Study Of Lobelia Chinensis Lour.Using Modern Liquid Chromatography Coupled With Mass Spectrometry

(Lobelia chinensis Lour.) is a traditional Chinese medicine. It is principally used in the treatment of poisonous snake bites, varies of inflammation and cancers. In this paper, we screened the extract method of Lobelia chinensis Lour., studied the chromatographic condition of the separation of extract and established the HPLC fingerprint of Lobelia chinensis Lour. for the first time. Similarity Analysis (the vectorial angle cosine method), Hierarchical Cluster and principal component analysis have been used to evaluate the quality of Lobelia chinensis Lour. from different area. An approach of comprehensive two-dimensional liquid chromatography combined with mass spectrometry for analysis of compounds in Lobelia chinensis Lour. using an ES/APCI multimode ionization source was established. At least 536 components were separated and 6 of them were identified.This paper is divided into four chapters as follows:Chapter 1 briefly introduced the background and significance of the thesis, including the chemical constituents and pharmacological activities of Lobelia chinensis Lour., the importance of TCM fingerprints and the principle and advances in studies on multidimensional HPLC.In Chapter 2, we developed the extraction method and chromatographic condition of the separation of Lobelia chinensis Lour.. The extraction method is:"1 g of powdered herb mixed with 50 mL methanol was heated to boil for 1 h."which was based on the standard of the number of total peaks and their area and the optimization of 3 factors: the extraction solvent, the extraction method, the extraction time.The chromatographic condition is: column: 250 mm×4.6 mm i.d. packed with 5μm Diaso ODS; mobile phase: water - methanol; gradient conditions: 0% - 100% - 100% methanol (0 - 40 - 50 min); Flow rate: 1.0 mL/min; detection wavelength: 260 nm. The methanol extract of Lobelia chinensis Lour. was separated well in the above condition and 11 peaks with good resolution were obtained.In Chapter 3, the HPLC fingerprint of Lobelia chinensis Lour. was established for the first time. The software of"similarity evaluation system for chromatographic fingerprint of TCM (Version 2004A)"was used to evaluate the similarity of Lobelia chinensis Lour. extract. The result showed that the similarity values of 8 batches of samples were more than 0.96 except Sample 5 (0.672) and Sample 10 (0.750) indicating that the quality of the 8 batches is stable. Besides, hierarchical cluster and principal component analysis were used to evaluate the quality of Lobelia chinensis Lour. from different area as well, the result was in accordance with the similarity evaluation and the identification of expert. The study of HPLC fingerprint of Lobelia chinensis Lour. may be used as a standard for the quality control of Lobelia chinensis Lour. which focused more on the chemical property of the plant rather than the different growth areas of the plant.In Chapter 4, an approach of comprehensive two-dimensional liquid chromatography combined with mass spectrometry for the analysis of compounds in Lobelia chinensis Lour. using an ES/APCI multimode ionization source was established. A CN column was used as first dimensional column and an ODS column was used as second dimensional column which followed by a photo diode array (PDA) detector and ES/APCI MS. The results demonstrated that high peak capacity and high resolution were achieved. More than 536 components in the Lobelia chinensis Lour. extract were detected and 6 of them were preliminary identified.In conclusion, the modern liquid chromatography coupled with MS was successfully used in the study on Lobelia chinensis Lour.. We established the HPLC fingerprint of Lobelia chinensis Lour. extract for the first time, evaluated the quality of this plant and developed 2D-HPLC-PDA-MS method for the separation and identification of the ingredients in the Lobelia chinensis Lour. extract. The method developed is suitable for the analysis of TCM and other complex samples.