- Development and Optimization of an in Vitro Multienzyme Synthetic System for Production of Kaempferol from Naringenin
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An in vitro multienzyme synthetic system was developed and optimized to efficiently produce kaempferol in a single reaction tube. Two key genes, Atf3h and Atfls1, in the biosynthetic pathway of kaempferol were cloned into a prokaryotic expression vector and overexpressed in Escherichia coli. The recombinant proteins were purified through affinity chromatography and showed activities of flavanone 3-hydroxylase and flavonol synthase, respectively, followed by development of an in vitro synthetic system for producing kaempferol. The system contains 8.2 mM α-ketoglutaric acid, 0.01 mM ferrous ion, 0.4% sodium ascorbate, 25 μg/mL of each recombinant enzyme, and 10% glycerol in 100 mM Tris-HCl (pH 7.2). When the reaction was carried out at 40 °C for 40-50 min, the yield of kaempferol was 37.55 ± 1.62 mg/L and the conversion rate from NRN to KMF was 55.89% ± 2.74%. Overall, this system provides a promising and efficient approach to produce kaempferol economically.
- Zhang, Zhiping,He, Yanzhi,Huang, Yue,Ding, Li,Chen, Lei,Liu, Yaxian,Nie, Yesen,Zhang, Xinyue
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p. 8272 - 8279
(2018/07/30)
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- Stereospecific inhibition of nitric oxide production in macrophage cells by flavanonols: Synthesis and the structure-activity relationship
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To explore the structure-activity relationships on the inhibitory activity of flavanonols against nitric oxide (NO) production in inflammatory cells, we synthesized 19 flavanonols which shared a common 3,5,7-trihydroxychroman scaffold. A range of substitutions was included in the B ring in order to investigate the structure-activity relationship. We also succeeded in isolating stereoisomers from 16 of the flavanonols using chiral column chromatography. The inhibitory effects of these compounds on NO production were examined in RAW 264.7 cells (a murine macrophage-like cell line), which were activated by lipopolysaccharide (LPS). We only observed inhibitory activity against NO production in (2R,3R) stereoisomers, while the inhibitory activities of (2S,3S) stereoisomers were significantly weaker. We also evaluated the free radical scavenging potential of the flavanonols using 1,1-diphenyl-2-picrylhydrazyl (DPPH). Each stereoisomer indicated the equivalent DPPH scavenging potential as expected. The radical scavenging activity was not correlated with the inhibitory activity against NO. The inhibition of NO production by flavanonols is stereospecific and cannot simply be explained by their radical scavenging activity. We propose the possible existence of a 'target' molecule for flavanonols which is involved in the production and/or regulation of NO in RAW 264.7 cells.
- Jiang, Wen-Jun,Ishiuchi, Kan'Ichiro,Furukawa, Megumi,Takamiya, Tomoko,Kitanaka, Susumu,Iijima, Hiroshi
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p. 6922 - 6929
(2015/11/11)
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- Heterocycles. XXII. Stereoselective Synthesis of (+)-Aromadendrin Trimethyl Ether and Its Enantiomer, and Their Reduction
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Two enantiomeric chalcone epoxides 2a and 2b are synthesized under phase-transfer conditions using 1-benzylquinidinium chloride and 1-benzylquininium chloride as catalysts, respectively.Stereoselective cyclisation of 2a and 2b, followed by methylation and
- Takahashi, Hiroshi,Li, Shaoshun,Harigaya, Yoshihiro,Onda, Masayuki
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p. 1877 - 1881
(2007/10/02)
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- HETEROCYCLES. XVIII. SYNTHESIS OF THE RACEMATES OF NATURALLY OCCURRING FLAVONOIDS
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Racemic aromadendrin and fustin have been stereoselectively synthesized.Reduction of the O-substituted derivatives of these flavanonols provides the corresponding derivatives of gleditsin, leucopelargonidin and mollisacacidin (leucofisetinidin).
- Takahashi, Hiroshi,Kubota, Yumiko,Igushi, Mieko,Fang, Lin,Onda, Masayuki
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p. 369 - 377
(2007/10/02)
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