Two New Cerebrosides from the Aerial Parts of Tithonia diversifolia

Two new cerebrosides, (2R)‐N‐{(1S,2S,3R,8E)‐1‐[(β‐D ‐glucopyranosyloxy)methyl]‐2,3‐dihydroxyheptadec‐8‐en‐1‐yl}‐2‐hydroxyhexadecanamide ( 1 ) and (2R)‐N‐{(1S,2R,8E)‐1‐[(β‐D ‐glucopyranosyloxy)methyl]‐2‐hydroxyheptadec‐8‐en‐1‐yl}‐2‐hydroxyhexadecanamide ( 2 ), were isolated from the aerial parts of Tithonia diversifolia (Hemsl .) A. Gray. Their structures were determined on the basis of spectroscopic analysis (IR, HR‐ESI‐MS, and 1D‐, and 2D‐NMR).     

FT-IR measurement of tagitinin C after solvent extraction from Tithonia diversifolia

Tagitinin C, an antiplasmodial compound, identified as one major compound of the subtropical medicinal plant, Tithonia diversifolia, was determined by FT-IR spectroscopy method. The crude ether extracts from aerial parts of the plant were evaporated to dryness and re-dissolved in tetrachloroethylene (C₂Cl₄) before analysis.The magnitude of the absorbance of the very specific CO stretching vibration (ν_CO) at 1664.8 cm⁻¹ was exploited in order to quantify tagitinin C. The determination coefficient (r²) of the calibration scale was 0.9994, the detection limit was lower than 3 μg ml⁻¹ and the quantification limit was lower than 10 μg ml⁻¹.Recovery values from 100.5 to 101.7% were found for spiked concentration levels from 19.91 to 89.95 μg ml⁻¹. The main characteristics of the curves obtained from the calibration standards and from the standard addition technique were not statistically different (Student t-test) suggesting that matrix effects were negligible.The results obtained for the determination of tagitinin C in the crude ether extract from aerial parts of T. diversifolia by LC and FT-IR spectroscopic method agreed well: 0.76±0.02 and 0.773±0.009, of tagitinin C in dried plant respectively.     

Sesquiterpenoids and flavonoids from the aerial parts of Tithonia diversifolia and their cytotoxic activity

Cytotoxicity-guided fractionation of the 80% EtOH extract of Tithonia diversifolia has resulted in the isolation of twelve sesquiterpenoids (1-12), including three new ones (4, 10, 12), and three known flavonoids (13-15). The structures of the new compounds were determined by analysis of their spectroscopic data. The isolated compounds showed cytotoxic activity against HL-60 leukemia cells with IC(50) values ranging from 0.13 to 13.0 microM, when etoposide used as a positive control gave an IC(50) value of 0.43 microM. The cancer growth inhibitory property of 9, the main cytotoxic compound in T. diversifolia, was examined using a disease-oriented panel composed of 39 human cancer cell lines in the Japanese Foundation for Cancer Research.     

A new isocoumarin from Hypericum annulatum

A new isocoumarin, annulatomarin (1), together with the known physcion and beta-sitosterol were isolated from the aerial parts of Hypericum annulatum. The structure of the new compound was established as 6,8-dihydroxy-7-methoxy-3-phenyl-3,4-dihydro-1H-isochromen-1-one on the basis of detailed spectroscopic analysis. Annulatomarin exhibited a modest growth-inhibitory activity in vitro against human chronic myeloid leukaemia LAMA-84 cells with an IC(50) = 111 microM.     

Urceolatin, a structurally unique bromophenol from Polysiphonia urceolata

6-Bromo-1-(3-bromo-4,5-dihydroxybenzyl)phenanthro[4,5-bcd]furan-2,3,5-triol (urceolatin, 1), a highly oxygenated bromophenol containing an unprecedented naturally occurring benzylphenanthro[4,5-bcd]furan unit, was isolated from the marine red alga Polysiphonia urceolata. Its structure was established on the basis of extensive spectroscopic analysis. Compound 1 displayed significant DPPH radical-scavenging activity with an IC50 value of 7.9 microM, which is 10-fold more potent than that of the positive control, butylated hydroxytoluene.     

Bioassay-guided isolation of an anti-ulcer compound, tagitinin C, from Tithonia diversifolia: role of nitric oxide, prostaglandins and sulfhydryls

Tithonia diversifolia is a medicinal plant from the Municipality of Suchiapa, Chiapas, Mexico, that according to local folk medicine is considered useful in the treatment of gastric ulcers. The aim of the present study was to investigate the gastroprotective activity of T. diversifolia by using an ethanol-induced gastric ulcer experimental model in male Wistar rats. The results showed that T. diversifolia had gastroprotective activity, and that the dichloromethane extract had the highest protective activity (close to 90% when using doses between 10 to 100 mg/kg), and that further the compound tagitinin C isolated from this extract was the main active gastroprotective agent. Rats treated with tagitinin C suspended in Tween 80 at 1, 3, 10 and 30 mg/kg showed 37.7, 70.1, 100, and 100% gastroprotection, respectively. The effect elicited by tagitinin C (30 mg/kg) was not attenuated by pretreatment with either N(G)-nitro-L-arginine methyl ester (70 mg/kg, i.p.), a nitric oxide (NO) synthase inhibitor, N-ethylmaleimide (10 mg/kg, s.c.), a blocker of sulfhydryl groups, or indomethacin (10 mg/kg, s.c.), a blocker of prostaglandin synthesis, which suggests that the gastroprotective mechanism of action of this sesquiterpene lactone does not involve NO, sulfhydryl groups or prostaglandins.     

Absolute configuration assignment of caffeic acid ester derivatives from Tithonia diversifolia by vibrational circular dichroism: the pitfalls of deuteration

Recently, it was observed that infrared (IR) and vibrational circular dichroism (VCD) calculations including deuterated hydroxyl groups in phenolic and saccharide moieties improved significantly the agreement with experimental data obtained in methanol-d₄. In the present study, the relative and absolute configurations of three methanol-soluble caffeic acid ester derivatives 1–3, isolated from Tithonia diversifolia, were established by a combined use of experimental and calculated ¹³C NMR chemical shifts, as well as electronic circular dichroism (ECD) and VCD spectroscopies. Interestingly, the attempt to reproduce the deuteration pattern arising from possible isotopic exchange in methanol-d₄ solution led to nearly mirror image calculated VCD spectra for 1 when compared to the non-deuterated molecule with the same absolute configuration. This latter fact can potentially lead to absolute configuration misassignments. A closer inspection of the vibrational chiroptical properties of 1 revealed that the deuteration status of the tertiary hydroxyl group at C-2 is critical for the correct reproduction of experimental VCD data in protic solvents. Therefore, in the case of stereochemical analysis of polar chiral natural product molecules, a combination of VCD and ECD is recommended.     

Newbouldiaquinone and newbouldiamide: a new naphthoquinone-anthraquinone coupled pigment and a new ceramide from Newbouldia laevis

Newbouldiaquinone (1), a new naphthoquinone-anthraquinone coupled pigment and a new ceramide named newbouldiamide (2), have been isolated from Newbouldia laevis, besides the known compounds lapachol (3), canthic acid, oleanolic acid, 2-methyl-9,10-anthracenedione, 2-acetylfuro-1,4-naphthoquinone, 2,3-dimethoxy-1,4-benzoquinone, 2-(4-hydroxyphenyl)ethyl triacontanoate, beta-sitosterol and beta-sitosterol glucopyranoside. The structure elucidations of the isolated new compounds were performed on the basis of spectroscopic and chemical evidence. Preliminary studies showed that 1 is moderately antibacterial against Gram-positive Bacillus megaterium and that 3 has moderate herbicidal and antibacterial activities.     

Drypetdimer A: a new flavone dimer from Drypetes gerrardii

A new flavone dimer, drypetdimer A (1), was isolated from Drypetes gerrardii J.Hutch The structure of the new compound was elucidated by detailed spectroscopic analysis such as 1H, 13C NMR, COSY, HMQC, HMBC and HREIMS.     

A new isocoumarin from the aerial parts of Aconitum gymnandrum

A new isocoumarin, along with 10 known compounds, was isolated from the aerial parts of Aconitum gymnandrum. Their structures were elucidated by spectroscopic methods including extensive 1D and 2D NMR techniques. Among the known compounds, compound 11 was obtained as a natural product for the first time, which was previously reported as a synthetic product. In addition, compounds 1–5, 7 and 9 were tested for their cytotoxicity against four human cancer cell lines. The results showed that compounds 3, 4 and 7 displayed cytotoxicity against lung cancer A549 and gastric cancer MGC80, respectively, whereas 5 and 9 showed selective cytotoxicity against hepatocellular carcinoma HepG2.     

Saccharonol B,a new cytotoxic methylated isocoumarin from Saccharomonospora azurea

From an antimicrobial gram-positive actinomycete strain of Saccharomonospora azurea (MTCC11714) isolated from high altitude soil of Kargil (J&K, India), a new isocoumarin saccharonol B (2) along with two known compounds viz. saccharonol A (1) and piericidin A₃ (3) was isolated and characterized. The structure of the new compound was established based on extensive 2D-NMR data. Saccharonol B (2) exhibited mild antimicrobial activity against a standard panel of microorganisms Staphylococcus aureus ATCC 29213, Candida albicans ATCC 90028, and Aspergillus fumigatus MTCC 1811 with MIC values in the range of 128–248 μg/mL. Saccharonol B (2) and piericidin A₃ (3) showed selective cytotoxic activity against human pancreatic carcinoma cell line (MIAPaCa-2) with IC₅₀ values of 9 and 8 μM, respectively. Mechanistic studies indicated that saccharonol B (2) arrests S-phase of the cell cycle and causes dose-dependent loss of mitochondrial potential in MIAPaCa-2 cells.     

A new natural ceramide from Trollius chinensis Bunge

A new natural product named trolliamide was isolated from Trollius chinensis Bunge. Its structure was determined as 2-hydroxy-tetracosanoic acid(2,3-dihydroxy-1-hydroxymethyl-heptadec-7-enyl)-amide by spectroscopic methods, including UV, IR, MS and NMR. This is the first report of a ceramide isolated from Trollius chinensis.     

Pestalotiopisorin B,a new isocoumarin derivative from the mangrove endophytic fungus Pestalotiopsis sp. HHL101

Abstract

A new isocoumarin derivative pestalotiopisorin B (1), along with six known compounds, (R)-(-)- mellein methyl ether (2), pestalotiopyrone G (3), (R)-mevalonolactone (4), pestalotiollides A–B (5–6) and pestalotiopsol A(7) were isolated from Pestalotiopsis sp., an endophytic fungus obtained from Chinese mangrove plant Rhizophora stylosa. Their structures were elucidated unambiguously by the comprehensive analysis of extensive spectroscopic data. Compound 1 exhibited modest antibacterial activity against Escherichia coli and Pseudomonas aeruginosa with 12.5?μg/ml, 50?μg/ml, respectively. Compound 4 showed moderate calcineurin inhibitory activity towards p-nitrophenyl phosphate (IC₅₀ =134.29?±?5.377?μM).     

Forsskamide,a new ceramide from aerial parts of Forsskaolea tenacissima Linn.

Although the various folk medicine uses and the biological activity of Forsskaolea tenacissima L., few chemical constituents of this plant have been reported, this provoked us to make our study. Forsskamide, a new ceramide was isolated from aerial parts of F. tenacissima L. (Urticaceae). The chemical structure was established by different spectroscopic methods (¹H, ¹³C-NMR, HMBC, HSQC, ROESY, FAB-MS and HR-FAB-MS). Forsskamide showed a moderate cytotoxic activity by (MTT) method against human colorectal carcinoma cell line (HCT-116) with IC₅₀ 33.25 μM in comparison with 5-fluorouracil IC₅₀ 26.42 μM. While, it did not show any activity against human hepatocarcinaoma cell line (HepG-2).     

Nitrous oxide dimer: observation of a new polar isomer

Spectra of the nitrous oxide dimer (N2O)2 are studied in the region of the N2O nu1 fundamental band around 2230 cm-1 using a rapid-scan tunable diode laser spectrometer to probe a pulsed supersonic jet expansion. The previously known band of the centrosymmetric nonpolar dimer is analyzed in improved detail, and a new band is observed and assigned to a polar isomer of (N2O)2. This polar form of the dimer has a slipped parallel structure, rather similar to the slipped antiparallel structure of the nonpolar form but with a slightly larger intermolecular distance. The accurate rotational parameters determined here should enable a microwave observation of the polar N2O dimer. The need for a modern ab initio investigation of the N2O-N2O intermolecular potential energy surface is emphasized.     

The chemistry of homophthalic acid: a new synthetic strategy for construction of substituted isocoumarin and indole skeletons

Homophthalic acid was reacted with thionylchloride/DMF and chloroethylformate/NEt₃ in the presence and absence of NaN₃. In all cases completely different isocoumarin derivatives were obtained. These unusual isocoumarin derivatives were isolated and characterized and their formation mechanisms are discussed. The homophthalic acid monomethyl ester was converted into the corresponding isocyanate. Reaction of the isocyanate with different amines produced the urea derivatives. Base-supported condensation reactions of these products gave first an indolinone derivative, which underwent further intermolecular condensation to give substituted indole derivatives. However, when the condensation reaction was carried out in the presence of acetic anhydride, the intermolecular reactions were suppressed. This methodology opens up a new way of synthesizing of various five-membered ring substituted indole derivatives.     

A new ceramide from transgenic crown galls of Panax quinquefolium

A new ceramide(1) was isolated from transgenic crown galls of Panax quinquefolium.The structure was elucidated as(2S,3S, 4R,20E)-2-[(2′R)-2′-hydroxylpalmitoylamino]- 20- hexacosene- 1,3,4-triol on the basis of spectroscopic and chemical methods.     

Spectra of water dimer from a new ab initio potential with flexible monomers

We report the definition and testing of a new ab initio 12-dimensional potential for the water dimer with flexible monomers. Using our recent accurate CCpol-8s rigid water pair potential [W. Cencek, K. Szalewicz, C. Leforestier, R. van Harrevelt, and A. van der Avoird, Phys. Chem. Chem. Phys. 10, 4716 (2008)] as a reference for the undistorted monomers' geometries, a distortion correction has been added, which was taken from a former flexible-monomer ab initio potential. This correction allows us to retrieve the correct binding energy D(e)=21.0 kJ mol(-1), and leads to an equilibrium geometry in close agreement with the one obtained from benchmark calculations. The kinetic energy operator describing the flexible-monomer water dimer has been expressed in terms of Radau coordinates for each monomer and a recent general cluster polyspherical formulation describing their relative motions. Within this formulation, an adiabatic scheme has been invoked in order to decouple fast (intramolecular) modes and slow (intermolecular) ones. Different levels of approximation were tested, which differ in the way in which the residual potential coupling between the intramolecular modes located on different monomers and the dependence of the monomer rotational constants on the dimer geometry are handled. Accurate calculations of the vibration-rotation-tunneling levels of (H(2)O)(2) and (D(2)O)(2) were performed, which show the best agreement with experiments achieved so far for any water potential. Intramolecular excitations of the two monomers were calculated within two limiting cases, to account for the lack of non-adiabatic coupling between intramolecular modes due to the intermolecular motion. In the first model, the excitation was assumed to stay either on the donor or the acceptor molecule, and to hop between the two moieties upon donor-acceptor interchange. In the second model, the excitation remains on the same molecule whatever is the dimer geometry. Marginal frequency differences, less than 2?cm(-1), were obtained for all modes, and the resulting infrared shifts are in good agreement with experiments.     

Fischelactone: a novel eremophilane dimer from Ligularia fischeri

<正>A novel eremophilane dimer,named fischelactone(1),was isolated from the roots of Ligularia fischeri.Complete structural elucidation of this compound was performed by HRESIMS,IR,1D NMR and 2D NMR(~1H-~1H COSY,HMBC,HMQC and NOESY) data.