Comparison of two Polygonum chinense varieties used in Chinese cool tea in terms of chemical profiles and antioxidant/anti-inflammatory activities.

Despite the extensive use of Polygonum chinense (PC) as a detoxifying ingredient of Chinese cool tea, the efficacy of different PC varieties remains underexplored. Herein, we compare the chemical profiles and antioxidant/anti-inflammatory activities of the aqueous extracts of two PC varieties, namely P. chinense var. chinense (PCC) and P. chinense var. hispidum (PCH). Ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MSMS) and multivariate analysis are used to rapidly identify extract components, while DPPH radical scavenging and xylene-induced mice ear edema assays are used to evaluate antioxidant and anti-inflammatory activities, respectively. Correlation analysis reveals that ellagic acid and quercitrin contents are positively correlated with the magnitude of the anti-inflammatory effect, and the adopted technique is concluded to allow for the rapid discrimination of PC varieties used in Chinese cool tea formulations.

Quantitative and Chemical Fingerprint Analysis of Desmodium styracifolium by High-Performance Liquid Chromatography Combined with Chemometrics.

In this study, a valid and comprehensive evaluation method for assessing the quality of Desmodium styracifolium (Osb.) Merr has been established, based on analysis of high-performance liquid chromatography fingerprint combined with the similarity analysis (SA), hierarchical cluster analysis (HCA), principal component analysis (PCA), discriminant analysis (DA) and the quantitative analysis multi-components by single marker (QAMS) method. Eleven peaks of the common model were obtained and analyzed using SA, HCA, PCA and DA analysis. These methods indicated a similar conclusion that 31 batches of D. styracifolium samples were categorized into two clusters basically coincident with their geographical regions of origin. Four peaks were identified as schaftoside, isoorientin, isoschaftoside and isovitexin. Schaftoside was selected as the internal standard, and the relative correction factors between schaftoside and the other three flavonoids were calculated using the QAMS method. The accuracy of the QAMS method was verified by comparing with the results calculated by the external standard method. No significant difference between the two methods was found. In conclusion, the established methods were scientifically applied in the quality evaluation of D. styracifolium.

Quantitative fingerprint and quality control analysis of Compound Liquorice Tablet combined with antioxidant activities and chemometrics methods.

BACKGROUND: Herbal medicine (HM), as a complex system, is difficult to investigate their quality consistency effectively by chromatographic fingerprinting obtained in a single detection method. Moreover, active compound discovery affords no information about pharmacological activity until late in the discovery process, and the interaction between HMs in vitro is not yet clear, which requires sufficient practice to prove their effectiveness. PURPOSE: Therefore, the purpose of this study was to improve the quality control methods of Compound Liquorice Tablet (CLT) using multi-wavelength fusion fingerprinting, explore the possible antioxidant components and assess the interaction between herbs combined with bioactivity evaluation. METHODS AND DESIGN: Once the theoretical standard preparation obtained in combination of multi-wavelength fusion fingerprinting and hierarchical clustering analysis, averagely linear quantified fingerprint method could rapidly calculate the composition similarities and efficiently quantify the multiple components of CLTs without any chemical standard. Furthermore, the fingerprint-efficacy relationship was investigated by integrating high performance liquid chromatography fingerprints with antioxidant activity assessment using the partial least squares model, which was capable of directly discovering the bioactive ingredients. Hereafter, combination index value was introduced to evaluate the correlation between the two antioxidant herbs in CLT formula. RESULTS: The results showed that CLT samples were effectively identified and quantified, and their quality was accurately distinguished. By analyzing the antioxidant evaluation results, it was found that CLT had strong antioxidant activity, and through the study on PLS model and antioxidant activity assay of individual compounds, it was found that the order of chemical constituents responsible for antioxidant activity in CLT was as follows: flavonoids > saponins > alkaloids. Finally, it was determined that the CI value of GE-PPCE was in the range of 1.20-1.61, indicating that the interaction of the GE-PPCE pair was a slight antagonism. CONCLUSION: Thus, this study provided a preferred way for monitoring the quality consistency of HM, exploring possible bioactive components of HMs and assessing the interaction between herbs.

Study on the source and characteristics of Evodia rutaecarpa based on chemical pattern recognition.

In this study, the appearance and texture of E. rutaecarpa were linked with the chemical constituents to explore methods of classification of E. rutaecarpa. The Chemometrics such as Hierarchical cluster analysis (HCA), principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) models were used for analysis. According to the models, samples of E. rutaecarpa were divided into three categories based on their source: Evodia, Stone Tiger and Sparse Evodia. The Evodia category could be subdivided into two categories, one representing large fruits with a greater degree of cracking and the other representing large fruits with little or no cracking. The method provided by this study combines chemometrics with HPLC fingerprints, which can provide a basis and reference for the identification of E. rutaecarpa and enables establishment of a grade standard.

Discovery of markers for discriminating the age of cultivated ginseng by using UHPLC-QTOF/MS coupled with OPLS-DA.

BACKGROUND: Ginseng (Ginseng Radix et Rhizoma, Panax ginseng C.A. Meyer) is gaining more publicity in modern society due to its health benefit and huge value in market. In the practice of grading and pricing of ginseng, the age is one of the major factor influencing the price and grade of ginseng. Therefore, the age discrimination is an important task for the quality control of ginseng. However, the traditional morphological methods are too subjective to be reproductive in discrimination. PURPOSE: To establish a method that can discriminate the ginseng samples with different cultivation years. STUDY DESIGN: To analyze the correlation between chemical compositions and cultivation years of cultivated ginseng samples of different age and thus discover potential quality marker (Q-marker) for discriminating the age of cultivated ginseng. METHODS: In the present study, the ultra-high performance liquid chromatography coupled with the quadrupole-time of flight mass spectrometry (UHPLC-QTOF/MS) were utilized for the age discrimination and marker discovery. A statistical data processing procedure was established to screen markers and reduce the false positive rate. RESULTS: The results showed that the ginseng samples from 2- to 6-year-old could be well separated in the orthogonal projections on the latent structure - discrimination analysis (OPLS-DA) using the markers screened by the established statistical procedure, which could reduce approximately 20% of the insignificant markers and false positive discoveries. Ultimately, more than 50 compounds contributing to the age discrimination were identified including one new compound (malonylginsenoside). One negative marker (1038.4825@8.98) was discovered for the 2-year-old ginseng, and an equation was established to effectively predict the age of 3- to 6-year-old of ginseng. CONCLUSION: The constructed method can discriminate the ginseng samples with different cultivation years and is a complement to the traditional discrimination method of ginseng age.

Application of a new method, orthogonal projection to latent structure (OPLS) combined with principal component analysis (PCA), to screening of prostaglandin E2 production inhibitory flavonoids in Scutellaria Root.

A new method consisting of orthogonal projection to latent structure (OPLS) and modified principal component analysis (PCA) was applied to a screening of bioactive compounds from natural products. In this report, extracts of 52 Scutellaria Root (the root of Scutellaria baicalensis Georgi) samples were analyzed by high-performance liquid chromatography (HPLC), and their inhibitory activities towards prostaglandin E2 (PGE2) production in a murine macrophage-like cell line J774.1 were examined. Wogonin and oroxylin A were predicted to be strong inhibitors of PGE2 production by OPLS analysis of the data. However, 6-methoxywogonin, which has been reported to have inhibitory activity, was omitted. Modified PCA was then applied to these data as a filter to exclude compounds less relevant to the activity, and OPLS analysis was applied to the modified data. As a result, this method predicted wogonin, oroxylin A and 6-methoxywogonin to be strong inhibitors of PGE2 production without any prior knowledge. The predictions by the OPLS combined with PCA method of PGE2 production inhibitory activities of 52 samples showed good agreement with the actual data. This method is simple and effective and can be used in screening of bioactive natural compounds without any prior knowledge.

Fingerprint analysis, multi-component quantitation, and antioxidant activity for the quality evaluation of Salvia miltiorrhiza var. alba by high-performance liquid chromatography and chemometrics.

Salvia miltiorrhiza Bge. var. alba C.Y. Wu and H.W. Li has wide prospects in clinical practice. A useful comprehensive method was developed for the quality evaluation of S. miltiorrhiza var. alba by three quantitative parameters: high-performance liquid chromatography fingerprint, ten-component contents, and antioxidant activity. The established method was validated for linearity, precision, repeatability, stability, and recovery. Principal components analysis and hierarchical clustering analysis were both used to evaluate the quality of the samples from different origins. The results showed that there were category discrepancies in quality of S. miltiorrhiza var. alba samples according to the three quantitative parameters. Multivariate linear regression was adopted to explore the relationship between components and antioxidant activity. Three constituents, namely, danshensu, rosmarinic acid, and salvianolic acid B, significantly correlated with antioxidant activity, and were successfully elucidated by the optimized multivariate linear regression model. The combined use of high-performance liquid chromatography fingerprint analysis, simultaneous multicomponent quantitative analysis, and antioxidant activity for the quality evaluation of S. miltiorrhiza var. alba is a reliable, comprehensive, and promising approach, which might provide a valuable reference for other herbal products in general to improve their quality control.

Development of on-line high performance liquid chromatography (HPLC)-biochemical detection methods as tools in the identification of bioactives.

Biochemical detection (BCD) methods are commonly used to screen plant extracts for specific biological activities in batch assays. Traditionally, bioactives in the most active extracts were identified through time-consuming bio-assay guided fractionation until single active compounds could be isolated. Not only are isolation procedures often tedious, but they could also lead to artifact formation. On-line coupling of BCD assays to high performance liquid chromatography (HPLC) is gaining ground as a high resolution screening technique to overcome problems associated with pre-isolation by measuring the effects of compounds post-column directly after separation. To date, several on-line HPLC-BCD assays, applied to whole plant extracts and mixtures, have been published. In this review the focus will fall on enzyme-based, receptor-based and antioxidant assays.

Application of a new optimization strategy for the separation of tertiary alkaloids extracted from Strychnos usambarensis leaves.

The HPLC separation of six alkaloids extracted from Strychnos usambarensis leaves has been developed and optimized by means of a powerful methodology for modelling chromatographic responses, based on three steps, i.e. design of experiments (DoE), independent component analysis (ICA) and design space (DS). This study was the first application of a new optimization strategy to a complex natural matrix. The compounds separated are the isomers isostrychnopentamine and strychnopentamine, 10-hydroxyusambarine and 11-hydroxyusambarine, also strychnophylline and strychnofoline. Three LC parameters have been optimized using a multifactorial design comprising 29 experiments that includes 2 center point replicates. The parameters were the percentage of organic modifiers used at the beginning of a gradient profile which consisted in different proportions of methanol (MeOH) and acetonitrile (MeCN), the gradient time to reach 70% of organic modifiers starting from the initial percentage and the percentage of MeCN found in the mobile phase. Subsequent to the experimental design application, predictive multilinear models were developed and used in order to provide optimal analytical conditions. The optimum assay conditions were: methanol/acetonitrile-sodium pentane sulfonate (pH 2.2; 7.5 mM) (33.4:66.6, v/v) at a mobile phase flow rate of 1 ml/min during a 40.6 min gradient time. The initial organic phase contained 3.7% MeCN and 96.3% MeOH. The method showed good agreement between the experimental data and predictive value throughout the studied parameters space. Improvement of the analysis time and optimized separation for the compounds of interest was possible due to the original and powerful tools applied. Finally, this study permitted the acquisition of isomers profiles allowing the identification of the optimal collecting period of S. usambarensis.

Validation, transfer and measurement uncertainty estimation of an HPLC-UV method for the quantification of artemisinin in hydro alcoholic extracts of Artemisia annua L.

Malaria is the world's most important parasitic infection with 500 millions cases annually and almost 2 millions death per year. This disease is more present in Sub-Saharan Africa where 90% of the infections are found. Artemisinin and its semi synthetic derivatives (artemether, artesunate) have actually the most powerful activity on malaria, even in its complicated forms and resistance cases. Various methods have been proposed for detection and quantification of artemisinin in Artemisia annua L. by HPLC-UV, but the plant extracts used for this quantification were extracts obtained with organic solvents (toluene, petroleum ether, hexane). To be able to use crude A. annua extracts prepared at low cost to formulate antipaludic drugs, we chose the use of a mixture of water and ethanol as solvent of extraction, but no adequate analytical method for this kind of extracts is published. The main objectives of this work were first to develop an analytical method for artemisinin quantification in hydro alcoholic extracts of A. annua. Second, this method had to be thoroughly validated by the research and development laboratory and, third, the transfer of this method to the routine laboratory had to be demonstrated. The final aim was to compare the estimation of measurement uncertainty obtained during the method validation with validation standards to measurement uncertainty estimates obtained during the method transfer study with real samples. The method was validated following the accuracy profile methodology and was found to be accurate in the concentration range of 10.0-54.0 µg/ml with CV<8%. Limit of detection and of quantification were 2.73 and 10.0 µg/ml, respectively. The method was then successfully transferred to a laboratory in Benin by showing that the quality of the results that it will generate during routine application of the method is sufficient. Finally, the measurement uncertainty of the method was estimated from the validation experiments as well as from the transfer study with authentic unspiked samples of A. annua. The comparison of these measurement uncertainty estimations showed that they were coherent. It confirmed thus that the estimation of measurement uncertainty from validation experiments predicts well the measurement uncertainty of real routine samples. This analytical method was thus shown to be convenient for routine analysis of hydro alcoholic extracts of A. annua in Benin.

Application of ultra-performance liquid chromatography/tandem mass spectrometry for the measurement of vitamin D in foods and nutritional supplements.

Ultra-performance liquid chromatography (UPLC)/MS/MS was applied to measure vitamin D in various foods and nutritional supplements. The run-time of the chromatographic separation was cut from 20 min in HPLC/MS/MS to 10 min in UPLC/MS/MS, while equal or better separation efficiency was achieved to deal with complex food matrixes. Under the optimized conditions, all the previtamins of vitamin D3, D2, and isotope-labeled vitamin D3 were baseline-separated from their corresponding vitamins. It was also demonstrated that many sterol isomers in complex food matrixes that interfere in the analysis could be well-separated from the analytes. Accuracy of this method was evaluated by analysis of NIST SRM 1849 infant formula reference material. With eight replicates, the average vitamin D3 concentration was 0.251 +/- 0.012 mg/kg, an excellent agreement with the certified value of 0.251 +/- 0.027 mg/kg. In addition, spike recovery from a commercial infant formula matrix was in the range of 100 to 108% for both vitamins D3 and D2 at three spike concentration levels. The spike recovery for an even more complex matrix, pet food, was 101-105%. LOQ values were 0.026 and 0.033 IU/g, or 0.086 and 0.11 IU/mL in solution, for vitamins D3 and D2, respectively. The dynamic range had three orders of magnitude, which made the method flexible and useful to deal with the wide concentration range of vitamin D in various samples. The method was robust based on the results of changing the parameters of LC separation and MS measurement. This accurate and reliable vitamin D method increased instrument efficiency and analysis productivity significantly.

[Theoretical and experimental studies on apparent solubility parameters of multiple components for Chinese materia medica with HPLC fingerprint].

OBJECTIVE: To establish the theories and methods to determine apparent solubility paraneters of multiple components for the Chinese materia medica (CMM) with HPLC fingerprint. METHOD: The mathematical functional expresses to determine the apparent solubility parameters for multiple constituents were established according to total quantum geometrical average retention time (TQGART) for HPLC fingerprint that characterized the entirety tendencies for all-over chromatographic peaks, validated by the aloe-emodin's solubility parameters which had been determined. The HPLC for the aloe-emodin's solubility parameters were carried out with an Alltech Apollo C18 as column, Acetone: Water as mobile phase, gradient elution,flow rate as 1.0 mL x min(-1), the detection wave-length as 430 nm and the temperature as 30 degrees C. RESULT: The mathematical functional model between the TQGART of HPLC chromatographic fingerprint and the total quantum apparent solubility parameters was established and used to determine the aloe-emodin's mixture solubility parameter as 36.12 J(1/2) x cm(-3/2), nearly equal to 35.57, 36.07 J(1/2) x cm(-3/2) calculated by ration of peak area ratios and molecular fraction, respectively. CONCLUSION: The TQGART of HPLC fingerprint can be used to determine simultaneously the apparent or single intrinsic solubility parameters for total quantum or intrinsic solubility parameters for single in multiple constitute systems, by which theoretical and technologic platform to study the compatibility rule and dosage form reform of the single CMM will be established.

Development of chromatographic methods for determination of agrimoniin and related polyphenols in pharmaceutical products.

Thin-layer chromatography (TLC) and liquid chromatography (LC) methods were developed for the qualitative and quantitative determination of agrimoniin, pedunculagin, ellagic acid, gallic acid, and catechin in selected herbal medicinal products from Rosaceae: Anserinae herba, Tormentillae rhizoma, Alchemillae herba, Agrimoniae herba, and Fragariae folium. Unmodified silica gel (TLC Si60, HPTLC LiChrospher Si60) and silica gel chemically modified with octadecyl or aminopropyl groups (HPTLC RP18W and HPTLC NH2) were used for TLC. The best resolution and selectivity were achieved with the following mobile phases: diisopropyl ether-acetone-formic acid-water (40 + 30 + 20 + 10, v/v/v/v), tetrahydrofuran-acetonitrile-water (30 + 10 + 60, v/v/v), and acetone-formic acid (60 + 40, v/v). Concentrations of the studied herbal drugs were determined by using a Chromolith Performance RP-18e column with acetonitrile-water-formic acid as the mobile phase. Determinations of linearity, range, detection and quantitation limits, accuracy, precision, and robustness showed that the HPLC method was sufficiently precise for estimation of the tannins and related polyphenols mentioned above. Investigations of suitable solvent selection, sample extraction procedure, and short-time stability of analytes at storage temperatures of 4 and 20 degrees C were also performed. The percentage of agrimoniin in pharmaceutical products was between 0.57 and 3.23%.

Chromatographic fingerprint analysis of Pycnogenol dietary supplements.

The bark of maritime pine (Pinus pinaster Aiton) has been widely used as a remedy for various degenerative diseases. A standard high-performance liquid chromatographic (HPLC) procedure for Pycnogenol analysis is a method specified in the United States Pharmacopeia (USP) monograph, which requires measurement of peak areas and identification of four components of the extract: caffeic acid, catechin, ferulic acid, and taxifolin. In this study, a fingerprint analysis using an HPLC method based on the USP monograph has been developed to provide additional qualitative information for the analysis of Pycnogenol-containing dietary supplements (PDS). Twelve commercially available PDS samples were purchased and analyzed along with a standard Pycnogenol extract. Their chromatographic fingerprints were analyzed using principal component analysis. The results showed that two of the samples were not consistent with the standard reference Pycnogenol extract. One contained other active ingredients in addition to Pycnogenol, and the other may have resulted from a quality control issue in manufacturing.

Quantitative determination of flavonoids by column high-performance liquid chromatography with mass spectrometry and ultraviolet absorption detection in Artemisia afra and comparative studies with various species of Artemisia plants.

A simple and specific analytical method for the quantitative determination of flavonoids from the aerial parts of the Artemisia afra plant samples was developed. By column high-performance liquid chromatography (HPLC) with UV absorption and mass spectrometry (MS) detection, separation was achieved on a reversed-phase octadecylsilyl (C18) column with water, methanol, and acetonitrile, all containing 0.1% acetic acid, as the mobile phase. These methods were used to analyze various species of Artemisia plant samples. The wavelength used for quantification of flavonoids with the diode array detector was 335 nm. The limits of detection (LOD) by HPLC/MS were found to be 7.5, 7.5, 10, 2.0, and 2.0 ng/mL; and by LC-UV the LODs were 500, 500, 500, 300, and 300 ng/mL for apigenin, chrysoeriol, tamarixetin, acacetin, and genkwanin, respectively. The HPLC/MS method was found to be 50-150 times more sensitive than the HPLC-UV method. HPLC/MS coupled with an electrospray ionization interface is described for the identification and quantification of flavonoids in various plant samples. This method involved the use of the [M+H]+ ions of the compounds at mass-to-charge ratio of 1.0606, 301.0712, 317.0661, 285.0763, and 285.0763 (calculated mass), respectively, in the positive ion mode with extractive ion monitoring.

Sampling and analytical variability associated with the determination of total aflatoxins and ochratoxin A in powdered ginger sold as a dietary supplement in capsules.

The U.S. Food and Drug Administration is studying the need to monitor dietary supplements for mycotoxins such as total aflatoxins and ochratoxin A. An effective mycotoxin-monitoring program requires knowledge of the sampling and analytical variability associated with the determination of total aflatoxins (AF) and ochratoxin A (OTA) in dietary supplements. Three lots of ginger sold as a powder in capsule form and packaged in individual bottles were analyzed for both AF and OTA. The total variability associated with measuring AF and OTA in powdered ginger was partitioned into bottle-to-bottle, within bottle, and analytical variances. The variances were estimated using a nested design. For AF and OTA, the within-bottle variance associated with the 5 g laboratory sample size was the largest component of variability accounting for about 43% and 85% of the total variance, respectively; the analytical variance accounted for about 34% and 9% of the total variability, respectively; and the bottle-to-bottle variance accounted for about 23% and 7% of the total variance, respectively. When the total variance is converted into the coefficient of variation (CV or standard deviation relative to the mean concentration), the CV is lower for AF (16.9%) than OTA (24.7%).

Multiple linear regression and artificial neural network retention prediction models for ginsenosides on a polyamine-bonded stationary phase in hydrophilic interaction chromatography.

The development of retention prediction models for the seven ginsenosides Rf, Rg1, Rd, Re, Rc, Rb2, and Rb1 on a polyamine-bonded stationary phase in hydrophilic interaction chromatography (HILIC) is presented. The models were derived using multiple linear regression (MLR) and artificial neural network (ANN) using the logarithm of the retention factor (log k) as the dependent variable for four temperature conditions (0, 10, 25, and 40 degrees C). Using stepwise MLR, the retention of the analytes in all the temperature conditions was satisfactorily described by a two-predictor model wherein the predictors were the percentage of ACN (%ACN) in the mobile phase and local dipole index (LDI) of the compounds. These predictors account for the contribution of the solute-related variable (LDI) and the influence of the mobile phase composition (%ACN) on the retention behavior of the ginsenosides. A comparison of the models derived from both MLR and ANN revealed that the trained ANNs showed better predictive abilities than the MLR models in all temperature conditions as demonstrated by their higher R(2) values for both training and test sets and lower average percentage deviation of the predicted log k from the observed log k of the test compounds. The ANN models also showed excellent performance when applied to the prediction of the seven ginsenosides in different sample matrices.

Statistical mixture design optimization of extraction media and mobile phase compositions for the characterization of green tea.

The influence of different solvents on the extraction medium and the RP-HPLC mobile phase composition were investigated by statistical mixture designs to optimize solvent proportions to prepare the fingerprint of a medicinal herbal extract. For modeling, the number of peaks was used as a measure of fingerprint information. The optimum compositions of solvent to extract chemical substances from green tea and for mobile phase chromatographic analysis were ethyl acetate/ ethanol/dichloromethane (20:5:75 v/v/v) and MeOH/ACN/water (7.5:57.5:35 v/v/v), respectively. This system results in 26 peaks in the chromatographic fingerprint. These results show that an incorrect choice of modifiers for mobile phase composition and solvent extraction hampers the detection of a maximum number of peaks and produces a poor chromatographic fingerprint.

High performance liquid chromatography for the determination of glucosamine sulfate in human plasma after derivatization with 9-fluorenylmethyl chloroformate.

In this study, we developed a simple, rapid, sensitive, and reliable method for the determination of glucosamine sulfate in human plasma, which was based on derivatization with 9-fluorenylmethyl chloroformate (FMOC-Cl) followed by reverse-phase HPLC-FLD. For the first time, FMOC-Cl was introduced into derivatization of glucosamine sulfate in human plasma. The amino groups of glucosamine sulfate and vertilmicin sulfate (the internal standard) were trapped with FMOC-Cl to form glucosamine-FMOC-Cl and vertilmicin-FMOC-Cl adducts, which can be very suitable for HPLC-FLD. Precipitation of plasma proteins by acetonitrile was followed by vortex mixing and centrifugation. Chromatographic separation was performed on a C18 column (DIAMONSIL 150 x 4 mm id, 5 microm) with a mobile phase gradient consisting of acetonitrile and water at a flow-rate of 1 mL/min. The retention times of glucosamine-FMOC-Cl and vertilmicin-FMOC-Cl adducts were 8.9 and 21.2 min, respectively. This method was shown to be selective and sensitive for glucosamine sulfate. The limit of detection was 15 ng/mL for glucosamine sulfate in plasma and the linear range was 0.1-10 mg/mL in plasma with a correlation coefficient (r) of 0.9999. The relative standard deviations (RSDs) of intra-day and inter-day assays were 5.2-8.1% and 6.1- 8.5%, respectively. Extraction recoveries of glucosamine sulfate in plasma were greater than 90%. The validated method was successfully applied to the determination of glucosamine sulfate in human plasma samples.

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.