Valproic acid induces three novel cytotoxic secondary metabolites in Diaporthe sp., an endophytic fungus from Datura inoxia Mill.

Addition of the valproic acid (histone deacetylases inhibitor) to a culture of an endophytic fungus Diaporthe sp. harbored from Datura inoxia significantly altered its secondary metabolic profile and resulted in the isolation of three novel compounds, identified as xylarolide A (1), diportharine A (2) and xylarolide B (3) along with one known compound xylarolide (4). The structures of all the compounds (1–4) were determined by detailed analysis of 1D and 2D NMR spectroscopic data. The relative configurations of compounds 1–3 were determined with the help of NOESY data and comparison of optical rotations with similar compounds with established stereochemistry. All the isolated compounds were screened for antibacterial, antioxidant and cytotoxic activities. Xylarolide A (1) and xylarolide (4) displayed significant growth inhibition of MIAPaCa-2 with an IC₅₀ of 20 and 32?µM respectively and against PC-3 with an IC₅₀ of 14 and 18?µM respectively. Moreover, compound 1 displayed significant DPPH scavenging activity with EC₅₀ of 10.3?µM using ascorbic acid as a positive control.     

Synthesis and biological properties of aryl methyl sulfones

A novel group of aryl methyl sulfones based on nonsteroidal anti-inflammatory compounds exhibiting a methyl sulfone instead of the acetic or propionic acid group was designed, synthesized and evaluated in vitro for inhibition against the human cyclooxygenase of COX-1 and COX-2 isoenzymes and in vivo for anti-inflammatory activity using the carrageenan induced rat paw edema model in rats. Also, in vitro chemosensitivity and in vivo analgesic and intestinal side effects were determined for defining the therapeutic and safety profile. Molecular modeling assisted the design of compounds and the interpretation of the experimental results. Biological assay results showed that methyl sulfone compounds 2 and 7 were the most potent COX inhibitors of this series and best than the corresponding carboxylic acids (methyl sulfone 2: IC₅₀ COX-1?=?0.04 and COX-2?=?0.10?μM, and naproxen: IC₅₀ COX-1?=?11.3 and COX-2?=?3.36?μM). Interestingly, the inhibitory activity of compound 2 represents a significant improvement compared to that of the parent carboxylic compound, naproxen. Further support to the results were gained by the docking studies which suggested the ability of compound 2 and 7 to bind into COX enzyme with low binding free energies.The improvement of the activity of some sulfones compared to the carboxylic analogues would be performed through a change of the binding mode or mechanism compared to the standard binding mode displayed by ibuprofen, as disclosed by molecular modeling studies. So, this study paves the way for further attention in investigating the participation of these new compounds in the pain inhibitory mechanisms. The most promising compounds 2 and 7 possess a therapeutical profile that enables their chemical scaffolds to be utilized for development of new NSAIDs.     

Optimisation of 2-cyano-pyrimidine inhibitors of cathepsin K: Improving selectivity over hERG

Several structure-guided optimisation strategies were explored in order to improve the hERG selectivity profile of cathepsin K inhibitor 1, whilst maintaining its otherwise excellent in vitro and in vivo profile. Ultimately, attenuation of c log P and pK_a properties proved a successful approach and led to the discovery of a potent analogue 23, which, in addition to the desired selectivity over hERG (>1000-fold), displayed a highly attractive overall profile.     

Design and synthesis of pyrrolo[3,2-d]pyrimidine HER2/EGFR dual inhibitors: Improvement of the physicochemical and pharmacokinetic profiles for potent in vivo anti-tumor efficacy

During the course of our studies on a novel HER2/EGFR dual inhibitor (TAK-285), we found an alternative potent pyrrolo[3,2-d]pyrimidine compound (1a). To enhance the pharmacokinetic (PK) profile of this compound, we conducted chemical modifications into its N-5 side chain and conversion of the chemically modified compounds into their salts. Among them, 2cb, the tosylate salt of compound 2c, showed potent HER2/EGFR kinase inhibitory activity (IC₅₀: 11/11 nM) and cellular growth inhibitory activity (BT-474 cell GI₅₀: 56 nM) with a good drug metabolism and PK (DMPK) profile. Furthermore, 2cb exhibited significant in vivo antitumor efficacy in both mouse and rat xenograft models with transplanted 4-1ST gastric cancer cell lines (mouse, T/C = 0%, 2cb po bid at 100 mg/kg; rat, T/C: -1%, 2cb po bid at 25 mg/kg).     

(R)-3-Amino-1-((3aS,7aS)-octahydro-1H-indol-1-yl)-4-(2,4,5-trifluorophenyl)butan-1-one derivatives as potent inhibitors of dipeptidyl peptidase-4: Design,synthesis, biological evaluation,and molecular modeling

A series of (R)-3-amino-1-((3aS,7aS)-octahydro-1H-indol-1-yl)-4-(2,4,5-trifluorophenyl)butan-1-one derivatives was designed, synthesized, and evaluated as novel inhibitors of dipeptidyl peptidase-4 (DPP-4) for the treatment of type 2 diabetes. Most of the synthesized compounds demonstrated good inhibition activities against DPP-4. Among these, compounds 3e, 4c, 4l, and 4n exhibited prominent inhibition activities against DPP-4, with IC₅₀s of 0.07, 0.07, 0.14, and 0.17 μM, respectively. The possible binding modes of compounds 3e and 4n with dipeptidyl peptidase-4 were also explored by molecular docking simulation. These potent DPP-4 inhibitors were optimized for the absorption, distribution, metabolism, and excretion (ADME) properties, and compound 4n displayed an attractive pharmacokinetic profile (F = 96.3%, t_1/2 = 10.5 h).     

Identification of maloyl glucans from Euphorbia tirucalli by ESI-(−)-FT-ICR MS analyses

Euphorbia tirucalli aerial parts are popularly used in Brazil for cancer treatment. The elution of the aqueous extract of the plant on silica gel C-18 cartridge furnished a water-soluble fraction, which was analyzed directly into the electrospray ionization (ESI) source combined with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and characterized as a mixture of malic acid glycosides 1–5. The compounds were detected in their deprotonated form [M−H]⁻, where their exact mass (mass error lower than 1 ppm), molecular formula (C_nH_hO_o), double bond equivalent (DBE) and connectivity were determined from ESI-(−)-MS and ESI-(−)-MS/MS experiments. The presence of malic acid and glucose, as part of the structures, could originate from crassulacean acid metabolism (CAM) of the plant.     

Exploring the relationship between bacterial genera and lipid metabolism in bovine rumen

The rumen is characterised by a complex microbial ecosystem, which is particularly active in lipid metabolism. Several studies demonstrated a role of diet and breed on bacterial community profile, with the effect on metabolic pathways. Despite the knowledge achieved on metabolism and the bacterial profile, little is known about the relationship between individual bacteria and metabolic pathways. Therefore, a multivariate approach was used to search for possible relationships between bacteria and products of several pathways. The correlation between rumen bacterial community composition and rumen lipid metabolism was assessed in 40 beef steers (20 Maremmana and 20 Aubrac) reared with the same system and fed the same diet. A canonical discriminant analysis combined with a canonical correlation analysis (CCA) was performed to explore this correlation. The variables showing a Pearson correlation higher than 0.6 as absolute value and significant were retained for CCA considering the relationship of bacterial composition with several metabolic pathways. The results indicated that some bacterial genera could have significant impacts on the presence of several fatty acids. However, the relationship between genera and fatty acid changes according to the breed, demonstrating that the metabolic pathways change according to the host genetic background, related to breed evolution, although there is also an intra-breed genetic background which should not be ignored. In Maremmana, Succiniclasticum and Rikenellaceae_RC9_gut_group showed a high positive correlation with dimethylacetals (DMAs) DMA_C13:0, DMA_C14:0, DMA_C14:0iso, DMA_C15:0, DMA_C15:0iso, and DMA_C18:0. Prevotellaceae_UCG-003 correlates with C18:3c9c12c15 and C18:1t11, while Fibrobacter and Succiniclasticum correlate with C18:2c9t11 and Lachnospiraceae_NK3A20_group correlates with C18:1c12. Prevotellaceae_UCG-003, Ruminococcaceae_UCG-010, and Oribacterium showed a positive correlation with C13:0iso, and C17:0. Conversely, in Aubrac, Treponema_2 and Rikenellaceae_RC9_gut_group correlated with DMA_C14:0iso, DMA_C16:0iso, DMA_C17:0iso, while Ruminococcaceae_UCG-010, Christensenellaceae_R-7_group and Ruminococcaceae_NK4A214_group correlated with DMA_C18:1t11, DMA_C14:0, DMA_C18:1c12. Acetitomaculum correlated with C18:2c9c12, C18:1c12, C18:1c13, C18:1t12 and Lachnospiraceae_NK3A20_group with C18:1t6-8 and C18:1t9. Saccharofermentas, Ruminococcaceae_UCG-010 and Rikenellaceae_RC9_gut_group correlated with C18:2c9t11 while, Prevotellaceae_UCG-001 and Ruminococcus_1 correlated with C14:0iso, C15:0, C15:0iso, C17:0. Saccharofermentans, Rikenellaceae_RC9_gut_group, Ruminococcaceae_NK4A214_group, and Ruminococcaceae_UCG-010 correlated with C13:1c12 and C16:0iso. These results lead to hypothesise a possible association between several metabolic pathways and one or a few bacterial genera. If these associations are confirmed by further investigations that verify the causality of a bacterial genus with a particular metabolic process, it will be possible to deepen the knowledge on the activity of the rumen population in lipid metabolism. This approach appears to be a promising tool for uncovering the correlation between bacterial genera and products of rumen lipid metabolism.     

Synthesis and in vitro affinities of various MDL 100907 derivatives as potential 18F-radioligands for 5-HT2A receptor imaging with PET

Radiolabelled piperidine derivatives such as [¹¹C]MDL 100907 and [¹⁸F]altanserin have played an important role in diagnosing malfunction in the serotonergic neurotransmission. A variety of novel piperidine MDL 100907 derivatives, possible to label with ¹⁸F-fluorine, were synthesized to improve molecular imaging properties of [¹¹C]MDL 100907. Their in vitro affinities to a broad spectrum of neuroreceptors and their lipophilicities were determined and compared to the clinically used reference compounds MDL 100907 and altanserin. The novel compounds MA-1 (53) and (R)-MH.MZ (56) show K_i-values in the nanomolar range towards the 5-HT_2A receptor and insignificant binding to other 5-HT receptor subtypes or receptors. Interestingly, compounds MA-1 (53), MH.MZ (55) and (R)-MH.MZ (56) provide a receptor selectivity profile similar to MDL 100907. These compounds could possibly be preferable antagonistic ¹⁸F-tracers for visualization of the 5-HT_2A receptor status. Medium affine compounds (VK-1 (32), (51), (52), (54)) were synthesized and have K_i values between 30 and 120 nM. All promising compounds show log P values between 2 and 3, that is, within the range of those for the established radiotracers altanserin and MDL 100907. The novel compounds MA-1 (53) and (R)-MH.MZ (56) thus appear to be promising high affine and selective tracers of ¹⁸F-labelled analogues for 5-HT_2A imaging with PET.     

Influence of pKa on the biotransformation of indene H1-antihistamines by CYP2D6

Structure-activity relationship studies were conducted to reduce CYP2D6-mediated metabolism in a series of indene H₁-antihistamines. Reductions in pK_a via incorporation of a β-fluoro substituent or a heteroaryl moiety were shown to reduce contributions to metabolism through this pathway. Several compounds, including 8l, 8o, and 12f were identified with promising primary in vitro profiles and reduced biotransformation via CYP2D6.     

Enzymes of adenosine metabolism in Hymenolepis diminuta (Cestoda)

Gaitanaki C. and Beis I. 1985. Enzymes of adenosine metabolism in Hymenolepis diminuta (Cestoda). International Journal for Parasitology15: 651–654. The activities of 5-nucleotidase (E.C. 3.1.3.5), adenosine deaminase (E.C. 3.5.4.4), adenosine kinase (E.C. 2.7.1.20), AMP deaminase (E.C. 3.5.4.6) and adenylate kinase (E.C. 2.7.4.3) were demonstrated in homogenates of Hymenolepis diminuta. The K_m values for adenosine and AMP of the above enzymes were determined. The importance of these enzymes in the maintenance of adenosine concentration on a steady state in H. diminuta is discussed     

Synthesis,crystal structure and biological activity of novel analogues of tricyclic drugs

A series of fourteen novel, eight-membered lactam- and dilactam-based analogues of tricyclic drugs were obtained in a simple one-pot procedure. Crystal structures of two compounds were determined by single-crystal X-ray diffraction analysis and their selected structural features were discussed and compared with those of imipramine and dibenzepine. Affinity of developed molecules for histamine receptor H₁, serotonin receptors 5-HT_1A, 5-HT_2A, 5-HT₆, 5-HT₇, serotonin transporter (SERT) and dopamine receptor D₂ was determined. The commercial drug dibenzepine was also checked on these molecular targets, as its mechanism of action is largely unknown. Two derivatives of 11,12-dihydrodibenzo[b,f]azocin-6(5H)-one (7,8) and two of dibenzo[b,f]azocin-6(5H)-one (9,10) were found to be active toward the H₁ receptor in sub-micromolar concentrations.     

Partially defatted olive cake in finishing pig diets: implications on performance,faecal microbiota,carcass quality,slurry composition and gas emission

One of the key factors to improve swine production sustainability is the use of agro-industrial by-products in feeds, such as olive by-products. However, it is necessary to assess its effects on the overall production process, including the animal and the environment. With this aim, an experiment was conducted to determine the effects of including a partially defatted olive cake (PDOC) in pig diets on growth performance, faecal microbiota, carcass quality and gas emission from the slurry. Two finishing diets were formulated, a control (C) diet and a diet with PDOC included at 120 g/kg. Eighty finishing male pigs Duroc-Danbred × (Landrace × Large White) of 60.4 ± 7.00 kg BW were divided between these two treatments. During the finishing period (60 to 110 kg BW, 55 days) average daily gain, average daily feed intake and feed conversion ratio were recorded. Faecal samples from the rectum of 16 animals per treatment were incubated for bacteria enumeration. At the end of finishing period, backfat thickness and loin depth (LD) were measured. Animals were slaughtered to obtain carcass weight and carcass composition parameters, and subcutaneous fat was sampled to analyse the fatty acid (FA) profile. In addition greenhouse gas and ammonia emissions were measured during pig slurry storage using the methodology of dynamic flux chambers. An initial slurry characterisation and biochemical methane potential (B₀) were also determined. No significant differences between treatments were found in performance, carcass quality and microbial counts with the exception of LD, which was lower in PDOC compared with C animals (45.5 v. 47.5 mm, SEM: 0.62; P = 0.020). The FA profile of the subcutaneous fat did not differ between treatments, but the monounsaturated FA (MUFA) concentration was higher and the polyunsaturated FA was lower in the animals fed PDOC (50.9 v. 48.3, SEM: 0.48, P < 0.001; 17.6 v. 19.3, SEM: 0.30, P < 0.001 in mg/100 g of Total FA, for PDOC and C animals, respectively). The initial pig slurry characterisation only showed differences in ADF concentration that was higher (P < 0.05) in the slurry from PDOC treatment. Regarding gas emission, slurries from both treatments emitted similar amounts of ammonia (NH₃), carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O), as well as B₀ values. The results obtained suggest that PDOC may be included in balanced pig diets at rates of up to 120 g/kg without negative effects on performance, carcass quality, gut microflora and slurry gas emission, while improving the MUFA concentration of subcutaneous fat.     

New 1,4-dihydro[1,8]naphthyridine derivatives as DNA gyrase inhibitors

Owing to the growing need for novel antibacterial agents, we synthesized a novel series of fluoroquinolones including 7-substituted-1-(2,4-difluorophenyl)-6-fluoro-4-oxo-1,4-dihydro[1,8]naphthyridine-3-carboxylic acid derivatives, which were tested against clinically relevant Gram positive and Gram negative bacteria. Chemical structures of the synthesized compounds were identified using spectroscopic methods. In vitro antimicrobial effects of the compounds were determined via microdilution assay. Microbiological examination revealed that compounds 13 and 14 possess a good antibacterial profile. Compound 14 was the most active and showed an antibacterial profile comparable to that of the reference drugs trovafloxacin, moxifloxacin, and ciprofloxacin. A significant MIC₉₀ value (1.95 μg/mL) against S. aureus ATCC 25923, E. coli ATCC 35218, and E. coli ATCC 25922 was recorded for compound 14. We observed reduced metabolic activity associated with compounds 13 and 14 in the relevant bacteria via a luminescence ATP assay. Results of this assay supported the antibacterial potency of compounds 13 and 14. An E. coli DNA gyrase inhibitory assay indicated that compound 14 is a potent inhibitor of E. coli DNA gyrase. Docking studies revealed that there is a strong interaction between compound 14 and the E. coli DNA gyrase enzyme. Genotoxicity and cytotoxicity evaluations of compounds 13 and 14 showed that compound 14 is non-genotoxic and less cytotoxic compared to the reference drugs (trovafloxacin, moxifloxacin, and ciprofloxacin), which increases its biological importance.     

Design,synthesis and evaluation of novel oxazaphosphorine prodrugs of 9-(2-phosphonomethoxyethyl)adenine (PMEA,adefovir) as potent HBV inhibitors

A series of novel oxazaphosphorine prodrugs of 9-(2-phosphonomethoxyethyl)adenine (PMEA, adefovir) were synthesized and their anti-hepatitis B virus (HBV) activity was evaluated in HepG2 2.2.15 cells, with adefovir dipivoxil as a reference drug. In the cell assays, compounds 7b and 7d exhibited anti-HBV activity comparable to that of adefovir dipivoxil, while compound 7c, with an IC₅₀ value of 0.12 μM, was found to be three times more potent than the reference compound. In vitro stability studies showed that (S_P,S)-7c, the diastereomer of compound 7c, was stable in human blood plasma but underwent rapid metabolism to release the parent drug PMEA in liver microsomes. The possible metabolic pathway of (S_P,S)-7c in human liver microsomes was described. These findings suggest that compound (S_P,S)-7c is a promising anti-HBV drug candidate for further development.     

Theoretical study on the mechanism of catalytic reduction of hydrazine to ammonia mediated by vanadium (III) thiolate complexes

DFT calculations on the free energy profile for the catalytic reduction of hydrazine to ammonia, the late stage of nitrogen fixation, mediated by vanadium (III) thiolate complexes VPS3 (1) and VNS3 (7) were carried out. The calculated energy profile revealed that all the reduction steps were exergonic while the protonation steps were endergonic. The generation of first equivalent of ammonia and the reduction of the cationic complex [V-NH₃]⁺ to the neutral V-NH₃ species were found to be the most exergonic of all the steps. Based on the calculated energy profile, both VPS3 and VNS3 were found to be catalytically active for the reduction of hydrazine to ammonia, although some quantitative differences in free energy profile had been observed.     

Novel fluorescent triazinobenzimidazole derivatives as probes for labelling human A1 and A2B adenosine receptor subtypes

The expression levels and the subcellular localization of adenosine receptors (ARs) are affected in several pathological conditions as a consequence of changes in adenosine release and metabolism. In this respect, labelled probes able to monitor the AR expression could be a useful tool to investigate different pathological conditions. Herein, novel ligands for ARs, bearing the fluorescent 7-nitrobenzofurazan (NBD) group linked to the N¹ (1,2) or N¹⁰ (3,4) nitrogen of a triazinobenzimidazole scaffold, were synthesized. The compounds were biologically evaluated as fluorescent probes for labelling A₁ and A_2B AR subtypes in bone marrow-derived mesenchymal stem cells (BM-MSCs) that express both receptor subtypes. The binding affinity of the synthetized compounds towards the different AR subtypes was determined. The probe 3 revealed a higher affinity to A₁ and A_2B ARs, showing interesting spectroscopic properties, and it was selected as the most suitable candidate to label both AR subtypes in undifferentiated MSCs.Fluorescence confocal microscopy showed that compound 3 significantly labelled ARs on cell membranes and the fluorescence signal was decreased by the cell pre-incubation with the A₁ AR and A_2B AR selective agonists, R-PIA and BAY 60-6583, respectively, thus confirming the specificity of the obtained signal. In conclusion, compound 3 could represent a useful tool to investigate the expression pattern of both A₁ and A_2B ARs in different pathological and physiological processes. Furthermore, these results provide an important basis for the design of new and more selective derivatives able to monitor the expression and localization of each different ARs in several tissues and living cells.     

Optimization of physicochemical properties and safety profile of novel bacterial topoisomerase type II inhibitors (NBTIs) with activity against Pseudomonas aeruginosa

Type II bacterial topoisomerases are well validated targets for antimicrobial chemotherapy. Novel bacterial type II topoisomerase inhibitors (NBTIs) of these targets are of interest for the development of new antibacterial agents that are not impacted by target-mediated cross-resistance with fluoroquinolones. We now disclose the optimization of a class of NBTIs towards Gram-negative pathogens, especially against drug-resistant Pseudomonas aeruginosa. Physicochemical properties (pK_a and log D) were optimized for activity against P. aeruginosa and for reduced inhibition of the hERG channel. The optimized analogs 9g and 9i displayed potent antibacterial activity against P. aeruginosa, and a significantly improved hERG profile over previously reported analogs. Compound 9g showed an improved QT profile in in vivo models and lower clearance in rat over earlier compounds. The compounds show promise for the development of new antimicrobial agents against drug-resistant Pseudomonas aeruginosa.     

Synthesis,antioxidant, antifungal,molecular docking and ADMET studies of some thiazolyl hydrazones

Some thiazolyl hydrazones were synthesized by one pot reaction of thiophene-2-carbaldehyde or 2, 4-dichlorobenzaldehyde, thiosemicarbazide and various phenacyl bromides which were preliminarily screened for in vitro antioxidant and antifungal activities. Excellent DPPH and H₂O₂ radical scavenged antioxidant activities were observed with almost all the tested compounds. Compounds 4a, 4b, 4c, 4e, 4f and 4i showed comparable DPPH scavenged antioxidant potential (90.26–96.56%) whereas H₂O₂ scavenged antioxidant activity (90.98–92.08%) was noticeable in case of 4a and 4f; showing significant antioxidant potential comparable with the standard ascorbic acid (95.3%). In vitro antifungal activity of synthesized compounds against fungal species Candida albicance, Aspergillus niger and Aspergillus flavus was found to be moderate to good as compared with the standard fluconazole and MIC values were found in the range of 3.12–25 μg/mL. Molecular docking studies revealed that the compounds 4a, 4b and 4c have a potential to become lead molecules in drug discovery process. In silico ADMET study was also performed for predicting pharmacokinetic and toxicity profile of the synthesized antioxidants which expressed good oral drug like behaviour and non-toxic nature.     

3H-1,2,4-Dithiazol-3-one compounds as novel potential affordable antitubercular agents

Small molecules with oxathiazol-2-one moiety were recently reported as potent inhibitors of Mycobacterium bovis var. bacilli Calmette–Guérin (BCG), among which HT1171 was the most potent and selective proteasome inhibitor. Herein we synthesized a series of novel compounds by bioisosteric replacement of the oxathiazol-2-one ring with 3H-1,2,4-dithiazol-3-one, and also fifteen 1,3,4-oxathiazol-2-one molecules in order for potency comparison and structure–activity relationship elucidation since their antibacterial effects on the virulent strains were not evaluated before. All the compounds were assessed for antitubercular activities on the virulent H37Rv strain by a serial dilution method. Among the tested compounds, 3H-1,2,4-dithiazol-3-one compound 4n was found to be the most active with a lowest MIC₉₀ value of 1 μg/mL. Furthermore, the cytotoxicities of all the compounds against normal human liver cell line L02 were determined by an MTT method. Compound 4n displayed a lower inhibitory ratio than HT1171 at the concentration of 100 μM, indicating its better safety profile.     

The identification of 4,7-disubstituted naphthoic acid derivatives as UDP-competitive antagonists of P2Y14

A weak, UDP-competitive antagonist of the pyrimidinergic receptor P2RY₁₄ with a naphthoic acid core was identified through high-throughput screening. Optimization provided compounds with improved potency but poor pharmacokinetics. Acylglucuronidation was determined to be the major route of metabolism. Increasing the electron-withdrawing nature of the substituents markedly reduced glucuronidation and improved the pharmacokinetic profile. Additional optimization led to the identification of compound 38 which is an 8 nM UDP-competitive antagonist of P2Y₁₄ with a good pharmacokinetic profile.