• Korean Journal of Pharmacognosy
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• v.51 no.4
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• pp.255-263
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• 2020

Ginsenosides are considered to be the most important ingredients in ginseng. They are chemically converted by endogenous organic acids contained in ginseng and the heat applied during red ginseng processing. During this procedure, various converted ginsenosides are produced through hydrolysis of substitute sugars of ginsenosides and forming double bonds through dehydration in the dammarane skeleton. In order to study the conversion mechanism of protopanaxadiol-type ginsenosides during the heat treatment process of ginseng, we purified the three final converted ginsenosides by heating fresh ginseng for a long time. The three isolated ginsenosides were identified as 25(OH)-ginsenoside Rg5, 25(OH)-ginsenoside Rz1 and 25(OH)-ginsenoside Rg3 through NMR spectrum analysis. As a result of quantification of ginseng heated at 100 ℃ for 0 to 6 days by HPLC/UV and TLC methods, the content of 25(OH)-ginsenosides tended to increase in proportion to the time exposed to heat. In particular, the content of 25(OH)-ginsenosid Rg5 was confirmed to be noticeably increased.

• Journal of Ginseng Research
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• v.15 no.3
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• pp.188-191
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• 1991

The mild hydrolysis of ginsenosie Re with 50% acetic acid gave a prosapogenin mixture, 20(R)- and 20(S)-ginsenoside Rg2. The products were acetylated to give the peracetates, which were further converted into 20(R)- and 20(S)-ginsenoside Rh1 by the alcoholic alkaline treatment.

• YAKHAK HOEJI
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• v.35 no.5
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• pp.432-437
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• 1991

A mixture of 20(R)- and 20(S)-ginsenoside Rg$_{3}$ was obtained under mild acidic hydrolysis from protopanaxadiol saponins, ginsenosides Rb$_{1}$, Rb$_{2}$, Rc and Rd. The product was acetylated to give the peracetates, which were further converted into 20(R)-ginsenoside Rg$_{3}$, 20(S)-ginsenoside Rg$_{3}$, 20(R)-ginsenoside Rh$_{2}$ and 20(S)-ginsenoside Rh$_{2}$ by the direct alkaline treatment depending upon two kinds of temperature conditions respectively. The structure and physicochemical properties of a prosapogenin, 20(R)-ginsenoside Rh$_{2}$, were investigated.

• Journal of Ginseng Research
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• v.40 no.4
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• pp.366-374
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• 2016

Background: In this study, we screened and identified an endophyte JG09 having strong biocatalytic activity for ginsenosides from Platycodon grandiflorum, converted ginseng total saponins and ginsenoside monomers, determined the source of minor ginsenosides and the transformation pathways, and calculated the maximum production of minor ginsenosides for the conversion of ginsenoside Rb1 to assess the transformation activity of endophyte JG09. Methods: The transformation of ginseng total saponins and ginsenoside monomers Rb1, Rb2, Rc, Rd, Rg1 into minor ginsenosides F2, C-K and Rh1 using endophyte JG09 isolated by an organizational separation method and Esculin-R2A agar assay, as well as the identification of transformed products via TLC and HPLC, were evaluated. Endophyte JG09 was identified through DNA sequencing and phylogenetic analysis. Results: A total of 32 ${\beta}$-glucosidase-producing endophytes were screened out among the isolated 69 endophytes from P. grandiflorum. An endophyte bacteria JG09 identified as Luteibacter sp. effectively converted protopanaxadiol-type ginsenosides Rb1, Rb2, Rc, Rd into minor ginsenosides F2 and C-K, and converted protopanaxatriol-type ginsenoside Rg1 into minor ginsenoside Rh1. The transformation pathways of major ginsenosides by endophyte JG09 were as follows: $Rb1{\rightarrow}Rd{\rightarrow}F2{\rightarrow}C-K$; $Rb2{\rightarrow}C-O{\rightarrow}C-Y{\rightarrow}C-K$; $Rc{\rightarrow}C-Mc1{\rightarrow}C-Mc{\rightarrow}C-K$; $Rg1{\rightarrow}Rh1$. The maximum production rate of ginsenosides F2 and C-K reached 94.53% and 66.34%, respectively. Conclusion: This is the first report about conversion of major ginsenosides into minor ginsenosides by fermentation with P. grandiflorum endophytes. The results of the study indicate endophyte JG09 would be a potential microbial source for obtaining minor ginsenosides.

• Journal of Ginseng Research
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• v.34 no.4
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• pp.288-295
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• 2010

Ginsenosides are the principal components responsible for the pharmacological and biological activities of ginseng. Ginsenoside Rd was transformed into compound K using cell-free extracts of food microorganisms, with Lactobacillus pentosus DC101 isolated from kimchi (traditional Korean fermented food) used for this conversion. The optimum time for the conversion was about 72 h at a constant pH of 7.0 and an optimum temperature of about $30^{\circ}C$. The transformation products were identified by thin-layer chromatography and high-performance liquid chromatography, and their structures were assigned using nuclear magnetic resonance analysis. Generally, ginsenoside Rd was converted into ginsenoside F2 by 36 h post-reaction. Consequently, over 97% of ginsenoside Rd was decomposed and converted into compound K by 72 h post-reaction. The bioconversion pathway to produce compound K is as follows: ginsenoside Rd$\rightarrow$ginsenoside F2$\rightarrow$compound K.

• Journal of Ginseng Research
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• v.38 no.1
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• pp.47-51
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• 2014

The transformation of ginsenoside Rb1 into a specific minor ginsenoside using Aspergillus niger KCCM 11239, as well as the identification of the transformed products and the pathway via thin layer chromatography and high performance liquid chromatography were evaluated to develop a new biologically active material. The conversion of ginsenoside Rb1 generated Rd, Rg3, Rh2, and compound K although the reaction rates were low due to the low concentration. In enzymatic conversion, all of the ginsenoside Rb1 was converted to ginsenoside Rd and ginsenoside Rg3 after 24 h of incubation. The crude enzyme (b-glucosidase) from A. niger KCCM 11239 hydrolyzed the ${\beta}$-($1{\rightarrow}6$)-glucosidic linkage at the C-20 of ginsenoside Rb1 to generate ginsenoside Rd and ginsenoside Rg3. Our experimental demonstration showing that A. niger KCCM 11239 produces the ginsenoside-hydrolyzing b-glucosidase reflects the feasibility of developing a specific bioconversion process to obtain active minor ginsenosides.

• Journal of Microbiology and Biotechnology
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• v.18 no.6
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• pp.1081-1089
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• 2008

A novel ginsenoside-hydrolyzing ${\beta}$-glucosidase was purified from Paecilomyces Bainier sp. 229 by a combination of Q-Sepharose FF, phenyl-Sepharose CL-4B, and CHT ceramic hydroxyapatite column chromatography. The purified enzyme was a monomeric protein with a molecular mass estimated to be 115 kDa. The optimal enzyme activity was observed at pH 3.5 and $60^{\circ}C$. It was highly stable within pH 3-9 and at temperatures lower than $55^{\circ}C$. The enzyme was specific to ${\beta}$-glucoside. The order of enzyme activities against different types of ${\beta}$-glucosidic linkages was ${\beta}$-(1-6)>${\beta}$-(1-2)>${\beta}$-(1-4). The enzyme converted ginsenoside Rb1 to CK specifically and efficiently. An 84.3% amount of ginsenoside Rb1, with an initial concentration of 2 mM, was converted into CK in 24 h by the enzyme at $45^{\circ}C$ and pH 3.5. The hydrolysis pathway of ginsenoside Rb1 by the enzyme was $Rb1{\to}Rd{\to}F2{\to}CK$. Five tryptic peptide fragments of the enzyme were identified by a newly developed de novo sequencing method of post-source decay (PSD) matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. By comparing the five identified peptide sequences with the NCBI database, this purified ${\beta}$-glucosidase proves to be a new protein that has not been reported before.

• Journal of Ginseng Research
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• v.42 no.4
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• pp.532-539
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• 2018

Background: Heat treatments are applied to ginseng products in order to improve physiological activities through the conversion of ginsenosides, which are key bioactive components. During heat treatment, organic acids can affect ginsenoside conversion. Therefore, the influence of organic acids during heat treatment should be considered. Methods: Raw ginseng, crude saponin, and ginsenoside $Rb_1$ standard with different organic acids were treated at $130^{\circ}C$, and the chemical components, including ginsenosides and organic acids, were analyzed. Results: The organic acid content in raw ginseng was 5.55%. Organic acids were not detected in crude saponin that was not subjected to heat treatment, whereas organic acids were found in crude saponin subjected to heat treatment. Major ginsenosides ($Rb_1$, Re, and $Rg_1$) in ginseng and crude saponin were converted to minor ginsenosides at $130^{\circ}C$; the ginsenoside $Rb_1$ standard was very stable in the absence of organic acids and was converted into minor ginsenosides in the presence of organic acids at high temperatures. Conclusion: The major factor affecting ginsenoside conversion was organic acids in ginseng. Therefore, the organic acid content as well as ginsenoside content and processing conditions should be considered important factors affecting the quality of ginseng products.

• Microbiology and Biotechnology Letters
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• v.42 no.4
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• pp.347-353
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• 2014

${\beta}$-Glucosidase from Aspergillus usamii KCTC 6954 was used to convert ginsenoside Rb1 to compound K, which has a high bio-functional activity. The enzymatic activities during culturing for 15 days were determined using ${\rho}$-nitrophenyl-${\beta}$-glucopyranoside. The growth rate of the strain and the enzymatic activity were maximized after 6 days (IU; $175.93{\mu}M\;ml^{-1}\;min^{-1}$). The activities were maximized at $60^{\circ}C$ in pH 6.0. During culturing, Rb1 was converted to Rd after 9 d and then finally converted to compound K at 15 d. In the enzymatic reaction, Rb1 was converted to the ginsenoside Rd within 1 h of reaction time and compound K could be detected after 8 h. As a result, this study demonstrates that $Rb1{\rightarrow}Rd{\rightarrow}F2{\rightarrow}$compound K is the main metabolic pathway catalyzed by ${\beta}$-glucosidase and that ${\beta}$-glucosidase is a feasible option for the development of specific bioconversion processes to obtain minor ginsenosides such as Rd and compound K.

• The Korean Journal of Food And Nutrition
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• v.25 no.3
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• pp.629-636
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• 2012

Ginsenosides, ginseng saponin, are the principal components responsible for the pharmacological and biological activities of ginseng. In order to improve absorption and biological activities, the biotransformation of major ginsenoside to minor ginsenoside, as the more active compound, is required. In this study, we isolated Lactobacillus brevis THK-D57, which has high ${\beta}$-glycosidase activity, from Kimchi. The major ginsenoside Rb1 was converted to the minor ginsenoside 'compound K' during the fermentation of L. brevis THK-D57. The results propose that the biotransformation pathway to produce compound K is as follows: ginsenoside $Rb_1{\rightarrow}ginsenoside$ $Rd{\rightarrow}ginsenoside$ $F_2{\rightarrow}ginsenoside$ compound K.