Studies on the Chemical Constituents of Astragalus membranaceus Seedlings and Inula japonica Leaves

다국어 초록 (Multilingual Abstract)

In order to enhance the utility of medicinal plants, this research focused on previously unexplored parts: the seedlings of A. membranaceus and the leaves of I. japonica. Employing compound identification workflow in an MS-based metabolomic approach, this study aims to provide their chemical profile by identifying and analyzing major constituents with LC-MS. Initially, an LC-MS analysis was conducted to identify the major constituents of A. membranaceus seedlings and I. japonica leaves. Next, compounds were annotated by matching the MS/MS spectrum with those in public databases, leading to the discovery of compounds not previously reported in public databases. Then, the isolation and structure elucidation of the major constituents from A. membranaceus seedlings and I. japonica leaves was carried out to provide accurate structural information. As a result, from A. membranaceus seedlings, 28 compounds were identified, including eight new flavonol glycosides and a new natural flavonol glycoside: astraflavonols A–H (1–3, 7–10, and 12) and astraflavnol G (11). Among them, sesquiterpene-acylated flavonol glycosides were confirmed as compounds specific to A. membranaceus seeds and seedlings. In I. japonica leaves, 22 compounds were identified, including three new caffeoyl glucaric acids: inulajaponic acids A– C (29, 30, and 32). Among these, the caffeoylglucaric acid derivatives were reported for the first time in I. japonica leaves. Subsequently, the biological activities of the isolated compounds were evaluated through ROS inhibition activity assays. Notably, the astraflavonols C (3) and D (7) from A. membranaceus seedlings and the caffeoyl glucaric acid derivatives from I. japonica leaves exhibited antioxidant activities, suggesting their potential applications. In conclusion, this study accurately identified the chemical constituents from non- traditionally used parts of medicinal plants by applying integrated compound identification methods, enhancing their medicinal utility.

목차 (Table of Contents)

• CONTENTS
• LIST OF ABBREVIATIONS
• LIST OF FIGURES
• LIST OF TABLES
• ABSTRACT
• I. General Introduction
• 1. Study background
• 1.1. Medicinal plants as important source of drugs
• 1.2. The MS-based metabolomic approach in natural products research
• 1.3. Reactive Oxygen Species (ROS)
• 2. The objective of the research
• II. Part A: Astragalus membranaceus
• 1. Literature review
• 2. Materials and methods
• 2.1. Materials
• 2.1.1. Plant materials
• 2.1.2. Instruments and reagents
• 2.1.3. Software
• 2.2. Methods
• 2.2.1. UHPLC-Orbitrap-MS analysis
• 2.2.2. Data pre-processing and statistical analysis
• 2.2.3. Extraction and isolation of compounds from A. membranceus seedlings
• 2.2.4. Physical and spectroscopic data of isolated compounds 1–28
• 2.2.5. Alkaline hydrolysis
• 2.2.6. Acid hydrolysis and sugar analysis
• 2.2.7. Computational chemistry
• 2.2.8. ROS generation analysis
• 3. Results and discussion
• 3.1. LC-MS fingerprint analysis and chemical profiling of A. membranaceus
• 3.2. Isolation and identification of compounds from A. membranaceus’ seedlings
• 3.2.1. Compound 1
• 3.2.2. Compound 2
• 3.2.3. Compound 3
• 3.2.4. Compound 7
• 3.2.5. Compound 8
• 3.2.6. Compound 9
• 3.2.7. Compound 10
• 3.2.8. Compound 12
• 3.2.9. Identification of isolated compounds from A. membranaceus seedlings
• 3.3. Effect on ROS production of new compounds from A. membranaceus seedlings
• III. Part B: Inula japonica
• 1. Literature review
• 2. Materials and methods
• 2.1. Materials
• 2.1.1. Plant materials
• 2.1.2. Instruments and reagents
• 2.1.3. Software
• 2.2. Methods
• 2.2.1. Sample preparation
• 2.2.2. UHPLC-Orbitrap-MS analysis
• 2.2.3. Data pre-processing and statistical analysis
• 2.2.4. Feature-Based Molecular Networking (FBMN)
• 2.2.5. In silico fragmentation analysis
• 2.2.6. Isolation of phenolic compounds from I. japonica
• 2.2.7. Physical and spectroscopic data of isolated compounds 29–50
• 2.2.8. Alkaline hydrolysis
• 2.2.9. Cell culture
• 2.2.10. Cell viability
• 2.2.11. Intracellular ROS generation assay
• 2.2.12. Statistical analysis
• 3. Results and Discussion
• 3.1. UHPLC-Orbitrap-MS analysis
• 3.2. Chemical profiling of INJAE
• 3.3. Isolation and identification of major compounds from I. japonica leaves
• 3.3.1. Compound 29
• 3.3.2. Compound 30
• 3.3.3. Compound 32
• 3.3.4. Identification of isolated compounds from I. japonica leaves extract
• 3.4. Antioxidative effects of phenolic compounds from I. japonica
• 3.4.1. The effect of I. japonica 30% EtOH extract on TNF-α induced NHDFs
• 3.4.2. Cell viability of phenolic compounds from I. japonica on TNF-α-induced NHDFs
• 3.4.3. Effect on ROS production of phenolic compounds from I. japonica on TNF-α-induced
• NHDFs
• 3.4.4. Structure-activity relationship
• IV. Conclusion
• REFERENCES
• 국문초록