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Characterization of Novel Astragalin Galactosides Synthesized by β-Galactosidase from Bacillus circulans : β-Galactosidase를 이용한 신규 아스트라갈린 배당체의 특성 연구
DC Field | Value | Language |
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dc.contributor.advisor | 김도만 | - |
dc.contributor.author | 한송희 | - |
dc.date.accessioned | 2017-10-31T07:43:13Z | - |
dc.date.available | 2018-10-25 | - |
dc.date.issued | 2017-08 | - |
dc.identifier.other | 000000145273 | - |
dc.identifier.uri | https://hdl.handle.net/10371/137471 | - |
dc.description | 학위논문 (석사)-- 서울대학교 국제농업기술대학원 국제농업기술학과, 2017. 8. 김도만. | - |
dc.description.abstract | Astragalin (kaempferol-3-O-β-D-glucopyranoside) is a kind of flavonoid known to have anti-oxidant, anti-HIV, anti-allergic, and anti-inflammatory effects and low solubility in water. In this study, novel astragalin galactosides (Ast-Gals) were enzymatically synthesized with β-galactosidase from Bacillus circulans. Reaction conditions were optimized to maximize the conversion yield of astragalin. Purified Ast-Gal1 (11.6% of Ast used, w/w) and Ast-Gal2 (6.7% of Ast used, w/w) were obtained by medium pressure chromatography (MPLC) with silica C18 column and open column packed with Sephadex LH-20. The structures of Ast-Gal1 and Ast-Gal2 were identified by nuclear magnetic resonance (NMR) to be kaempferol-3-O-β-D-glucopyranosyl-(1→6)-O-β-D-galactopyranoside and kaempferol-3-O-β-D-glucopyranosyl-(1→6)-O-β-D-galactopyranosyl-(1→4)-O-β-D-galactopyranoside, respectively. The water solubility of Ast, Ast-Gal1, and Ast-Gal2 were 28.2 mg/L, 38,300 mg/L, and 38,800 mg/L, respectively. The antioxidant activities (The half maximal scavenging capacity, SC50) of Ast, Ast-Gal1, and Ast-Gal2 based on ABTS∙+ radical scavenging activity were 5.05 µM, 6.54 µM, and 4.91 µM, respectively. The angiotensin converting enzyme inhibition activities (ACE, the half maximal inhibitory capacity, IC50) of Ast, Ast-Gal1, and Ast-Gal2 were 171 µM, 191 µM, and 138 µM, respectively. | - |
dc.description.tableofcontents | Introduction 1
1. Flavonoid and astragalin 1 2. Glycosylation and acceptor reaction 2 3. β-Galactosidase 3 4. Purpose of this study 4 Materials and Methods 5 1. Transgalactosylation of astragalin 5 2. Optimization of acceptor reaction using RSM 6 3. Purification of Ast-Gals 8 4. Structure analysis of Ast-Gals using NMR 9 5. Biological characterization of novel Ast-Gals 10 5.1. Water solubility 10 5.1. ABTS·+ radical scavenging activity 11 5.1. ACE inhibitory activity 12 Results 13 1. Synthesis of novel Ast-Gals using β-galactosidase from Bacillus circulans 13 2. Optimization of acceptor reaction using RSM 16 3. Purification of Ast-Gals 22 4. Structure determination by NMR analysis 26 5. Biological characterization of Ast-Gals 42 5.1. Water solubility 42 5.1. ABTS·+ radical scavenging activity 44 5.1. ACE inhibitory activity 47 Discussion 51 Conclusion 53 References 54 Abstract in Korean 59 | - |
dc.format | application/pdf | - |
dc.format.extent | 1674322 bytes | - |
dc.format.medium | application/pdf | - |
dc.language.iso | en | - |
dc.publisher | 서울대학교 국제농업기술대학원 | - |
dc.subject | Astragalin | - |
dc.subject | Transgalactosylation | - |
dc.subject | β-Galactosidase | - |
dc.subject | Astragalin galactosides | - |
dc.subject.ddc | 631 | - |
dc.title | Characterization of Novel Astragalin Galactosides Synthesized by β-Galactosidase from Bacillus circulans | - |
dc.title.alternative | β-Galactosidase를 이용한 신규 아스트라갈린 배당체의 특성 연구 | - |
dc.type | Thesis | - |
dc.contributor.AlternativeAuthor | Songhee Han | - |
dc.description.degree | Master | - |
dc.contributor.affiliation | 국제농업기술대학원 국제농업기술학과 | - |
dc.date.awarded | 2017-08 | - |
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