Heteronuclear Multiple Bond Correlation Research Articles

Synthesis, spectroscopic characterization, and anticancer activity of new 10-substituted 1,6-diazaphenothiazines.

New phenothiazine derivatives as 10-substituted dipyridothiazines of the 1,6-diazaphenothiazine structure were obtained in the cyclization reaction of 3-amino-3′-nitro-2,2′-dipyridinyl sulfide and 3,3′-dinitro-2,2′-dipyridinyl disulfide, and in the reaction of 2-chloro-3-ntropyridine with sodium 3-amino-2-pyridinethiolate followed by various alkylation and arylation reactions. The reaction of the thiazine ring formation ran via the Smiles rearrangement of the S-N type. As the alkylation reactions could proceed at the thiazine, azine or both nitrogen atoms, the product structure elucidation was based on the 2D NMR (Rotating-frame Overhauser Effect Spectroscopy, Correlated Spectroscopy, Heteronuclear Single Quantum Coherence, and Heteronuclear Multiple Bond Correlation) spectra of the N-methylated product. Some 10-substituted 1,6-diazaphenothizines (5, 10, 12, 13) were at least anticancer active against melanoma C-32 and breast cancer MCF-7 cell lines as a reference drug – cisplatin. The monoazaphenothiazine drug, prothipendyl, turned out to be less active than least 6 derivatives of the 1,6-diazaphenothiazine structure.

NMR characterization of pentaerythritol glycolysis products of polyethylene terephthalate

ABSTRACTThe degradation of polyethylene terephthalate (PET) bottles has been successfully achieved by depolymerization through glycolysis with pentaerythritol. The reaction was performed at 250°C in the presence of an organotin catalyst. The glycolyzed products were characterized by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy. The existence of the chemical bond between the polyol and the PET was detected through heteronuclear multiple bond correlation spectroscopy, and the NMR signals of different species were separated according to their diffusion coefficient by diffusion-ordered spectroscopy. This method offers a rapid quantification of glycolyzed products. Furthermore, it was found that the major product was the mono-pentaerythritol ester followed by the di-pentaerythritol ester, and lastly the tri-pentaerythritol ester.

The chemical fixation of carbon dioxide by tetramethylguanidine and triazabicyclo dec-5-ene bases

The fixation of CO 2 using guanidine bases; 1,1,3,3-tetramethylguanidine (TMG) and 5,7-triazabicyclo[4.4.0] dec-5-ene (TBD) has been investigated. Solution Nuclear magnetic resonance (NMR) studies were carried out for the reaction between CO 2 and the guanidine bases at normal temperature and pressure, i.e Ca. 30 °C and 1 atm. Analysis of results obtained using 1- dimentional 13 C NMR and 2-dimentional 15 N (HMBC) both indicated successful reaction between CO 2 and TBD and also CO 2 with TMG. Both products were observed to be stable at room temperature and pressure. Based on the results obtained, it was concluded that, the CO 2 can be fixed with TMG and TBD at normal conditions of temperature and pressure. Finally it was also proposed that, the method used could be useful for the uptake and release of atmospheric CO 2 . Keywords: Carbon dioxide, Chemical fixation, Heteronuclear Multiple-Bond Correlation Tetramethylguanidine, Triazabicyclo decene

Advanced NMR Methods and DFT Calculations on the Regioselective Deprotonation and Functionalization of 1,1′‐Methylenebis(3‐methylimidazole‐2‐thione)

Depending on the temperature, the twofold deprotonation of 1,1′‐methylenebis(3‐methylimidazole‐2‐thione) (1) and the subsequent reaction with 2 equiv. of trimethylsilyl chloride (TMSCl) gives two different bis‐TMS‐functionalized isomers, namely, 1,1′‐methylenebis(3‐methyl‐4‐trimethylsilylimidazole‐2‐thione) (2) and 1,1′‐methylenebis(3‐methyl‐5‐trimethylsilylimidazole‐2‐thione) (3). The cyclic dimethylsilyl‐bridged derivative 1,1′‐methylene‐5,5′‐dimethylsilylenebis(3‐methylimidazole‐2‐thione) (4) can also be obtained, corroborating the 5/5′ addition under certain conditions. All compounds have been examined by multinuclear 1D and 2D NMR experiments (1–4) together with single‐crystal X‐ray diffraction (3 and 4). Additionally, the dilithiated species 5 was synthesized by reacting 1 with 2 equiv. of nBuLi at ambient temperature in solution (THF). 1H and 7Li pulsed field‐gradient spin‐echo (PGSE) NMR, 7Li–1H heteronuclear Overhauser spectroscopy (HOESY), gradient heteronuclear multiple quantum correlation (gHMQC) and gradient heteronuclear multiple bond correlation (gHMBC) experiments showed that 5 exists as a monomeric contact ion pair (CIP) in THF solution. On the contrary, the X‐ray diffraction analysis of 5 revealed a polymeric chain, which can be described as [{5(thf)2}2]∞. Quantum chemical DFT and MP2 calculations were also conducted to determine the energies required for the deprotonation of 1. These results explain the regioselective deprotonation of 1 by CIP formation depending on the temperature and fully support the results of the synthetic and spectroscopic experiments.

Synthesis and structure analysis of polyesteramides modified with bio-based diaminopentane hexanedioic salt

Abstract Two series of bio-based diaminopentane hexanedioic salt (DHS) modified polyesteramides were successfully synthesized by two different synthesis processes in which DHS reacted with bis-hydroxyethyl terephthalate (BHET) and low molecular weight polyester (LPET), respectively. The intrinsic viscosities of the polyesteramides ranged from 0.62 dl/g to 0.78 dl/g, which correlated greatly with the requirements of subsequent processing such as spinning. The results of the heteronuclear multiple bond correlation (HMBC) indicated that the diaminopentane segment was directly connected with the purified terephthalic acid (PTA) segment. The presence of ester and amide group characteristic peaks in the Fourier transform-infrared (FT-IR) spectroscopy confirmed that the final resultant products were polyesteramides. The results of elemental analysis showed that the ratio of actual nitrogen content to theoretical nitrogen content of two series of polyesteramides was 76%~90%, and the actual nitrogen content in both series was proportional to the addition of DHS.

A novel diarylheptanoid-bearing sesquiterpene moiety from the rhizomes of Alpinia officinarum

A new diarylheptanoid analogue-bearing sesquiterpene moiety, named Alpinisin A, was isolated from the rhizomes of Alpinia officinarum Hance. The new structure was determined by various spectroscopic techniques 1H-nuclear magnetic resonance (1H NMR), 13C-attached proton test (13C-APT), heteronuclear single quantum coherence (HSQC), heteronuclear multiple bond correlation (HMBC), 1H-1H correlation spectroscopy (1H–1HCOSY), nuclear overhauser effect spectroscopy (NOESY) and high resolution electrospray ionization mass spectrometry (HR–ESI–MS). The compound was tested for cytotoxic activity in vitro against human tumour cell lines (gastric carcinoma cell -7901 (SGC-7901), Michigan Cancer Foundation-7 (MCF-7) and Caski), which showed significant inhibitory effects with IC50 levels of 11.42, 15.14 and 14.78 μM, respectively. The novel chemical structure characterised with a diarylheptanoid linked to a chain-like sesquiterpenoid should be highlighted.

Logic Structure Determination (LSD) as a Computer Assisted Structure Elucidation (Case) for Molecular Structure Determination of Cytotoxic Cembranoids from Soft Coral

The tropical Indonesian soft corals are a valuable resources that produce pharmacological cytotoxic cembranoids. However, manual structure determination into these compounds requires adequate knowledge of organic chemistry. This study presents the application of Logic Structure Determination (LSD), as a freeware Computer Assisted Structure Elucidation (CASE) for automatic molecular structure determination of cembranoid compounds from soft corals species. 12 Nuclear Magnetic Resonance (NMR) dataset of cytotoxic cembranoids were used to evaluate the accuracy of LSD in generating the possible structures. Results of this study shows LSD generated numerous possible molecular structures, as the data input file derived only from 2D-NMR HMQC (Heteronuclear Multiple-Quantum Correlation), COSY (Homonuclear Correlation Spectroscopy), and HMBC (Heteronuclear Multiple Bond Correlation). The accuracy significantly enhanced (only 2-4 possible cembranoid structures from each NMR dataset) with addition of H2BC (Heteronuclear 2 Bond Correlation) experimental data. This may indicates that VLRC (Very Long-Range Correlations) affects significantly to LSD capability. Furthermore, LSD with direct 2 bond NMR experimental data is a reliable CASE technique for identification of cembranoid compounds. In general, this freeware-CASE is potential to be applied to other type of small molecule compounds and may serves as a potential solution for elucidation bottleneck step in Indonesian natural products studies.

NMR characterization of sodium carboxymethyl cellulose 2: Chemical shift assignment and conformation analysis of substituent groups

The chemical shifts of the substituent groups of sodium carboxymethyl cellulose (CMC) were assigned by examining a series of CMC samples with different degrees of substitution. Comparative analysis of the 1H–13C heteronuclear single quantum coherence (HSQC) and heteronuclear multiple bond correlation (HMBC) spectra allowed the complete assignment of the substituent groups at the 2-, 3-, and 6-positions of the seven substituted monomers comprising the CMC chains, namely, 2-mono-, 3-mono-, 6-mono-, 2,3-di-, 2,6-di-, 3,6-di-, and 2,3,6-tri-substituted anhydroglucose units (AGUs). In addition, the mole fractions of the monomers were determined by lineshape analysis of the carbonyl carbon resonances. The comparison between the chemical shifts of the substituents revealed strong interactions between 2- and 3-substituents in the same AGU, and showed that the steric hindrance by a substituent at the 2- or 3-position suppresses subsequent substitution at the adjacent position.

Regioselective deprotection of the monosaccharide-bearing thiocyanomethyl group at the anomeric position monitored by reversed-phase HPLC method.

In the current work, the investigation and development of a chemo-enzymatic approach for the synthesis of neo-glycoproteins have been studied. This strategy is based on the regioselective enzymatic hydrolysis of peracetylated monosaccharide, functionalized at the anomeric position (C1) as 1-thio-(S-cyanomethyl) group, a precursor of the 2- iminomethoxyethyl thioglycosides-linker for protein glycosylation, catalyzed by immobilized enzymes to obtain selectively monodeprotected compounds. The use of this activation in C1 is the most frequently used strategy for glycoprotein preparation. The selected biocatalysts are the lipase from Candida rugosa and the acetyl xylan esterase from Bacillus pumilus. A reversed-phase high-performance liquid-chromatographic (HPLC) method for monitoring the regioselective deprotection reaction has been developed. The developed HPLC method was used as a fingerprint to follow the hydrolysis of substrate 1 to substrate 1a and to determine its purity and yield. Moreover, the obtained compound was further purified by flash chromatography. The obtained compound 1a was further characterized using (1) H, (13) C NMR, correlation spectroscopy (COSY) and heteronuclear multiple bond correlation. The resulting product can be used as an intermediate for the preparation of di- and more complex oligosaccharides aimed at protein conjugation. Copyright © 2016 John Wiley & Sons, Ltd.

Conformation analysis of d-glucaric acid in deuterium oxide by NMR based on its JHH and JCH coupling constants.

d-Glucaric acid (GA) is an aldaric acid and consists of an asymmetric acyclic sugar backbone with a carboxyl group positioned at either end of its structure (i.e., the C1 and C6 positions). The purpose of this study was to conduct a conformation analysis of flexible GA as a solution in deuterium oxide by NMR spectroscopy, based on J-resolved conformation analysis using proton-proton ((3) JHH ) and proton-carbon ((2) JCH and (3) JCH ) coupling constants, as well as nuclear overhauser effect spectroscopy (NOESY). The (2) JCH and (3) JCH coupling constants were measured using the J-resolved heteronuclear multiple bond correlation (HMBC) NMR technique. NOESY correlation experiments indicated that H2 and H5 were in close proximity, despite the fact that these protons were separated by too large distance in the fully extended form of the chain structure to provide a NOESY correlation. The validities of the three possible conformers along the three different bonds (i.e., C2C3, C3C4, and C4C5) were evaluated sequentially based on the J-coupling values and the NOESY correlations. The results of these analyses suggested that there were three dominant conformers of GA, including conformer 1, which was H2H3:gauche, H3H4:anti, and H4H5:gauche; conformer 2, which was H2H3:gauche, H3H4:anti, and H4H5:anti; and conformer 3, which was H2H3:gauche, H3H4: gauche, and H4H5:anti. These results also suggested that all three of these conformers exist in equilibrium with each other. Lastly, the results of the current study suggested that the conformational structures of GA in solution were 'bent' rather than being fully extended. Copyright © 2016 John Wiley & Sons, Ltd.

A New Antifungal Isocoumarin from The Endophytic Fungus Trichoderma Sp. 09 of Myoporum bontioides A. Gray.

Background:Myoporum bontioides A. Gray is a commonly used medicinal plant in China. Recently, the chemical and bioactive investigations to the endophytic fungi of this plant have led to several new compounds with antimicrobial and cytotoxic activities. To find out more active molecules, the metabolites of an endophytic fungus, Trichoderma sp. 09 from the root of Myoporum bontioides were investigated.Materials and Methods:The metabolites were isolated by column chromatography on silica gel, and their structures were elucidated on the basis of spectroscopic analysis[one-dimensional (1D), two-dimensional (2D)-nuclear magnetic resonance (NMR), Mass spectrometry (MS)], and by comparison with the published data. The dilution method was used for the evaluation of antifungal activity.Results:Four metabolites were isolated and identified as: dichlorodiaportinolide (1), dichlorodiaportin (2), diaportinol (3), and diaportin (4). Compounds 1 and 2 showed weak to high antifungal activities against Colletotrichum musae (Berk. and M. A. Curtis) Arx and Rhizoctonia solani Kühn, as compared with the positive control.Conclusions:Compound 1 was a new isocoumarin being worthy of consideration for the development and research of antifungal agents.SUMMARY A new isocoumarin named dichlorodiaportinolide, along with dichlorodiaportin, diaportinol, and diaportin were isolated from the endophytic fungus Trichoderma sp. 09 of the root of Myoporum bontioides.Dichlorodiaportinolide and dichlorodiaportin showed weak to high antifungal activities against musae and R. solani (MIC values from 6.25 to 150 μg/mL).Dichlorodiaportinolide and dichlorodiaportin were inactive to P. italic and F. graminearum (MIC values > 200 μg/mL). Abbreviations used: IR: Infrared Radiation, HR-ESI-MS: High resolution electrospray ionization mass spectroscopy, LCMS-IT-TOF: Liquid chromatography mass spectroscopy-Ion trap-Time-of-flight, UV: Ultraviolet-visible, HMBC: Heteronuclear multiple bond correlation, NOE: Nuclear Overhauser effect.

Ursolic Acid, a Natural Pentacylcic Triterpene from Ochrosia elliptica and Its Role in The Management of Certain Neglected Tropical Diseases.

Background:Leishmaniasis and African trypanosomiasis are recognized as the leading causes of mortality and morbidity with the greatest prevalence in the developing countries. They affect more than one billion of the poorest people on the globe.Objective:To find a cheap, affordable, safe, and efficacious antileshmanial and antitrypanosomal natural drug and to elucidate its probable mode of action.Materials and Methods:Phytochemical investigation of the non-polar fraction of the methanol extract of leaves of Ochrosia elliptica Labill. (Apocyanaceae) resulted in the isolation of ursolic acid, which was unambiguously determined based on HR-ESI-FTMS, extensive 1D and 2D NMR spectroscopy. It was further tested for its cytotoxicity, antimicrobial, antimalarial, antileishmanial, and trypanocidal potency. in-silico molecular modeling studies were conducted on six vital parasitic enzymes including farnesyl diphosphate synthase, N-myristoyl transferase, pteridine reductase 1, trypanothione reductase, methionyl-tRNA synthetase, and inosine–adenosine–guanosine nucleoside hydrolase to discover its potential mode of action as antitrypanosomal and antileishmanial agent.Results:Ursolic acid displayed considerable antitrypanosomal and antileishmanial activities with IC50 values ranging between 1.53 and 8.79 μg/mL. It showed superior antitrypanosomal activity as compared to the standard drug difluoromethylornithine (DFMO), with higher binding affinities towards trypanothione reductase and pteridine reductase 1. It displayed free binding energy of -30.73 and -50.08 kcal/mole towards the previously mentioned enzymes, respectively. In addition, ursolic acid exhibited considerable affinities to farnesyl diphosphate synthase, N-myristoyl transferase and methionyl-tRNA synthetase with free binding energies ranging from -42.54 to -63.93 kcal/mole.Conclusion:Ursolic acid offers a safe, effective and cheap antitrypanosomal and antileishmanial candidate acting on several key parasitic enzymes.SUMMARY The fresh leaves of Ochrosia elleptica Labill., family Apocyanaceae are a reliable source of ursolic acid.Ursolic acid displayed considerable antitrypanosomal and antileishmanial activities. It showed superior antitrypanosomal activity as compared to difluoromethylornithine (DFMO), potent antitrypanosomal reference drug.In silico molecular modeling studies revealed that the antileishmanial and antitrypanosomal activities of ursolic acid could be partially explained in view of its multiple inhibitory effects on vital parasitic enzymes with the highest potency exerted in the inhibition of pteridine reductase 1 and trypanothione reductase. Abbreviations used: AHT: African Human Trypanosomiasis, ATCC: American type cell culture, BuOH: n-butanol, DCM: dichloromethane, DFMO: difluoromethylornithine, EtOAc: ethyl acetate, FCS: fetal calf serum, HMBC: Heteronuclear Multiple Bond Correlation, HMQC: Heteronuclear Multiple-Quantum Correlation, HR-ESI-FTMS: High Resolution Electrospray ionozation Mass Spectrometry, MENA: Middle East and North Africa, MeOH: Methanol, MRSA: Methicillin-resistant Staphylococcus aureus, NTDs: Neglected tropical diseases, TLC: Thin layer chromatography, UA: Ursolic acid, UV: Ultra violet, WHO: World Health Organization.

Methoxyflavones from New Lingzhi Medicinal Mushroom, Ganoderma lingzhi (Agaricomycetes).

Ganoderma lingzhi is one of the most famous medicinal fungi in the world. It has been used in folk medicine, especially in East Asian countries. It is also a white-rot fungus with strong wood degradation ability, especially against lignin. Different classes of bioactive natural products have been reported in Ganoderma, including triterpenes, polysaccharides, sterols, and peptides. The triterpenes and polysaccharides are the primary bioactive compounds of Ganoderma. We report for the first time the presence of 3 methoxyflavones as minor constituents in G. linghzi. The 3 compounds were identified based on different spectroscopic techniques, including 1- and 2-dimensional nuclear magnetic resonance (1H-1H correlation spectroscopy, heteronuclear single quantum coherence, and heteronuclear multiple bond correlation) and mass spectrometry (high-resolution electrospray ionization mass spectrometry). Our report provides an approach to a possible biosynthetic pathway for biosynthetic genes in the mushrooms. Another great possibility is that these compounds may exist or be formed through degradation of the components in the woody substrate, such as lignin, and then subsequently translocate to the fruiting bodies.

New Isorhamnetin Derivatives from Salsola imbricata Forssk. Leaves with Distinct Anti-inflammatory Activity.

Background:Salsola imbricata Forssk. is a shrub widely growing in Egypt, used as a camel food, traditionally, used as anti-inflammatory agent. Literature survey showed no report about the anti-inflammatory activity of S. imbricata.Aim of the Study:This work was designed to study the phenolic constituents and to provide evidence for the traditional use of S. imbricata as an anti-inflammatory agent.Materials and Methods:The in vitro anti-inflammatory activity of the total aqueous methanol extract and some isolated compounds were investigated in RAW 264.7 macrophage cells using nitric oxide assay. All chemical structures were identified on the basis of electrospray ionization-mass spectrometry, one- and two-dimension nuclear magnetic resonance.Results:Nine phenolic compounds, among them two new natural products; isorhamnetin-3-O-β-D-glucuronyl (1’’’→4’’) glucuronide (1) and its dimethyl ester; isorhamnetin-3-O-β-D-di glucuronate dimethyl ester (2), two isorhamnetin glycosides: Isorhamnetin-3-O-β-D-galactopyranoside (3), isorhamnetin-3-O-β-D-glucopyranoside (4), and isorhamnetin (5). In addition, an alkaloidal phenolic; trans N-feruloyl tyramine (6), three phenolic acids: Isovanillic acid (7), ferulic acid (8), and p-hydroxy benzoic acid (9) were isolated from salsola imbricata leaves. All compounds were isolated and identified for the first time from this plant except compound (6). The extract and the tested compounds showed distintict anti-inflammatory activities with no toxicity on RAW 264.7 macrophage cells.Conclusion:The extract and the tested compounds showed distintict anti-inflammatory activities with no toxicity on RAW 264.7 macrophage cells.SUMMARY Investigation of the chemical constituents of the leaves of Salsola imbricata led to isolation of two new isorhamnetin derivatives: isorhamnetin.3-O-β-D.glucuronyl (1’“→”) glucuronide (1) and its dimethyl ester (2), together with seven known phenolic compounds. The extract and the tested compounds showed distintict anti-inflammatory activities with no toxicity on RAW 264.7 macrophage cells. Abbreviations used: PC: Paper chromatography, MPLC : Medium Pressure Liquid Chromatography, HMBC: Heteronuclear multiple bond correlation, HMQC: Heteronuclear single quantum correlation, NMR: Nuclear magnetic resonance

A New Sucrase Enzyme Inhibitor from Azadirachta indica.

Background:Sucrase enzyme inhibitor considered as an oral anti-diabetic therapy that delays the absorption of eaten carbohydrates, reducing the postprandial glucose and insulin peaks to reach normoglycemia.Materials and Methods:Chromatographic fractionation of the hydroalcoholic extract of leaves of Azadirachta indica growing in KSA, followed by in-vitro assay of sucrase enzyme inhibition activity.Results:This investigation led to the isolation of a new remarkable sucrase enzyme inhibitor; 4’-methyl Quercetin-7-O-β-D-glucuronopyranoside (1) alongside with four known compounds; 2,3-hexahydroxydiphenoyl-(α/β)-D-4C1-glucopyranose (2), Avicularin (3), Castalagin (4) and Quercetin-3-O-glucoside (5). The structure of the new compound (1) was elucidated on the basis of its spectral data, including ESI-MS, UV, 1H NMR, 13C NMR, 1H-1H COSY, HSQC, NOESY and HMBC.Conclusion:Under the assay conditions, hydroalcoholic extract of A. indica and compounds 1-5 exhibited significant sucrase enzyme inhibitory activity.SUMMARY Chromatographic fractionation of the hydroalcoholic extract of leaves of Azadirachta indica, led to the Isolation of a new flavonoid glycoside named 4’-methyl Quercetin-7-O-β-D-glucuronopyranoside, alongside to other 4 known polyphenols. The hydroalcoholic extract as well as the isolated compounds exhibited significant sucrase enzyme inhibitory activity. Abbreviations used: ESI-MS; electrospray ionization-mass spectrometry, UV; ultraviolet, NMR; nuclear magnetic resonance, 1H-1H COSY; 1H-1H correlation spectroscopy, NOESY; nuclear overhauser effect spectroscopy, and HSQC; heteronuclear multiple bond correlation. A. indica; Azadirachta indica.

Design, Synthesis and Comparative Study of Anti-Microbial Activities on Barbituric Acid and Thiobarbituric Acid based Chalcone Derivatives Bearing the Pyrimidine Nucleus

A new comparative series of barbituric acid and thiobarbituric acid based chalcone derivatives bearing the pyrimidine nucleus were synthesized. The chemical structures of the resulting molecules were characterised by means of FT-IR (Fourier Transform Infrared) 1H NMR, 13C-NMR (Nuclear Magnetic Resonance) and HMBC (Heteronuclear Multiple-Bond Correlation) and Elemental Analysis. All synthesized compounds were subjected to in vitro antimicrobial screening against four bacterial strains i.e., one Gram Positive (Bacillus subtilis MTCC 441), two Gram Negative (E. coli MTCC 443, P. aeruginosa MTCC 1688), and one Fungal (C. albicans MTCC 227) Strains. The structure activity relationship is discussed on the basis of bioactivity results, various functional groups present and position of the functional group at various positions of the synthesized compounds. The comparative antimicrobial activity study of both of the series elucidated that shows the chalcone compounds containing -thioketo group are more potent than the -keto group.

Neuroprotective Properties of Compounds Extracted from Dianthus superbus L. against Glutamate-induced Cell Death in HT22 Cells.

Background:Dianthus superbus L. has been used in Chinese herbal medicine as a diuretic and anti-inflammatory agent.Objective:In this study, we isolated ten bioactive compounds from D. superbus and evaluated their neuroprotective activity against glutamate-induced cell death in the hippocampal neuronal HT22 cells.Materials and Methods:New compound, (E)-methyl-4-hydroxy-4-(8a-methyl-3-oxodecahydronaphthalen-4a-yl) (1) and, nine known compounds, diosmetin-7-O (2’’,6’’-di-O-α-L-rhamnopyranosyl)-β-D-glucopyranoside (2), 4-hydroxy-3-methoxy-pentyl ester benzenepropanoic acid (3), vanillic acid (4), 4-hydroxy-benzeneacetic acid (5), 4-methoxybenzeneacetic acid (6), (E)-4-methoxycinnamic acid (7), 3-methoxy-4-hydroxyphenylethanol (8), hydroferulic acid (9), and methyl hydroferulate (10), were isolated by bioactivity-guided separation. Structures of the isolated compounds were identified on the basis of 1H nuclear magnetic resonance (NMR), 13C NMR, and two-dimensional NMR spectra, while their neuroprotective properties were evaluated by performing the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.Results:D. superbus extract had a neuroprotective effect and isolated 10 compounds. Among the compounds, compounds 5 and 6 effectively protected HT22 cells against glutamate toxicity.Conclusion:In conclusion, the extract of D. superbus and compounds isolated from it exhibited neuroprotective properties, suggesting therapeutic potential for applications in neurotoxic diseases.SUMMARY D. superbus extract significantly protected on glutamate-induced cell death in HT22 cellsNew compound, (E)-methyl-4-hydroxy-4-(8a-methyl-3-oxodecahydronaphthalen-4a-yl) (1) and, nine known compounds, diosmetin-7-O(2’’,6’’-di-O-α-L-rhamnopyranosyl)-β-D-glucopyranoside (2), 4-hydroxy-3-methoxy-pentyl ester benzenepropanoic acid (3), vanillic acid (4), 4-hydroxy-benzeneacetic acid (5), 4-methoxybenzeneacetic acid (6), (E)-4-methoxycinnamic acid (7), 3-methoxy-4-hydroxyphenylethanol (8), hydroferulic acid (9), and methyl hydroferulate (10) were isolated from D. superbus extract4-hydroxy-benzeneacetic acid and 4-methoxybenzeneacetic acid showed significant protective activity against glutamate-induced toxicity in HT22 cells. Abbreviations used: CNS: Central nervous system, ROS: Reactive oxygen species, CHCl3: Chloroform, EtOAc: Ethyl acetate, BuOH: Butanol, HPLC: High performance liquid chromatography, TLC: Thin layer chromatography, MPLC: Middle performance liquid chromatography, MeOH: Methanol, OD: Optical density, COSY: Correlation spectroscopy, HMQC: Heteronuclear multiple-quantum correlation, HMBC: Heteronuclear multiple-bond correlation, HR-MS: High-resolution molecular spectroscopy, MTT: 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide.

Free-Radical Scavenging Activities of Cultured Mycelia of Paecilomyces hepiali (Ascomycetes) Extracts and Structural Characterization of Bioactive Components by Nuclear Magnetic Resonance Spectroscopy.

Current research is focused on testing the cultivation of Paecilomyces hepiali mycelia on various plant substrates and producing fungus or mycelial biomass with qualitatively interesting substances. P. hepiali mycelia was cultivated using solid-state fermentation of different substrates. Mycelial biomass was then analyzed, and antioxidant activity was evaluated using the DPPH radical scavenging method for different ethanolic extracts based on a millet substrate (extract 1) or a chickpea substrate (extract 2). Extract 1 corresponds to a half-maximal DPPH radical inhibitory concentration of 1.73 mg/mL; the inhibitory concentration of ethanol extract 2 was almost 4.5 times higher at 7.92 mg/mL. Extracts 1 and 2 were separated into fractions by column chromatography and the chemical structures were determined for the substances that formed the most effective fraction of sample 1. The chemical structures of all compounds in the most active fraction of sample 1 were analyzed by 1H, 13C, distortionless enhancement by polarization transfer, correlation spectroscopy, heteronuclear single-quantum correlation spectroscopy, and heteronuclear multiple-bond correlation spectra.

Kajian Kimia Dari Fraksi Etil Asetat Kulit Batang Kayu Pahit (Picrasma Javanica Bl.)

Senyawa utama N-1 dari fraksi etil asetat kulit batang kayu pahit (Picrasma Javanica Bl) telah diisolasi dan dikarakterisasi dengan kromatografi kolom dan dilanjutkan dengan kromatografi preparatif. elusidasi struktur dan analisis data spektrum yang digunakan ultraviolet (UV) spektroskopi, infra merah (IR), 1H RMI (Resonansi Magnet Inti), 13C RMI, Massa, COSY (Correlated Spectroscopy), HSQC (Heteronuclear Single Quantum Correlation), HMBC (Heteronuclear Multiple Bond Correlation) dan studi literatur menunjukkan bahwa senyawa yang isolasi adalah Javanicin A.

Estimation of σ-Donation and π-Backdonation of Cyclic Alkyl(amino) Carbene-Containing Compounds

Herein, we present a general method for a reliable estimation of the extent of π-backdonation (CcAAC←E) of the bonded element (E) to the carbene carbon atom and CcAAC→E σ-donation. The CcAAC←E π-backdonation has a significant effect on the electronic environments of the (15)N nucleus. The estimation of the π-backdonation has been achieved by recording the chemical shift values of the (15)N nuclei via two-dimensional heteronuclear multiple-bond correlation spectroscopy. The chemical shift values of the (15)N nuclei of several cAAC-containing compounds and/or complexes were recorded. The (15)N nuclear magnetic resonance chemical shift values are in the range from -130 to -315 ppm. When the cAAC forms a coordinate σ-bond (CcAAC→E), the chemical shift values of the (15)N nuclei are around -160 ppm. In case the cAAC is bound to a cationic species, the numerical chemical shift value of the (15)N nucleus is downfield-shifted (-130 to -148 ppm). The numerical values of the (15)N nuclei fall in the range from -170 to -200 ppm when σ-donation (CcAAC→E) of cAAC is stronger than CcAAC←E π-backacceptance. The π-backacceptance of cAAC is stronger than σ-donation, when the chemical shift values of the (15)N nuclei are observed below -220 ppm. Electron density and charge transfer between CcAAC and E are quantified using natural bonding orbital analysis and charge decomposition analysis techniques. The experimental results have been correlated with the theoretical calculations. They are in good agreement.