΔG = -16.99, -17.66, and -17.13 Kcal/mol, respectively. On the potassium oxonate-induced hyperuricemic mice model, oral administration of Xc-Ac (40 mg/ Kg), the per-O-acetylated Xc, could reduce the blood uric acid level by 60% in comparison to the normal control group and is statistically significant (p < .01) while compared with the hyperuricemic mice group.

Design, synthesis and the structure-activity relationship of agonists targeting on the ALDH2 catalytic tunnel.

ALDH2, a key enzyme in the alcohol metabolism process, detoxifies several kinds of toxic small molecular aldehydes, which induce severe organ damages. The development of novel Alda-1 type ALDH2 activators was mostly relied on HTS but not rational design so far. To clarify the structure-activity relationship (SAR) of the skeleton of Alda-1 analogs by synthesis of the least number of analogs, we prepared 31 Alda-1 analogs and 3 isoflavone derivatives and evaluated for their ALDH2-activating activity. Among these, the ALDH2-activating activity of mono-halogen-substituted (Cl and Br) N-piperonylbenzamides 3b and 3 k, and non-aromatic amides 8a-8c, were 1.5-2.1 folds higher than that of Alda-1 at 20 µM. The relationship between binding affinity in computer aided molecular docking model and the ALDH2-activating activity assays were clarified as follows: for Alda-1 analogs, with the formation of halogen bonds, the enzyme-activating activity was found to follow a specific regression curve within the range between -5 kcal/mol and -4 kcal/mol. For isoflavone derivatives, the basic moiety on the B ring enhance the activating activity. These results provide a new direction of utilizing computer-aided modeling to design novel ALDH2 agonists in the future.

Acylated glucosylflavones as α-glucosidase inhibitors from Tinospora crispa leaf.

The ethanolic extract of Tinospora crispa leaf had shown inhibitory activity toward α-glucosidase. Bioassay guided fractionation and separation of this extract led to the isolation of 17 flavonoids. Among them, four acylated glycosylflavonoids (6, 8, 9, 15) are new compounds. Their structures were elucidated on the basis of spectroscopic analysis. Among the isolated compounds, isovitexin 2″-(E)-p-coumarate (8) showed the best activity against α-glucosidase with an IC50 value of 4.3±1.4µM. However, isoorientin 2″-(E)-p-coumarate (7), the 3'-hydroxylated 8, is much less active (IC50 35.7µM). Such significant difference was rationalized by CAD study on α-glucosidase.

Tetrahydropyran- and tetrahydrofuran-containing diarylheptanoids from Hedychium coronarium rhizomes.

Seven new diarylheptanoids (1-7) were isolated from the n-BuOH-soluble fraction of the rhizome of Hedychium coronarium. Hedycoropyrans A-C (1-3) contain a tetrahydropyran moiety, while hedycorofurans A-D (4-7) contain a tetrahydrofuran moiety, belonging to a rare structural class of diarylheptanoids. Their structures including stereochemistry were elucidated on the basis of 1D and 2D NMR and ECD spectroscopic analyses and HRESIMS data of the parent compounds and the isopropylidene derivatives of 4 and 7.

Highly conjugated norditerpenoid and pyrroloquinoline alkaloids with potent PTP1B inhibitory activity from Nigella glandulifera.

Three norditerpenoid alkaloids, nigelladines A-C (1-3), and one pyrroloquinoline alkaloid, nigellaquinomine (4), all possessing new skeletons with highly conjugated systems, were isolated from Nigella glandulifera. The 8aS-configuration for 1 and 2 was determined by comparison of the experimental and calculated electronic circular dichroism spectra. These alkaloids exhibited potent protein tyrosine phosphatase 1B (PTP1B) inhibitory activity but are devoid of cytotoxicity against the A431 cell line at 100 µM.

Metabolites of antroquinonol found in rat urine following oral administration.

Four metabolites (1-4) of antroquinonol from rat urine, collected within 24 h after oral administration of antroquinonol, were characterized by HPLC-SPE-NMR. Compounds 1-4 were further isolated by semipreparative HPLC for structure confirmation. Their structures were elucidated on the basis of 1D and 2D NMR spectroscopic analyses and HRESIMS data.

Semisynthesis and myocardial activity of thaliporphine N-homologues.

The N-homologues and optical isomers of thaliporphine (5a), a potent antiarrhythmic agent, were prepared starting from laurolitsine (1), an abundant aporphine present in Phoebe formosana. Treating N-propylnorglaucine with 90% H2SO4 yielded one additional product, an 11-sulfonyl-1,11-anhydroaporphine. Reaction of N-formylnorglaucine (3a) with 90% H2SO4, however, yielded the 9-sulfonyl-seco product as a major product. Treatment of 3a with 98% H2SO4 yielded pancordine (10), which, upon catalytic hydrogenation, yielded (±)-wilsonirine. (1)H NMR spectroscopic analysis was applied successfully to monitor the optical purity of the crystalline salt while undertaking optical resolution. Thaliporphine (5a) was demonstrated to possess better positive inotropic and less negative chronotropic effects than the left-hand optical isomer and showed the best activity on rat cardiac tissue among the N-homologues prepared.

Analysis and identification of phenolic compounds with antiproliferative activity from Chinese olive (Canarium album L.) fruit extract by HPLC-DAD-SPE-TT-NMR.

Chinese olives (Canarium album L.) are rich in phenolic compounds, exhibiting a broad spectrum of potential clinical applications. This study is the first report on the isolation and elucidation of bioactive compounds with high antiproliferative activity from the ethyl acetate fraction of a Chinese olive fruit methanolic extract (CO-EtOAc). We used the WST-1 assay to determine which subfractions of CO-EtOAc had significant antiproliferative activity using the murine colon cancer cell line CT26. Subsequently, the functional compounds were characterized by the hyphenated technique and high-performance liquid chromatography-diode array detector-solid phase extraction-transfer tube-nuclear magnetic resonance (HPLC-DAD-SPE-TT-NMR). Thirteen phenolic constituents were identified from the antiproliferation-enhancing subfractions of CO-EtOAc, including two new compounds, 2,4-didehydrochebulic acid 1,7-dimethyl ester (5) and 1-hydroxybrevifolin (7), which were further purified and found to exhibit marked antiproliferative activity. Chebulic acid dimethyl ester (2), which was isolated from C. album for the first time, also possessed antiproliferative activity.

Isolation of GLP-1 enhancing indolizidine alkaloids from Boehmeria formosana.

Boehmeria formosana, with its related species, demonstrates anti-glycemic effect, inhibition of HBV production, anti-cancer activities, etc. Some indolizidine alkaloids from the same genus are bioactive but sensitive to light. To overcome this problem and obtain more phenanthroindolizidine alkaloids, isolation was performed in darkness, yielding 10 new indolizidine alkaloids and 17 known compounds. Among them, seven enhanced glucagon-like receptor 1 (GLP-1) activity at 50 mM, especially 14 and 6 (3.5- and 2.3-fold than the negative control). This procedure yielded bioactive indolizidine alkaloids with novel structures.

Metabolism of (2S)-pterosin A: identification of the phase I and phase II metabolites in rat urine.

The metabolic profile of the potent hypoglycemic agent, (2S)-pterosin A (1), in rat urine via intragastrical oral administration was investigated. In total, 19 metabolites (M1-M19) were identified. Among these, 16 metabolites were characterized by high-performance liquid chromatography solid-phase extraction-tube transfer-NMR, and seven metabolites were further isolated from the treated urine to enable further structural determination. Twelve of these are new compounds. The phase I metabolites of 1 were formed via various oxidations at positions C-3, C-10, C-12, C-13, or C-1 followed by decarboxylation of C-10 or C-14, and lactonization at C-12/C-14 or C-14/C-12. The phase II metabolites were glucuronide conjugates from the parent compound or phase I metabolites. The major metabolites were found to be (2S)-14-O-glucuronylpterosin A (M9), (2S)-2-hydroxymethylpterosin E (M14), and (±)-pterosin B (M19). Quantitative HPLC analysis of metabolites, based on similar UV absorption and use of the regression equation of 1, indicated that ∼71% 1 was excreted as metabolites in rat urine.

Dibenzocycloheptanoids from the leaves of Cinnamomum subavenium.

Five dibenzocycloheptatrienes (1-3, 5, and 6) and one dibenzocycloheptadiene (8) together with 16 known compounds were isolated from the leaves of Cinnamomum subavenium. Application of HPLC-SPE-NMR to a selected fraction afforded two additional dibenzocycloheptatrienes (4, 7). The glycosides 2-7 comprise two diastereomers because of the chiral glycosyl moiety and the axial chirality of the biphenyl system. Their structures were elucidated via ECD and 2D NMR analyses and chemical degradation. Subavenosides D (5) and E (6) showed moderate inhibitory activity against α-glucosidase type IV from Bacillus stearothermophilus with IC50 values of 50.7 and 19.0 µM, respectively.

Hypoglycemic diterpenoids from Tinospora crispa.

Three new diterpenoids, 2-O-lactoylborapetoside B (1), 6'-O-lactoylborapetoside B (2), and tinocrispol A (3), and nine known diterpenoids (4-12) were isolated from an EtOH extract of Tinospora crispa vines. Their structures were elucidated by spectroscopic analyses. The C-6 glucosyloxy group in borapetoside C (6) was revised to be α-oriented. The in vivo hypoglycemic activities of the major components, borapetosides A-C (4-6), were examined. Intraperitoneal injection of 4 and 6 (5 mg/kg) showed significant lowering of plasma glucose levels in normal and streptozotocin-induced type 1 diabetic mice. Borapetoside C increased glucose utilization in peripheral tissues and reduced hepatic gluconeogenesis, accounting for the hypoglycemic effect.

Aqueous Extract of Paeonia suffruticosa Inhibits Migration and Metastasis of Renal Cell Carcinoma Cells via Suppressing VEGFR-3 Pathway.

Renal cell carcinoma (RCC) cells are characterized by strong drug resistance and high metastatic incidence. In this study, the effects of ten kinds of Chinese herbs on RCC cell migration and proliferation were examined. Aqueous extract of Paeonia suffruticosa (PS-A) exerted strong inhibitory effects on cancer cell migration, mobility, and invasion. The results of mouse xenograft experiments showed that the treatment of PS-A significantly suppressed tumor growth and pulmonary metastasis. We further found that PS-A markedly decreased expression of VEGF receptor-3 (VEGFR-3) and phosphorylation of FAK in RCC cells. Moreover, the activation of Rac-1, a modulator of cytoskeletal dynamics, was remarkably reduced by PS-A. Additionally, PS-A suppressed polymerization of actin filament as demonstrated by confocal microscopy analysis and decreased the ratio of F-actin to G-actin in RCC cells, suggesting that PS-A inhibits RCC cell migration through modulating VEGFR-3/FAK/Rac-1 pathway to disrupt actin filament polymerization. In conclusion, this research elucidates the effects and molecular mechanism for antimigration of PS-A on RCC cells and suggests PS-A to be a therapeutic or adjuvant strategy for the patients with aggressive RCC.

Comprehensive study of alkaloids from Crinum asiaticum var. sinicum assisted by HPLC-DAD-SPE-NMR.

A comprehensive study of the alkaloids presentin the leaves of Crinum asiaticum var. sinicum, assisted by HPLC-SPE-NMR, led to the characterization of 21 compounds of similar polarity on an analytical scale. Thirteen of these were isolated for further structural confirmation. Seven are proved to be new, namely, (+)-siculine (4), 1-epijosephinine (11), 7-methoxycrinamabine (10), 2-O-acetylcrinamabine (16), 3-O-acetyl-8-O-demethylmaritidine (17), 2-O-acetylbulbisine (18), and 1-O-acetylbulbisine (19). In addition, dihydrovittatine (6) and 8-O-demethyloxomaritidine (21) were isolated for the first time from Nature, although they have been prepared previously as synthetic products. Their structures were established by spectroscopic analysis.

Rapid screening of lignans from Phyllanthus myrtifolius and stilbenoids from Syagrus romanzoffiana by HPLC-SPE-NMR.

INTRODUCTION: Application of on-line solid-phase extraction (SPE) as an interface between HPLC and NMR has gained great improvement in solving sensitivity problems and signal interferences by the eluents. OBJECTIVE: Rapid analysis and characterisation by HPLC-SPE-NMR and LC/MS of the arylnaphthalene-type lignans present in Phyllanthus myrtifolius and the minor stilbenoids present in the polyphenol-rich fraction from the ethanol extract of the seeds of Syagrus romanzoffiana. METHODOLOGY: Pretreatment of fractions by liquid-liquid partitioning, followed by Sephadex LH-20 fractionation, was found very useful to facilitate the focusing and analysis of the polyphenolic fraction. HPLC-DAD-SPE-NMR (400 MHz and 600 MHz) analysis was carried out using an Agilent 1100 liquid chromatography, followed by a Prospekt 2 automated solid-phase extraction unit, containing 96 HySphere-Resin GP cartridges (10 × 2 mm, 10-12 µm), which was connected to a 120 or 60 µL LC probe. RESULTS: Seven arylnaphthalene-type lignans from the chloroform-soluble fraction of P. myrtifolius and nine stilbenoids from a polyphenol-rich butanol-soluble fraction of the seeds of S. romanzoffiana were characterised. CONCLUSIONS: HPLC-SPE-NMR associated with HR-ESI/MS, which consumed only analytical amounts of partially purified mixtures, was demonstrated to be a good tool for rapid screening of both known and new natural products.

Two new morphinane alkaloids from Sinomenium acutum.

Two new morphinane alkaloids, 1-hydroxy-10-oxo-sinomenine (1) and 4,5-epoxy-14-hydroxy sinomenine N-oxide (2), have been isolated from the stems of Sinomenium acutum. Their structures were established by various spectral analyses, especially 2D NMR experiments. The structure of 2 was confirmed by single crystal X-ray diffraction. The absolute configurations of 1 and 2 were deduced by comparison of CD spectra with the known alkaloid sinomenine (3). Compound 1 was tested for DPPH inhibition and gave IC(50) of 27.9 µM. Compound 2 was tested for neuroprotective effect and showed significant activity against ß-amyloid(25-35)-induced oxidative injury (*P < 0.05) at 10 µM in PC-12 cells.

Characterization of a fluorescent glucose derivative 1-NBDG and its application in the identification of natural SGLT1/2 inhibitors.

Glucose is an important energy source for cells. Glucose transport is mediated by two types of glucose transporters: the active sodium-coupled glucose cotransporters (SGLTs), and the passive glucose transporters (GLUTs). Development of an easy way to detect glucose uptake by the cell can be valuable for research. 1-(N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl) amino)-1-deoxy-d-glucose (1-NBDG) is a newly synthesized fluorescent glucose analogue. Unlike 2-NBDG, which is a good substrate of GLUTs but not SGLTs, 1-NBDG can be transported by both GLUTs and SGLTs. Thus, 1-NBDG is useful for the screening of SGLT1 and SGLT2 inhibitors. Here we further characterized 1-NBDG and compared it with 2-NBDG. The fluorescence of both 1-NBDG and 2-NBDG was quenched under alkaline conditions, but only 1-NBDG fluorescence could be restored upon neutralization. HPLC analysis revealed that 2-NBDG was decomposed leading to loss of fluorescence, whereas 1-NBDG remained intact in a NaOH solution. Thus, after cellular uptake, 1-NBDG fluorescence can be detected on a plate reader simply by cell lysis in a NaOH solution followed by neutralization with an HCl solution. The fluorescence stability of 1-NBDG was stable for up to 5 h once cells were lysed; however, similar to 2-NBDG, intracellular 1-NBDG was not stable and the fluorescence diminished substantially within one hour. 1-NBDG uptake could also be detected at the single cell level and inhibition of 1-NBDG uptake by SGLT inhibitors could be detected by flow cytometry. Furthermore, 1-NBDG was successfully used in a high-throughput cell-based method to screen for potential SGLT1 and SGLT2 inhibitors. The SGLT inhibitory activities of 67 flavonoids and flavonoid glycosides purified from plants were evaluated and several selective SGLT1, selective SGLT2, as well as dual SGLT1/2 inhibitors were identified. Structure-activity relationship analysis revealed that glycosyl residues were crucial since the aglycon showed no SGLT inhibitory activities. In addition, the sugar inter-linkage and their substitution positions to the aglycon affected not only the inhibitory activities but also the selectivity toward SGLT1 and SGLT2.

Doubled production of cordycepin analogs in cultured Cordyceps militaris by addition of Andrea droppings.

Cordyceps sinensis is a traditional Chinese medicine with various biological activities. With its limited natural supply, cultured C. militaris has become the major alternative source, and the culture conditions may affect the chemical compositions. To improve the production of chemical ingredients, C. militaris was cultured with three different media, including rice only, rice plus 3% tea leaves, and rice plus 3% droppings of Andraca theae. The fractions of dried C. militaris cultured with rice were chromatographic separated to afford ten compounds: phenylalanine, dimerumic acid, nicotinic acid, tryptophan, N6-(2-hydroxyethyl)-adenosine, uracil, uridine, cordycepin, ergosterol, and mannitol. Of these, in the cultured medium of rice plus 3% Andraca droppings, the amount of one major compound cordycepin is about two folds than the highest reported data, and dimerumic acid and N6-(2-hydroxyethyl)-adenosine were isolated for the first time from this species.[Figure: see text].

Synergistic interactions between sorafenib and bortezomib in hepatocellular carcinoma involve PP2A-dependent Akt inactivation.

BACKGROUND & AIMS: Previously we reported that Akt inactivation determines the sensitivity of hepatocellular carcinoma (HCC) cells to bortezomib. Here we report that combined treatment with sorafenib and bortezomib shows synergistic effects in HCC. METHODS: HCC cell lines (PLC/PRF/5, Huh-7, and Hep3B) were treated with sorafenib and/or bortezomib and analyzed in terms of apoptosis signal transduction. In vivo efficacy was determined in nude mice with PLC/PRF/5 xenografts. RESULTS: Pretreatment with sorafenib enhanced bortezomib-induced apoptotic cell death by restoring bortezomib's ability to inactivate Akt in PLC/PRF/5 cells. Knocking down Akt1 by RNA-interference overcame apoptotic resistance to bortezomib in PLC/PRF/5 cells and ectopic expression of active Akt in HCC cells abolished the bortezomib sensitizing effect of sorafenib, indicating Akt inactivation plays a key role in mediating the combinational effects. Moreover, okadaic acid, a protein phosphatase 2A (PP2A) inhibitor, reversed down-regulation of phospho-Akt (P-Akt) expression induced by co-treatment with sorafenib and bortezomib, and 1, 9 di-deoxy-forskolin, a PP2A agonist, restored bortezomib's effect on P-Akt and apoptosis. Importantly, silencing of PP2A by RNA-interference reduced the apoptotic effect induced by sorafenib-bortezomib co-treatment, indicating that PP2A is indispensable for mediating the effects of these drugs. Notably, sorafenib with bortezomib increased PP2A activity in PLC/PRF/5 cells without altering protein levels of PP2A complex or the interaction between PP2A and Akt proteins. Finally, sorafenib plus bortezomib significantly suppressed PLC/PRF/5 xenograft tumor growth, down-regulated P-Akt expression, and up-regulated PP2A activity. CONCLUSIONS: The combination of sorafenib and bortezomib shows synergy in HCC through PP2A-dependent Akt inactivation.

Metabolism of dicentrine: identification of the phase I and phase II metabolites in miniature pig urine.

The metabolic profile of dicentrine, a selective α(1)-adrenoceptor antagonist with potent antiarrhythmic and antihypertensive activities, in miniature pig urine via oral administration was investigated for the first time. The urine, collected after a single oral administration of dicentrine, was pretreated using solvent extraction and column chromatographic methods to identify the metabolites containing fractions. Twenty-four metabolites (MI-1-9 and MII-1-15), of which 21 compounds are new, were identified by mass spectrometry and high-performance liquid chromatography-diode array detector solid-phase extraction-NMR techniques. Of these, 14 metabolites (MI-5, MII-1 and 2, and MII-5-15) were further isolated for structure confirmation. The phase I metabolic transformations of dicentrine were found to be N-demethylation, N-oxidation, O-demethylation (9,10-OMe), O,O-demethylenation (1-OCH(2)O-2), and hydroxylation at the benzylic (C-4) and the aromatic (C-3) positions, whereas those for the phase II were O-glucuronidation and O-glucosylation of the phenolic group of the phase I metabolites.