FAB-MS Experiments Research Articles

Pakistamide C, a new sphingolipid from Abutilon pakistanicum

The Abutilon genus from the Malvaceae family is of medicinal importance, and members of this genus are distributed in the tropical and subtropical regions of Asia and other parts of the world. Abutilon pakistanicum Jafri & Ali is mainly found in Pakistan. It has been used by different systems of traditional medicines to treat different diseases. Pakistamide C, a new sphingolipid, has been isolated from the ethyl acetate soluble fraction of the methanolic extract of A. pakistanicum. Different spectroscopic techniques such as NMR (1H, 13C, COSY, NOESY, HSQC, HMBC) and Mass spectrometry (EI-MS, and FAB-MS experiments) were used to elucidate the structure of pakistamide C.

Spiraeamide, new sphingolipid from Spiraea brahuica

Spiraeamide (1), a new sphingolipid, has been isolated from the ethyl acetate-soluble fraction of the methanolic extract of the whole plant of Spiraea brahuica, along with marrubiin (2), 19-acetylmarrubenol (3), and 6-acetylmarruenol (4). Their structures were elucidated by 1H and 13C NMR spectra, and COSY, NOESY, HMQC, HMBC, EI-MS, and FAB-MS experiments.

New Sphingolipids from Abutilon pakistanicum

Pakistamides A and B (1and 2, respectively), two new sphingolipids, have been isolated from the AcOEt-soluble sub-fraction of the MeOH extract of the whole plant of Abutilon pakistanicum. Their structures were assigned by 1H and 13C NMR spectra, and by DEPT and COSY, NOESY, HMQC, HMBC, EI-MS, and FAB-MS experiments.

New Secondary Metabolites from Croton sparsiflorus

Sparsifol (1), a new stereoisomer of inositol, and proaporphine alkaloid crotsparsidine (2), have been isolated from the EtOH extract of Croton sparsiflorus. Their structures were determined on the basis of 1H and 13C NMR spectra, DEPT, COSY, NOESY, HMBC, HMQC, EI-MS, and FAB-MS experiments

Five new pregnane glycosides from the stems of Marsdenia tenacissima

Activity-guided fractionation of the stems of Marsdenia tenacissima led to the isolation of five new pregnane glycosides, namely marstenacissides E (1), F (2), G (3), H (4), and I (5). Their structures were determined on the basis of 1H and 13C NMR, COSY, TOCSY, ROESY, and FABMS experiments.

Acylated pregnane glycosides from Caralluma tuberculata and their antiparasitic activity

Five pregnane glycosides were isolated from Caralluma tuberculata (1–5), in addition to a known one (russelioside E, 6). The structures of the isolated compounds were elucidated by the analysis of NMR data and FAB–MS experiments. All the isolated compounds were tested for their antimalarial and antitrypanosomal activities as well as their cytotoxicity against human diploid embryonic cell line (MRC5).

A New Acylated Triterpene from the Roots of Chaenomeles japonica.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Covilanone: a new rearranged labdane type diterpene

A bicyclic diterpene triol with a new rearranged labdane carbon skeleton was isolated from the aerial parts of Halimium viscosum (Willk.) Pinto da Silva (S. João da Pesqueira). Its structure was established by FAB MS and two-dimensional NMR experiments ( 1H/ 1H, 1H/ 13C) and its stereochemistry by NOE and X-ray study.

A new acylated triterpene from the roots of Chaenomeles japonica.

A new acylated triterpene together with prunasin, (-)-epicatechin, daucosterol, and three triterpenes, ursolic, oleanolic, and pomolic acids was isolated from the root of Chaenomeles japonica (THUNB.) LINDL. (Rosaceae) and determined to be 3-O-(E)-3, 5-dihydroxycinnamoylursolic acid on the basis of NMR and FAB-MS experiments.

Biomolecule structure characterization in the gas phase using mass spectrometry

Carbohydrate/cation interactions were examined in the gas phase using mass spectrometry and the results were compared with computer generated models of the complexes. Monosaccharide/alkali cation complexes of five carbohydrates, D‐fructose, D‐glucose, D‐galactose, D‐mannose, and a deuterated analog of D‐glucose, 6,6‐D‐glucose‐d2, were studied. Among the technuques used in this effort were electrospray ionization (ESI), desorption/ionization on silicon (DIOS), matrix‐assisted laser desorption/ionization (MALDI) and fast atom/ion bombardment (FAB) mass spectrometry. A series of ESI, DIOS, MALDI and FAB‐MS experiments were used to obtain relative cation binding preferences of each monosaccharide. Heterodimers of 6,6‐D‐glucose‐d2 formed with each of the monosaccharides show that Na+ binding for D‐fructose, D‐mannose and D‐galactose is similar, while D‐glucose was 25% weaker. Modeling studies and energy minimization calculations on the alpha and beta forms of the monosaccharide alkali cation complexes are consistent with the experimental data and indicate that D‐fructose, D‐galactose, and D‐mannose undergo tridentate and tetradentate binding with Na+ and Li+ while D‐glucose would only form a bidentate complex.

Iridoids from Dunnia sinensis

A plumieride type iridoid glucoside, dunnisinoside, and a non-glucosidic iridoid, dunnisinin, were isolated from the leaves of Dunnia sinensis. Their structures were established by 1D and 2D NMR and FABMS experiments.

1-epi-Deacetylaconitine, a New Norditerpenoid Alkaloid from Aconitum nemorum

1-epi-Deacetylaconitine, a New Norditerpenoid Alkaloid from Aconitum nemorum

Loasafolioside, a minor iridoid dimer from the leaves of Loasa acerifolia1The investigation here presented is part of a joint venture between the Institute of Systematic Botany and the Institute of Pharmaceutical Biology, Munich, for the investigation of the biology and systematics of Loasaceae and a screening program for antiinflammatory plant drugs from ethnopharmacology.1

Abstract In continuation of our phytochemical studies on Loasa acerifolia Dombey, Loasaceae, a further novel dimeric iridoid glucoside named loasafolioside, 1 , was isolated from the leaves. The structure of 1 is similar to the recently isolated iridoid dimer, asaolaside, but owns an hemiacetalic group at position 3 of unit b. Compound 1 exists as an isomeric mixture like the iridoid dimer, laciniatoside I, which has an identical unit b. The structure of 1 was established by 1D and 2D NMR (H H COSY, HMQC, HMBC) and FABMS experiments.

IC202B and C, new siderophores with immunosuppressive activity produced by Streptoalloteichus sp. 1454-19.

IC202B (1) and C (2) were isolated from the culture filtrate of Streptoalloteichus sp. 1454-19. The structures were elucidated by various NMR spectral analyses including 1H-15N HMBC and FAB-MS experiments. IC202B and C showed immunosuppressive activity on a mixed lymphocyte culture reaction at the same IC50 value of 1.6 microg/ml.

IC202A, a new siderophore with immunosuppressive activity produced by Streptoalloteichus sp. 1454-19. II. Physico-chemical properties and structure elucidation.

IC202A (1) was isolated from the culture filtrate of Streptoalloteichus sp. 1454-19. The structure of 1 was determined by spectral analysis including a variety of two-dimentional NMR and FAB-MS experiments. IC202A is a ferrioxamine-related compound containing a butylidene N-oxide function.

A dimeric iridoid from loasa acerifolia

Reinvestigation of leaf material from Loasa acerifolia Dombey led to the isolation of secoxyloganin and an additional novel dimeric iridoid glucoside named asaolaside. The latter consists of a secoxyloganin moiety esterified to the 7-hydroxy group of sylvestroside IV. The structure of asaolaside was established by 1D and 2D NMR ( 1H 1H COSY, HMQC, HMBC) and FABMS experiments.

A triterpenoid saponin from Patrinia scabiosaefolia.

A new triterpenoid saponin, patrinia saponin H3 (3), was isolated from the aerial parts of Patrinia scabiosaefolia Fisch. and determined to be 3-O-beta-D-glucopyranosyl(1-->3)-alpha-L-rhamnopyranosyl (1-->2)-alpha-L-arabinopyranosyl hederagenin 28-O-alpha-L-rhamnopyranosyl (1-->4)-beta-D-glucopyranosyl(1-->6)-beta-D-glucopyranosyl ester on the basis of NMR and FAB MS experiments and acid hydrolysis.

Boussingoside E, a New Triterpenoid Saponin from the Tubers of Boussingaultia baselloides

A new triterpenoid saponin, boussingoside E (1), 3-O-[β-d-glucuronopyranosyl]-20(29)-ene-30-norhederagenin 28-O-(β-d-glucopyranosyl) ester, along with quinoasaponin-9 (2) were isolated as sodium/choline salts from the methanolic extracts of the tubers of Boussingaultia baselloides H. B. K. (syn.: Anredera baselloides Baill.). Their structures were established on the basis of 1D and 2D NMR (DQFCOSY, HOHAHA, HSQC, HMBC, and ROESY spectra), FABMS experiments, and hydrolysis.

New cytochalasins from the fungus Xylaria hypoxylon

Abstract Six new cytochalasins together with the known compounds cytochalasins Q, 19,20-epoxy Q and R have been isolated from the fermentation broth of the fungus Xylaria hypoxylon. The structures of the new compounds were established by extensive NMR inverse spectrometry and FAB-MS experiments.

Boussingoside E, a New Triterpenoid Saponin from the Tubers of Boussingaultia baselloides

A new triterpenoid saponin, boussingoside E (1), 3-O-[β-d-glucuronopyranosyl]-20(29)-ene-30-norhederagenin 28-O-(β-d-glucopyranosyl) ester, along with quinoasaponin-9 (2) were isolated as sodium/choline salts from the methanolic extracts of the tubers of Boussingaultia baselloides H. B. K. (syn.: Anredera baselloides Baill.). Their structures were established on the basis of 1D and 2D NMR (DQFCOSY, HOHAHA, HSQC, HMBC, and ROESY spectra), FABMS experiments, and hydrolysis.