Biotransformation Of Ginsenosides Research Articles

Biotransformation of ginsenosides by glycoside hydrolase from an endophytic fungus of Panax ginseng

Endophytes, symbiotically with their host plants, are frequently found in the roots of Panax ginseng. To explore ginsenosides biotransformation by endophytic fungi, 26 such fungi were isolated from ginseng roots sourced from four distinct planting regions, and their glycosyl hydrolysis activities were measured. Of these endophytic, 20 isolates exhibited glycosidase enzymes capable of cleaving glycosidic bonds of glucose, arabinofuranose and arabinopyranose. Notably, the glycosidase BglNh gene was isolated and cloned from Nectria haematococca, one of the endophytic fungi. Enzymatic assessments unveiled that BglNh specifically catalyzes the hydrolysis of glucose residues located external to the C-3 position of protopanaxadiol ginsenosides under optimal reaction conditions (pH 6.0 and temperature 35 °C). Our findings demonstrate the efficient conversion of major ginsenosides Rb1, Rb2 and Rc to minor ginsenosides Gyp17, CO and CMc1, highlighting the potential of these fungi for ginsenoside biotransformation and bioactive compound production.

Biotransformation of Ginsenoside Rb1 to Ginsenoside Rd and 7 Rare Ginsenosides Using Irpex lacteus with HPLC-HRMS/MS Identification.

The biotransformation of ginsenosides using microorganisms represents a promising and ecofriendly approach for the production of rare ginsenosides. The present study reports on the biotransformation of ginsenoside Rb1 using the fungus Irpex lacteus, resulting in the production of ginsenoside Rd and seven rare ginsenosides with novel structures. Employing high-performance liquid chromatography coupled with high-resolution tandem mass spectrometry, the identities of the transformation products were rapidly determined. Two sets of isomers with molecular weights of 980.56 and 962.55 were discovered among the seven rare ginsenosides, which were generated through the isomerization of the olefin chain in the protopanaxadiol (PPD)-type ginsenoside skeleton. Each isomer exhibited characteristic fragment ions and neutral loss patterns in their tandem mass spectra, providing evidence of their unique structures. Time-course experiments demonstrated that the transformation reaction reached equilibrium after 14 days, with Rb1 initially generating Rd and compound 5, followed by the formation of other rare ginsenosides. The biotransformation process catalyzed by I. lacteus was found to involve not only the typical deglycosylation reaction at the C-20 position but also hydroxylation at the C-22 and C-23 positions, as well as hydrogenation, transfer, and cyclization of the double bond at the C-24(25) position. These enzymatic capabilities extend to the structural modification of other PPD-type ginsenosides such as Rc and Rd, revealing the potential of I. lacteus for the production of a wider range of rare ginsenosides. The transformation activities observed in I. lacteus are unprecedented among fungal biotransformations of ginsenosides. This study highlights the application of a medicinal fungi-based biotransformation strategy for the generation of rare ginsenosides with enhanced structural diversity, thereby expanding the variety of bioactive compounds derived from ginseng.

The interaction between ginseng and gut microbiota.

The importance of the gut microbiota to human health is attracting increasing attention. It is also involved in ginseng metabolism, mediating the bioactive metabolites of ginsenosides. In response, ginseng, known as the king of herbs, can regulate intestinal flora, including promoting probiotics and restricting the growth of harmful bacteria. Specifically, the interactions between ginseng or ginsenosides and gastrointestinal microbiota are complex. In this review, we summarized the effects of ginseng and ginsenosides on the composition of gut microbiota and discussed the gut microbiota-mediated biotransformation of ginsenosides. In particular, their therapeutic potential and clinical application in related diseases were also summarized.

Engineered β-glycosidase from Hyperthermophilic Sulfolobus solfataricus with Improved Rd-hydrolyzing Activity for Ginsenoside Compound K Production.

Hyperthermophilic Sulfolobus solfataricus β-glycosidase (SS-βGly), with higher stability and activity than mesophilic enzymes, has potential for industrial ginsenosides biotransformation. However, its relatively low ginsenoside Rd-hydrolyzing activity limits the production of pharmaceutically active minor ginsenoside compound K (CK). In this study, first, we used molecular docking to predict the key enzyme residues that may hypothetically interact with ginsenoside Rd. Then, based on sequence alignment and alanine scanning mutagenesis approach, key variant sites were identified that might improve the enzyme catalytic efficiency. The enzyme catalytic efficiency (kcat/Km) and substrate affinity (Km) of the N264D variant enzyme for ginsenoside Rd increased by 60% and decreased by 17.9% compared with WT enzyme, respectively, which may be due to a decrease in the binding free energy (∆G) between the variant enzyme and substrate Rd. In addition, Markov state models (MSM) analysis during the whole 1000-ns MD simulations indicated that altering N264 to D made the variant enzyme achieve a more stable SS-βGly conformational state than the wild-type (WT) enzyme and corresponding Rd complex. Under identical conditions, the relative activities and the CK conversion rates of the N264D enzyme were 1.7 and 1.9 folds higher than those of the WT enzyme. This study identified an excellent hyperthermophilic β-glycosidase candidate for industrial biotransformation of ginsenosides.

Biotransformation of ginsenosides from Korean wild-simulated ginseng (Panax ginseng C. A. Mey.) using the combination of high hydrostatic pressure, enzymatic hydrolysis, and sonication

High hydrostatic pressure is a non-thermal processing technique for extracting functional compounds from herbal plants. This study aims to investigate the effectiveness of the combination of high hydrostatic pressure (HHP), enzymatic hydrolysis, and sonication for extracting wild-simulated ginseng (WSG) to improve yields of major and minor ginsenosides. By using LC-MS/MS analysis, the total ginsenoside yield was enhanced by 25.62% by increasing the pressure of HHP and sonication treatment (HHP-soni) extraction from 100 to 300 MPa. Furthermore, compared to HHP-soni at 100 MPa, adding two commercial food-grade enzymes (Viscozyme and Pectinex) resulted in a 1.23–1.43-fold increase in total ginsenoside contents, as well as a 1.09–1.95-fold increase in the contents of seven major ginsenosides. Similarly, HHP-soni with enzymes increased the yields of five minor ginsenosides (Ro, Rh1, F2, CO, and Rg3) by 1.76–30.24 times compared to extraction with Pectinex at 0.1 MPa. Ginsenoside compound K and protopanaxadiol were detected after extraction using Pectinex with HHP-soni, but not after extraction using Pectinex and sonication at 0.1 MPa. While the contents of the stereoisomers 20(S)-Rg3 and 20(R)-Rg3 were similar after extraction at pressures of 100 and 200 MPa, the 20(S)-Rg3 content was 1.87 times higher than the 20(R)-Rg3 content after HHP treatment at 300 MPa. From the analytical data, we inferred the hydrolytic pathways of the major to minor ginsenosides, and specifically the ginsenoside Rb1 standard, when using Pectinex under experimental conditions. These findings suggest that the combination process of HHP, sonication, and Pectinex treatment could improve the quality of WSG.

Pharmacological bioactivity of enzymatically bio-transformed ginsenosides

Many ginsenosides have shown positive effects, including anti-cancer potential and anti-inflammatory effects. Of note, protopanaxadiol (PPD) and protopanaxatriol (PPT) are not easily absorbed by the body through the digestive tract due to their hydrophilicity. From this point of view, the cytotoxic potencies of the hydrolysates of PPD and PPT on CRC are much stronger than their source compounds. Moreover, several minor ginsenosides that are absent naturally but have high disease ameliorative efficacy can be obtained from major ginsenoside by enzymatic hydrolysis. Therefore, the first aim of this study was to determine the effectiveness of the biotransformation of ginsenosides via enzymatic hydrolysis to improve their bioactivity. Second, the anti-inflammatory and anti-cancer effects of the raw and bio-transformed ginseng metabolites were determined in vitro. The results suggest that enzymes can effectively biotransform major ginsenosides (i.e., PPD and PPT) into minor ginsenosides (i.e., compound K) by hydrolyzing the β-glucosidic linkage. Moreover, the bio-transformed ginsenosides were effective in inhibiting the proliferation of HCT-116 cells and suppressing lipopolysaccharide-induced nitric oxide production in RAW 264.7 murine macrophages. Therefore, the enzymatic hydrolysis of ginsenosides can be employed to functionally produce hydrolysates with increased bioactivity.

Enhancement of biotransformation of ginsenosides in white ginseng roots by aerobic co-cultivation of Bacillus subtilis and Trichoderma reesei.

In the present work, the biotransformation of ginsenosides in white ginseng roots was innovatively investigated using the aerobic fermentation by the co-cultivation of Bacillus subtilis and Trichoderma reesei. It is found that in the co-cultivation mode, the optimal nitrogen source was corn steep liquor, and the loading of ginseng powder and inoculation proportion of B. subtilis and T. reesei were 15g/L and 1:4, respectively. The total ginsenoside yield and production of minor ginsenosides in the co-cultivation mode obviously enhanced in comparison to the monoculture mode. Meanwhile, the maximal total ginsenoside yield of 21.79% and high hydrolase activities were achieved using the staged inoculation at the inoculation proportion of 1:4 in the co-cultivation mode, the production of minor ginsenosides such as Rg3 and Rh1, Rh2 was significantly strengthened, and the pharmacological activities of the fermented solution obviously improved. The enhancement of ginsenoside transformation can be mainly attributed to hydrolysis of the produced hydrolases and metabolism of two probiotics. This result clearly reveals that using the staged inoculation in co-cultivation fermentation mode was favor of the ginsenoside biotransformation in ginseng due to non-synchronous cell growth and different metabolic pathways of both probiotics. This work can provide a novel method for enhancing ginsenoside transformation of ginseng.Key points• Co-cultivation fermentation significantly promoted ginsenoside biotransformation.• The staged inoculation in co-culture mode was an optimal operation method.• The pharmacological activity of the co-cultured solution was significantly enhanced.

Different absorption and metabolism of ginsenosides after the administration of total ginsenosides and decoction of Panax ginseng.

Panax ginseng C.A. Meyer (PG), which contains polysaccharides and ginsenosides as the major bioactive components, has been used to promote health and treat diseases for thousands of years in China. Total ginsenosides were extracted from a decoction of Panax ginseng (GD), which included both ginsenosides and polysaccharides, and dissolved in water to obtain a total ginsenosides aqueous solution (TGAS). To study their absorption and metabolism, the pharmacokinetics (PK) and metabolites of ginsenosides in vivo were investigated after the administration of GD and TGAS. Rat and mice plasma samples were collected after the administration of GD and TGAS. Ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry was used with the UNIFI platform to identify metabolites in the plasma sample. The pharmacokinetic parameters were calculated using a noncompartmental method in the Drug and Statistics software package. Thirty ginsenoside metabolites were identified in mice plasma, of which only seven were found in the rat plasma after the administration of GD. The PK of ginsenosides Rb1 , Rc, and Rd were also determined after the oral administration of GD and TGAS and showed significant differences in the pharmacokinetic parameters. There was no difference in the biotransformation pathways after the oral administration of GD and TGAS, indicating that there was no influence of polysaccharides on the biotransformation of ginsenosides in vivo. However, the pharmacokinetic parameters were different after the administration of GD and TGAS, possibly because of the polysaccharides in GD. This study should be of significance in exploring the basis of PG bioactivities and lays the foundation for the further development of new drugs using PG.

Biotransformation of Ginsenosides by Eoyukjang-derived Lactic Acid Bacteria in Mountain-cultivated Ginseng

Hyojin Lee , Seung Il Ahn , Byung Wook Yang , Jong Dae Park , Wang Soo Shin , Sung Kwon Ko and Young Tae Hahm . Microbiol. Biotechnol. Lett. 2019;47:201-10. https://doi.org/10.4014/mbl.1810.10003

Effects of gut microbiota on the pharmacokinetics of protopanaxadiol ginsenosides Rd, Rg3, F2, and compound K in healthy volunteers treated orally with red ginseng

BackgroundIt is well recognized that gut microbiota is involved in the biotransformation of ginsenosides by converting the polar ginsenosides to nonpolar bioactive ginsenosides. However, the roles of the gut microbiota on the pharmacokinetics of ginsenosides in humans have not yet been fully elucidated. MethodsRed ginseng (RG) or fermented red ginseng was orally administered to 34 healthy Korean volunteers, and the serum concentrations of the ginsenosides were determined using liquid chromatography–tandem mass spectrometry. In addition, the fecal ginsenoside Rd– and compound K (CK)–forming activities were measured. Then, the correlations between the pharmacokinetic profiles of the ginsenosides and the fecal ginsenoside–metabolizing activities were investigated. ResultsFor the RG group, the area under the serum concentration–time curve values of ginsenosides Rd, F2, Rg3, and CK were 8.20 ± 11.95 ng·h/mL, 4.54 ± 3.70 ng·h/mL, 36.40 ± 19.68 ng·h/mL, and 40.30 ± 29.83 ng·h/mL, respectively. For the fermented red ginseng group, the the area under curve from zero to infinity (AUC∞) values of ginsenosides Rd, F2, Rg3, and CK were 187.90 ± 95.87 ng·h/mL, 30.24 ± 41.87 ng·h/mL, 28.68 ± 14.27 ng·h/mL, and 137.01 ± 96.16 ng·h/mL, respectively. The fecal CK-forming activities of the healthy volunteers were generally proportional to their ginsenoside Rd–forming activities. The area under the serum concentration–time curve value of CK exhibited an obvious positive correlation (r = 0.566, p < 0.01) with the fecal CK-forming activity. ConclusionThe gut microbiota may play an important role in the bioavailability of the nonpolar RG ginsenosides by affecting the biotransformation of the ginsenosides.

BIOTRANSFORMATION OF GINSENOSIDE Rb1 BY BACTERIAL CRUDE ENZYME OF Paenibacillus spp. strain E3 ISOLATED FROM VIETNAMESE GINSENG SOIL

In ginseng, minor ginsenosides were more effective pharmacological properties than major ginsenosides. Therefore, finding bacteria that can convert major ginsenosides has been paying attention. Ginsenoside Rb1 is one of major ginsenosides of ginseng and its biotransformation produces pharmacologically active compounds such as compound K. In this study, the isolation of bacterial strains from Vietnamese ginseng cultivated soil was carried out with the objective of evaluating their hydrolytic capacity for use in biotransformation of ginsenosides Rb1. In the screening of β-glucosidase producing bacteria, seven isolates exhibited black color zones on R2A agar medium containing esculine. Among seven isolates, strain E3 showed the highest ability biotransformation of ginsenosides Rb1 in Luria-Bertani broth. Therefore, strain E3 was selected for further research. Biotransformation of Rb1 was observed by using thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) with ginsenoside standards for comparison. We determined the optimal conditions for biotransformation of ginsenoside Rb1 into the compound K of crude enzymes of strain E3 were at 30°C, pH 7,0 and 3 days. Ginsenoside Rb1 was converted into compound K via ginsenoside Rd and F2. The analyses of 16S rRNA gene and phylogenetic tree indicated that strain E3 was closely related to Paenibacillus terrigena with 99,4% identity and formed a discrete cluster with type strain Paenibacillus terrigena A35T with high bootstrap support (99%), supporting strain E3 belonging to the species Paenibacillus terrigena. Physiological characteristics also supported strain E3 belonging to the genus Peanibacillus. This is the first report of biotransformation of ginsenosides using bacterial strains isolated from Vietnamese ginseng cultivated soil in Vietnam. Based on our the obtained results, strain E3 could be applied for the preparation of ginsenoside compound K for use in the cosmetic and pharmaceutical industries.

Complete Biotransformation of Protopanaxatriol-Type Ginsenosides in Panax ginseng Leaf Extract to Aglycon Protopanaxatriol by β-Glycosidases from Dictyoglomus turgidum and Pyrococcus furiosus.

Aglycon protopanaxatriol (APPT) has valuable pharmacological effects such as memory enhancement and tumor inhibition. β-Glycosidase from the hyperthermophilic bacterium Dictyoglomus turgidum (DT-bgl) hydrolyzes the glucose residues linked to APPT, but not other glycoside residues. β-Glycosidase from the hyperthermophilic bacterium Pyrococcus furiosus (PF-bgl) hydrolyzes the outer sugar at C-6 but not the inner glucose at C-6 or the glucose at C-20. Thus, the combined use of DT-bgl and PF-bgl is expected to increase the biotransformation of PPT-type ginsenosides to APPT. We optimized the ratio of PF-bgl to DT-bgl, the concentrations of substrate and enzyme, and the reaction time to increase the biotransformation of ginsenoside Re and PPT-type ginsenosides in Panax ginseng leaf extract to APPT. DT-bgl combined with PF-bgl converted 1.0 mg/ml PPT-type ginsenosides in ginseng leaf extract to 0.58 mg/ml APPT without other ginsenosides, with a molar conversion of 100%. We achieved the complete biotransformation of ginsenoside Re and PPT-type ginsenosides in ginseng leaf extract to APPT by the combined use of two β-glycosidases, suggesting that discarded ginseng leaves can be used as a source of the valuable ginsenoside APPT. To the best of our knowledge, this is the first quantitative production of APPT using ginsenoside Re, and we report the highest concentration and productivity of APPT from ginseng extract to date.

Ginseng fermented by mycotoxin non-producing Aspergillus niger: ginsenoside analysis and anti-proliferative effects.

Korean ginseng was fermented using Aspergillus niger (A. niger) FMB S494 and mycotoxins such as ochratoxin and fumonisin were not detected in the fermented ginseng. Protopanaxadiol-type ginsenosides such as glycosylated forms of Rb1, Rb2, Rc, and Rd decreased to 0 while compound K (cK) increased from 0 to 9×104ppm in the extract of fermented ginseng. Protopanaxtriol-type ginsenosides such as Re and Rg1 decreased from 7.1×104 to 3.0×104ppm and 6.8×104 to 4.6×104ppm, respectively. Rg2 and Rh1 increased from 0 to 1.9×104ppm and 0 to 2.7×104ppm, respectively. We can demonstrate that A. niger was more inclined to transform protopanaxadiol-type ginsenosides. Moreover, fermented ginseng extract showed a dramatically enhanced anti-proliferative effect on human HT-29 cell line with a minimum effective concentration of about 1µg/mL, which might be attributed to the high degree of biotransformation of ginsenosides, especially the high output of ginsenoside cK.

Cloning and Characterization of Ginsenoside-Hydrolyzing β-Glucosidase from Lactobacillus brevis That Transforms Ginsenosides Rb1 and F2 into Ginsenoside Rd and Compound K.

The ginsenoside-hydrolyzing β-glucosidase gene (bgy2) was cloned from Lactobacillus brevis. We expressed this gene in Escherichia coli BL21(DE3), isolated the resulting protein, and then utilized the enzyme for the biotransformation of ginsenosides. The bgy2 gene contains 2,223 bp, and encodes a protein of 741 amino acids that is a member of glycosyl hydrolase family 3. β-Glucosidase (Bgy2) cleaved the outer glucose moieties of ginsenosides at the C-20 position, and the inner glucose at the C-3 position. Under optimal conditions (pH 7.0, 30°C), we used 0.1 mg/ml Bgy2 in 20 mM sodium phosphate buffer (PBS) for enzymatic studies. In these conditions, 1.0 mg/ml ginsenoside Rb1 and ginsenoside F2 were converted into 0.59 mg/ml ginsenoside Rd and 0.72mg/ml compound K, with molar conversion productivities of 69% and 91%, respectively. In pharmaceutical and commercial industries, this recombinant Bgy2 would be suitable for producting ginsenoside Rd and compound K.

Biotransformation of major ginsenosides in ginsenoside model culture by lactic acid bacteria

BackgroundSome differences have been reported in the biotransformation of ginsenosides, probably due to the types of materials used such as ginseng, enzymes, and microorganisms. Moreover, most microorganisms used for transforming ginsenosides do not meet food-grade standards. We investigated the statistical conversion rate of major ginsenosides in ginsenosides model culture during fermentation by lactic acid bacteria (LAB) to estimate possible pathways. MethodsGinsenosides standard mix was used as a model culture to facilitate clear identification of the metabolic changes. Changes in eight ginsenosides (Rb1, Rb2, Rc, Rd, Re, Rf, Rg1, and Rg2) during fermentation with six strains of LAB were investigated. ResultsIn most cases, the residual ginsenoside level decreased by 5.9–36.8% compared with the initial ginsenoside level. Ginsenosides Rb1, Rb2, Rc, and Re continuously decreased during fermentation. By contrast, Rd was maintained or slightly increased after 1 d of fermentation. Rg1 and Rg2 reached their lowest values after 1–2 d of fermentation, and then began to increase gradually. The conversion of Rd, Rg1, and Rg2 into smaller deglycosylated forms was more rapid than that of Rd from Rb1, Rb2, and Rc, as well as that of Rg1 and Rg2 from Re during the first 2 d of fermentation with LAB. ConclusionGinsenosides Rb1, Rb2, Rc, and Re continuously decreased, whereas ginsenosides Rd, Rg1, and Rg2 increased after 1–2 d of fermentation. This study may provide new insights into the metabolism of ginsenosides and can clarify the metabolic changes in ginsenosides biotransformed by LAB.

Conversion of ginsenosides by Lactobacillus plantarum studied by liquid chromatography coupled to quadrupole trap mass spectrometry

Ginsenosides are the active components responsible for the pharmacological properties of ginseng, a commonly used medicinal plant and food ingredient. This study aimed to determine the changes of ginsenosides during fermentation of ginseng extract or reference ginsenosides with Lactobacillus plantarum. Chemically acidified ginseng extracts served as controls. High performance liquid chromatography coupled with quadrupole-trap (Q-TRAP) mass spectrometry method was employed for analysis and quantification of ginsenosides, and for identification of metabolites. A total of 14 metabolites were identified; the quantification of metabolites was achieved by tandem mass spectrometry in MRM mode. Metabolism of L. plantarum removed glucosyl moieties from ginsenosides Rb1, Rd, and Re at the C-20 position to produce a racemic mixture of products. Remarkably, removal of glycosyl residues occurred not only by hydrolysis but also by dehydration to produce racemic mixtures of Δ20(21) or Δ20(22) products. Biotransformation occurred more rapidly with the di-substituted ginsenoside Rb1 when compared to the mono-substituted ginsenoside Rd. This study thus extends the knowledge of biotransformation of ginsenosides to produce bioactive derivatives.

A prebiotic fiber increases the formation and subsequent absorption of compound K following oral administration of ginseng in rats

BackgroundGut microflora play a crucial role in the biotransformation of ginsenosides to compound K (CK), which may affect the pharmacological effects of ginseng. Prebiotics, such as NUTRIOSE, could enhance the formation and consequent absorption of CK through the modulation of gut microbial metabolic activities. In this study, the effect of a prebiotic fiber (NUTRIOSE) on the pharmacokinetics of ginsenoside CK, a bioactive metabolite of ginsenosides, and its mechanism of action were investigated. MethodsMale Sprague–Dawley rats were given control or NUTRIOSE-containing diets (control diet + NUTRIOSE) for 2 wk, and ginseng extract or vehicle was then orally administered. Blood samples were collected to investigate the pharmacokinetics of CK using liquid chromatography–tandem mass spectrometry. Fecal activities that metabolize ginsenoside Rb1 to CK were assayed with fecal specimens or bacteria cultures. ResultsWhen ginseng extract was orally administered to rats fed with 2.5%, 5%, or 10% NUTRIOSE containing diets, the maximum plasma concentration (Cmax) and area under the plasma concentration–time curve values of CK significantly increased in a NUTRIOSE content-dependent manner. NUTRIOSE intake increased glycosidase activity and CK formation in rat intestinal contents. The CK-forming activities of intestinal microbiota cultured in vitro were significantly induced by NUTRIOSE. ConclusionThese results show that prebiotic diets, such as NUTRIOSE, may promote the metabolic conversion of ginsenosides to CK and the subsequent absorption of CK in the gastrointestinal tract and may potentiate the pharmacological effects of ginseng.

Biotransformation of Ginsenoside Rc into C-Mc1 by the Bacterium Sphingopyxis sp. BG97

The principal biologically active compounds of Panax ginseng C. A. Meyer are triterpenoid glycosides, ginsenosides [1], which exhibit immunostimulating, anti-inflammatory, anticarcinogenic, antitumor, antidiabetic, hepatoprotective, neuromodulating, and other properties [2]. Greater than 50 different ginsenosides have been isolated from P. ginseng. Six of these (Rb1, Rb2, Rc, Rd, Re, and Rg1) make up >80% of total saponins and have protopanaxadiol or protopanaxatriol as the aglycon [1]. Furthermore, it is well known that minor glycosides of P. ginseng in several instances have broader spectra of biological activity or are more active than them [2]. This stimulates great interest in producing the minor ginsenosides, including biotransformation of the principal ginsenosides using various microorganisms [3, 4]. We reported earlier the transformation of ginsenoside Rb1 into the minor glycoside F-2 and compound K [5] and glycoside Rd into minor ginsenoside (20S)-Rg3 [6] using bacteria isolated from soil samples taken from a ginseng field. Among these, strains belonging to the genus Sphingopyxis were identified [7]. Herein we communicate data on the transformation of principal ginsenoside Rc (1) into minor compound C-Mc1 (2) by the bacterium Sphingopyxis sp. BG97.

Identification of human cytochrome P450 enzymes involved in the hepatic and intestinal biotransformation of 20(S)‐protopanaxadiol

20(S)-Protopanaxadiol (aPPD), a ginseng sapogenin, has been shown to be a promising anti-cancer compound and anti-depressant agent. Although the bacterial biotransformation of ginsenosides has been studied thoroughly, few have reported on the cytochrome P450 (P450) mediated metabolism of aPPD. Taken orally, aPPD must first undergo absorption and metabolism in the intestine before further metabolism in the liver. The present study investigated the comparative biotransformation profile of aPPD in human intestinal microsomes (HIM) and human liver microsomes (HLM) and characterized the human P450 enzymes involved in aPPD metabolism. Three major monooxygenated metabolites and five minor dioxygenated metabolites were identified as the predominant products in aPPD incubations with HIM and HLM using liquid chromatography-mass spectrometry. Reaction phenotyping studies were performed with a panel of specific P450 chemical inhibitors, antibody inhibition and human recombinant P450 enzymes. Ketoconazole, a CYP3A inhibitor, blocked the formation of oxygenated metabolites of aPPD in both HIM and HLM in a concentration dependent manner. Among the human recombinant P450 enzymes assayed, CYP3A4 exhibited the highest activity towards aPPD oxidative metabolite formation, followed by CYP3A5. In summary, the results have shown that aPPD is extensively metabolized by HIM and the metabolite profile following in vitro incubations is similar in HIM and HLM. CYP3A4 and CYP3A5 isoforms are the predominant enzymes responsible for oxygenation of aPPD in HIM and HLM. The characterization of aPPD as a CYP3A substrate may facilitate better prediction of drug-herb interactions when aPPD is taken concomitantly with other therapeutic agents.

Biotransformation of ginsenoside Rd in the ginseng extraction residue by fermentation with lingzhi (Ganoderma lucidum)

Ginseng and lingzhi (Ganoderma lucidum) both are valuable traditional Chinese medicines and have been extensively utilised in functional foods and traditional medicines in many Asian countries. However, massive quantity of ginseng residue is produced after extraction of ginseng which still contains a lot of bioactive compounds such as ginsenosides. The goal of this study was to reuse the American ginseng extraction residue as the fermentation medium of G. lucidum to produce bioactive ginsenoside enriched biotransformation products. The changes of ginsenosides in the fermentation products were analysed during fermentation. Our results showed that after 30days of fermentation, ginsenoside Rg1, Rd, and compound K (CK) significantly increased, especially Rd, while other ginsenosides (Re, Rb1 and Rc) decreased during fermentation. Ginsenoside Rd is the major ginsenoside in the final fermentation product. Furthermore, the biotransformation of ginsenosides was the major reaction in this fermentation process.