Comparative quantitative analysis of fruit oil from Hippophae rhamnoides (seabuckthorn) by qNMR, FTIR and GC-MS / 中草药·英文版

OBJECTIVE@#To develop a qNMR method for quantitative analysis of triacylglycerols in fruit oil of Hippophae rhamnoides (seabuckthorn, SBT) and analyze commercial samples of SBT oils using GC-MS and FTIR.@*METHODS@#SBT fruit oil (IPHRFH) was extracted with hexane and the triglyceride (TAG) was isolated by vacuum liquid chromatography. Six different branded SBT oils purchased from e-commerce suppliers (Amazon) and in-house prepared SBT oil was analyzed by qNMR and fatty acyl composition of TAGs determined by using NMR. In-house oil was also analysed by GC-MS and FTIR spectroscopy.@*RESULTS@#The qNMR results showed that the oil contained 80.3% of triacylglycerol (TAG). The SBT oil TAGs comprised of linolenate 6.6%, palmitoleate/oleate 65.4%, and total saturated fatty acyl chain including palmitate 28% as determined by qNMR. GC-MS analysis revealed that the major acyl functionalities present in the TAG were palmitoleic acid 36.5%, oleic acid 12.9%, palmitic acid 21.2%, and linoleic acid 18%. Of the six commercial samples analyzed, samples from only one supplier (SW) were fruit oil; All others were the seed oils or mix of fruit oil and seed oil. The labels for samples except for the SW did not indicate whether it was fruit oil or seed oil.@*CONCLUSION@#The results suggest that SBT oil should be analyzed by combination of GC-MS, FTIR and qNMR for factual content of free fatty acid or TAGs, which are chemically different in nature and affect the quality of oil. GC-MS showed the content of omega free fatty acids after hydrolysis, while qNMR and FTIR showed the content of TAGs. The major acyl functionalities found in SBT fruit oil TAGs are palmitoleate/palmitate/oleate, while linoleate and linonelate make up a minor fraction. Furthermore, analysis of commercial samples showed discrepancies between label claims and actual content.

~1H-qNMR quantification of total ginsenosides in Shenmai Injection / 中国中药杂志

A content determination method based on ~1H-qNMR was developed for the determination of total ginsenosides in Shenmai Injection. The parameters were optimized with CD_3OD as the solvent, dimethyl terephthalate as the internal standard, the peak at δ 8.11 as the internal standard peak, and the peaks at δ 1.68 and δ 0.79 as quantitative peaks of total ginsenosides. The developed ~1H-qNMR-based method was validated methodologically. The results showed that the method could achieve accurate measurement of total ginsenosides in Shenmai Injection in the range of 0.167 6-3.091 1 mmol·L~(-1). The developed ~1H-qNMR-based method for total ginsenosides is simple in operation, short in analysis time, strong in specificity, independent of accompanying standard curve, and small in sample volume, which can serve as a reliable mean for the quality control of Shenmai Injection. This study is expected to provide new ideas for the development of quantification methods of total ginsenosides.

Quality evaluation of ginsenoside reference substances based on qNMR spectroscopy / 中国中药杂志

The present study established a quality evaluation method for ginsenoside reference substances based on quantitative nuclear magnetic resonance(qNMR) spectroscopy. ~1H-NMR spectra were collected on Bruker Avance Ⅲ 500 MHz NMR spectrometer equipped with a 5 mm BBO probe. The acquire parameters were set up as follows: pulse sequence of 30°, D_1=20 s, probe temperature= 303 K, and the scan number = 32. Dimethyl terephthalate, a high-quality ~1H-qNMR standard, was used as the internal standard and measured by the absolute quantitative method. Methyl peaks of comparatively good sensitivity were selected for quantification, and linear fitting deconvolution was adopted to improve the accuracy of integration results. The qNMR spectroscopy-based method was established and validated, which was then used for the quality evaluation of ginsenoside Rg_1, ginsenoside Re, ginsenoside Rb_1, ginsenoside Rd, and notoginsenoside R_1. The results suggested that the content of these ginsenoside reference standards obtained from the qNMR spectroscopy-based method was lower than that detected by the normalization method in HPLC provided by the manufacturers. In conclusion, the qNMR spectroscopy-based method can ensure the quality of ginsenoside reference substances and provide powerful support for the accurate quality evaluation of Chinese medicine and its preparations. The qNMR spectroscopy-based method is simple, rapid, and accurate, which can be developed for the quantitative assay of Chinese medicine standard references.

Assessment of the Purity of Emodin by Quantitative Nuclear Magnetic Resonance Spectroscopy and Mass Balance

Quantitative nuclear magnetic resonance (qNMR) is a well-established method adopted by international pharmacopoeia for quantitative and purity analyses. Emodin is a type of anthraquinone, well known as the main active component of Fabaceae, Polygonaceae and Rhamnaceae. Purity analysis of emodin is usually performed by using the high-performance liquid chromatography (HPLC)-UV method. However, it cannot detect impurities such as salts, volatile matter, and trace elements. Using the qNMR method, it is possible to determine the compound content as well as the nature of the impurities. Several experimental parameters were optimized for the quantification, such as relaxation delay, spectral width, number of scans, temperature, pulse width, and acquisition time. The method was validated, and the results of the qNMR method were compared with those obtained by the HPLC and mass balance analysis methods. The qNMR method is specific, rapid, simple, and therefore, a valuable and reliable method for the purity analysis of emodin.

Determination of Phenanthrenes in the Anxiolytic Fraction of Juncus effusus L. by QNMR / 中国药学杂志

OBJECTIVE: To establish a method for quantification of phenanthrenes in the anxiolytic fraction of Juncus effusus L by QNMR. METHODS: The analysis was conducted using terephthalic acid as an internal standard, the 5 mm SEI probe temperature was 298.2 K with NS=16 and d1=1 s. C4-H of dehydroeffusol, C4-H of effusol and C4-H juncusol peaks were chosen as the characteristic peaks. RESULTS: The contents of effusol, dehydroeffusol, juncusol and dehydrojuncusol were 338.75, 41.14 and 109.13 mg·g-1, respectively, by QNMR, and 340.87, 42.99, 107.73 and 9.561 mg·g-1, respectively, by HPLC. CONCLUSION: The determined contents of phenanthrenes by QNMR are in accordance with the results by HPLC, indicating that QNMR can be applied to determine phenanthrenes in the anxiolytic fraction of Juncus effusus L. QNMR is rapid, accurate, and does not need reference substances and complex sample preparation.