On the Selectivity in the Synthesis of 3-Fluoropiperidines Using BF3-Activated Hypervalent Iodine Reagents.

Fluorinated piperidines find wide applications, most notably in the development of novel therapies and agrochemicals. Cyclization of alkenyl N-tosylamides promoted by BF3-activated aryliodine(III) carboxylates is an attractive strategy to construct 3-fluoropiperidines, but it suffers from selectivity issues arising from competitive oxoaminations and the inability to easily modulate the reactions diastereoselectivity. Herein, we report an itemized optimization of the reaction conditions carried out on both cyclic and acyclic substrates and outline the origins of substrate- and reagent-based stereo-, regio-, and chemoselectivity. Extensive mechanistic studies encompassing multinuclear NMR spectroscopy, deuterium labeling, rearrangements on stereodefined substrates, and careful structural analyses (NMR and X-ray) of the reaction products are performed. This revealed the processes and interactions crucial for achieving controlled preparation of 3-fluoropiperidines using I(III) chemistry and has provided an advanced understanding of the reaction mechanism. In brief, we propose that BF3-coordinated I(III) reagents attack C═C to produce the corresponding iodiranium(III) ion, which then undergoes diastereodetermining 5-exo-cyclization. Transiently formed pyrrolidines with an exocyclic σ-alkyl-I(III) moiety can further undergo aziridinium ion formation or reductive ligand coupling processes, which dictate not only the final product's ring size but also the chemoselectivity. Importantly, the selectivity of the reaction depends on the nature of the ligand bound to I(III) and the presence of electrolytes such as TBABF4. Reported findings will facilitate the usage of ArI(III)-dicarboxylates in the reliable construction of fluorinated azaheterocycles.

Metabolomic Profiling of Bipolar Disorder by 1H-NMR in Serbian Patients.

Bipolar disorder (BD) is a brain disorder that causes changes in a person's mood, energy, and ability to function. It has a prevalence of 60 million people worldwide, and it is among the top 20 diseases with the highest global burden. The complexity of this disease, including diverse genetic, environmental, and biochemical factors, and diagnoses based on the subjective recognition of symptoms without any clinical test of biomarker identification create significant difficulties in understanding and diagnosing BD. A 1H-NMR-based metabolomic study applying chemometrics of serum samples of Serbian patients with BD (33) and healthy controls (39) was explored, providing the identification of 22 metabolites for this disease. A biomarker set including threonine, aspartate, gamma-aminobutyric acid, 2-hydroxybutyric acid, serine, and mannose was established for the first time in BD serum samples by an NMR-based metabolomics study. Six identified metabolites (3-hydroxybutyric acid, arginine, lysine, tyrosine, phenylalanine, and glycerol) are in agreement with the previously determined NMR-based sets of serum biomarkers in Brazilian and/or Chinese patient samples. The same established metabolites (lactate, alanine, valine, leucine, isoleucine, glutamine, glutamate, glucose, and choline) in three different ethnic and geographic origins (Serbia, Brazil, and China) might have a crucial role in the realization of a universal set of NMR biomarkers for BD.

NMR Metabolomics in Serum Fingerprinting of Schizophrenia Patients in a Serbian Cohort.

Schizophrenia is a widespread mental disorder that leads to significant functional impairments and premature death. The state of the art indicates gaps in the understanding and diagnosis of this disease, but also the need for personalized and precise approaches to patients through customized medical treatment and reliable monitoring of treatment response. In order to fulfill existing gaps, the establishment of a universal set of disorder biomarkers is a necessary step. Metabolomic investigations of serum samples of Serbian patients with schizophrenia (51) and healthy controls (39), based on NMR analyses associated with chemometrics, led to the identification of 26 metabolites/biomarkers for this disorder. Principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) models with prediction accuracies of 0.9718 and higher were accomplished during chemometric analysis. The established biomarker set includes aspartate/aspartic acid, lysine, 2-hydroxybutyric acid, and acylglycerols, which are identified for the first time in schizophrenia serum samples by NMR experiments. The other 22 identified metabolites in the Serbian samples are in accordance with the previously established NMR-based serum biomarker sets of Brazilian and/or Chinese patient samples. Thirteen metabolites (lactate/lactic acid, threonine, leucine, isoleucine, valine, glutamine, asparagine, alanine, gamma-aminobutyric acid, choline, glucose, glycine and tyrosine) that are common for three different ethnic and geographic origins (Serbia, Brazil and China) could be a good start point for the setup of a universal NMR serum biomarker set for schizophrenia.

Cytotoxic triterpenoids and triterpene sugar esters from the medicinal mushroom Fomitopsis betulina.

Thirteen undescribed 24-methylene lanostane triterpenoids, named polyporenic acids E-M and fomitosides L-O, as well as seventeen known analogues, were isolated from the fruiting bodies of the mushroom Fomitopsis betulina. Their structures were determined using 1D, 2D NMR, IR, and HRESIMS. Fomitoside L and fomitoside N exhibited cytotoxicity against HL60 leukemia cells (IC50 = 15.8 and 23.7 µM, respectively). Among the known compounds, notable cytotoxicities against HL60 leukemia cells and selectivity with respect to MRC-5 healthy cells were noticed for dehydropachymic acid (IC50 = 10.9 µM, SI 8.6), pachymic acid (IC50 = 11.0 µM, SI 9.8), 3-epi-dehydrotumulosic acid (IC50 = 19.9 µM, SI 5.8) and 12α-hydroxy-3α-(3'-hydroxy-4'-methoxycarbonyl-3'-methylbutyryloxy)-24-methyllanosta-8,24 (31)-dien-26-oic acid (IC50 = 19.2 µM, SI 2.2).

New aurone epoxide and auronolignan from the heartwood of Cotinus coggygria Scop.

New aurone epoxide, 2,10-oxy-10-methoxysulfuretin (14), and new auronolignan (15), named cotinignan A, were isolated by silica gel column and semipreparative HPLC chromatography from the methylene chloride/methanol extract of Cotinus coggygria Scop. heartwood. In addition, thirteen known secondary metabolites namely sulfuretin, 2,3-trans-fustin, fisetin, butin, butein, taxifolin, eriodictyol, 3',5,5',7-tetrahydroxyflavanone, 3',4',7-trihydroxyflavone, 3-O-methyl-2,3-trans-fustin, 3-O-galloyl-2,3-trans-fustin, ß-resorcylic acid and 3-O-ß-sitosterol glucoside were isolated as well. Their structures were elucidated by 1D and 2D NMR, HR-ESI-MS, IR and UV. Ten out of eleven isolated flavonoids possess 7, 3' and 4' hydroxy groups. These structural features could be considered as chemotaxonomic characteristic of flavonoids from C. coggygria. Cotinignan A (15) represents new subclass of secondary metabolites - auronolignans.

Jatrophane diterpenoids with multidrug-resistance modulating activity from the latex of Euphorbia nicaeensis.

Seven previously undescribed jatrophane diterpenoids, nicaeenin A-G, with eight known jatrophane diterpenoids, namely euphodendrophanes A-C, F, N, O, Q, S, were isolated from latex of Euphorbia nicaeensis collected in Serbia. The chemical structures of the compounds were determined by spectroscopic analysis including 1D and 2D NMR and HRESIMS experiments. All but one of the previously undescribed jatrophanes, showed significant potential to inhibit P-glycoprotein (P-gp) activity in two MDR cancer cells (NCI-H460/R and DLD1-TxR). The most powerful were nicaeenin F and nicaeenin G. Moreover nicaeenin G significantly stronger sensitized NCI-H460/R cells to DOX than Dex-VER.

Research on Chemical Composition and Biological Properties Including Antiquorum Sensing Activity of Angelica pancicii Vandas Aerial Parts and Roots.

The essential oil, different extracts, and isolated compounds of Angelica pancicii Vandas (Apiaceae) were investigated for the first time. The GC-FID and GC-MS analyses revealed sesquiterpenoids as the main constituents of A. pancicii essential oil of aerial parts with bornyl acetate (8.08%), n-octanol (5.82%), kessane (4.26%), and ß-selinene (4.26%) as the main constituents. Analysis of methanol extracts, using an HPLC-DAD/ESI-ToF-MS system, showed a total of 52 compounds in the aerial parts and 53 in the roots, indicating coumarins as the main constituents. In addition, new chromone (1) and six known furanocoumarins (2-7) were isolated from the roots and structurally elucidated by combined spectroscopic methods. The aerial part extracts exhibited higher polyphenolic contents and antioxidant activity evaluated by three radical scavenging assays. Using a microwell dilution method, the strongest antibacterial activity profiles were determined for ethanol and methanol root extracts (minimum bactericidal concentrations (MBCs) = 0.25-3.00 mg/mL), which were comparable to the activity of streptomycin (MBCs = 0.34-1.24 mg/mL), while the strongest antibacterial compound of A. pancicii was oxypeucedanin hydrate (MBCs = 0.50-8.00 mg/mL). Antifungal potential was in moderate extent, and the highest activity was obtained for root methanol extract (minimum fungicidal concentrations (MFCs) = 4.00-14.00 mg/mL). Tested sub-minimum inhibitory concentrations (subMICs) of the extracts and isolated compounds inhibited selected Pseudomonas aeruginosa PAO1 virulence determinants. The most reduced growth of P. aeruginosa colony was in the presence of isolated oxypeucedanin. Ethanol (17.36-46.98%) and methanol (34.54-52.43%) root extracts showed higher anti-biofilm activity compared to streptomycin (49.40-88.36%) and ampicillin (56.46-92.16%).

Antioxidants of Edible Mushrooms.

Oxidative stress caused by an imbalanced metabolism and an excess of reactive oxygen species (ROS) lead to a range of health disorders in humans. Our endogenous antioxidant defense mechanisms and our dietary intake of antioxidants potentially regulate our oxidative homeostasis. Numerous synthetic antioxidants can effectively improve defense mechanisms, but because of their adverse toxic effects under certain conditions, preference is given to natural compounds. Consequently, the requirements for natural, alternative sources of antioxidant foods identified in edible mushrooms, as well as the mechanistic action involved in their antioxidant properties, have increased rapidly. Chemical composition and antioxidant potential of mushrooms have been intensively studied. Edible mushrooms might be used directly in enhancement of antioxidant defenses through dietary supplementation to reduce the level of oxidative stress. Wild or cultivated, they have been related to significant antioxidant properties due to their bioactive compounds, such as polyphenols, polysaccharides, vitamins, carotenoids and minerals. Antioxidant and health benefits, observed in edible mushrooms, seem an additional reason for their traditional use as a popular delicacy food. This review discusses the consumption of edible mushrooms as a powerful instrument in maintaining health, longevity and life quality.

Diarylheptanoids from green alder bark and their potential for DNA protection.

Nine diarylheptanoids, 1-9, catechin (11), and a phenolic glucoside, 10, were isolated from the bark of green alder (Alnus viridis). Four of the isolated compounds, i.e., 2, 5, 8, 10, are new. The structures of 1-11 were determined on the basis of spectroscopic data. All isolated compounds were evaluated for their in vitro protective effects on chromosome aberrations in peripheral human lymphocytes using cytokinesis-block micronucleus (CBMN) assay. Almost all of them exerted a pronounced effect of decreasing DNA damage of human lymphocytes, acting stronger than the known synthetic protector amifostine.

Diarylheptanoids from the bark of black alder inhibit the growth of sensitive and multi-drug resistant non-small cell lung carcinoma cells.

An extended study of minor diarylheptanoids from the bark of black alder has resulted in the isolation of twenty diarylheptanoids, ten of which have not previously been reported (14-18, 20-24). The structures and configurations of all compounds were elucidated by NMR, HRESIMS, UV, IR, and CD. The anti-cancer potency of twenty diarylheptanoids and four previously isolated compounds (7, 10, 12, 13) was investigated in human non-small cell lung carcinoma cell lines (sensitive and multi-drug resistant variants) as well as in normal human keratinocytes. Diarylheptanoids with a p-coumaroyl group, 14 and 18, platyphylloside (1), platyphyllonol-5-O-ß-D-xylopyranoside (2), alnuside B (4) and hirsutenone (9) exhibited strong anti-cancer activity, considerably higher than diarylheptanoid curcumin, which served as a positive control. Compounds 4, 9, 14, and 18 displayed significant selectivity towards the cancer cells. Structure/activity analysis of twenty-four closely related diarylheptanoids revealed a high dependence of cytotoxic action on the presence of a carbonyl group at C-3. Substitution of a heptane chain on C-5 and a number of hydroxyl groups in the aromatic rings also emerged as a significant structural feature that influenced their cytotoxic potential.

Novel anthraquinone based chalcone analogues containing an imine fragment: synthesis, cytotoxicity and anti-angiogenic activity.

A new class of imine derivatives of hybrid chalcone analogues containing anthraquinone scaffold was synthesized and evaluated for their in vitro cytotoxic activity against HeLa, LS174, and A549 cancer cells. The compound 5n with furan ring linked to imino group showed potent activity against all target cells with IC50 values ranging from 1.76 to 6.11µM. A mode of action study suggested that compounds induced changes typical for apoptosis in HeLa cells. The most active compounds inhibited tubulogenesis and 5h was found to exhibit a strong anti-angiogenic effect.

Dietary polysaccharide extracts of Agaricus brasiliensis fruiting bodies: chemical characterization and bioactivities at different levels of purification.

Polysaccharides of the European strain of A. brasiliensis were obtained by hot water extraction and ethanol precipitation (HWPE I) of fruiting bodies, and further purified by dialysis (HWPE II) and pronase incubation (PPE). These polysaccharides consisted mainly of (1→6)-ß-d-glucans. PPE was free of proteins and polyphenols as demonstrated by quantitative assays and NMR profiling. They showed a clear IFN-γ inducing activity in human PBMCs, which suggests these polysaccharides to have proinflammatory effects. Treatment by ß-glucosidase caused the polysaccharides to be degraded into smaller fragments and at the same time increased their IFN-γ inducing activity in PBMCs fourfold. In vitro, PPE showed a dose-dependent inhibition of the proliferation of the human leukemia Jurkat cell. At 100µg/mL the cells' viability was decreased by appr. 51% compared to the control. EPR spin trapping demonstrated a high antioxidative activity against •OH and •O2- radicals of HWPE I and PPE. Further, the results of the antioxidant assays indicated that antioxidant activity against •OH radicals in the Fenton system was achieved through scavenging or through chelating iron mechanisms. The good immunomodulating and antioxidative properties of A. brasiliensis polysaccharide extract obtained by hot water extraction and ethanol precipitation make it suitable for everyday use as an inexpensive dietary supplement.

Chemistry of the sternal gland secretion of the Mediterranean centipede Himantarium gabrielis (Linnaeus, 1767) (Chilopoda: Geophilomorpha: Himantariidae).

The geophilomorph centipede, Himantarium gabrielis, when disturbed, discharges a viscous and proteinaceous secretion from the sternal glands. This exudate was found by gas chromatography-mass spectrometry, liquid chromatography-high resolution mass spectrometry, liquid chromatography-mass spectrometry-mass spectrometry and NMR analyses to be composed of hydrogen cyanide, benzaldehyde, benzoyl nitrile, benzyl nitrile, mandelonitrile, mandelonitrile benzoate, 3,7,6O-trimethylguanine (himantarine), farnesyl 2,3-dihydrofarnesoate and farnesyl farnesoate. This is the first report on the presence of benzyl nitrile and mandelonitrile benzoate in secreted substances from centipedes. Farnesyl 2,3-dihydrofarnesoate is a new compound, while himantarine and farnesyl farnesoate were not known as natural products. A post-secretion release of hydrogen cyanide by reaction of mandelonitrile and benzoyl nitrile was observed by NMR, and hydrogen cyanide signals were completely assigned. In addition, a protein component of the secretion was analysed by electrophoresis which revealed the presence of a major 55 kDa protein. Analyses of the defensive exudates of other geophilomorph families should produce further chemical surprises.

Synthesis, cytotoxic activity and DNA-interaction studies of novel anthraquinone-thiosemicarbazones with tautomerizable methylene group.

A series of novel anthraquinone-thiosemicarbazone derivatives in a tautomerizable keto-imine form was synthesized and tested for their in vitro cytotoxic activity against human cancer cells (HeLa, MDA-MB-361, MDA-MB-453, K562, A549) and human normal MRC-5 cells. Several compounds efficiently inhibited cancer cell growth at micromolar concentrations, especially against K562 and HeLa cells. As determined by flow cytometric analysis, anthraquinone-thiosemicarbazone caused significant increase in the number of sub-G1 phase of HeLa cells and apoptosis in a concentration-dependent manner. Also, inhibition of caspase-3, -8, and -9 with specific caspase inhibitors reduced the apoptosis mediated by the tested compounds in HeLa cells. All anthraquinone-thiosemicarbazones exhibit calf thymus DNA-binding activity, but no cleavage of plasmid DNA was observed.

Diarylheptanoids from Alnus glutinosa bark and their chemoprotective effect on human lymphocytes DNA.

A study of secondary metabolites from the bark of Alnus glutinosa led to the isolation of fourteen diarylheptanoids: oregonin (1), platyphylloside (2), rubranoside A (3), rubranoside B (4), hirsutanonol (5), hirsutenone (6), hirsutanonol-5-O-ß-D-glucopyranoside (7), platyphyllonol-5-O-ß-D-xylopyranoside (8), aceroside VII (9), alnuside A (10), alnuside B (11), 1,7-bis-(3,4-dihydoxyphenyl)-5-hydroxy-heptane-3-O-ß-D-xylopyranoside (12), (5S)-1-(4-hydroxyphenyl)-7-(3,4-dihydroxyphenyl)-5-O-ß-D-glucopyranosyl-heptan-3-one (13), and (5S)-1,7-bis-(3,4-dihydroxyphenyl)-5-O-ß-D-[6-(3,4-dimethoxycinnamoylglucopyranosyl)]-heptan-3-one (14). All of the diarylheptanoids, except 1 and 5, were found in A. glutinosa for the first time, while 13 and 14 were new compounds. The structures were determined by spectroscopic techniques: 1D and 2D NMR, HR-ESI-MS, FTIR, UV, and CD. All isolated compounds were analyzed for an in vitro protective effect on chromosome aberrations in peripheral human lymphocytes using the cytokinesis-block micronucleus assay. The majority of them, including the new compounds 13 and 14, exerted a pronounced effect in decreasing DNA damage in human lymphocytes. Diarylheptanoids 1, 2, 5, 13, and 14 at a concentration of 1 µg/mL decreased the frequency of micronuclei by 52.8 %, 43.8 %, 63.6 %, 44.4 %, and 56.0 %, respectively, exerting a much stronger effect than the synthetic protector amifostine (17.2 %, c = 1 µg/mL).

The edible mushroom Laetiporus sulphureus as potential source of natural antioxidants.

Hot water extract (LN), partially purified polysaccharides (LP) and hot alkali extracted polysaccharides (LNa) obtained from fruiting bodies of the wild basidiomycete Laetiporus sulphureus were examined for their antioxidant activities. LNa was the most active antioxidant, as shown by the median effective concentrations (EC50 values) of 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity (0.5 ± 0.2 mg/ml), reducing power (4.0 ± 0.3 mg/ml) and ferrous ion-chelating ability (1.5 ± 0.1 mg/ml). LNa contained the highest level of α-glucan (17.3 ± 1.2 g/100 g dw), whereas LP contained mostly ß-glucans (66.8 ± 1.3 g/100 g dw). The prevalent monosaccharide in all extracts was glucose. The EC50 values of all three antioxidant activity assays were well-correlated with the α-glucan content. Strong and significant correlation was found between total phenolic compounds and DPPH scavenging ability and also reducing power. The three investigated extracts (at concentrations of 0.1-10 mg/ml) were not toxic to HTR-8/SVneo trophoblast cell line.

Jatrophane diterpenoids from the latex of Euphorbia dendroides and their anti-P-glycoprotein activity in human multi-drug resistant cancer cell lines.

Thirteen jatrophane diterpenoids (1-10, 13-15), three previously isolated (11, 12, 16) and a known tigliane (17) were isolated from the latex of Euphorbia dendroides. The structures and relative configurations of compounds were elucidated by spectroscopic techniques. The P-glycoprotein (P-gp) inhibiting activities of the representative set of jatrophanes (1-6 and 11-16) have been assessed. Jatrophanes 2 and 5 demonstrated the most powerful inhibition of P-gp, higher than R(+)-verapamil and tariquidar in colorectal multi-drug resistant (MDR) cells (DLD1-TxR).

New anti-cancer characteristics of jatrophane diterpenes from Euphorbia dendroides.

Jatrophane diterpenes were shown to be inhibitors of P-glycoprotein (P-gp). There are also evidences on their microtubule-interacting activity in cancer cells. We evaluated new anti-cancer characteristics of two jatrophane type compounds from Euphorbia dendroides. For that purpose, the model system of sensitive non-small cell lung cancer cell line (NCI-H460) and its resistant counterpart (NCI-H460/R) was used. Although both jatrophanes showed inhibitory effect on cancer cell growth, they were non-toxic for peripheral blood mononuclear cells (PBMC). We examined their effects in combination with paclitaxel (PTX), a well-known mitotic spindle interacting chemotherapeutic. Jatrophanes overcome PTX resistance in concentration-dependent manner in MDR cancer cell line (NCI-H460/R). We observed that this synergistic effect is not caused merely by P-gp inhibition. In combination with PTX, jatrophanes induce cell killing and change cell cycle distribution leading to G2/M arrest. Furthermore, they exert an anti-angiogenic effect by decreasing the vascular endothelial growth factor (VEGF) secretion. The reduction of the level of mdr1 mRNA expression in sensitive cells, suggests that these compounds could not contribute to the development of resistance. In conclusion, present study provides a rational basis for the new cancer treatment approach with jatrophanes that are non-toxic to normal cells and have new favorable anti-cancer characteristics.

Antiproliferative activity and QSAR studies of a series of new 4-aminomethylidene derivatives of some pyrazol-5-ones.

Twenty five 4-aminomethylidene derivatives obtained from 3-phenyl-2-pyrazolin-5-one and 1,3-diphenyl-2-pyrazolin-5-one were synthesized and tested for their antiproliferative activity against human breast cancer MDA-MB-361 and MDA-MB-453 cell lines. The compounds derived from 1,3-diphenyl-2-pyrazolin-5-one exhibited the most remarkable activity in the treatment of both cell lines. In vitro antiproliferative activities were accompanied by an important apoptotic fraction of both cell lines; also, compounds inhibited key endothelial cell functions implicated in invasion and angiogenesis. QSAR methods were performed in order to analyze the influence of structural features of the compounds investigated on the antiproliferative potential on MDA-MB-361 and MDA-MB-453 cancer cells. One-parameter heuristic analysis was performed and different whole molecule and fragmental descriptors were considered for rationalization of mechanism of interaction of these compounds with active place of hypothetical target included in tumorigenesis.

Isolation and biological evaluation of jatrophane diterpenoids from Euphorbia dendroides.

From the Montenegrin spurge Euphorbia dendroides, seven new diterpenoids [jatrophanes (1-6) and a tigliane (7)] were isolated and their structures elucidated by spectroscopic techniques. The biological activity of the new compounds was studied against four human cancer cell lines. The most effective jatrophane-type compound (2) and its structurally closely related derivative (1) were evaluated for their interactions with paclitaxel and doxorubicin using a multi-drug-resistant cancer cell line. Both compounds exerted a strong reversal potential resulting from inhibition of P-glycoprotein transport.