• Korean Journal of Medicinal Crop Science
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• v.13 no.2
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• pp.91-94
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• 2005

Plants have been known to accumulate a very diverse range of triterpene saponins. We have investigated the regulation of saponin biosynthesis in higher plants using Centella asiatica (L.) Urban as a model plant. Effects of a feeding precursor on asiaticoside production from leaves and on the level of two-type OSCs mRNA were investigated. As a feeding precursor, squalene negatively affected the levels of CYS and bAS mRNA, but it also decreased the production of asiaticoside from whole plants. Plant hormones regulate secondary metabolism, and in plant tissue cultures they could affect both culture growth and secondary metabolite production. Although enhancement of asiaticoside production from whole plant cultures by addition of TDZ (thidiazuron) has been reported, the positive effect of TDZ on the levels of OSCs transcripts was not observed.

• Korean Journal of Medicinal Crop Science
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• v.13 no.5
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• pp.233-236
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• 2005

Centella asiatica accumulates large amounts of triterpene saponin, such as centellasaponin, asiaticoside, madecassoside. We examined the effect of two candidates, MJ (Methyl jasmonate) and TDZ (thidiazuron), on asiaticoside production and the accumulation of bAS mRNA associated with asiaticoside biosynthesis in leaves of cultured whole plants. The growth of whole plants treated with 0.1 mM MJ was found to decrease significantly, however, the growth of whole plants treated with 0.1 mM MJ plus 0.025 mg/l TDZ was better than that treated with MJ alone. When MJ alone was added to culture medium, asiaticoside contents in leaves were higher than that of control after 7 days of treatments. The maximum level of bAS $({\beta}-amyrin\;synthsae)$ mRNA in leaves of whole plant treated TDZ and MJ was transiently observed after exposure to 5 days. These results showed the up-regulation of bAS gene by adding TDZ and MJ at the molecular level, however, synergic effects of TDZ and MJ on asiaticoside biosynthesis were not testified.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.284-284
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• 2005

• Journal of Plant Biotechnology
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• v.36 no.4
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• pp.352-359
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• 2009

Panax ginseng roots produce triterpene saponins called ginsenosides, which are high value secondary metabolites and has been used as drugs, detergents, sweeteners, and cosmetics. In the recent years plant cell, tissue and organ cultures have developed as important alternative sources for the saponin production in Panax ginseng. Adventitious roots and hairy roots have been successfully induced and cultured for the improvement of saponin contents. Genetic and metabolic engineering to regulate saponin biosynthesis in P. ginseng might be important way to improve the medicinal values of P. ginseng. Here we introduced the protocol of genetic transformation and recent progress of functional characterization of genes involved in saponin biosynthesis in P. ginseng.

• 한국인삼전략화협의회:학술대회논문집
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• v.2003 no.09
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• pp.54-63
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• 2003

"Korea ginseng (Panax ginseng C.A Meyer) is an important medicinal plant. Its root has been used as an herbal medicine that provides resistance to stress and disease, and prevents exhaustion since the ancient time. Ginsenosides, glycosylated triterpene (saponin), are considered to be the main active compounds of the ginseng root. Despite of considerable commercial interests of ginsenosides, very little is known about the genes and their biochemical pathways for ginsenoside biosynthesis. This work will focus on the identification of genes involved in ginsenoside biosynthesis and the dissection of ginsenoside biosynthetic pathway using a functional genomics tool. Expression sequence tags (ESTs) provide a valuable tool to discovery the genes in secondary metabolite biosynthesis. We generated over 21,155 ginseng ESTs that is now sufficient to facilitate discovering the genes involved in ginsenoside biosynthesis such as oxidosqualene cyclase(OSC), cytochrome P450 and glycosyltransferase. With ESTs information, microarray technology will be used for the analysis of gene expression, and the identification of genes including transcription factors expressed in tissues under given experimental condition. Heterogous system such as yeast and plants will allow us to do the functional analysis. And selected ginseng hairy root which show variation in ginsenoside production will be used as a material for functional analysis of candidate gene. Functional genomics approach will successfully accelerate gene discovery, and also provide promises of metabolic engineering for the ginsenoside production."

• Proceedings of the Plant Resources Society of Korea Conference
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• 2012.05a
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• pp.20-20
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• 2012

Isoprenoids represent the most diverse group of metabolites, which are functionally and structurally identified in plant organism to date. Ginsenosides, glycosylated triterpenes, are considered to be the major pharmaceutically active ingredient of ginseng. Its backbones, categorized as protopanaxadiol (PPD), protopanaxatriol (PPT), and oleanane saponin, are synthesized via the isoprenoid pathway by cyclization of 2,3-oxidosqualene mediated with dammarenediol synthase or beta-amyrin synthase. The rate-limiting 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR), which is the first committed step enzyme catalyzes the cytoplasmic mevalonate (MVA) pathway for isoprenoid biosynthesis. DXP reductoisomerese (DXR), yields 2-C-methyl-D-erythritol 4-phosphate (MEP), is partly involved in isoprenoid biosynthesis via plastid. Squalene synthase and squalene epoxidase are involved right before the cyclization step. The triterpene backbone then undergoes various modifications, such as oxidation, substitution, and glycosylation. Here we will discuss general biosynthesis pathway for the production of ginsenoside and its modification based on their subcellular biological functions.

• 한국약용작물학회:학술대회논문집
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• 2007.11a
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• pp.322.2-322.2
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• 2007

• Archives of Pharmacal Research
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• v.22 no.4
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• pp.428-431
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• 1999

Seven known oleanolic acid glycosides (1-7) were isolated form the MeOH extract of Tiarella polyphylla. The structures were identified to be 3-O-($\beta$-glucopyranosyl) oleanolic acid (1), 3-O-[$\beta$-D-glucopyranosyl-(1 3)-$\beta$-D-glucopyranosyl] oleanolic acid (2), 3-O-D-[$\beta$-D-glucopyranosyl-(1 2)-$\beta$-D-glycopyranosyl] oleanolic acid (3), 3-O-[$\beta$-D-glucopyranosyl-(1 3)-$\beta$-D-glucopyranosyl] oleanolic acid 28-O-$\beta$D-glucopyranosyl ester (4), 3-O-[$\beta$-D-glucopyranosyl-(1 2)-$\beta$-D-glucopyranosyl] oleanolic acid 28-O-$\beta$-D-glucopyranosyl ester (5), 3-O-[a-L-rahmnopyranosyl-(1 3)-$\beta$-D-glucururonopyranosyl] oleanolic acid (6), and 3-O-[$\alpha$-L-rhamnopyranosyl-(1 3)-$\alpha$-D-glucuronopyranosyl] oleanolic acid 28-O-$\alpha$-D-glucopyranosyl ester (7) on the basis of physicochemical and spectral data. These triterpene glycosides were tested for the anti-complement activity and hemolytic activity. Bisdesmosidic saponins, 4, 5, and 7, showed anti-complement activity; in contrast, monodesmosidic saponins, 1-3, and 6, showed direct hemolytic activity. Methyl esterified monodesmosidic saponins showed anti-complement activity at a low concentration and hemolytic activity at a high concentration.

• Molecules and Cells
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• v.22 no.3
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• pp.269-274
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• 2006

In order to characterize saikosaponin biosynthesis in Bupleurum falcatum, the expression of five isoprenoid pathway genes and their relationship to saikosaponin accumulation in the hairy roots were analyzed. The hairy roots exhibited a rapid accumulation of saikosaponins when incubated in a root culture medium (3XRCM). Homology-based RT-PCR was used to isolate core fragments of five genes, HMGR, IPPI, FPS, SS, and OSC, from the hairy roots. The deduced amino acid sequences exhibited amino acid identities of more than 85% to previously reported genes. Using the fragments as probes, the expression of these five genes in the hairy roots during incubation in 3XRCM medium was examined. Expression of all five genes in the hairy roots increased soon after incubation. In particular, the SS and OSC genes were coordinately induced at 8 days of incubation, and their expression persisted throughout the incubation period. A quantitative HPLC analysis showed that the saikosaponin content of the hairy root culture also began to increase at 8 days of culture. The correlation between SS transcript level and saikosaponin content in the hairy roots suggests that transcriptional regulation plays a regulatory role in saikosaponin biosynthesis.

• Korean Journal of Medicinal Crop Science
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• v.21 no.1
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• pp.32-38
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• 2013

FPS (farnesyl diphosphate synthase) plays an essential role in organ development in plants. However, FPS has not previously been identified as a key regulatory enzyme in triterpene biosynthesis. In order to investigate the effect of FPS on ginsenosides biosynthesis, we over-expressed FPS of Centella asiatica (CaFPS) in Panax giseng adventitious roots. PCR analysis showed the integrations of the CaFPS and hygromycin phosphotransferase genes and we ultimately selected three lines. The result of Southern blot analysis demonstrated the introduction of the CaFPS gene into genome of ginseng. In addition, the results of RT-PCR analysis revealed that CaFPS gene overexpression induced an accumulation of its transcription in the ginseng adventitious roots. To determine whether or not the overexpression of the CaFPS gene contributes to the downstream gene expression associated with triterpene biosynthesis, the level of mRNAs was analyzed by real-time PCR. The result showed that no differences were detected in any expression of all genes. To determine quantitatively the content of ginsenosides in transgenic ginseng adventitious roots, HPLC analysis was conducted. The content of total 7 ginsenosides was increased to 1.8, 1.4, and 1.7 times than that of the controls, respectively. This indicated that the overexpression of CaFPS in ginseng adventitious roots causes an increase in ginsenoside content, although down stream genes of FPS gene were suppressed by CaFPS overexpression.