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Choi Jungwon,Lee Hak-Dong,Cho Hyejin,Lee Chang-Dae,Tran Gia Han,Kim Hoon,Moon Sung-Kwon,Lee Sanghyun 한국응용생명화학회 2023 Applied Biological Chemistry (Appl Biol Chem) Vol.66 No.-
The constituents and antioxidant activities of Cyperus exaltatus var. iwasakii (CE) have not been studied to date. In this study, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzothiazoline-6 sulfonic acid) (ABTS) assays were used to evaluate the radical-scavenging activities of the ethanol extract, four fractions, and isolated compounds of CE. In addition, phenolic acids and flavonoids were isolated from the ethanol extract of CE using column chromatography. The compounds identified by spectroscopy were gallic acid, protocatechuic acid, vanillic acid, p-coumaric acid, rutin, ferulic acid, isoquercitrin, astragalin, quercetin, luteolin, apigenin, tricin, and kaempferol. Quantitative analysis using high-performance liquid chromatography (HPLC) revealed that the major flavonoids of CE were astragalin and tricin and that the major phenolic acid was p-coumaric acid. In addition, comparative analysis of CE from Ganghwa and Hampyeong habitats using HPLC showed that the Hampyeong CE had a higher phytochemical content. Comparative analyses of the isolated compounds were also conducted among five Cyperus species. The highest antioxidant activities were found in the ethyl acetate (EtOAc) fraction, and among the compounds isolated from CE, vanillic acid and quercetin showed remarkable antioxidant activity even when compared with ascorbic acid. The results demonstrate the usefulness of CE, which has not been sufficiently studied previously, and will facilitate the evaluation of its potential effectiveness as antioxidant functional plant material.
Development of an Analytical Approach for the Utilization of Edible Tree Sprouts
Jungwon Choi,김주리,이학동,조혜진,Leo Adrianne Paje,Hanna Shin,이상현 한국생약학회 2022 Natural Product Sciences Vol.28 No.1
This study evaluated the general nutritional ingredients such as crude fats, crude ashes, crude proteins, total polyphenols, and total flavonoids in 18 kinds of edible tree sprouts. The tree sprouts of Philadelphus schrenckii, Lycium chinense, and Morus alba had the highest crude fat, crude ash, and crude protein content, respectively. The tree sprouts of Cedrela sinensis (CSS) with high ABTS+ radical scavenging activities had a high content of total polyphenols (175.65 mg/g ext.) and total flavonoids (75.18 mg/g ext.). The simultaneous determination of flavonoids such as rutin, isoquercitrin, quercitrin, afzelin, and quercetin in CSS was conducted using high-performance liquid chromatography with a wavelength of 270 nm. Among the flavonoids, the content of quercitrin in CSS was the highest at 59.28 mg/g ext. This study also aids the quality control of many edible tree sprouts by analyzing the general components, total polyphenols, and total flavonoids.
REP1 Modulates Autophagy and Macropinocytosis to Enhance Cancer Cell Survival
Choi, Jungwon,Kim, Hyena,Bae, Young Ki,Cheong, Heesun MDPI 2017 INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES Vol.18 No.9
<P>Rab escort protein 1 (REP1), a component of the Rab geranyl-geranyltransferase 2 complex, plays a role in Rab protein recruitment in proper vesicles during vesicle trafficking. In addition to having well-known tissue degenerative phenotypes in the REP1 mutant, REP1 is tightly associated with cancer development and contributes to cell growth and survival. However, the functional mechanism of REP1 in cancer progression is largely uninvestigated. Here, we show that REP1 plays a crucial role in regulating mammalian target of rapamycin (mTOR) signaling and its downstream pathways, as well as autophagy and macropinocytosis, which are essential for cancer cell survival during metabolic stresses including starvation. REP1 small interfering RNA (siRNA) treatment downregulates mTORC1 activity in growing media, but blocks autophagosome formation under nutrient-depleted conditions. In contrast to the mild decrease of lysosomal enzyme activity seen in REP1 depletion, in REP1 knockdown the subcellular localization of lysosomes is altered, and localization of REP1 itself is modulated by intracellular nutrient levels and mTOR activity. Furthermore, REP1 depletion increases macro pinocytosis which may be a feedback mechanism to compensate autophagy inhibition. Concomitant treatment with macropinocytosis inhibitor and REP1siRNAresults in more significant cell death than autophagy blockade with REP1 knockdown. Therefore, REP1-mediated autophagy and lysosomal degradation processes act as novel regulatory mechanisms to support cancer cell survival, which can be further investigated as a potential cancer-targeting pathway.</P>
Resource Allocation for H-FDD OFDMA Systems
Choi, Jihwan P.,Jaesub Shin,Jungwon Lee,Hui-Ling Lou,Ji-Woong Choi IEEE 2014 IEEE communications letters Vol.18 No.7
<P>Half-frequency-division duplexing (H-FDD) has recently attracted attention since it can serve as a cost-effective solution for machine-to-machine (M2M) communication networks. This letter proposes a method to jointly optimize resource allocation, mobile station grouping, and frame partitioning for H-FDD orthogonal frequency-division multiplexing access systems. We develop a near-optimal and low-complexity algorithm that is also applicable to frequency-division duplexing and time-division duplexing as special cases. Simulation results demonstrate that our algorithm with reduced computation can provide performance close to that of the optimal but time-consuming exhaustive search.</P>
A Study on an Experience Exhibition Space for the Hearing-disabled using Ubiquitous Technology
Jungwon Choi,Hyunsuk Son,Yongseong Kim 한국콘텐츠학회 2009 ICCC International Digital Design Invitation Exhib Vol.2009 No.12
Modern Korea beings are more likely to pay attention to and spend time in leisure activities amid rapidly changing economic growth. However, unluckily, there are less cultural facilities and feasible plans for the disabled in spite of more efforts to set up environments for them. The purpose of this study is to present an exhibition space where the hearing-disabled can experience for themselves and meet their needs through applying ubiquitous technology. With ubiquitous technology applied for the disabled and to the space, auditory data could be imagined via visual means. This study presented a space where the handicapped can have more optimized experiences by applying ubiquitous technology while enhancing their limited hearing ability form visual and tactile means, in order to get information on sounds and rhythms.
( Jungwon Choi ),( Juree Kim ),( Sam Sik Kang ),( Sanghyun Lee ) 한국응용생명화학회(구 한국농화학회) 2021 Journal of Applied Biological Chemistry (J. Appl. Vol.64 No.1
Saikosaponin derivatives such as saikosaponins A, B1, B2, B3, B4, C, and D present in Bupleurum falcatum were analyzed by a high performance liquid chromatograph equipped with an evaporative light scattering detector, using different extraction solvents (water and 70% ethanol). The samples were injected into a YMC Pack Pro C<sub>18</sub> column and separated using a gradient elution system with a mobile phase composed of acetonitrile and water at a flow rate of 1.1 mL/min. The content of saikosaponin derivatives was higher in 70% ethanol extract than in water extract. This study provides an efficient analytical method for determining the optimal conditions for extraction of saikosaponin derivatives, which can be used as a basis for development of functional foods and pharmaceutical products from B. falcatum.
Quantitative analysis of cordycepin in Cordyceps militaris under different extraction methods
( Jungwon Choi ),( Leo Adrianne Paje ),( Baekjun Kwon ),( Jaekyu Noh ),( Sanghyun Lee ) 한국응용생명화학회(구 한국농화학회) 2021 Journal of Applied Biological Chemistry (J. Appl. Vol.64 No.2
Cordyceps militaris (CM) is one of the most important medicinal mushrooms known to possess various biological activities. Cordycepin (CP) is a bioactive compound present in the fruiting bodies of CM and is known to have anti-tumor, anti-metastatic immunomodulatory and anti-inflammatory activities. In this study, we aim to analyze CP quantitatively under various CM extraction conditions. CP was measured using high-performance liquid chromatography, quantified using a reversed phase column using a gradient elution system of water and acetonitrile, and detected with a UV absorbance wavelength of 260 nm. The CP content of CM was the highest in 100% ethanol extract of the fruiting bodies and 60% ethanol extract of the mycelium. This study provides an efficient analysis method to determine the optimal extraction conditions for CP that can be used as a basis for developing functional foods and pharmaceutical products derived from CM.
부모의 정신질환이 자녀의 영유아기 발달에 미치는 영향과 개입 방안에 대한 고찰
최정원(Jungwon Choi),박한선(Hanson Park) 대한신경정신의학회 2021 신경정신의학 Vol.60 No.1
The impact of maternal mental health on parenting and infant development is significant. Infants of mothers who have experienced perinatal mental health problems have genetic risks as well as risks in establishing a stable mother-child relationship, which interferes with the infants’ emotional, cognitive, and social development. Biological, psychological, and inpatient treatments, such as mother-baby unit at the highest risk after childbirth, have been attempted to minimize the negative consequences of perinatal mental disorder. Mother-child psychotherapy is also helpful in improving a mother-child relationship and strengthening the parenting ability.