DEPT Experiments Research Articles

Larvicidal activity of the black pepper, Piper nigrum (Fam: Piperaceae) extracts on the cattle tick, Rhipicephalus australis (Acari: Ixodidae)

BackgroundThe cattle farming parasite Rhipicephalus australis is the main tick and one of the most important in the world from an economic point of view. Various studies have been developed in order to find plant extracts with effective acaricidal properties and environmentally friendly. Studies involving plant extracts for parasite control on commercial animal herds is a developing area in New Caledonia. Bioactive natural products play an important role as lead compounds in the development of new pesticides.ResultsThe ethanolic extract of Piper nigrum L. dried fruits as well as the ethyl acetate extract and the methanolic extract of stems exhibited 100% larvicidal activity (50 mg/mL) against Rh. australis larvae, the cattle tick, an hematophagous parasite. Bioguided fractionation of the ethanolic extract of dried mature fruits using the same assay led to the isolation of five compounds belonging to piperamide family. The structures of isolated compounds were elucidated using spectroscopic methods: ESI-HRMS, 1H- and 13C-NMR spectral data, including DEPT and 2D-NMR experiments (COSY, HSQC, HMBC, and NOESY). These include 1 compound described for the first time in P. nigrum, homopellitorine (2) and 4 known compounds, namely pellitorine (1), pipyaqubine (3), 2-methylpropylamide (4), and N-isobutyl-2,4-eicosadienamide (5).ConclusionThis first report on the larvicidal activity of P. nigrum extract and pure compounds on this tick species suggests that P. nigrum could be a natural biosourced alternative for the control of the larval stage of Rh. australis.Graphical

Monoterpene-stilbenes and other constituents from Machaerium isadelphum

• Machaerium isadelphum is characterized for its aromatic and triterpene compounds. • Leaves, branches, and stems share chemical compounds, the roots content is different. • The roots include monoterpene-estilbenes and chalcones. • In this study, 26 chemical compounds were identified for this species. • Three compounds were characterized for the first time. Twenty-six secondary metabolites were isolated from the roots and stems of Machaerium isadelphum (Fabaceae). The monoterpene-stilbene machaeriol E [(6a S ,9 S ,10a S )-3-( E )-4-hydroxystyryl)-6,6,9-trimethyl-6a,7,8,9,10,10a-hexahydro-6 H -benzo[c]chromen-1-ol, 1 ], and the geranyl-chalcones isadelphone A [( E )-1-(5-(3,7-dimethylocta-2,6-dien-1-yl)-2,4-dihydroxyphenyl)-3-hydroxy-3-phenylpropan-1-one, 2 ], and isadelphone B [( E )-1-(2,4-dihydroxyphenyl)-3-(4-(( Z )-3,7-dimethylocta-2,6-dien-1-yl)phenyl)prop-2-en-1-one, 3 ] are isolated for the first time and their complete 1 H and 13 C NMR data analysis, assessed by means of the COSY, DEPT, HSQC and HMBC experiments, is reported within. Also, this is the first report of the NMR data for (+)- trans -4,7,2′-trihydroxy-4′-methoxyisoflavanol ( 4 ).

Isolation, characterization and semi-synthesis of natural products dimeric amide alkaloids

Isolation, characterization and semi-synthesis of natural products dimeric amide alkaloids

Study and optimization of Diels-Alder reaction of piperine in aqueous ionic solutions using Gn.HCl as a catalyst

Study and optimization of Diels-Alder reaction of piperine in aqueous ionic solutions using Gn.HCl as a catalyst

Identification and structural characterization of potential degraded impurities of ribociclib by time of flight -tandem mass spectrometry, and their toxicity prediction

The US FDA and EMA approved Ribociclib (RIBO) to treat metastatic breast cancers in 2017. Formation of impurities during storage of any drug can significantly contribute to its overall toxicity and therapeutic efficacy, which ultimately leads to a safety concern. Over the period, it has been observed that impurities sometimes cause serious unwanted toxicity, which can even lead to withdrawal of a drug from market. Therefore, complete characterization of potential impurities is extremely important to identify molecular hot spots regarding structural changes. To the best of our knowledge, till date, the potential degraded impurities of RIBO are unknown. No study reported in literature on the structural characterization of the degradation impurities of RIBO. In this study, an ICH recommended comprehensive stress study under hydrolytic, oxidative, photolytic and thermolytic conditions was performed on RIBO. The degradation products were characterized by tandem mass spectrometry utilising time of flight mass analyzer majorly after electrospray ionisation. The atmospheric pressure chemical ionisation mode was employed in characterization of the N-oxide degradation products where Meisenheimer rearrangement occurred. A degradation product was synthesized in house and fully characterized with the help of NMR (1H NMR, 13C NMR, DEPT, 2D NMR and D2O exchange experiments). The source of formylation for the generation of degradation products was investigated employing different solvent systems. The degradation pathways were delineated by explaining the putative mechanism of degradation in various conditions. The in silico toxicity of the degradation impurities was evaluated with the help of ProTox-II toxicity prediction platform.

1H and 13C NMR chemical shifts of 2-n-alkylamino-naphthalene-1,4-diones

1H as well as 13C chemical shifts of 32 compounds of C (3) substituted 2-(n-alkylamino)-3R-naphthalene-1,4-dione (where n-alkyl: methyl, to octyl, R = H, Cl, Br, and CH3) are investigated through 1H, 13C, DEPT, gDQCOSY, and gHSQCAD NMR experiments and M06-2X/6-311++G (d,p) density functional theory are discussed. Single crystal X-ray structure of Br-3, as well as 18 different derivatives of naphthalene-1,4-diones, are revealed for its inter and intra-molecular hydrogen bonding interactions.

Coumarins and other constituents from Deverra battandieri

• Deverra battandieri is a Saharan medicinal plant. • Three new furanocoumarins were isolated. • Nine additional known coumarins were obtained. • D. battandieri is an important source of coumarin derivatives. Three undescribed coumarin derivatives, pituranthosin A–C ( 1 - 3 ), along with nineteen known compounds were isolated and identified from the chloroform and ethyl acetate fractions of the hydroalcoholic extract of Deverra battandieri (Apiaceae). The structures of the compounds were established by interpretation of their spectral data using 1D-NMR ( 1 H, 13 C, DEPT experiments), 2D-NMR (COSY, NOESY, HSQC and HMBC), HRESIMS, and by comparison with the literature data.

α- and γ-Apienes, Ferovinal, and Ferocin from Ferula ovina

The esters ferovinal (α-apiene-type) and ferocin (γ-apiene-type) were isolated from Ferula ovina. Their structures were established by analyzing IR, PMR, and 13C NMR spectra; DEPT, HSQC, COSY, NOESY, and HMBC experiments; and X-ray crystal structure analyses (XSAs). The XSAs determined the molecular structures and absolute configurations of ferovinal and ferocin and established that their 11-membered humulane macrocycles adopted the 14,15U78 and 14,15U78 conformations. The C8 p-hydroxybenzoate groups in these apienes occupied β-equatorial positions. The only chiral center in ferovinal and ferocin had the 8S-configuration.

Synthesis and antioxidant activities of phenol derivatives from 1,6-bis(dimethoxyphenyl)hexane-1,6-dione.

Starting from the compound (3,4-dimethoxyphenyl)(2-(3,4-dimethoxyphenyl)cyclopent-1-en-1-yl)methanone (4), two diols and three tetrol derivatives were synthesised. Morover, from the reactions of 1,3-dimethoxybenzene and 1,4-dimethoxybenzene with adipoyl chloride, fifteen new along with nine known compounds were obtained. For the characterizations of compounds, spectroscopic methods such as NMR including DEPT, COSY, HMQC and HMBC experiments and X-ray diffraction were used. The antioxidant activities of novel synthesized seventeen molecules were investigated by analytical methods like ABTS•+ and DPPH• scavenging. Also, reducing power these molecules were investigated by Fe3+, Cu2+, and [Fe3+-(TPTZ)2]3+. Some of the molecules record powerful antioxidant profile when compared to putative standards. The inhibition effects of the phenols compounds against AChE and BChE activities were analysed. Also, these phenols were found as effective inhibitors for AChE, hCA I, hCA II, and BChE with Kis in the range of 122.95±18.41-351.31±69.12nM for hCA I, 62.35±9.03-363.17±180.1nM for hCA II, 134.57±3.99-457.43±220.10nM for AChE, and 27.06±9.12-72.98±9.53nM for BChE, respectively.

A New Steroid Isolated from Leucas cephalotes

A new steroidal triterpenoid was isolated from hexane washed ethanolic extract of flowers of Leucas cephalotes. Its structure was elucidated as (Z)-17-(4,4-dimethylhept-2en-2-yl)-8,10,14-trimethyl- 2,3,4,5,6,7,8,10,12,13,14,15,16,17-tetradecahydro-1H-cyclopent[a]phenanthren-3-ol (1). The structure of the new compound was determined by 1D and 2D NMR and MS and DEPT experiments as well as by comparison of their data with the reported values.

Synthesis of tetrahydroindazol-4(5H)one and 7-thione from reaction of functionalized cyclic enaminones with hydrazine

Functionalized enaminones; 3-N-(aryl)amino-1--oxo-cyclohex-2-ene-2-dithiocarboxylates cyclohex-2-en-1-ones and 3-N-(aryl)amino-2-(N-aryl)thioamido-cyclohex-2-en-1-ones were obtained upon reaction of 3-N(aryl)amino-5,5-dimethyl-1-oxo-cyclohex-2-enes with carbon disulfide in presence of sodium hydroxide in DMSO, followed by methylation with dimethyl sulfate or with phenyl and p-bromophenyl isothiocyanates in toluene or under solvent-free condition, respectively. The cyclization of the dithioesters or the thioamides with hydrazine hydrate was accompanied by a displacement of the 3-N- arylamine moiety by a hydrazine group to give 6-hydrazino-4,4-dimethyl-1,3,4,5-tetrahydroindazole-7-thione or 3-N-(aryl)amino-4,5,6,7-tetrahydro-1H-indazole-4(5H)one respectively. Structure of the indazole derivatives formed was further confirmed from their reaction with acetone or p-nitrobenzaldehyde. The new structures were confirmed using 1HNMR, 13CNMR, 2DNMR, DEPT experiments and mass spectra.

On the use of benzaldehyde to improve the storage stability of one-pot, epoxy ionic liquid formulations

A series of adducts were prepared based on the reaction of 1-ethyl-3-methylimidazolium acetate and benzaldehyde in various stoichiometries (from equimolar reaction to benzaldehyde in 10-fold excess) and the resulting adducts were characterized using nuclear magnetic resonance spectroscopy (1H, 13C, DEPT, and HQSC experiments). Differential scanning calorimetry was used to examine the initiating behaviour of the adducts towards mono- and di-functional epoxy resins and the data were used to determine kinetic parameters for the polymerization. The lower temperature peak, due to carbene formation, is sensitive to adduct concentration; the residual ionic liquid in the adduct mixture contributes towards the initiation of the curing reaction. When a monofunctional epoxy and the 1:1 adduct was subjected to a 2-week period of storage at room temperature and sub-zero temperatures in the freezer, the profiles of the thermograms for the frozen samples do not change considerably over the storage period and the formulation retains a light yellow colour (rather than the viscous, dark red appearance of the formulation stored at room temperature).

Phytotoxic Potential of Zanthoxylum affine and Its Major Compound Linarin as a Possible Natural Herbicide.

Four compounds, the flavone linarin (1), the triterpene lupenone (2), the tocopherol (vitamin E, 3), and the new natural alkaloid 1,2,3,4-tetrahydro-1,1-dimethyl-6,7-isoquinolindiol (affineine, 4), were the major natural products isolated from Zanthoxylum affine (syn. Zanthoxylum fagara, Rutaceae). Compound 1 is highly abundant in this plant and was isolated as a white precipitate obtained from the acetone and methanol extracts. The structure of these four compounds was established by 1D and 2D NMR spectroscopy including 1H, 13C, DEPT, COSY, HSQC, and HMBC experiments. The hexane, acetone, and methanol extracts, as well as 1, were evaluated for their potential phytotoxic effects in pre- and post-emergent assays, as well as to identify their mechanisms of action. As pre-emergent phytotoxic agents, the hexane, acetone, and methanol extracts inhibited germination and residual growth (root and stem elongation) of Lactuca sativa (lettuce) and Lolium perenne (perennial ryegrass). As post-emergent agents, they inhibited dry biomass. Compound 1 acts as a pre-emergent herbicide, by inhibiting germination, seed respiration, residual seedling growth and, notably, root hair development. Furthermore, 1 inhibited the synthesis of ATP and the electron transport chain of isolated spinach chloroplasts; in this way, it behaves as a Hill reaction inhibitor. The site of inhibition was located at the donor site of PSII from the oxygen evolving complex to QA, thus acting as a multisite compound. These results suggest that compound 1 can be used as a lead for a potential green herbicide with different targets.

Flavanonol Glycosides from Leaves of Phellodendron lavallei Introduced in Georgia

The new flavanonol glycoside (2S,3S)-3,5-dihydroxy-2-(4′-hydroxyphenyl)-8-(3-methylbut-2-en-1-yl)-4-oxo-3,4-dihydro-2H-chromen-7-yl-β-D-glucopyranosyl-(3→1)-xylopyranoside (lavaloside) (1) and the known compound phellamurin (2) were isolated from leaves of Phellodendron lavallei. The structures of the flavanone glycosides were elucidated using chemical transformations and UV, PMR, and 13C NMR spectroscopy combined with HSQC, HMBC, COSY, and DEPT experiments and mass spectroscopy.

Limonoids from the roots of Trichilia sinensis and their cytotoxicities.

Six new compounds (1-4, 8, 10), along with six known limonoids (5-7, 9, 11, 12), were isolated from the roots of Trichilia sinensis. Their structures were elucidated on the basis of extensive spectroscopic methods including 1H NMR, 13C NMR, DEPT, HSQC, HMBC, 1H-1H COSY and ROESY experiments, as well as by comparison with the literature. All the compounds were evaluated for cytotoxicities against K562, SGC-7901 and BEL-7402 cell lines. Compounds 2, 7, 10, 11, and 12 showed weak inhibitory activity to the selected cell lines.

Structural characterization of birch lignin isolated from a pressurized hot water extraction and mild alkali pulped biorefinery process

In this work we have characterized a mild soda pulped birch (betula pendula) lignin after a novel pressurized hot water extraction pilot process. In the process hemicelluloses are first isolated from woods chips with hot water at oxygen-starved conditions, followed by mild alkali pulping at oxygen-starved conditions to remove lignin from the cellulose. Lignin was precipitated, washed and fractionated from the black liquor and characterized by quantitative 13C NMR, 13C DEPT experiments, 31P NMR, 2D HSQC, FTIR, size exclusion chromatography (SEC), elemental analysis, pyrolysis-gas chromatography-mass spectrometry (py-GC–MS), methoxyl group quantification and residual carbohydrate analysis after methanolysis. The structure was compared to a MWL of birch obtained from the same wood chips and the differences were an increase in phenolic hydroxyl groups, carboxylic groups, polydispersity index, and reduction of aliphatic hydroxyl groups. The process resulted in β-O-4 cleavage and condensation of the structure. This lignin is therefore suitable to be used in its polymeric form, rather than for degradation of the structure to small building blocks.

Polyethylene glycol-promoted synthesis of pyrimido[1,2-a]benzimidazole and pyrano[2,3-c]pyrazole derivatives in water

ABSTRACTSynthesis of pyrimido[1,2-a]benzimidazole and pyrano[2,3-c]pyrazole derivatives were achieved using polyethylene glycol (PEG-400) as promoting reaction medium in water under catalyst-free conditions at reflux and room temperature, respectively. The structure of pyrimido[1,2-a]benzimidazole was confirmed using 1H NMR, 13C NMR, DEPT, and HMBC experiments. The promising points for the present methodology are efficiency, generality, high yield, short reaction time, cleaner reaction profile, ease of product isolation, simplicity, potential of recycling reaction medium, and finally agreement with green chemistry protocols.

Reaction of Imperialine with Isocyanates

Three new imperialine derivatives, i.e., 3-O-2-nitrophenylcarbamatoimperialine, 3-O-ethylaminocarbonylimperaline, and 3-O-allylaminocarbonylimperialine, were synthesized. The structures of the synthesized compounds were established using PMR and 13C NMR spectroscopy and a DEPT experiment and were confirmed by an X-ray crystal structure analysis (XSA). A comparison of the steric structures of imperialine and its 3-O-2-nitrophenyl and 3-O-ethylaminocarbonyl derivatives showed that H-bonds and crystal packing factors could cause conformational changes of the conditionally middle rings of the polycyclic imperialine framework.

Polyphenolic compounds with anti-tumour potential from Corchorus olitorius (L.) Tiliaceae, a Nigerian leaf vegetable

Chromatographic fractionation of the methanolic extract of Corchorus olitorius (L.) (Tiliaceae), on silica gel yielded two polyphenolic compounds. The structures of the compounds were elucidated as Methyl-1,4,5-tri-O-caffeoyl quinate and trans-3-(4-Hydroxy-3-methoxyphenyl)acrylic anhydride, based on extensive use of spectroscopic techniques such as 1H and 13C NMR, DEPT and 2D NMR experiments (COSY, HSQC, HMBC), IR and MS. To establish an initial proof-of-concept for the biological relevance of these compounds, their cytotoxicity against the cancer cell lines HeLa, HL460 and PC3, which might indicate their anti-tumour potential, was assessed. The compounds when tested at a range of concentrations up to 1.6mM were found to possess mild cytotoxic activity which was significant against HeLa cells at ⩾800μM. The trans-3-(4-Hydroxy-3-methoxyl phenyl)acrylic anhydride was found to be related to curcumin, a compound known to have anti-cancer activity. Docking of each of the two compounds and also of curcumin into some molecular targets implicated in tumourigenesis revealed that the three compounds had binding affinities that were superior to those obtained for the co-crystallized inhibitors of metalloproteinase-9, fibroblast growth factor receptor 2 (FGFR2) and epidermal growth factor receptor (EGFR). The plant Corchorus olitorius therefore represents a potential source of natural ‘lead’ compounds with anti-tumour potential.

A New Cytotoxic Cadinane Sesquiterpene from Berberis koreana

methylene group. The 13 C NMR spectrum along with the DEPT and HMQC experiments revealed the presence of three methyls, five methylenes, five methines, and two quaternary carbon atoms. A detailed comparison of the above spectral data with those reported for (−)-torreyol revealed the structural resemblance of the two compounds, implying the skeleton of a cadinane sesquiterpenoid of 1. 16,17 Major differences were the disappearance of a methyl signal and the downfield-shifted signal of C-12 in the NMR spectra of 1 by compared to those of (−)-torreyol, indicating the presence of a hydroxyl group at C-12 in compound 1. The