• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.186-186
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• 1998

Persicaria lapathifolia Gray (Polygonaceae) is a common weed in Korea. This plant and other Persicaria species including P. orientale and P. pubescens have been used as an analgesic and stomachic as well as for the treatment of rheumatoid arthritis and malaria. During the screening program of plant extracts, MeOH extract of P. scabrum showed anticomplement activity and the MeOH extract was partitioned with hexane, chloroform, ethyl acetate, and buthanol. EtOAc fraction showed strong activity and activity guided separation yielded eight flavonoids. Two known galloylated and a novel ferulloylated flavonoid glycosides showed strong anticomplement activity. Other flavonoid glycosides, kaempferol 3-O-${\alpha}$-$\sub$L/-arabinopyranoside, kaempferol 3-O-${\beta}$-$\sub$D/-glucopyranoside, kaempferol 3-O-${\beta}$-$\sub$D/-galactopyranoside, quercetin 3-O-${\alpha}$-$\sub$L/-arabinopyranoside, quercetin 3-O-${\beta}$-$\sub$D/-glucopyranoside, quercetin O-${\beta}$-$\sub$D/-galactopyranoside did not showed anicomplement activity.

• Journal of Plant Biotechnology
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• v.29 no.4
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• pp.265-275
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• 2002

Flavonoid biosynthesis is one of the most extensively studied areas in the secondary metabolism. Due to the study of flavonoid metabolism in diverse plant system, the pathways become the best characterized secondary metabolites and can be excellent targets for metabolic engineering. These flavonoid-derived secondary metabolites have been considerably divergent functional roles: floral pigment, anticancer, antiviral, antitoxin, and hepatoprotective. Three species have been significant for elucidating the flavonoid metabolism and isolating the genes controlling the flavonoid genes: maize (Zea mays), snapdragon (Antirrhinum majus) and petunia (Prtunia hybrida). Recently, many genes involved in biosynthesis of flavonoid have been isolated and characterized using mutation and recombinant DNA technologies including transposon tagging and T-DNA tagging which are novel approaches for the discovery of uncharacterized genes. Metabolic engineering of flavonoid biosynthesis was approached by sense or antisense manipulation of the genes related with flavonoid pathway, or by modified expression of regulatory genes. So, the use of a variety of experimental tools and metabolic engineering facilitated the characterization of the flavonoid metabolism. Here we review recent progresses in flavonoid metabolism: confirmation of genes, metabolic engineering, and applications in the industrial use.

• Korean Journal of Breeding Science
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• v.50 no.4
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• pp.351-363
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• 2018

In ornamental crops, the color and shape of flowers are one of the important traits. Generally, flower colors are determined by accumulating pigments such as carotenoids, flavonoids, and betalains. Among them, flavonoids are responsible for broad ranges of colors. Chrysanthemums are one of the most popular ornamental crops in the world, and there have been many efforts to change their flower color. In chrysanthemum flowers, cyanidin-based anthocyanin confers pink or red color, whereas terpenoid-based carotenoids are mainly responsible for yellow and green colors. However, blue colored chrysanthemums do not occur in nature. To date, there have been attempts to obtain blue or violet-colored chrysanthemum flowers through the introduction of a novel gene for accumulating delphinidin-based anthocyanins, while other studies have reported changing endogenous metabolites through the reconstruction of flavonoid biosynthesis. Since various transcription factors are involved in the regulation of flavonoid biosynthesis, it is important to understand not only the structural genes, but also the transcription factors required for the modification of flavonoid-based flower color. Therefore, in this paper, we describe the flavonoid biosynthetic pathway and its regulation, and review previous studies on the change in flower color through modification of flavonoid biosynthesis. This effort could be an important milestone in successfully achieving the modification of chrysanthemum flower color by means of plant biotechnology.

• Journal of Microbiology and Biotechnology
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• v.24 no.11
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• pp.1536-1541
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• 2014

Pinocembrin is a flavonoid that exhibits diverse biological properties. Although the major source of pinocembrin is propolis, it can be synthesized biologically using microorganisms such as Escherichia coli, which has been used to synthesize diverse natural compounds. Pinocembrin is synthesized from phenylalanine by the action of three enzymes; phenylalanine ammonia lyase (PAL), 4-coumarate:CoA ligase (4CL), and chalcone synthase (CHS). In order to synthesize pinocembrin from glucose in Escherichia coli, the PAL, 4CL, and CHS genes from three different plants were introduced into an E. coli strain. Next, we tested the different constructs containing 4CL and CHS. In addition, the malonyl-CoA level was increased by overexpressing acetyl-CoA carboxylase. Through these strategies, a high production yield (97 mg/l) of pinocembrin was achieved.

• Journal of Microbiology and Biotechnology
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• v.21 no.11
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• pp.1143-1146
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• 2011

Metabolic engineering of plant-specific phenylpropanoid biosynthesis has attracted an increasing amount of attention recently, owing to the vast potential of flavonoids as nutraceuticals and pharmaceuticals. Recently, we have developed a recombinant Streptomyces venezuelae as a heterologous host for the production of flavonoids. In this study, we successfully improved flavonoid production by expressing two sets of genes predicted to be involved in malonate assimilation. The introduction of matB and matC encoding for malonyl-CoA synthetase and the putative dicarboxylate carrier protein, respectively, from Streptomyces coelicolor into the recombinant S. venezuelae strains expressing flavanone and flavone biosynthetic genes resulted in enhanced production of both flavonoids.

• Journal of Microbiology and Biotechnology
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• v.6 no.5
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• pp.347-351
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• 1996

Flavonoid production by suspended cells of Scutellaria baicalensis Georgi was studied and the medium was optimized for cell growth and baicalin production. In SH medium the flavonoid production was not closely associated with the cell growth. A modified SH medium, FPM, was therefore designed for enhanced baicalin production. In FPM, both cell growth and baicalin production were increased by 1.5 times and 1.67 times than in the original SH medium, respectively. The increases could be attributed to the increased metabolic activities involved in the flavonoid biosynthesis as represented by enhanced activities of phenylalanine ammonia-lyase.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1361-1364
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• 2008

The inhibitory effects of naringenin, kaempherol, and apigenin on the production of cholesterol in HepG2 KCLB 88065 and MCF-7 KCLB 30022 cells were evaluated. In this study, quercetin was used as a reference reagent. After incubation for 3 days, fat-soluble contents of both cell types were extracted by using the Folch method and the cholesterol contents in both cultured cells were determined by high performance liquid chromatography. The concentration of cholesterol in untreated each tissue cells was $12.2{\pm}0.11$ and $8.83{\pm}0.12\;mg/g$ of lipid, respectively. The total concentration of each flavonoid was adjusted to 0, 35, or $350{\mu}M$ in the culture broth. As the results, the addition of 2% methanol and dimethyl sulfoxide (DMSO) to the media (control for flavonoid solvents) did not significantly affect cell growth; however, DMSO caused an increase in the production of cholesterol. Each flavonoid inhibited the production of cholesterol in both HepG2 and MCF-7 cells at the concentration of $35{\mu}M$ above. In addition, the inhibitory effect of kaempherol on the production of cholesterol in these cells was greater than the other flavonoids tested and HepG2 cells are more sensitive to flavonoids than MCF-7. From the results, the inhibitory effects of flavonoids on cholesterol production are different depending on the cell type.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2003.04a
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• pp.182-182
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• 2003

• Proceedings of the Korean Society of Crop Science Conference
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• 2019.09a
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• pp.155-155
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• 2019

• Proceedings of the Korean Society of Crop Science Conference
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• 2020.06a
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• pp.146-146
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• 2020