Quantification of ligustilides in the roots of Angelica sinensis and related umbelliferous medicinal plants by high-performance liquid chromatography and liquid chromatography-mass spectrometry

A reversed phase high-performance liquid chromatographic method was developed for quantifying E-ligustilide (1) and Z-ligustilide (3) in the roots of Angelica sinensis (Oliv.) Diels with confirmation using UV, atmospheric pressure chemical ionisation (APCI) MS and APCI-MS-MS techniques. Based on the UV spectra of compounds 1, E-butylidenephthalide (2), 3 and Z-butylidenephthalide (4), the absorption at 350 nm was chosen as measuring wavelength in which baseline separation of compounds 1 and 3 could be obtained but avoided the interference of compounds 2 and 4. The identity of compounds 1 and 3 in samples were unambiguously determined by the respective quasi-molecular ions ([M+H]+) in APCI-MS. According to the stability data, acetonitrile was chosen for the preparation of standard solutions in order to minimize the isomerization of compound 3. Compounds 1 and 3 were qualitatively and quantitatively analyzed in seven samples of the roots of Angelica sinensis (Oliv.) Diels, Angelica acutiloba Kitagawa, Angelica acutiloba Kitagawa var. sugiyamae Hikino and the rhizome of Ligusticum chuanxiong Hort. Analysis of an extract from a sample root of Angelica gigas Nakai using LC-MS for the first time could not detect the presence of ligustilide in this herb. The overall analytical procedure is rapid and reproducible which is considered suitable for quantitative analysis of large number of samples.     

Evaluation of the Quality of Angelica sinensis by High-Performance Liquid Chromatography

Quality control and consistent quality are prerequisites to guarantee the safety and efficacy of pharmaceutical preparations and dietary supplements. In this paper, the intra- and inter-annual consistency and stability of Angelica sinensis (Oliv.) Diels, cultivated according to Good Agricultural Practices (GAP) in the main production areas of China, were evaluated by high-performance liquid chromatographic fingerprints composed of twenty-four common components. Subsequently, thirteen compounds were identified in the chromatograms using diode array detection and mass spectrometry. Z-Ligustilide, senkyunolide H, senkyunolide I, and ferulic acid were determined to evaluate the distribution of chemical components. In addition, robust principal component analysis was applied to further evaluate the samples, and four discriminatory “markers” among the common twenty-four were pinpointed by the loading plots that were used to distinguish quality differences of Angelica sinensis from different harvest years.     

GC-MS fingerprints for discrimination of Ligusticum chuanxiong from Angelica

A GC-MS fingerprinting technique based on the essential oil components has been developed for the discrimination of chuanxiong against Chinese Angelica (Angelica sinensis (Oliv.) Diels) or other herbs with similar compositions. The analytical performance of four different extraction methods for the separation of essential oil components have been compared and these include: ultrasound-assisted extraction (UAE), supercritical fluid extraction (SFE), Soxhlet extraction (SHE) and hydro-distillation extraction (HDE). The results showed that UAE was the most effective extraction method, and the operational parameters of UAE were optimized. 3-Butylphthalide, Z-butylidenephthalide, senkyunolide I, senkyunolide H, E-butylidenephthalide, senkyunolide A, neocnidilide, Z-ligustilide and E-ligustilide were tentatively identified in chromatograms of chuanxiong based on their GC-EI-MS data. Similarity coefficient calculations based on correlation methods have been performed on the GC-MS fingerprints. Using an authentic standard Chuanxiong as the reference, the similarity coefficients between the standard and all other chuanxiong samples ranged from 0.90 to 1.0 (with 1.0 being the perfect match), which as a group can be readily separated from the Angelica samples for which the similarity index against the chuanxiong standard ranged from 0.75 to 0.77. Conversely, when an authentic Angelica standard was used as the reference, the respective similarity coefficients fall in the range of 0.70-0.75 and 0.98-1.00 for the chuanxiong and Angelica sample groups. Our results thus demonstrate that the fingerprinting technique developed in the study can indeed discriminate the two herbs with high reliability.     

Fingerprint chromatogram analysis of Pseudostellaria heterophylla (Miq.) Pax root by high performance liquid chromatography

A simple and reliable high performance liquid chromatographic (HPLC) method has been developed and validated for the fingerprinting of extracts from the root of Pseudostellaria heterophylla (Miq.) Pax. HPLC with gradient elution was performed on an authentic reference standard of powdered P. heterophylla (Miq.) Pax root and 11 plant samples of the root were collected from different geographic locations. The HPLC chromatograms have been standardized through the selection and identification of reference peaks and the normalization of retention times and peak intensities of all the common peaks. The standardized HPLC fingerprints show high stability and reproducibility, and thus can be used effectively for the screening analysis or quality assessment of the root or its derived products. Similarity index calculations based on cosine angle values or correlation methods have been performed on the HPLC fingerprints. As a group, the fingerprints of the P. heterophylla (Miq.) Pax samples studied are highly correlated with closely similar fingerprints. Within the group, the samples can be further divided into subgroups based on hierarchical clustering analysis (HCA). Sample grouping based on HCA coincides nicely with those based on the geographical origins of the samples. The HPLC fingerprinting techniques thus have high potential in authentication or source-tracing types of applications.     

用高效液相色谱组方指纹图谱智能预测中药质量的新模式

建立大黄、黄芩、黄连的高效液相色谱(HPLC)组方指纹图谱,确定其融合模型,观察组方融合指纹图谱(CSF)与一清片复方样品指纹图谱的一致性,从而以CSF代替复方整体来智能预测复方制剂质量。用二极管阵列检测器(DAD)同时测定黄芩、大黄、黄连和一清片在268 nm波长下的HPLC指纹图谱,并使用系统指纹定量法进行定性、定量评价。结果 CSF涵盖各单味药主要色谱峰信息,即CSF共有峰(55个)涵盖一清片样品共有峰(50个)的主要指纹图谱信息。15批样品的质量除YQT-S01为5级外,其他质量均为3级及以上。各组合模式CSF质量除CSF-2为6级外,其余均为2级或1级。该文探讨了标准指纹图谱和中药组方融合指纹图谱的相关性,可以与相应的计算机评价软件相结合,通过组方融合指纹图谱所代表复方制剂的整体指纹图谱来实现智能预测中药成方制剂质量的新模式。     

Assay of free ferulic acid and total ferulic acid for quality assessment of Angelica sinensis

Activity of Chinese Danggui (DG), the processed root of Angelica sinensis (Oliv.) Diels, is linked to the ferulic acid content but the stability of ferulic acid during extraction for medicinal use is not known. The stabilities of ferulic acid and coniferyl ferulate were evaluated in the extracts of DG using a variety of extraction solvents. These included various combinations and proportions of methanol, water, formic acid, 1 M aqueous hydrochloric acid and 2% sodium hydrogen carbonate (NaHCO3) in water. Coniferyl ferulate was found liable to hydrolyze into ferulic acid in neutral, strongly acidic and basic solvents, where heat and water could facilitate this hydrolysis. However, the hydrolysis was relatively resisted in weakly organic acid. Based on the stability evaluation, two new terms, namely: free ferulic acid and total ferulic acid, were suggested and defined. Free ferulic acid refers to the natural content of ferulic acid in herbs. Total ferulic acid means the sum of free ferulic acid plus the amount of related hydrolyzed components. Meanwhile, the high-performance liquid chromatographic (HPLC) method was developed to assay free ferulic acid and total ferulic acid in DG using methanol-formic acid (95:5) and methanol-2% NaHCO3 in water (95:5) as extraction solvents, respectively. Ten DG samples were investigated on their contents of free and total ferulic acid. The results indicated that the amount variety of free ferulic acid was larger than that of their counterparts, and the ratio of total ferulic acid to free ferulic acid was 4.07 +/- 2.73 (mean +/- SD, n = 10). The chemical assay of DG using total ferulic acid content would be a better choice to assess the herbal quality and was recommended.     

LC-DAD-APCI-MS-based screening and analysis of the absorption and metabolite components in plasma from a rabbit administered an oral solution of danggui

A valid chromatographic fingerprint method using liquid chromatography-diode array detection-atmospheric pressure chemical ionization mass spectrometry in negative mode (LC-DAD-APCI-MS) is proposed for studying the absorption and metabolites of a traditional Chinese medicine (TCM) Angelica sinensis (danggui) in rabbit plasma, after the rabbit is administered with danggui oral solution (DOS). More than thirty-two common components were detected in both DOS and rabbit plasma, which shows that the components in the DOS were absorbed into the body of the rabbit. Of these, senkyunolide I, senkyunolide H, Z-6,7-epoxyligustilide, 3-butylidene-7-hydroxyphthalide, Z-ligustilide, Z-butylidenephthalide, Diels-Alder dimers of ligustilide, linolenic acid, linoleic acid and falcarindiol were tentatively identified from their MS, UV spectra and retention behavior by comparing the results with the published literature. At least ten components were found in rabbit plasma but not in DOS, indicating that these components must be metabolites of some of the components in the original extract. The results prove that the proposed method can be used to rapidly analyze multiple constituents in TCMs, and to screen for bioactive compounds by comparing and contrasting the chromatographic fingerprints of DOS and plasma samples.     

Microwave-assisted extraction and fingerprint studies of Schisandra chinensis (Turcz.) by high performance liquid chromatography and gas chromatography

In order to choose an appropriate extraction method, samples of Schisandra chinensis (Turcz.) Baill were extracted by different methods and it was found that microwave-assisted extraction gave the best results. The contents of schisandrin, schisantherin, deoxyschizandrin, and r-schizandrin of 10 samples collected from different regions in China were determined by HPLC. The chromatograms of ten samples were used to establish the fingerprints of Schisandra chinensis (Turcz.) Baill and two methods based on HPLC and GC were applied to them simultaneously. The fingerprints consisted of 18 common peaks obtained by HPLC and 17 common peaks obtained by GC, which showed good stability and repeatability with RSD less than 3% for retention time. The fingerprints are suitable for identifying and differentiating samples by geographical origin and can be used for quality control.     

Fractal fingerprinting of chromatographic profiles based on wavelet analysis and its application to characterize the quality grade of medicinal herbs

Extracting chemical fingerprints is an important step for representing and interpreting chromatographic data. In this paper, the chromatographic profile is decomposed into components at different resolution levels using wavelet analysis, then the fractal dimensions of these components are computed as the chemical fingerprints. The chromatographic fingerprint is characterized by the vector composed of these chemical fingerprints, which can represent the chemical patterns of different categories of complex samples. Computer simulations reveal that the fractal fingerprints are more stable than the original chromatographic profile data with respect to variations of peak retention time. To demonstrate the validity of this method, the evaluation of the quality of the medicinal herb Angelica sinensis (Oliv.) diels is investigated. Principal component analysis of the fractal fingerprints indicates that samples belonging to the same quality grade are clustered together, while those belonging to different quality grades are separated. Using these fractal fingerprints taken from the chromatographic scans as inputs for an artificial neural network (ANN). The quality grades of two sets of the herbs were verified by cross-validation, indicating that 96.7% of the herbs are correctly identified with respect to their quality grades evaluated by experienced experts, and 100.0% of the herbs are correctly identified with respect to their quality grades determined by pharmacodynamical evaluation.     

Authentication of cassia seeds on the basis of two-wavelength HPLC fingerprinting with the use of chemometrics

<正>High performance liquid chromatographic(HPLC) fingerprints of Cassia seed,a traditional Chinese medicine(TCM),were developed by means of the chromatograms at two wavelengths of 238 and 282 nm.Then,the two data sets were combined into one matrix.The application of principal component analysis(PCA) for this data matrix showed that the samples were clustered into four groups in accordance with the plant sources and preparation procedures.Furthermore,partial least squares(PLS),back propagation artificial neural network(BP-ANN),and radial basis function artificial neural network(RBF-ANN) were effectively applied to predict the category of the four different samples in the test set.     

New approach on similarity analysis of chromatographic fingerprint of herbal medicine

A new approach to the construction and similarity analysis of chromatographic fingerprint for herbal medicine is presented in this paper. Samples of chuanxiong, a herbal medicine for headache, from three producing areas of China were used to evaluate the utility of this study. The samples were analyzed with high-performance liquid chromatography (HPLC) and the peak areas of the chromatograms were used to construct the fingerprints of the herbal medicines. A vector of differences was defined between the two fingerprints. The scalar mean of the difference vector was taken as a statistic and both the t-test and Bayesian hypothesis testing were implemented to provide a one-to-one comparison of the fingerprints. Compared with principal component analysis (PCA), correlation coefficient and vector cosine, the new method offers a better differentiation of the similarity or difference between the fingerprints from same sample of chuanxiong. When the new method was used in the similarity analysis of the fingerprints of chuanxiong from different production areas, a clear-cut signature was obtained that reveals the significant difference between them.     

Screening and analysis of an antineoplastic compound in Rhizoma Chuanxiong by means of in vitro metabolism and HPLC-MS

A new screening and analysis method that combines in vitro metabolism with high-performance liquid chromatography-mass spectrometry (HPLC-MS) was developed for the screening and analysis of an antineoplastic compound, coniferyl ferulate, which is present in the rhizome of Rhizoma Chuanxiong. Infrared (IR), ultraviolet visible spectroscopy (UV-Vis), nuclear magnetic resonance (NMR) and element analysis were used to identify the molecular structure of coniferyl ferulate. The quantitative analysis of coniferyl ferulate in different extracts of Rhizoma Chuanxiong was carried out, and the metabolism of coniferyl ferulate was investigated by in vitro incubation with rat liver homogenate. The metabolite of coniferyl ferulate, ferulic acid ethyl ester, was identified by HPLC-MS, UV-Vis and IR. In addition, antineoplastic activities of coniferyl ferulate and ferulic acid ethyl ester were detected by the MTT assay. The observed inhibition rate of coniferyl ferulate on the activity of HeLa cells was over 80% at 5.4 ng μl⁻¹. However, its metabolite, ferulic acid ethyl ester, showed no antineoplastic activity in vitro.      

Correction of retention time shifts for chromatographic fingerprints of herbal medicines

In this study, the combination of chemometric resolution and cubic spline data interpolation was investigated as a method to correct the retention time shifts for chromatographic fingerprints of herbal medicines obtained by high-performance liquid chromatography-diode array detection (HPLC-DAD). With the help of the resolution approaches in chemometrics, it was easy to identify the purity of chromatographic peak clusters and then resolve the two-dimensional response matrix into chromatograms and spectra of pure chemical components so as to select multiple mark compounds involved in chromatographic fingerprints. With these mark components determined, the retention time shifts of chromatographic fingerprints might be then corrected effectively. After this correction, the cubic spline interpolation technique was then used to reconstruct new chromatographic fingerprints. The results in this work showed that, the purity identification of the chromatographic peak clusters together with the resolution of overlapping peaks into pure chromatograms and spectra by means of chemometric approaches could provide the sufficient chromatographic and spectral information for selecting multiple mark compounds to correct the retention time shifts. The cubic spline data interpolation technique was user-friendly to the reconstruction of new chromatographic fingerprints with correction. The successful application to the simulated and real chromatographic fingerprints of two Cortex cinnamomi, fifty Rhizoma chuanxiong, ten Radix angelicae and seventeen Herba menthae samples from different sources demonstrated the reliability and applicability of the approach investigated in this work. Pattern recognition based on principal component analysis for identifying inhomogenity in chromatographic fingerprints from real herbal medicines could further interpret it.     

Quality assessment of radix salviae miltiorrhizae

This paper describes an improved quality assessment method for Radix Salviae Miltiorrhizae (Root of Salvia miltiorrhiza BGE.) which was established using chromatographic fingerprinting and quantification of multiple marker compounds in the crude drug. High-performance thin-layer chromatography (HPTLC) fingerprinting of water-soluble phenolics and nonpolar tanshinones was performed separately and the authentication of Radix Salviae Miltiorrhizae was achieved by comparing the fingerprints of the samples with those of the reference crude drug and by comparing the Rf values of the bands in TLC fingerprints with those of reference compounds. HPLC fingerprints were obtained by simultaneous separation of phenolics and diterpenoids in Radix Salviae Miltiorrhizae. The HPLC fingerprints of seven batches of samples from different regions of China showed similar chromatographic patterns, and seven peaks were selected as characteristic peaks. The relative retention time of these characteristic peaks in the HPLC fingerprints was established as an important parameter for the identification of this herbal medicine. The pharmacologically active marker compounds salvianolic acid B, rosmarinic acid, and tanshinone IIA in herbal medicine were quantitatively determined using reverse-phase HPLC techniques. The HPLC quantitation methods of the three marker compounds were validated and the measurement uncertainty, which is important for setting the proposed content limit of the marker compounds in herbal medicine, were further evaluated.     

Determination of volatile flavor components in danggui cultivars by solvent free injection and hydrodistillation followed by gas chromatographic-mass spectrometric analysis

The rhizome of Angelica gigas Nakai, Angelica sinensis Diels and Angelica acutiloba Kitagawa (Umbelliferae) were chopped and extracted by hydrodistillation (HD) and solvent free solid injector (SFSI) methods to obtain the volatile compounds that were then characterized and identified by gas chromatography-mass spectrometry (GC/MS). SFSI extraction yielded a generally higher amount of volatile compounds than that produced by HD. A total of 48 components [including terpenes (8), aldehydes (4), alcohol (2), coumarins (9), Phthalide (3), acids (2) and sterols (2)] were identified by SFSI and gas chromatography-mass spectrometry from the three species of danggui cultivars, whereas, 24-essential oil was obtained by HD for Korean danggui only. According to these analyses, several coumarin derivatives such as decursinol angelate (16.83%) and decursin (29.34%) were found to be the dominant ones, followed by lomatin (10.25%) and marmesin (9.33%) in Korean danggui. Furfural and butylidene phthalide were the main components in Japanese in addition to butylidene dihydro-phthalide in Chinese danggui. Some parameters affecting the extraction efficiency such as injector temperature, injection time and pre-heating time were optimized. The results showed that the SFSI-method gave a higher yield of components with higher molecular mass than hydrodistillation. SFSI required little time to prepare the sample, little sample mass and a small quantity of organic solvent was needed. It can be concluded that analysis of volatile flavor compounds by SFSI in combination with gas chromatography/mass spectrometry is a suitable monitoring technique to differentiate danggui cultivars.     

Quality control and discrimination of pericarpium citri reticulatae and pericarpium citri reticulatae viride based on high-performance liquid chromatographic fingerprints and multivariate statistical analysis

High-performance liquid chromatographic (HPLC) fingerprints of Pericarpium Citri Reticulatae (PCR) and Pericarpium Citri Reticulatae Viride (PCRV) were firstly measured for deliberately collected 39 authentic samples and 21 commercial samples. Both correlation coefficients of similarity for chromatograms and absolute peak areas of characteristic compounds were calculated for quantitative expression of the HPLC fingerprints. After principal component analysis (PCA) successfully distinguished the ‘mixed peels’ samples from authentic samples, partial least squares-linear discrimination analysis (PLS-LDA) was then effectively applied to class separation between authentic PCR and PCRV. Furthermore, the unequivocally determined compounds, hesperidin, nobiletin and tangeretin, were screened out by loadings plots of PCA and PLS-LDA. The results indicated that they could be used as chemical markers for discrimination among different groups of samples. The proposed method shows an efficient strategy for quality control of PCR and PCRV, which cannot only distinguish the ‘mixed peels’ but also discriminate authentic PCR and PCRV. This method has potential perspective for quality control of traditional Chinese medicine (TCM).     

Chromatographic and mass spectrometric fingerprinting analyses of Angelica sinensis (Oliv.) Diels-derived dietary supplements

Angelica sinensis (Oliv.) Diels (“Danggui” in Chinese) is one of the most commonly used traditional Chinese medicines. It has been used to invigorate blood circulation for the treatment of anemia, hypertension, chronic bronchitis, asthma, rheumatism, and cardiovascular diseases. There are a number of A. sinensis-derived dietary supplements in the US markets. However, no study have been conducted to investigate the quality of these dietary supplements. In this paper, high-performance liquid chromatographic and flow-injection mass spectrometric fingerprints were both evaluated to assess the consistency of A. sinensis-derived dietary supplements. Similarity analysis was carried out on the high-performance liquid chromatographic (HPLC) fingerprints. Meanwhile, principal component analysis (PCA) was performed on the data obtained from flow-injection mass spectrometric (FIMS) fingerprints, which can analyze each sample in 2 min, compared with 30 min required for the chromatographic fingerprint. Both methods show significant chemical differences between samples that may be due to differences in growing locations, growing conditions, harvesting times, and/or botanical processing. The loading plots obtained from PCA singled out the discriminatory ions that were responsible for chemical differences of A. sinensis-derived dietary supplements.

High-performance liquid chromatographic method with quantitative comparisons of whole chromatograms of raw and steamed Panax notoginseng

A high-performance liquid chromatographic (HPLC) method coupled with chromatographic pattern matching was developed to differentiate whole chromatograms of raw and steamed Panax notoginseng objectively and quantitatively. The major peaks differentiating chromatograms of raw and steamed samples were also identified for the first time in this herb. The raw and steamed P. notoginseng roots and its products were successfully differentiated. The quantitative differences between the chromatograms were correlated to the duration of steaming. Chromatographic pattern matching allows rapid, simple, automated, and quantitative comparisons of complex chromatograms. It is a useful tool in ensuring safety and quality of herbal products.     

High-performance liquid chromatographic fingerprint analysis for different origins of sea buckthorn berries

Using high-performance liquid chromatography (HPLC), a chemical fingerprint method was developed for investigating and demonstrating the variance of flavonoids among different origins of sea buckthorn berries. Thirty-four samples were analyzed including 15 RS (Hippophae rhamnoides ssp. sinensis) samples, 7 RY (H. rhamnoindes ssp. yunnanensis) samples, 5 RW (H. rhamnoides ssp. wolongensis) samples, 4 NS (H. neurocarpa ssp. stellatopilosa) samples and 3 TI (H. tibetana) samples. In the HPLC chromatograms, 12 compounds were identified as flavonoids, including quercetin 3-O-sophoroside-7-rhamnoside, kaempferol 3-O-sophoroside-7-O-rhamnoside, isorhamnetin 3-O-sophoroside-7-O-rhamnoside, isorhamnetin 3-O-glucoside-7-O-rhamnoside, quercetin 3-O-rutinoside, quercetin 3-O-glucoside, isorhamnetin 3-O-rutinoside, isorhamnetin 3-O-glucoside, quercetin, kaempferol 7-O-rhamnoside, kaempferol and isorhamnetin. Both correlation coefficient of similarity in chromatograms and relative peak areas of characteristic compounds were calculated for quantitative expression of the HPLC fingerprints. Our results revealed that the chromatographic fingerprint combining similarity evaluation could efficiently identify and distinguish sea buckthorn berries from different species. However, no obvious difference between RS and RY suggested that the two subspecies might have very close relationship in terms of chemotaxonomy. The established method was considered to be suitable for fingerprint analysis to check the genuine origin and control the quality of sea buckthorn berries and extracts.     

LC–DAD–MS Determination of the Major Constituents in Radix Angelicae sinensis

Column liquid chromatography with diode array and mass spectrometric detection was developed for the qualitative and quantitative analysis of the major constituents in Radix Angelicae sinensis. Sixteen compounds including phthalic acid, vanillic acid, ferulic acid, guaiacol, Z-6,7-epoxyligustilide, senkyunolide F, carvacrol, Z-ligustilide, Z-butylidenephthalide, E-6,7-dihydroxydihydroligustilide, senkyunolide I or senkyunolide H, coniferyl ferulate, sendanelolide, butylphthalide, E-ligustilide, E-butylidenephthalide except guaiacol and carvacrol were identified using online ESI–MS in comparisons with literature data and standard compounds. Nine compounds were quantified by LC–DAD simultaneously. For chromatographic analysis, a Merck C₁₈ column (5 μm, 250 mm × 4.6 mm) with a compatible guard column (C₁₈, 5 μm, 7.5 mm × 4.6 mm) was used. The mobile phase consisted of (A) 0.1% aqueous formic acid and (B) acetonitrile. Ten microliters of each sample solution were injected and eluted at a flow rate of 1 mL min^-1. The column temperature was maintained at 30 °C. The validation of this method proved good linear regression (r ² > 0.9992) within the test ranges, desirable repeatability with overall intra- and inter-day variations of less than 4.91% and well acceptable recoveries varied between 90.91 and 96.73% while the RSDs were below 3.23% (n = 3). The proposed method was successfully applied to the quantification of the nine components in sixteen samples from different localities in China. This assay provides a valid and an overall quality control of Radix Angelicae sinensis.