Optimisation of ultra-performance LC conditions using response surface methodology for rapid separation and quantitative determination of phenolic compounds in Artemisia minor.

A method that couples rapid, sensitive, reproducible and accurate ultra-performance LC (UPLC) with quadrupole-TOF-MS was established for the first simultaneous qualitative and quantitative analysis of phenolic compounds in Artemisia minor. Box-Behnken designs (BBDs) were applied as an effective tool to optimise major parameters that influence the resolution of UPLC, including three gradient steps and column temperature. Under optimal UPLC conditions, a total of 23 phenolic compounds in the crude methanol extracts of A. minor were well separated on a Waters Acquity UPLC BEH C(18) column (100×2.1 mm, 1.7 µm particle size) within 16.5 min, and the compounds were unequivocally or tentatively identified via comparisons with authentic standards and literature. In this study, a total of six major phenolic compounds were quantified in A. minor and the method was validated to be sensitive, precise and accurate within the LOD from 1.24 to 5.27 µg/mL, and the overall intra- and inter-day variations in detection were less than 3.76%. The recovery of the method ranged from 97.9 to 103.8% with RSDs that were less than 5.8%. These results demonstrate that this approach has the potential for quality control of A. minor and other Tibetan herbal medicines.

An experimental design approach using response surface techniques to obtain optimal liquid chromatography and mass spectrometry conditions to determine the alkaloids in Meconopsi species.

A statistic approach using response surface methodology (RSM) for optimization of the ultra-high performance liquid chromatography (UHPLC) gradient and ionization response of electrospray ionization mass spectrometry (ESI-MS) to analyze the main alkaloids from the plant matrices of six Meconopsi species is presented. The optimization was performed with Box-Behnken designs (BBD) and the multicriteria response variables were described using global Derringer's desirability. Four parameters of UHPLC and six major parameters of ESI-MS were investigated for their contribution to analytes separation and response, leading to a total of 27 and 54 experiments being performed for each instrument, respectively. Quantitative analysis of four main alkaloids in nine samples from six Meconopsis species was employed to evaluate the statistical significance of the parameters on UHPLC-QTOF/ESI-MS analytes response. The results indicated that the optimized UHPLC-QTOF-MS method is very sensitive with the limit of detections (LODs) ranging from 0.5 to 0.1 ng/ml. The overall intra-day and the inter-day variations were less than 2.45%. The recovery of the method was in the range of 94.3-104.8% with RSD less than 4.0%. This approach has important implication in sensitivity enhancement of the ultra-trace determination of alkaloids from complex matrixes in the fields of natural products, metabolomics and pharmacokinetics.

Chemical constituents of the whole plants of Saussurea medusa.

The chemical constituents of the traditional Tibetan medicine of Saussurea medusa Maxim. (Compositae) were investigated and a new flavonoid glucoside, together with 14 known compounds, was isolated. The structure of the new compound was established as 6''-O-crotonoylhomoplantaginin by using one- and two-dimensional nuclear magnetic resonance spectroscopy and mass spectrometry analyses.

Development of an HPLC-DAD-ESI-MS(n) method for quantitative analysis of Saussurea tridactyla.

An improved HPLC-DAD-ESI-MS(n) method has been developed to simultaneously quantify eight major compounds in Saussurea tridactyla Sch.-Bip. ex Hook. f. which has long been used as a traditional Tibetan medicine. This method was validated to be sensitive, precise and accurate with the LODs of 0.11-5.01 microg/ml, the overall intra-day and inter-day variations less than 2.70%, and the overall recovery over 98.0%, respectively. The correlation coefficients (r(2)) of the calibration curves were higher than 0.991. This newly established method was successfully applied to reveal the difference in the chemical profiles and contents of these analyses in S. tridactyla from different localities. In addition, by comparison UV and MS spectra with those of authentic compounds and literatures, a total of fourteen peaks were identified. It can be concluded that this method was effective to ensure the safety and efficacy consistency of S. tridactyla, and can be applied to other traditional Tibetan medicinal plants from different resources in Tibet.

[Studies on chemical constituents of Saussurea laniceps].

OBJECTIVE: To investigate the chemical constituents of Saussurea laniceps. METHOD: The ethanol extract of S. laniceps was separated by means of silica gel chromatography. The compounds isolated from the plant were identified by their spectral evidence. RESULT: Fifteen compounds were isolated and identified as beta-stiosterol (1), umbelliferone (2), 4-hydroxyacetophenone (3), scopoletin (4), isoscopoletin (5), xuelianlactone (6), methyl 3-(2', 4'-dihydroxyphenyl) propanoate (7), apigenin (8), neoechinulin A (9), daucosterol (10), scopolin (11), xuelianlactone 8-O-beta-D-glcuoside (12), apigenin 7-glcuoside (13), apigenin 7-lutinoside (14) and syringin (15). CONCLUSION: Compounds 5-15 were isolated from S. laniceps, and among them, 7 and 9 were isolated from genus Saussurea for the first time.

Chemical fingerprint analysis of rhizomes of Gymnadenia conopsea by HPLC-DAD-MSn.

A high-performance liquid chromatography-diode array detection-tandem mass spectrometry (HPLC-DAD-MS(n)) method has been firstly developed for chemical fingerprint analysis of rhizomes of Gymnadenia conopsea R. Br. and rapid identification of major compounds in the fingerprints. Comparing the UV and MS spectra with those of reference compounds, seven main peaks in the fingerprints were identified as adenosine (1), 4-hydroxybenzyl alcohol (2), 4-hydroxybenzyl aldehyde (3), dactylorhin B (4), loroglossin (5), dactylorhin A (6) and militarine (7). Compounds 4-7 were succinate derivative esters and firstly discovered from this species. The Computer Aided Similarity Evaluation System (CASES) for chromatographic fingerprint of traditional Chinese medicine was employed to evaluate the similarities of 10 samples of the rhizomes of G. conopsea collected from Sichuan, Qinghai and Hebei provinces, Tibet autonomous region of China, and Nepal. These samples from different sources had similar chemical fingerprints. This method is specific and may serve for quality identification and comprehensive evaluation of this traditional Tibetan remedy.