31P Nuclear Magnetic Resonance Analysis of Phospholipids in a Ternary Homogeneous System

Branca, Mario; Culeddu, Nicola; Fruianu, Michelina; Serra, M.V.

doi:10.1006/abio.1995.9968

Cited by 22 publications

(22 citation statements)

References 2 publications

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“…The peak locations around 0 ppm are similar to those published for phospholipid extracts in other studies (Branca et al, 1995;Culeddu et al, 1998;Meneses and Glonek, 1988;Meneses et al, 1993;Schiller et al, 2001Schiller et al, , 2007Sotirhos et al, 1986) but could be produced by other soluble phosphatecontaining compounds in algae (e.g., soluble orthophosphates, polynucleotides, and soluble nucleotides). The shape of the dominant peak at $À23.4 ppm (a broad, shouldered peak) resembles that produced by intact membrane phospholipids reported in other studies (Cullis and De Kruijff, 1979;McLaughlin et al, 1975;Murphy et al, 1989;Schiller et al, 2007).…”

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confidence: 70%

Lipid analysis of Neochloris oleoabundans by liquid state NMR

Beal¹,

Webber²,

Ruoff³

et al. 2010

Biotech & Bioengineering

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This study is an evaluation of liquid state NMR as a tool for analyzing the lipid composition of algal cultures used for biodiesel production. To demonstrate the viability of this approach, (13)C NMR was used to analyze the lipid composition of intact cells of the algal species, Neochloris oleoabundans (UTEX #1185). Two cultures were used in this study. One culture was "healthy" and grown in conventional media, whereas the other culture was "nitrogen-starved" and grown in media that lacked nitrate. Triglyceride was determined to be present in both cultures by comparing the algal NMR spectra with published chemical shifts for a wide range of lipids and with a spectrum obtained from a triglyceride standard (glyceryl trioleate). In addition, it is shown that (1) the signal-to-noise ratio of the approximately 29.5 ppm methylene peak is indicative of the lipid content and (2) the nitrogen-starved culture contained a greater lipid content than the healthy culture, as expected. Furthermore, the nitrogen-starved culture produced spectra that primarily contained the characteristic peaks of triglyceride (at approximately 61.8 and approximately 68.9 ppm), whereas the healthy culture produced spectra that contained several additional peaks in the glycerol region, likely resulting from the presence of monoglyceride and diglyceride. Finally, potential interferences are evaluated (including the analysis of phospholipids via (31)P NMR) to assess the specificity of the acquired spectra to triglyceride. These results indicate that NMR is a useful diagnostic tool for selectively identifying lipids in algae, with particular relevance to biodiesel production.

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supporting

confidence: 70%

Lipid analysis of Neochloris oleoabundans by liquid state NMR

Beal¹,

Webber²,

Ruoff³

et al. 2010

Biotech & Bioengineering

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“…The mixture was transferred to a 5-mm tube, and two 13 C NMR spectra were acquired with 24 hours in between measurements using a 400 MHz Bruker Avance DRX spectrometer (Bruker Biospin) at 300 K. The spectra were acquired with a pulse length corresponding to a 30°pulse, a spectral width of 24 kHz, collecting 1024 scans into 64 k data points with a relaxation delay of 4.0 sec. The time domain data were zero filled to 128 k data points and multiplied with a 0.3 Hz exponential function before Fourier transform and referencing of the chemical shift axis to the residual methanol signal at 47.5 ppm.…”

Section: Test Of Esterificationmentioning

confidence: 99%

“…Lowering the pH by adding trifluoroacetic acid (TFA) to the solvent mixture increased the yield further. However, TFA and methanol react slowly to form the ester (CF 3 COO-CD 3 ) as shown by separate 13 C NMR experiments of a mixture (data not shown). Therefore the non-nucleophile, and less reactive, perchloric acid (HClO 4 ) was considered a better choice.…”

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confidence: 93%

“…The extraction solvent was thus augmented with water and perchloric acid, and for simplicity the employed ratios of chloroform-d 1 , methanol-d 4 , D 2 O, and aqueous 70% perchloric acid were determined to be 5 : 5 : 1 : 1. The ternary molar ratios of this solvent system were approximately 22 : 48 : 31, which forms a one-phase mixture [13]. The concentration of water and perchloric acid was 7.5 and 1.0 M, respectively.…”

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confidence: 99%

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Extraction of Alkaloids for NMR-Based Profiling: Exploratory Analysis of an Archaic Cinchona Bark Collection

2012

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Introduction !The crude drug cinchona (Cinchonae cortex) used against malaria is known since the colonization of South America in the beginning of the 17th century. The antimalarial effect is mainly due to the content of quinine (1), which interferes with the development of the Plasmodium parasites in the red blood cells [1]. Cinchona also contains the likewise active analogue alkaloids quinidine (2), cinchonine (3), and cinchonidine (4) (l " Fig. 1) [1][2][3]. The most abundant alkaloid is quinine that accounts for 70-90 % of the total alkaloid content which can be as high as 25 % of the dry weight [4]. Even though there are effective artemisinin-based combination therapies against malaria, there is still an interest in using the bark of Cinchona species (Rubiaceae) for reasons of availability and evolved malaria drug resistance [5,6]. As a result of the economical values of cinchona during the 19th century, plantations were spread to different tropical regions such as Indonesia and India. Different species and hybrids were tested for production of the drug in order to maximize the yield of quinine. During this period, samples of Cinchonae cortex were collected from different parts of the world and eventually ended up in a collection hosted by the Museum of Natural Medicine at the University of Copenhagen. A profiling study of this archaic collection, focused on alkaloids, could possibly indicate species that were not selected due to the quinine content but to other types of antimalarial alkaloids. Since the samples are collected over a long time period, from many different sites, and for many different reasons, we expect a large variation of types and amounts of alkaloids. Profiling of extracted alkaloids might indicate odd samples that contain other types of alkaloids than the expected and so allows finding out about the possible variations and combinations of the known and major alkaloids. NMR is a rational choice of analytical platform for this study. It is rapid, robust and gives reproducible results [7,8]. NMR also gives different spectra of diastereomers, and this makes it possible to differentiate between the main alkaloids. However, the traditional liquid-liquid extraction to separate alkaloids based on their basic properties is not practical for a profiling study in terms of sample throughput and potential problems with robustness. In this study, we present the use of a direct Abstract ! A museum collection of Cinchonae cortex samples (n = 117), from the period 1850-1950, was extracted with a mixture of chloroform-d 1 , methanol-d 4 , water-d 2 , and perchloric acid in the ratios 5 : 5 : 1 : 1. The extracts were directly analyzed using 1 H NMR spectroscopy (600 MHz) and the spectra evaluated using principal component analysis (PCA) and total statistical correlation spectroscopy (STOCSY). A new method called STOCSY-CA, where CA stands for component analysis, is described, and an analysis using this method is presented. It was found that the samples had a rather homogenous content of the well-known cinc...

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“…Two phases could be observed in the definitive sample: a small aqueous upper phase and a much larger organic lower phase which was used later for 31 P-MRS analysis. The final proportion in the ternary system chloroform/methanol/EDTA-Cs was 100/40/20 (22).…”

Section: P-mrs Analysismentioning

confidence: 99%

Assessment of ³¹P‐NMR analysis of phospholipid profiles for potential differential diagnosis of human cerebral tumors

Castaño¹,

Cerdán²,

Pascual³

et al. 2009

NMR in Biomedicine

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We describe a novel protocol for the non‐histological diagnosis of human brain tumors in vitro combining high‐resolution 31P magnetic resonance spectroscopy (31P‐MRS) of their phospholipid profile and statistical multivariate analysis. Chloroform/methanol extracts from 40 biopsies of human intracranial tumors obtained during neurosurgical procedures were prepared and analyzed by high‐resolution 31P‐MRS. The samples were grouped in the following seven major classes: normal brain (n = 3), low‐grade astrocytomas (n = 4), high‐grade astrocytomas (n = 7), meningiomas (n = 9), schwannomas (n = 3), pituitary adenomas (n = 4), and metastatic tumors (n = 4). The phospholipid profile of every biopsy was determined by 31P‐NMR analysis of its chloroform/methanol extract and characterized by 19 variables including 10 individual phospholipid contributions and 9 phospholipid ratios. Most tumors depicted a decrease in phosphatidylethanolamine (PtdEtn) and phosphatidylserine (PtdSer), the former mainly in neuroepithelial neoplasms and the latter in metastases. An increase in phosphatidylcholine (PtdCho) and phosphatidylinositol (PtdIns) appeared predominantly in primary non‐neuroepithelial tumors. Linear discriminant analysis (LDA) revealed the optimal combination of variables that could classify each biopsy between every pair of classes. The resultant discriminant functions were used to calculate the probability of correct classifications for each individual biopsy within the seven classes considered. Multilateral analysis classified correctly 100% of the normal brain samples, 89% of the meningiomas, 75% of the metastases, and 57% of the high‐grade astrocytomas. The use of phospholipid profiles may complement appropriately previously proposed methods of intelligent diagnosis of human cerebral tumors. Copyright © 2009 John Wiley & Sons, Ltd.

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31P Nuclear Magnetic Resonance Analysis of Phospholipids in a Ternary Homogeneous System

Cited by 22 publications

References 2 publications

Lipid analysis of Neochloris oleoabundans by liquid state NMR

Lipid analysis of Neochloris oleoabundans by liquid state NMR

Extraction of Alkaloids for NMR-Based Profiling: Exploratory Analysis of an Archaic Cinchona Bark Collection

Assessment of ³¹P‐NMR analysis of phospholipid profiles for potential differential diagnosis of human cerebral tumors

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31P Nuclear Magnetic Resonance Analysis of Phospholipids in a Ternary Homogeneous System

Cited by 22 publications

References 2 publications

Lipid analysis of Neochloris oleoabundans by liquid state NMR

Lipid analysis of Neochloris oleoabundans by liquid state NMR

Extraction of Alkaloids for NMR-Based Profiling: Exploratory Analysis of an Archaic Cinchona Bark Collection

Assessment of 31P‐NMR analysis of phospholipid profiles for potential differential diagnosis of human cerebral tumors

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Assessment of ³¹P‐NMR analysis of phospholipid profiles for potential differential diagnosis of human cerebral tumors