Acetylenic spiroketal enol ethers from Artemisia rupestris and their synergistic antibacterial effects on methicillin-resistant Staphylococcus aureus.

Synergistic bioassay-guided isolation of the extracts of Artemisia rupestris L, which belongs to the family Asteraceae, afforded two acetylenic spiroketal enol ethers, namely rupesdiynes A (1) and B (2). Their structures were determined based on spectroscopic analysis and experimental and calculated ECD investigations. The two compounds exhibited synergistic activity and were able to reduce the minimum inhibitory concentration (MIC) of oxacillin four-fold, with a fractional inhibitory concentration index (FICI) of 0.5 in combination with oxacillin against the oxacillin-resistant EMRSA-16. Biofilm formation inhibitory and Ethidium bromide (EtBr) efflux assay were further employed to verify the possible mechanism of the synergistic antibacterial effect. Additionally, molecular docking studies were conducted to investigate the binding affinities of the two compounds with penicillin-binding protein 2a (PBP2a) of EMRSA-16. Taken together, rupesdiynes A (1) and rupesdiyne B (2) showed moderate synergistic activity against EMRSA-16 with oxacillin via inhibiting biofilm formation and efflux pump activity, respectively.

Effects of dietary supplementation of peanut skins (Arachis hypogaea) on performance, digestibility, and rumen fermentation of cattle: a meta-analysis.

This study aimed to estimate the magnitude of the effects of dietary inclusion of peanut skins (PS) byproduct (Arachis hypogea L.) on intake, total-tract digestibility, and rumen fermentation of cattle via meta-analysis. Data were collected following the PRISMA methodology. Nine manuscripts and a graduate thesis met the inclusion criteria from 1983 to 2010. The effect size was estimated by calculating the weighted raw mean differences (RMD) between PS vs. control diets. The RMD was compared with a robust variance estimation method followed by a meta-regression and a dose-response analysis fitting the diet characteristics like crude protein content (CP), NDF content, ether extract content (EE), tannin content, and PS level in diet (0 to 40%) as covariates. Dietary PS decreased (P < 0.01) total-tract CP digestibility (52.0 vs. 64.3%), final body weight (371.5 vs. 397.9 kg), and average daily gain (1.14 vs. 1.44 kg/day) among treatment comparisons. Likewise, PS decreased total VFA (92.6 vs. 107.6 mmol/L) and NH3-N (8.22 vs. 12.1 mg/dL), but no effects were observed on rumen pH (6.47 vs. 6.14) and VFA molar proportions. Despite the between-cluster variance, dietary PS increased the ether extract digestibility (77.5 vs. 70.2%) among treatment comparisons. The subset and dose-response analysis revealed that PS should not exceed 8% (DM basis) in the diet to prevent negative effects on CP digestibility and animal performance. In conclusion, the results of this meta-analysis do not support the dietary inclusion of PS in cattle diets beyond 8%.

Synthesis and biological activities of novel chalcone derivatives containing pyrazole oxime ethers.

A series of novel chalcone derivatives containing pyrazole oxime ethers were designed and synthesized. The structures of all the target compounds were determined by NMR and HRMS. The structure of H5 was further confirmed via single-crystal X-ray diffraction analysis. The results of biological activity test showed that some of the target compounds exhibited significant antiviral and antibacterial activities. The test results of EC50 value against tobacco mosaic virus showed that H9 had the best curative and protective effect, and the EC50 value of curative activity of H9 was 166.9 µg/mL, which was superior to ningnanmycin (NNM) 280.4 µg/mL, the EC50 value of protective activity of H9 was 126.5 µg/mL, which was superior to ningnanmycin 227.7 µg/mL. Microscale thermophoresis (MST) experiments demonstrated that H9 (Kd = 0.0096 ± 0.0045 µmol/L) exhibited a strong binding ability with tobacco mosaic virus capsid protein (TMV-CP), which was far superior to ningnanmycin (Kd = 1.2987 ± 0.4577 µmol/L). In addition, molecular docking results showed that the affinity of H9 to TMV protein was significantly higher than ningnanmycin. The results of against bacterial activity showed that H17 has a good inhibiting effect against Xanthomonas oryzae pv. oryzae (Xoo), the EC50 value of H17 was 33.0 µg/mL, which was superior to the commercial drugs thiodiazole copper (68.1 µg/mL) and bismerthiazol (81.6 µg/mL), and the antibacterial activity of H17 was verified by scanning electron microscopy (SEM).

A Perfluoropolyether Microfluidic Device for Cell-Based Drug Screening with Accurate Quantitative Analysis.

Microfluidic drug screening technologies have been extensively explored to evaluate the pharmacology and therapeutic implications of promising chemical compounds in multiplexed physiological microenvironments in vivo. However, conventional poly(dimethylsiloxane) microchips are susceptible to adsorption by hydrophobic molecules on channel surfaces and permeation in the matrix. These can significantly compromise the drug availability and accuracy of dose-dependent quantitative analyses. Here, we prepared a perfluorinated polyether (PFPE) microchip via digital light processing 3D printing as a quantitative drug screening platform for precise concentration-dependent pharmaceutical assays. Cells cultured on PFPE microchips exhibited excellent viability with a spread morphology as well as superior proliferative capability. Importantly, PFPE constructions with a low surface energy significantly prevented the nonspecific molecular adsorption into their surfaces or permeation into the matrix. In particular, the PFPE multibranched channel preserved the concentration of the pharmaceutical drug during the perfusion process and generated a linear concentration gradient, resulting in a dose-dependent chemotherapeutic effect. We suggest that the biocompatible and nonadsorbing PFPE microchannel can provide a cell-based drug screening platform for concentration-dependent quantitative analyses.

Brevenal, a Marine Natural Product, is Anti-Inflammatory and an Immunomodulator of Macrophage and Lung Epithelial Cells.

Chronic respiratory diseases, including chronic obstructive pulmonary disease (COPD), cystic fibrosis, and asthma, are some of the leading causes of illness and fatalities worldwide. The search for novel treatments led to the exploration of marine natural products as drug candidates to combat the debilitating effects of mucus accumulation and chronic inflammation. Previous research showed that an alga-derived compound, brevenal, could attenuate the effects of inflammatory agents, but the mechanisms by which it exerted its effects remained unclear. We investigated the effects of brevenal on lipopolysaccharide (LPS) induced cytokine/chemokine production from murine macrophages and human lung epithelial cells. It was found that brevenal reduces proinflammatory mediator secretion while preserving anti-inflammatory secretion from these cells. Furthermore, we found that brevenal does not alter cell surface Toll-like receptor 4 (TLR4) expression, thereby maintaining the cells' ability to respond to bacterial infection. However, brevenal does alter macrophage activation states, as demonstrated by reduced expression of both M1 and M2 phenotype markers, indicating this putative anti-inflammatory drug shifts innate immune cells to a less active state. Such a mechanism of action would be ideal for reducing inflammation in the lung, especially with patients suffering from chronic respiratory diseases, where inflammation can be lethal.

Discovery of Oxime Ethers as Hepatitis B Virus (HBV) Inhibitors by Docking, Screening and In Vitro Investigation.

A series of oxime ethers with C6-C4 fragment was designed and virtually bioactively screened by docking with a target, then provided by a Friedel-Crafts reaction, esterification (or amidation), and oximation from p-substituted phenyl derivatives (Methylbenzene, Methoxybenzene, Chlorobenzene). Anti-hepatitis B virus (HBV) activities of all synthesized compounds were evaluated with HepG2.2.15 cells in vitro. Results showed that most of compounds exhibited low cytotoxicity on HepG2.2.15 cells and significant inhibition on the secretion of HBsAg and HBeAg. Among them, compound 5c-1 showed the most potent activity on inhibiting HBsAg secretion (IC50 = 39.93 µM, SI = 28.51). Results of the bioactive screening showed that stronger the compounds bound to target human leukocyte antigen A protein in docking, the more active they were in anti-HBV activities in vitro.

Petroleum ether extract of Njavara rice (Oryza sativa) bran upregulates the JAK2-STAT3-mediated anti-inflammatory profile in macrophages and aortic endothelial cells promoting regression of atherosclerosis.

"Njavara" (Oryza sativa L.) is a unique rice variety grown in Kerala that is reported to have significantly higher antioxidant, anti-inflammatory, chemical indices, and bioactive components compared with staple rice varieties. However, the role of NBE in reversing the atherosclerosis development remains unclear. The present study aimed to elucidate the role of NBE in promoting atherosclerotic regression. Male New Zealand white breed rabbits were divided into three groups. Group I was the control, group II was the regression control, and group III was NBE treated (100 mg/kg body mass). Serum and tissue lipids, CRP, antioxidant enzyme activities, mRNA, and protein expression of genes of RTC and mRNA expression of cytokines were studied. The current study showed that hypercholesterolemic rabbits treated with NBE decreased the serum and tissue lipids concentrations, ApoB expression, and CRP levels and enhanced the activities of antioxidant enzymes and PON1expression, JAK2, STAT3, ABCA1, and ApoA. Our results indicate that NBE attenuates proinflammatory cytokine production (IL-1ß), enhanced expression and interactions of ABCA1/ApoA1 leading to JAK2/STAT3 activation in macrophages switching to an anti-inflammatory milieu in the system, and enhanced expression of IL-10 and decreased expression of ApoB, indicating that treatment with NBE facilitates plaque regression.

A new dicoumarinyl ether from the roots of Stellera chamaejasme L.

A new dicoumarinyl ether, 3-hydroxy-6-methoxy-7,7'-dicoumarinyl ether (1), was isolated from the roots of Stellera chamaejasme L, together with the known compound umbelliferone (2). Their structures were determined on the basis of spectroscopic techniques, including IR, NMR, and HR-ESI-MS.

Monounsaturated fatty acid ether oligomers formed during heating of virgin olive oil show agglutination activity against human red blood cells.

The present work focuses on the characterization of molecules formed when virgin olive oil is heated at 130 °C for 24 h open in air, which are found to be strong agglutinins. The hemagglutinating activity of the newly formed molecule isolated from the heated virgin olive oil sample was estimated against human red blood cells (RBCs). Dimers and polymers (high molecular weight molecules) were identified through thin layer chromatography (TLC) of the oil mixture. (1)H and (13)C nuclear magnetic resonance (NMR) and gas chromatography-mass spectroscopy (GC-MS) were the methods used for structural characterization. Among others, oligomerization of at least two monounsaturated fatty acids (FA) by an ether linkage between the hydrocarbon chains is involved. Light microscopy was used to characterize and visualize the agglutination process. Agglutination without fusion or lysis was observed. It was concluded that the heating of virgin olive oil open in air, among other effects, produces oligomerization as well as polymerization of unsaturated FA, possibly of monohydroxy, monounsaturated FA that is associated with strong hemagglutinating activity against human RBCs. The nutritional value and the effects on human health of such oligomers are not discussed in the literature and remain to be investigated.

Antidiabetic activity of Kalanchoe pinnata in streptozotocin-induced diabetic rats by glucose independent insulin secretagogue action.

CONTEXT: Kalanchoe pinnata Lam. (Crassulaceae) is used as a traditional medicine worldwide to treat several ailments, including diabetes. However, the mechanism for the antihyperglycemic action is unknown. OBJECTIVE: The present study evaluates the antihyperglycemic and insulin secretagogue potential of Kalanchoe pinnata and assessment of the probable mechanism of action. MATERIALS AND METHODS: Steam distillate of Kalanchoe pinnata leaves was subjected to solvent fractionation and antidiabetic activity was detected in dichloromethane (DCM) fraction. In the in vivo studies, rats were treated with 5 and 10 mg/kg body weight of DCM fraction for 45 days orally. Lipid profile and other biochemical parameters were estimated. The probable mechanism for insulin secretagogue action was evaluated through studies using diazoxide and nifedipine. The bioactive component from DCM fraction was studied using HPTLC, GCMS and IR. RESULTS AND DISCUSSION: Fasting blood glucose values were reduced to 116 mg/dl from 228 mg/dl on treatment with 10 mg/kg body weight of DCM fraction, while glycated hemoglobin improved to 8.4% compared with 12.9% in diabetic controls. The insulin level and lipid profile values were close to normal values. In vitro studies demonstrated a dose-dependent insulin secretagogue action. Insulin secretion was 3.29-fold higher at 10 µg/ml as compared to the positive control. The insulin secretagogue activity was glucose independent and K(+)-ATP channel dependent. The bioactive component of the DCM fraction was identified to be a phenyl alkyl ether derivative. CONCLUSION: The DCM fraction of Kalanchoe pinnata demonstrates excellent insulin secretagogue action and can be useful in treatment of diabetes mellitus.

Biopharmaceutical characterization of decursin and their derivatives for drug discovery.

Angelica gigas Nakai and its components are known to have neuroprotective, antiplatelet, and anticancer activities. The present study evaluated the in vitro and in vivo biopharmaceutical characterization of Angelica gigas component substances, including decursin (the main substance), decursinol angelate (decursin isomer), JH714 (ether form of decursin) and epoxide decursin (epoxide form of decursin). Decursin, decursinol angelate and JH714 exhibited acceptable metabolic stability (>50%) in liver microsomes from human and higher bound fraction (>90%) in human plasma operating ultrafiltration. Decursin and decursinol angelate in CYP1A2 and CYP2C19 indicated less than 50% CYP activity, suggesting inhibition of the CYP isoforms using Vivid® CYP screening kit. JH714 only showed an apparent permeability coefficient of <10 × 10⁻6 cm/s in MDCK cells, suggesting that it is poorly absorbed. Blood brain barrier permeability was examined after oral administration to male Sprague-Dawley (SD) rats, and pharmacokinetic studies were performed after oral and intravenous administration of 10 mg/kg compounds. Decursin, decursinol angelate and JH714 showed ratios of compound concentration in brain with respect to plasma (Cbrain/Cplasma) of >1.5, suggesting good brain/plasma ratio at 0.5, 1, 3, and 5 h. In contrast, Cbrain/Cplasma was <0.5 for epoxide decursin. For all test compounds, >1.5% of the dose remained in GI tract after 8 h, and the excretion rate in urine was <0.5% which suggests that gastro intestinal tract may be major site of disposition following oral administration. Finally, these results may be useful for the design of dosage regimens of decursin and its derivatives.

Dual-acting diether derivatives of piperidine and homopiperidine with histamine H(3) receptor antagonistic and anticholinesterase activity.

The study presents novel biological properties of diether derivatives of homo- or substituted piperidine ligands of the histamine H(3) receptor. The compounds were evaluated for their inhibitory potency against acetylcholinesterase (AChE) from the electric eel and butyrylcholinesterase (BuChE) from horse serum. The most interesting multifunctional compound 13 displayed high affinity for the cloned hH(3) R (K(i) = 3.48 nM) and moderate inhibitory potency against both enzymes (IC(50) AChE = 7.91 µM and BuChE = 4.97 µM). Molecular modeling studies revealed interactions with key amino acid residues in the homology model of histamine H(3) receptor ligands, as well as the binding model for AChE and BuChE in the catalytic and peripheral active sites.

Phomosines H-J, novel highly substituted biaryl ethers, isolated from the endophytic fungus Phomopsis sp. from Ligustrum vulgare.

From the endophytic fungus Phomosis sp., four known phomosines A-D (1-4) and three new phomosines H-J (5-7) have been isolated. The structures of the new compounds were determined on the basis of their spectroscopic data analysis (1H, 13C, 1H-1H COSY, HMQC, and HMBC NMR, as well as mass spectrometry). The structures of phomosine H (5) and J (7) were also confirmed by semisynthesis from phomosine A (1). The remaining four known compounds [phomosines A-D (1-4)] were identified by comparing their spectroscopic data with those reported in the literature. The four known metabolites were biologically active. Of the novel metabolites, only 6 was antifungal and antibacterial.

Peptidomimetic inhibitors of farnesyltransferase with high in vitro activity and significant cellular potency.

2-o-Tolyl or 2-o-anisyl substituted 4-hydroxy- and 4-carboxybenzamides of methionine, etherified and amidified with 2-hydroxymethyl- and 2-aminomethylpyridodioxane, respectively, are described as inhibitors of Ras protein farnesyltransferase (FTase). Of the sixteen compounds, resulting from the substitution pattern of benzamide and the configuration of the two stereocenters, seven inhibited FTase activity with potencies in the nanomolar range. They were all 2-oxymethylpyridodioxane ethers and, among them, the four o-tolyl substituted stereoisomers also showed micromolar antiproliferative effect on human aortic smooth muscle cells interfering with Ras farnesylation. The docking analysis enlightened significant differences in enzyme interaction between oxymethylpyridodioxane and aminomethylpyridodioxane derivatives.

Solid-phase synthesis and structure-activity relationships of novel biarylethers as melanin-concentrating hormone receptor-1 antagonists.

Melanin-concentrating hormone (MCH) is a cyclic 19 amino acid orexigenic neuropeptide. The action of MCH on feeding is thought to involve the activation of its respective G protein-coupled receptor MCH-R1. Consequently, antagonists that block MCH regulated MCH-R1 activity may provide a viable approach to the treatment of diet-induced obesity. This communication reports the discovery of a novel MCH-R1 receptor antagonist, the biarylether 7, identified through high throughput screening. The solid-phase synthesis and structure-activity relationship of related analogs is described.

Screening the oxidative potential of several mono- and di-halogenated biphenyls and biphenyl ethers in rat hepatocytes.

The present study was designed to investigate the potential of reactive oxygen species (ROS) generating and subsequent ROS-mediated lipid peroxidation (LPO) inducing effect of several mono- and di-halogenated biphenyls and biphenyl ethers in rat hepatocytes in vitro. For this aim, 4-chloro- and 4-bromo biphenyl (4-CB and 4-BB), 4-OH, 4'-BB, 4-bromo diphenylether (4-BDE), 4,4'-dichlorobiphenyl (4,4'-DCB), 4,4'-dibromobiphenyl (4,4'-DBB), and 3,4-dichlorobiphenyl (3,4-DCB) were incubated with freshly isolated rat hepatocytes. Their oxidative potential was evaluated by detecting the intracellular ROS formation by oxidant-sensing fluorescent probes (2',7'-dichlorofluorescein diacetate and C(11)-BODIPY(581/591)) using a multiplate reader and determining the levels of eight LPO products (formaldehyde, malondialdehyde, propanal, butanal, pentanal, hexanal, octanal, and nonanal) by a gas chromatography-electron capture detection. 4-BDE was found to be active both in cytoplasm and in the cell membrane in terms of inducing the formation of ROS. Another important finding was the increase in ROS-inducing potential of 4-BB when the same concentration of the hydroxylated derivative, 4-OH,4'-BB, was incubated with hepatocytes. 4-BDE was also found to be the most effective among all tested compounds in inducing LPO where 4-OH, 4'-BB was again more potent than its unmetabolized form, 4-BB. Lactate dehydrogenase leakage analyses indicated that all tested compounds are cytotoxic; 4-BDE caused the highest LDH leakage compared to other mono-halogenated biphenyls tested. Our results suggest that ROS formation by chlorinated biphenyls and mono-hydroxylated bromobiphenyls, and concomitant induction of LPO might be involved in the cytotoxic effects of these industrial pollutants. Similar effects of mono-BDE are also reported, which is a novel observation.

In vitro and in vivo CYP3A64 induction and inhibition studies in rhesus monkeys: a preclinical approach for CYP3A-mediated drug interaction studies.

In this study, induction and inhibition of rhesus monkey CYP3A64 versus human CYP3A4 were characterized in vitro, and the corresponding pharmacokinetic consequences were evaluated in rhesus monkeys. In monkey hepatocytes, rifampin markedly induced CYP3A64 mRNA (EC50 = 0.5 microM; Emax = 6-fold) and midazolam (MDZ) 1'-hydroxylase activity (EC50 = 0.2 microM; Emax = 2-fold). Compound A (N-[2(R)-hydroxy-1(S)-indanyl-5-[2(S)-(1,1-dimethylethylaminocarbonyl)-4-[(furo[2,3-b]pyridin-5-yl)-methyl]piperazin-1-yl]-4(S)-hydroxy-2(R)-phenylmethylpentanamide), a known potent and mechanism-based inhibitor of CYP3A4, strongly inhibited the formation of 1'-hydroxy MDZ by recombinant CYP3A64 in a concentration- and time-dependent manner (KI = 0.25 microM; k(inact) = 0.4 min(-1)). Similar corresponding results also were obtained with human CYP3A4 in the presence of rifampin or compound A. In rhesus monkeys, MDZ exhibited a relatively high metabolic clearance (primarily via 1'-hydroxylation followed by glucuronidation) and a low hepatic availability (Fh = 16%). Consistent with the induction of hepatic metabolism of a high-clearance compound, pretreatment with rifampin (18 mg/kg p.o. for 5 days) did not significantly affect the i.v. kinetics of MDZ, but caused a pronounced reduction (approximately 10-fold) in the systemic exposure to MDZ and, consequently, its Fh following intrahepatic portal vein administration (i.pv.) of MDZ. A comparable extent of the pharmacokinetic interaction also was obtained after a 1.8 mg/kg rifampin dose. Also consistent with the in vitro CYP3A64 inhibition finding, compound A (6 mg/kg i.v.) markedly increased (10-fold) the i.pv. administered MDZ exposure. At the doses studied, plasma concentrations of rifampin or compound A reached or exceeded their respective in vitro EC50 or KI values. These findings suggest the potential applicability of the in vitro-in vivo relationship approach in rhesus monkeys for studying CYP3A-mediated interactions in humans.

Piperazinyl oxime ethers as NK-1 receptor antagonists.

The synthesis and structure-activity relations for a new class of centrally active NK-1 receptor antagonists are described. The new compounds are based on piperazine 2 and contain an oxime ether functionality. Several new compounds have high affinity for the NK-1 receptor and show good antagonistic activity in the gerbil foot-tapping assay.

Synthesis and in vivo analgesic and anti-inflammatory activity of some bi heterocyclic coumarin derivatives.

Sets of coumarinyl ethers having chromone, benzofuranyl and 4-hydroxy coumarins (4, 5, 6) were prepared and tested for analgesic and antiinflammatory activity. The 4-(4'-acetyl-3'-hydroxy-phenoxymethyl)-coumarin 3 were synthesised by the reaction of 4-bromo methyl coumarin with 2, 4-dihydroxy acetophenones, were found to less active. Further compound 3 having the ortho hydroxy moiety was cyclised to chromones 4 and benzofurans 5 were found to enhance the analgesic and anti-inflammatory activity. The cyclisation to 4-hydroxy coumarin 6 was found to be reducing the anti-inflammatory and analgesic activity in this series. These newly synthesized compounds were found to produce less toxicity and less ulcerogenic effects.

Synthesis and antiamoebic activity of new oxime ether derivatives containing 2-acetylpyridine/2-acetylfuran.

Various oxime ether derivatives of 2-acetylpyridine and 2-acetylfuran series have been synthesised. O-Alkylation of the oximes by various alkylaminoethyl halides gave the corresponding oxime ether derivatives. The structures of these compounds were elucidated by UV, IR, 1H NMR, 13C NMR spectroscopic methods and elemental analyses. All the compounds were screened in vitro against the HM1:IMSS strain of Entamoeba histolytica. Based on the 50% inhibitory concentration (IC50) data of the 12 compounds evaluated, two of the 2-acetylpyridine series and two in the 2-acetylfuran series showed better IC50 values in vitro when compared with the standard amoebicidal drug, metronidazole. Moreover, one compound showed the most promising antiamoebic activity (IC50=0.5 microM vs IC50=1.9 microM of metronidazole).