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LC–NMR for Natural Product Analysis: A Journey from an Academic Curiosity to a Robust Analytical Tool. SCI 2021. [DOI: 10.3390/sci3010006] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Liquid chromatography (LC)–nuclear magnetic resonance (NMR) combines the advantage of the outstanding separation power of liquid chromatography (LC) and the superior structural elucidating capability of nuclear magnetic resonance (NMR). NMR has proved that it is a standout detector for LC by providing maximum structural information about plant originated extracts, particularly on the isolating ability of isomeric (same molecular formula) and/or isobaric (same molecular weight) compounds as compared to other detectors. The present review provides an overview of the developmental trends and application of LC–NMR in natural product analysis. The different LC–NMR operational modes are described, and how technical improvements assist in establishing this powerful technique as an important analytical tool in the analysis of complex plant-derived compounds is also highlighted. On-flow, stop-flow and loop-storage modes, as well as the new offline mode LC–solid phase extraction (SPE)–NMR and capillary LC (capLC)–NMR configurations which avoid the ingestion of expensive deuterated solvents throughout the experiment, are mentioned. Utilization of cryogenic probe and microprobe technologies, which are the other important promising approaches for guaranteeing sensitivity, are also described. Concluding remarks and future outlooks are also discussed.
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Bhandari P, Sendri N, Devidas SB. Dammarane triterpenoid glycosides in Bacopa monnieri: A review on chemical diversity and bioactivity. PHYTOCHEMISTRY 2020; 172:112276. [PMID: 32058865 DOI: 10.1016/j.phytochem.2020.112276] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 01/11/2020] [Accepted: 01/13/2020] [Indexed: 06/10/2023]
Abstract
Bacopa monnieri (L.) is a reputed medicinal herb in traditional system of medicine of India, where it is used as nervine tonic to sharpen intellect and memory. This review discusses chemical characterization of dammarane triterpenoid glycosides which are well accepted for improvement in memory and for potential pharmacological activities. In addition, this review provides information on the chemical composition of specialized metabolites of B. monnieri and in the formulations by different analytical techniques. This comprehensive review covers literature up to 2019 with an emphasis on structural characterization of dammarane triterpenoid glycosides by spectroscopic techniques, chemical composition by analytical methods and pharmacological activities.
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Affiliation(s)
- Pamita Bhandari
- Natural Product Chemistry & Process Development, CSIR-Institute of Himalayan Bioresource Technology, Palampur, India.
| | - Nitisha Sendri
- Natural Product Chemistry & Process Development, CSIR-Institute of Himalayan Bioresource Technology, Palampur, India
| | - Shinde Bhagatsing Devidas
- Natural Product Chemistry & Process Development, CSIR-Institute of Himalayan Bioresource Technology, Palampur, India
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LC-NMR for Natural Products Analysis: A Journey from an Academic Curiosity to a Robust Analytical Tool. SCI 2019. [DOI: 10.3390/sci1010031] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
LC–NMR combines the advantage of the outstanding separation power of liquid chromatography (LC) and the superior structural elucidating capability of nuclear magnetic resonance (NMR). NMR has proved that it is a standout detector for LC by providing maximum structural information about plant originated extracts particularly in its isolating ability of isomeric (same molecular formula) and/or isobaric (same molecular weight) compounds as compared to other detectors. The present review provides an overview of the LC–NMR developmental trends and its application in natural products analysis. The different LC–NMR operational modes are described, as well as how technical improvements assist in establishing this powerful technique as an important analytical tool in the analysis of complex plant-derived compounds. On-flow, stop-flow and loop-storage modes, as well as the new offline mode LC–SPE–NMR and capLC-NMR configurations that avoid the ingestion of expensive deuterated solvents throughout the experiment are mentioned. Utilization of cryogenic probe and microprobe technologies which are the other important promising approaches for guaranteeing the sensitivity issues are also described. Concluding remarks and future outlooks are also discussed.
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Nuengchamnong N, Sookying S, Ingkaninan K. LC-ESI-QTOF-MS based screening and identification of isomeric jujubogenin and pseudojujubogenin aglycones in Bacopa monnieri extract. J Pharm Biomed Anal 2016; 129:121-134. [PMID: 27423009 DOI: 10.1016/j.jpba.2016.06.052] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 06/19/2016] [Accepted: 06/29/2016] [Indexed: 11/29/2022]
Abstract
Bacopa monnieri (L.) Wettst. (Scrophulariaceae) is an Ayurvedic medicinal plant used as a memory enhancer. Its major chemical constituents are Bacopa saponins consisting of jujubogenin and pseudojujubogenin glycosides. These two aglycones are isomers different at the positions of prenyl substitution i.e., at C-23 for jujubogenin and at C-22 for pseudojujubogenin. In this study, we demonstrate the rapid and comprehensive characterization of saponin glycosides in B. monnieri using liquid chromatography with electrospray ionization quadrupole time-of-flight mass spectrometer (LC-ESI-QTOF-MS). This shows that ESI-QTOF-MS in positive-ion mode, jujubogenin and pseudojujubogenin glycosides could be discriminated by the peak abundance ratio of m/z 455 [Aglycone+H-H2O](+) to m/z of 473 [Aglycone+H](+). Furthermore, the sequence of sugar moieties can be observed. In a similar manner, the isomeric saponins; deoxyjujubogenin and deoxypseudojujubogenin glycosides can be distinguished using the m/z 437[Aglycone+H-H2O](+) and m/z 455[Aglycone+H](+) peak ratio. Use of the negative-ion mode with MS/MS fragmentation can provide information about the type of sugar linked to the aglycone i.e., at m/z 633 (aglycone+glucose) or at m/z 603 (aglycone+arabinose). With our method, 62 chemical constituents in B. monnieri including saponin glycosides, flavonoids, and alkaloids were identified. This is the first systematic study in structural characterization on isomeric saponins and other metabolites in B. monnieri using ESI-QTOF-MS.
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Affiliation(s)
- Nitra Nuengchamnong
- Science Laboratory Centre, Faculty of Science, Naresuan University, Phitsanulok 65000, Thailand.
| | - Sontaya Sookying
- Department of Pharmaceutical Chemistry and Pharmacognosy, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000, Thailand
| | - Kornkanok Ingkaninan
- Department of Pharmaceutical Chemistry and Pharmacognosy, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000, Thailand
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Zehl M, Pittenauer E, Jirovetz L, Bandhari P, Singh B, Kaul VK, Rizzi A, Allmaier G. Multistage and Tandem Mass Spectrometry of Glycosylated Triterpenoid Saponins Isolated fromBacopa monnieri: Comparison of the Information Content Provided by Different Techniques. Anal Chem 2007; 79:8214-21. [DOI: 10.1021/ac070008s] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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6
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Phrompittayarat W, Putalun W, Tanaka H, Jetiyanon K, Wittaya-Areekul S, Ingkaninan K. Determination of pseudojujubogenin glycosides from Brahmi based on immunoassay using a monoclonal antibody against bacopaside I. PHYTOCHEMICAL ANALYSIS : PCA 2007; 18:411-8. [PMID: 17624902 DOI: 10.1002/pca.996] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Bacopa monnieri (L.) Wettst. (Brahmi) is an Ayurvedic medicinal plant used for centuries as a memory enhancer. Dammarane-type triterpenoid saponins classified as pseudojujubogenin and jujubogenin glycosides are reported as the active components in this plant. In this study, the monoclonal antibody (MAb) against bacopaside I, a major pseudojujubogenin glycoside found in Brahmi, was produced and characterised. Bacopaside I was conjugated with bovine albumin serum to prepare an immunogen. Hybridomas secreting a monoclonal antibody against bacopaside I was produced by fusing splenocytes from an immunised mouse and SP2/0-Ag14 myeloma cells. The results showed that the antibodies were raised specifically against pseudojujubonin glycosides. An enzyme-linked immunosorbant assay (ELISA) using anti-bacopaside I MAb was performed in the range of 1.95-62.5 ng/mL of bacopaside I, with a limit of detection of 0.5 ng/mL. The method was validated and the practical use of the ELISA for analysing saponin glycosides from Brahmi was demonstrated.
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Affiliation(s)
- Watoo Phrompittayarat
- Department of Pharmaceutical Chemistry and Pharmacognosy, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000, Thailand
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Phrompittayarat W, Putalun W, Tanaka H, Wittaya-Areekul S, Jetiyanon K, Ingkaninan K. An enzyme-linked immunosorbant assay using polyclonal antibodies against bacopaside I. Anal Chim Acta 2006; 584:1-6. [PMID: 17386577 DOI: 10.1016/j.aca.2006.11.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2006] [Revised: 11/06/2006] [Accepted: 11/07/2006] [Indexed: 11/25/2022]
Abstract
Bacopa monnieri (L.) Wettst. (Brahmi) is a medicinal plant used as a memory enhancer in Ayurvedic medicines. Its active components are triterpenoid glycosides namely pseudojujubogenin and jujubogenin glycosides. In order to analyze these saponin glycosides, an enzyme-linked immunosorbant assay (ELISA) was developed using polyclonal antibodies against bacopaside I, one of the pseudojujubogenin glycosides found in the plant. Bacopaside I was conjugated with a bovine albumin serum (BSA) to prepare an immunogen. The bacopaside I-BSA conjugate was immunized to a rabbit for producing polyclonal antibodies (PAbs). The results showed that the antibodies were raised specifically against pseudojujubogenin glycosides. An ELISA using anti-bacopaside I PAbs was performed in the range of 1.95-62.5 ng mL(-1) of bacopaside I and the limit of detection was 0.1 ng mL(-1). The method was validated and the applicability of the ELISA for analyzing saponin glycosides from Brahmi was demonstrated.
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Affiliation(s)
- Watoo Phrompittayarat
- Department of Pharmaceutical Chemistry and Pharmacognosy, Faculty of Pharmaceutical Sciences, Naresuan University, Phitsanulok 65000, Thailand
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Ng KM, Che CM, Wo SK, Tam PKH, Lau ASY. Analytical application of acetate anion in negative electrospray ionization mass spectrometry for the analysis of triterpenoid saponins--ginsenosides. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2006; 20:1545-50. [PMID: 16628596 DOI: 10.1002/rcm.2465] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Ginsenosides containing different numbers of glycosyl groups can be easily differentiated based on the formation of characteristic ginsenoside-acetate adduct anions and deprotonated ginsenosides generated by electrospray ionization (ESI) of methanolic solutions of ginsenosides (M) and ammonium acetate (NH4OAc). Ginsenosides containing two glycosyl groups gave a characteristic mass spectral pattern consisting of [M+2OAc]2-, [M-H+OAc]2- and [M-2H]2- ions with m/z values differing by 30 Th, while this mass spectral pattern was not observed for ginsenosides containing one glycosyl group. Formation of [M+2OAc]2- was influenced by the chain length of glycosyl groups and was used to differentiate the ginsenosides containing different combinations of monosaccharide and disaccharide units in the glycosyl groups. Under identical collisional activation conditions, [M+OAc]-, [M-H+OAc]2- and [M+2OAc]2- underwent proton abstractions predominantly to generate [M-H]-, [M-2H]2- and [M-H+OAc]2- ions, respectively. The ion intensity ratios, I[M-H](-/I) [M+OAc]-, I[M-2H](2-/I) [M-H+2OAc]2- and I[M-H+OAc](2-/I) [M+OAc]2-, being sensitive to the structural differences of ginsenosides, could differentiate the isomeric ginsenosides, including (i) Rf, F11 and Rg1, (ii) Rd and Re, and (iii) Rb2 and Rc. Additionally, NH4OAc was found to enhance the sensitivity of detection of ginsenosides in the form of [M-H]- down to the femtomole level.
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Affiliation(s)
- Kwan-Ming Ng
- Department of Chemistry and Open Laboratory of Chemical Biology of the Institute of Molecular Technology for Drug Discovery and Synthesis, The University of Hong Kong, Hong Kong.
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Murthy PBS, Raju VR, Ramakrisana T, Chakravarthy MS, Kumar KV, Kannababu S, Subbaraju GV. Estimation of Twelve Bacopa Saponins in Bacopa monnieri Extracts and Formulations by High-Performance Liquid Chromatography. Chem Pharm Bull (Tokyo) 2006; 54:907-11. [PMID: 16755069 DOI: 10.1248/cpb.54.907] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A simple and sensitive reversed phase high performance liquid chromatographic (HPLC) method has been developed for the simultaneous determination of twelve bacopa saponins present in the extracts of the Indian Medicinal Plant, Bacopa monnieri. The separation was achieved on a reversed phase C(18) column (Luna C(18)), 5 microm by isocratic elution with 0.05 M sodium sulphate buffer (pH 2.3) and acetonitrile (68.5 : 31.5, v/v) as the mobile phase at a flow rate of 1.0 ml/min with an operating temperature of 30 degrees C. The method was validated for linearity, precision, intra- and inter-day precision and accuracy. Several Bacopa samples (plant materials, extracts and commercial formulations) were successfully analyzed. Major bacopasaponins were bacosides A(3) (3), bacopaside II (4), bacopaside I (5), bacopaside X (6), bacopasaponin C (7), bacopaside N2 (9) and the minor components were bacopasaponin F (1), bacopasaponin E (2), bacopaside N1 (8) bacopaside III (10), bacopaside IV (11) and bacopaside V (12). The total saponin content in the samples, plant materials and extracts varied from 5.1 to 22.17% and 1.47 to 66.03 mg/capsule or tablet in the commercial formulations.
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Pham LH, Vater J, Rotard W, Mügge C. Identification of secondary metabolites from Streptomyces violaceoruber TU22 by means of on-flow LC-NMR and LC-DAD-MS. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2005; 43:710-23. [PMID: 16049955 DOI: 10.1002/mrc.1633] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
For rapid screening of natural products from Actinomycetes, a combination of on-line couplings LC-NMR, LC-DAD-MS and HPLC-PDA, as well as MALDI-TOF-MS is particularly suitable. Simultaneous use of these coupling techniques provides considerable advantages for the rapid identification of natural compounds in mixtures. The results of our present investigation on secondary metabolite products of Streptomyces violaceoruber TU 22 showed that more than 50% of the identified metabolites are new compounds. The structures of four new polyketides (granaticin C, metenaticin A, B and C) as well as four known ones (granaticin A, granatomycin E, daidzein and genistein) have been elucidated using LC-NMR, LC-MS/MS and -MS(n) techniques in combination with two-dimensional NMR spectroscopy.
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Affiliation(s)
- L H Pham
- Inst. f. Chemie, AG Biochemie u. Molekulare Biologie, Technische Universität Berlin, Germany
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11
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Deepak M, Sangli GK, Arun PC, Amit A. Quantitative determination of the major saponin mixture bacoside A in Bacopa monnieri by HPLC. PHYTOCHEMICAL ANALYSIS : PCA 2005; 16:24-29. [PMID: 15688952 DOI: 10.1002/pca.805] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Bacoside A, the putative bioactive component of the Indian medicinal plant Bacopa monnieri, was found to be a mixture of saponins with bacoside A3 (1), bacopaside II (2), jujubogenin isomer of bacopasaponin C (3) and bacopasaponin C (4) as major constituents. An HPLC method together with an optimised extraction procedure was developed for the estimation of 1-4 in B. monnieri to enable standardisation of the latter. Concentration ranges of the analytes in samples of B. monnieri collected from different regions of India were 0.14-0.85% (w/w) (1), 0.12-0.69% (2), 0.05-0.72% (3) and 0.05-0.44% (4). The importance of using bacoside A, with known concentrations of 1-4, as a reference standard for the routine analysis of B. monnieri is highlighted. Two common flavonoids, luteolin and apigenin, were present in all samples of B. monnieri.
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Affiliation(s)
- M Deepak
- Department of Phytochemistry, Research and Development Centre, Natural Remedies Pvt Ltd, Veerasandra Industrial Area, Bangalore-560 100, India.
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Ganzera M, Gampenrieder J, Pawar RS, Khan IA, Stuppner H. Separation of the major triterpenoid saponins in Bacopa monnieri by high-performance liquid chromatography. Anal Chim Acta 2004. [DOI: 10.1016/j.aca.2004.04.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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13
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Advantages and disadvantages of nuclear magnetic resonance spectroscopy as a hyphenated technique. Anal Chim Acta 2003. [DOI: 10.1016/j.aca.2003.08.048] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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14
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Biomedical applications of directly-coupled chromatography–nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s1567-7192(03)80011-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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15
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Abstract
This review examines the discovery of naturally occurring phytochemicals antagonistic toward plant-parasitic and other nematodes. Higher plants have yielded a broad spectrum of active compounds, including polythienyls, isothiocyanates, glucosinolates, cyanogenic glycosides, polyacetylenes, alkaloids, lipids, terpenoids, sesquiterpenoids, diterpenoids, quassinoids, steroids, triterpenoids, simple and complex phenolics, and several other classes. Many other antinematodal compounds have been isolated from biocontrol and other fungi. Natural products active against mammalian parasites can serve as useful sources of compounds for examination of activity against plant parasites. The agricultural utilization of phytochemicals, although currently uneconomic in many situations, offers tremendous potential.
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Affiliation(s)
- David J Chitwood
- Nematology Laboratory, USDA-ARS, Building 011A, BARC-West, Beltsville, Maryland 20705, USA.
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Bringmann G, Wohlfarth M, Rischer H, Heubes M, Saeb W, Diem S, Herderich M, Schlauer J. A photometric screening method for dimeric naphthylisoquinoline alkaloids and complete on-line structural elucidation of a dimer in crude plant extracts, by the LC-MS/LC-NMR/LC-CD triad. Anal Chem 2001; 73:2571-7. [PMID: 11403302 DOI: 10.1021/ac001503q] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An efficient evaluation procedure for the chemical screening and on-line structural elucidation of dimeric naphthylisoquinoline alkaloids has been developed. The method is based on the lead tetraacetate oxidation of the central binaphthalene core of the alkaloids. UV spectra of the extracts after addition of the oxidant show, in the presence of naphthylisoquinoline dimers, the appearance of a characteristic long-wavelength absorption indicative of dinaphthoquinones. The efficiency and relevance of the method has been demonstrated in the discovery of a constitutionally and configurationally new dimeric naphthylisoquinoline alkaloid, named ancistrogriffithine A (4), from the previously uninvestigated Asian liana Ancistrocladus griffithii. After verification of this screening result by LC-ESI-MS/MS, the constitution and the relative configuration of the compound were elucidated on line, by LC-NMR and LC-CD on the extract. Using an LC-NMR-WET-ROESY experiment, itwas possible for the first time to determine the relative axial configuration of a natural biaryl compound on line, by observing long-range ROE interactions. Finally, an oxidative degradation right on the extract delivered the absolute configuration of 4, without isolation of the alkaloid. Ancistrogriffithine A is the as yet only dimeric naphthylisoquinoline from an Asian Ancistrocladaceae plant.
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Affiliation(s)
- G Bringmann
- Institute of Organic Chemistry, University of Würzburg, Am Hubland, Germany.
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Sandvoss M, Weltring A, Preiss A, Levsen K, Wuensch G. Combination of matrix solid-phase dispersion extraction and direct on-line liquid chromatography-nuclear magnetic resonance spectroscopy-tandem mass spectrometry as a new efficient approach for the rapid screening of natural products: application to the total asterosaponin fraction of the starfish Asterias rubens. J Chromatogr A 2001; 917:75-86. [PMID: 11403494 DOI: 10.1016/s0021-9673(01)00668-9] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A combination of matrix solid-phase dispersion extraction (MSPD) and LC-NMR-MS hyphenation is proposed as a rapid screening method of natural products for unknown compounds. In this report, this new analytical approach is applied for the first time. MSPD represents a significant simplification compared to classical extraction procedures and is thus an excellent complement to the fast and powerful LC-NMR-MS: MSPD yields extracts suitable for LC-NMR-MS in one simple preparation step, while LC-NMR-MS yields a wealth of information in one single chromatographic run. The suitability of this technique to characterise glycosidic compounds in the molecular mass range of 1200 to 1400 a.m.u. is demonstrated. The information on the number of exchangeable protons provided by an additional back-exchange experiment proved to be particularly valuable for structural elucidation. The possibility of semi-quantitative LC-NMR measurements through methyl signals H(3)-18 and 19 of the steroidal skeleton is demonstrated and is ensuingly used to provide relative quantitative data of the steroid oligosaccharide fraction.
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Affiliation(s)
- M Sandvoss
- Fraunhofer-Institut für Toxikologie und Aerosolforschung, Abteilung Bio- und Umweltanalytik, Hannover, Germany
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Bringmann G, Wohlfarth M, Heubes M. Observation of exchangeable protons by high-performance liquid chromatography-nuclear magnetic resonance spectroscopy and high-performance liquid chromatography-electrospray ionization mass spectrometry: a useful tool for the hyphenated analysis of natural products. J Chromatogr A 2000; 904:243-9. [PMID: 11204237 DOI: 10.1016/s0021-9673(00)00926-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The first high-performance liquid chromatography-nuclear magnetic resonance (HPLC-NMR) investigation of exchangeable protons of low-molecular-mass natural products is reported. Model alkaloids or crude plant extracts were dissolved in 2H2O-1H2O-MeCN (deuterium oxide-water-acetonitrile) or 2H2O-MeCN and, after direct injection or chromatographic separation, examined in a 60-microl NMR flow probe. Exchangeable amino protons initially detected by HPLC-electrospray ionization mass spectrometry were subsequently identified and investigated by stop-flow 1H-NMR, two-dimensional (2D) total correlation spectroscopy (TOCSY), and 2D nuclear Overhauser effect spectroscopy (NOESY). These experiments extend the applicability of HPLC-NMR for the investigation and structure elucidation of natural products.
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Affiliation(s)
- G Bringmann
- Institute of Organic Chemistry, University of Würzburg, Germany.
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Buschmann H, Reilly K, Rodriguez MX, Tohme J, Beeching JR. Hydrogen peroxide and flavan-3-ols in storage roots of cassava (Manihot esculenta crantz) during postharvest deterioration. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2000; 48:5522-9. [PMID: 11087513 DOI: 10.1021/jf000513p] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Cassava storage roots are an important staple food throughout the lowland humid tropics. However, cassava suffers from a poorly understood storage disorder, known as postharvest physiological deterioration (PPD), which constrains its exploitation. In an attempt to broaden the understanding of PPD, nine different cassava cultivars were analyzed for specific compounds accumulating during the process. The production of hydrogen peroxide (H(2)O(2)) is involved in the early stages of PPD in cassava roots. H(2)O(2) was quantified and localized histochemically at the tissue and cell level in deteriorating roots. This reactive oxygen species accumulated during the first 24 h after harvest, especially in the inner parenchymatic tissue. Three flavan-3-ols, (+)-catechin, (+)-catechin gallate, and (+)-gallocatechin, accumulated during the storage of cassava roots. However, these potential antioxidants cannot be related to early storage disorders or wound responses because they start to accumulate only after 4-6 days.
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Affiliation(s)
- H Buschmann
- Department of Biology and Biochemistry, University of Bath, Bath BA2 7AY, United Kingdom, and Centro International de Agricultura Tropical, CIAT, Cali A.A.6713, Colombia
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Lindon JC, Nicholson JK, Wilson ID. Directly coupled HPLC-NMR and HPLC-NMR-MS in pharmaceutical research and development. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 2000; 748:233-58. [PMID: 11092602 DOI: 10.1016/s0378-4347(00)00320-0] [Citation(s) in RCA: 164] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The methodology for the direct coupling of HPLC with NMR spectroscopy and the simultaneous double coupling of HPLC with NMR and mass spectrometry (MS) is described. Indications of the necessary technical developments to achieve this are given, and the applications of these new techniques to studies of pharmaceutical relevance are reviewed. These include studies of combinatorial chemistry libraries, synthetic chemical impurities, characterisation of drug mixtures, identification of natural products of possible pharmaceutical interest and identification of xenobiotic metabolites in human, animal and in vitro systems. In addition, HPLC-NMR has been used to investigate xenobiotic metabolite reactivity. Finally, the potential future directions of the techniques are discussed.
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Affiliation(s)
- J C Lindon
- Biological Chemistry, Biomedical Sciences, Imperial College of Science, Technology and Medicine, South Kensington, London, UK.
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