Structure elucidation and complete NMR spectral assignment of an unusual aromatic monacolin analog from <i>Monascus purpureus</i>‐fermented rice

Liu, Mingtao; Li, Jinjie; Shang, Xiao-Ya; Li, Shuai; Li, Lingling; Luan, Na; Zhang, Jin

doi:10.1002/mrc.2714

Cited by 27 publications

(19 citation statements)

References 7 publications

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“…[28,32] It is not only possible to assign all resonances and identify active substances, [21] but also reveal and characterize synthetic chemicals that may be illegally added to dietary supplements. [28,32] It is not only possible to assign all resonances and identify active substances, [21] but also reveal and characterize synthetic chemicals that may be illegally added to dietary supplements.…”

Section: Resultsmentioning

confidence: 99%

Standardless ¹H NMR determination of pharmacologically active substances in dietary supplements and medicines that have been illegally traded over the Internet

Monakhova

Kuballa

Löbell-Behrends

et al. 2012

Drug Testing and Analysis

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Dietary supplements and medicines are widely marketed over the Internet. Such products may be counterfeited and lack some or all of the labelled ingredients, or, in the case of lifestyle supplements, illegally contain pharmacologically active substances, such as anorectic or androgenic compounds. The market control - especially in the case of customs seizures - is complex, as reference substances necessary for identification and calibration in traditional high performance liquid chromatography (HPLC) or gas chromatography-mass spectrometry (GC-MS) analysis are often unavailable, or extremely expensive. In this study, we introduce a 400 MHz (1) H NMR methodology, which allows identification and quantitative estimation even without such pure compound standards. The identification can be based on literature spectra, or if these data are unavailable, by applying computational NMR spectra prediction. For standardless NMR determination, simple peak-area comparison of the target compound with the TSP reference was used. The applicability was demonstrated for a wide range of compounds, such as mesterolone, oxymetholone, sibutramine, monacolin K, vinpocetine, evodiamine, caffeine, kavain, and dehydroepiandrosterone. The average relative standard deviations were 5.0% for peak area comparison, and 3.3% for external calibration with standard substance. The method uncertainty is therefore higher in standardless determination, but acceptable for the purpose of proving the presence or absence of pharmacologically active substances. The limit of detection of 0.5-2 mg/kg is sufficient for the purpose. NMR is ideally suited to controlling dietary supplements or illegal medicines as it provides qualitative and at least semi-quantitative information more rapidly (measurement time 20 min) than with any other currently available spectroscopic or chromatographic method.

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Section: Resultsmentioning

confidence: 99%

Standardless ¹H NMR determination of pharmacologically active substances in dietary supplements and medicines that have been illegally traded over the Internet

Monakhova

Kuballa

Löbell-Behrends

et al. 2012

Drug Testing and Analysis

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show abstract

Section: Resultsmentioning

confidence: 99%

“…[24,25] ). It is not only possible to assign all resonances and identify active substances [26], but also reveal and characterize synthetic chemicals that may be illegally added to dietary supplements [24,27]. As a first step, we reviewed the scientific literature to identify compounds, which can be illegally present in slimming products [5,12,28,29].…”

Section: Resultsmentioning

confidence: 99%

¹H NMR screening of pharmacologically active substances in weight‐loss supplements being sold online

et al. 2012

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Weight-loss or slimming food supplements may be adulterated with synthetic pharmaceuticals, such as anorectic, anxiolytic and antidepressant compounds, especially when sold over the internet. An NMR screening method to detect these pharmacologically active compounds in slimming products is introduced in this study. As a first step, we gathered NMR-related information ( chemical shifts, multiplicity ) both from the scientific literature and own theoretical spectra prediction for 53 substances, which are likely to be illegally present in weight-loss products. The experimental strategy consists of dissolving the samples in a proper solvent ( most commonly ethanol ) and manually comparing each observed chemical shift with table values and thus identifying possible adulteration. A compound is considered to be identified if all the compound's resonances were present with correct multiplicity ( finally confirmed by J-resolved 2D spectra ). The method has been introduced in routine practise in our institute and we have already detected sibutramine, caffeine and L-carnitine in slimming products. Furthermore, quantification can be conducted by simple integration of a target resonance in comparison with the internal reference standard ( e. g., TSP ), or by using standard solutions ( when available ). We believe that NMR is ideally suited to controlling dietary supplements as it provides qualitative and at least semi-quantitative information more rapidly ( measurement time of about 20 min ) than with any other currently available spectroscopic or chromatographic method. Future research regarding the automation of spectral processing and inclusion of non-targeted analysis is necessary.

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“…A large diaxial coupling constant (14.0 Hz) between H-12a and H-11 and strong ROE correlation between H12b (β-orientation) and H-11 established that H-12a and H-11 were in the axial positions and the H-11 possessed β-configuration, respectively. [13] Likewise, A large diaxial coupling constant (14.5 Hz) between H-2a and H-3 established that H-2a and H-3 were in the axial positions and defined H-2a as having a β-orientation, indicating the H-3 in α-orientation. The coupling constants (2.0 Hz) between H-1 and 2H-2 and the strong ROE correlation between H-1 and 2H-2 clearly implied that the H-1 was in an equatorial position and H-1 and H-2a were cis-configuration, so the H-1 was determined to be β-orientation [14,15] (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…1). Therefore, the structure of monacophenylone B (2) was unambiguously established as (S)-(1α,3β)-8-(2-((2α,4β)-4-hydroxy-6-oxotetrahydro-2H-pyran-2-yl)ethyl)-3,7-dimethyl-4-oxo-1,2,3,4-tetrahydronaphthalen-1-yl 2-methylbutanoate, and the full assignments of 1 H and 13 C NMR data (Table 1) were achieved.…”

Section: Resultsmentioning

confidence: 99%

Structure elucidation and NMR assignments of two unusual isomeric aromatic monacolin analogs fromMonascus purpureus

Wei

Luan

et al. 2014

Magn. Reson. Chem.

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Structure elucidation and complete NMR spectral assignment of an unusual aromatic monacolin analog from Monascus purpureus‐fermented rice

Cited by 27 publications

References 7 publications

Standardless ¹H NMR determination of pharmacologically active substances in dietary supplements and medicines that have been illegally traded over the Internet

Standardless ¹H NMR determination of pharmacologically active substances in dietary supplements and medicines that have been illegally traded over the Internet

¹H NMR screening of pharmacologically active substances in weight‐loss supplements being sold online

Structure elucidation and NMR assignments of two unusual isomeric aromatic monacolin analogs fromMonascus purpureus

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Structure elucidation and complete NMR spectral assignment of an unusual aromatic monacolin analog from Monascus purpureus‐fermented rice

Cited by 27 publications

References 7 publications

Standardless 1H NMR determination of pharmacologically active substances in dietary supplements and medicines that have been illegally traded over the Internet

Standardless 1H NMR determination of pharmacologically active substances in dietary supplements and medicines that have been illegally traded over the Internet

1H NMR screening of pharmacologically active substances in weight‐loss supplements being sold online

Structure elucidation and NMR assignments of two unusual isomeric aromatic monacolin analogs fromMonascus purpureus

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Product

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Standardless ¹H NMR determination of pharmacologically active substances in dietary supplements and medicines that have been illegally traded over the Internet

Standardless ¹H NMR determination of pharmacologically active substances in dietary supplements and medicines that have been illegally traded over the Internet

¹H NMR screening of pharmacologically active substances in weight‐loss supplements being sold online