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Young Hae Choi

Bio: Young Hae Choi is an academic researcher from Leiden University. The author has contributed to research in topics: Metabolomics & Supercritical fluid extraction. The author has an hindex of 66, co-authored 255 publications receiving 14921 citations. Previous affiliations of Young Hae Choi include Kyung Hee University & Sogang University.


Papers
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Journal ArticleDOI
TL;DR: Based on the results the novel NADES may be expected as potential green solvents at room temperature in diverse fields of chemistry.

1,614 citations

Journal ArticleDOI
TL;DR: In this article, the authors studied metabolic networks and the reactions of organisms to various external conditions and showed that metabolic networks are a major tool for studying the metabolism of organisms and cells, and through this approach much has been learned about metabolic networks.
Abstract: Over the past decade, metabolomics has developed into a major tool for studying the metabolism of organisms and cells, and through this approach much has been learned about metabolic networks and the reactions of organisms to various external conditions ([Lay et al., 2006][1]). Most of this work

801 citations

Journal ArticleDOI
TL;DR: This protocol is particularly suited for the analysis of secondary metabolites such as phenolic compounds and for primary metabolites, and is rapid; it takes not more than 30 min for sample preparation and a further 10 min for NMR spectrum acquisition.
Abstract: Nuclear magnetic resonance (NMR)-based metabolomics has many applications in plant science. Metabolomics can be used in functional genomics and to differentiate plants from different origin, or after different treatments. In this protocol, the following steps of plant metabolomics using NMR spectroscopy are described: sample preparation (freeze drying followed by extraction by ultrasonication with 1:1 CD3OD:KH2PO4 buffer in D2O), NMR analysis (standard 1H, J-resolved, 1H–1H correlation spectroscopy (COSY) and heteronuclear multiple bond correlation (HMBC)) and chemometric methods. The main advantage of NMR metabolomic analysis is the possibility of identifying metabolites by comparing NMR data with references or by structure elucidation using two-dimensional NMR. This protocol is particularly suited for the analysis of secondary metabolites such as phenolic compounds (usually abundant in plants), and for primary metabolites (e.g., sugars and amino acids). This procedure is rapid; it takes not more than 30 min for sample preparation (multiple parallel) and a further 10 min for NMR spectrum acquisition.

751 citations

Journal ArticleDOI
TL;DR: The dilution effect on the structures and physicochemical properties of NADES and their improvements of applications using quercetin and carthamin are explored and provides the basis for modulating NADES in a controllable way for their applications in food processing, enzyme reactions, pharmaceuticals and cosmetics.

710 citations

Journal ArticleDOI
TL;DR: The potential of NADES for applications involving the extraction of bioactive compounds from natural sources is revealed and it is revealed that the extractability of both polar and less polar metabolites was greater with NADES than conventional solvents.
Abstract: Developing green solvents with low toxicity and cost is an important issue for the biochemical industry. Synthetic ionic liquids and deep eutectic solvents have received considerable attention due to their negligible volatility at room temperature, high solubilization ability, and tunable selectivity. However, the potential toxicity of the synthetic ionic liquids and the solid state at room temperature of most deep eutectic solvents hamper their application as extraction solvents. In this study, a wide range of recently discovered natural ionic liquids and deep eutectic solvents (NADES) composed of natural compounds were investigated for the extraction of phenolic compounds of diverse polarity. Safflower was selected as a case study because its aromatic pigments cover a wide range of polarities. Many advantageous features of NADES (such as their sustainability, biodegradability combined with acceptable pharmaceutical toxicity profiles, and their high solubilization power of both polar and nonpolar compounds) suggest their potential as green solvents for extraction. Experiments with different NADES and multivariate data analysis demonstrated that the extractability of both polar and less polar metabolites was greater with NADES than conventional solvents. The water content in NADES proved to have the biggest effect on the yield of phenolic compounds. Most major phenolic compounds were recovered from NADES with a yield between 75% and 97%. This study reveals the potential of NADES for applications involving the extraction of bioactive compounds from natural sources.

484 citations


Cited by
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28 Jul 2005
TL;DR: PfPMP1)与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1(PfPMP1)与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用,在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员,通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

18,940 citations

Journal ArticleDOI
TL;DR: All works discussed in this review aim at demonstrating that Deep Eutectic Solvents not only allow the design of eco-efficient processes but also open a straightforward access to new chemicals and materials.
Abstract: Within the framework of green chemistry, solvents occupy a strategic place. To be qualified as a green medium, these solvents have to meet different criteria such as availability, non-toxicity, biodegradability, recyclability, flammability, and low price among others. Up to now, the number of available green solvents are rather limited. Here we wish to discuss a new family of ionic fluids, so-called Deep Eutectic Solvents (DES), that are now rapidly emerging in the current literature. A DES is a fluid generally composed of two or three cheap and safe components that are capable of self-association, often through hydrogen bond interactions, to form a eutectic mixture with a melting point lower than that of each individual component. DESs are generally liquid at temperatures lower than 100 °C. These DESs exhibit similar physico-chemical properties to the traditionally used ionic liquids, while being much cheaper and environmentally friendlier. Owing to these remarkable advantages, DESs are now of growing interest in many fields of research. In this review, we report the major contributions of DESs in catalysis, organic synthesis, dissolution and extraction processes, electrochemistry and material chemistry. All works discussed in this review aim at demonstrating that DESs not only allow the design of eco-efficient processes but also open a straightforward access to new chemicals and materials.

3,325 citations

Journal ArticleDOI
TL;DR: In this article, the authors discuss evidence that upon pathogen or insect attack, plants are able to recruit protective microorganisms, and enhance microbial activity to suppress pathogens in the rhizosphere.

3,228 citations