Mass spectrometry-based ginsenoside profiling: Recent applications, limitations, and perspectives.

Ginseng, the roots of Panax species, is an important medicinal herb used as a tonic. As ginsenosides are key bioactive components of ginseng, holistic chemical profiling of them has provided many insights into understanding ginseng. Mass spectrometry has been a major methodology for profiling, which has been applied to realize numerous goals in ginseng research, such as the discrimination of different species, geographical origins, and ages, and the monitoring of processing and biotransformation. This review summarizes the various applications of ginsenoside profiling in ginseng research over the last three decades that have contributed to expanding our understanding of ginseng. However, we also note that most of the studies overlooked a crucial factor that influences the levels of ginsenosides: genetic variation. To highlight the effects of genetic variation on the chemical contents, we present our results of untargeted and targeted ginsenoside profiling of different genotypes cultivated under identical conditions, in addition to data regarding genome-level genetic diversity. Additionally, we analyze the other limitations of previous studies, such as imperfect variable control, deficient metadata, and lack of additional effort to validate causation. We conclude that the values of ginsenoside profiling studies can be enhanced by overcoming such limitations, as well as by integrating with other -omics techniques.

Genetic diversity among cultivated and wild Panax ginseng populations revealed by high-resolution microsatellite markers.

BACKGROUND: Ginseng (Panax ginseng Meyer) is one of the world's most valuable medicinal plants with numerous pharmacological effects. Ginseng has been cultivated from wild mountain ginseng collections for a few hundred years. However, the genetic diversity of cultivated and wild ginseng populations is not fully understood. METHODS: We developed 92 polymorphic microsatellite markers based on whole-genome sequence data. We selected five markers that represent clear allele diversity for each of their corresponding loci to elucidate genetic diversity. These markers were applied to 147 individual plants, including cultivars, breeding lines, and wild populations in Korea and neighboring countries. RESULTS: Most of the 92 markers displayed multiple-band patterns, resulting from genome duplication, which causes confusion in interpretation of their target locus. The five high-resolution markers revealed 3 to 8 alleles from each single locus. The proportion of heterozygosity (He) ranged from 0.027 to 0.190, with an average of 0.132, which is notably lower than that of previous studies. Polymorphism information content of the markers ranged from 0.199 to 0.701, with an average of 0.454. There was no statistically significant difference in genetic diversity between cultivated and wild ginseng groups, and they showed intermingled positioning in the phylogenetic relationship. CONCLUSION: Ginseng has a relatively high level of genetic diversity, and cultivated and wild groups have similar levels of genetic diversity. Collectively, our data demonstrate that current breeding populations have abundant genetic diversity for breeding of elite ginseng cultivars.

Comparative Analysis of Panax ginseng Berries from Seven Cultivars Using UPLC-QTOF/MS and NMR-Based Metabolic Profiling.

The commercial use of Panax ginseng berries is increasing as P. ginseng berries are known to contain large amounts of ginsenosides, and many pharmacological activities have been reported for the various ginsenosides. For the proper use of P.ginseng berries, it is necessary to study efficient and accurate quality control and the profiling of the overall composition of each cultivar. Ginseng berry samples from seven cultivars (Eumseung, Chung-buk Province, Republic of Korea) were analyzed using ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry (UPLC-QTOF/MS) for profiling of the ginsenosides, and high-resolution magic-angle-spinning nuclear magnetic resonance (HR-MAS NMR) spectroscopy for profiling of the primary metabolites. Comparing twenty-six ginsenoside profiles between the variant representatives and between the violet-stem variant, Kumpoong and Sunwon were classified. In the case of primary metabolites, the cultivars Kumpoong and Gopoong were classified. As a result of correlation analyses of the primary and secondary metabolites, in the Gopoong cultivar, the metabolism was found to lean toward energy metabolism rather than ginsenoside synthesis, and accumulation of osmolytes was low. The Gopoong cultivar had higher levels of most of the amino acids, such as arginine, phenylalanine, isoleucine, threonine, and valine, and it contained the highest level of choline and the lowest level of myo-inositol. Except for these, there were no significant differences of primary metabolites. In the Kumpoong cultivar, the protopanaxatriol (PPT)-type ginsenosides, ginsenoside Re and ginsenoside Rg2, were much lower than in the other cultivars, while the other PPT-type ginsenosides were inversely found in much higher amounts than in other cultivars. The Sunwon cultivar showed that variations of PPT-type ginsenosides were significantly different between samples. However, the median values of PPT-type ginsenosides of Sunwon showed similar levels to those of Kumpoong. The difference in primary metabolites used for metabolism for survival was found to be small in our results. Our data demonstrated the characteristics of each cultivar using profiling data of the primary and secondary metabolites, especially for Gopoong, Kumpoong, and Sunwon. These profiling data provided important information for further research and commercial use.

Genome and evolution of the shade-requiring medicinal herb Panax ginseng.

Panax ginseng C. A. Meyer, reputed as the king of medicinal herbs, has slow growth, long generation time, low seed production and complicated genome structure that hamper its study. Here, we unveil the genomic architecture of tetraploid P. ginseng by de novo genome assembly, representing 2.98 Gbp with 59 352 annotated genes. Resequencing data indicated that diploid Panax species diverged in association with global warming in Southern Asia, and two North American species evolved via two intercontinental migrations. Two whole genome duplications (WGD) occurred in the family Araliaceae (including Panax) after divergence with the Apiaceae, the more recent one contributing to the ability of P. ginseng to overwinter, enabling it to spread broadly through the Northern Hemisphere. Functional and evolutionary analyses suggest that production of pharmacologically important dammarane-type ginsenosides originated in Panax and are produced largely in shoot tissues and transported to roots; that newly evolved P. ginseng fatty acid desaturases increase freezing tolerance; and that unprecedented retention of chlorophyll a/b binding protein genes enables efficient photosynthesis under low light. A genome-scale metabolic network provides a holistic view of Panax ginsenoside biosynthesis. This study provides valuable resources for improving medicinal values of ginseng either through genomics-assisted breeding or metabolic engineering.

Comprehensive Profiling and Quantification of Ginsenosides in the Root, Stem, Leaf, and Berry of Panax ginseng by UPLC-QTOF/MS.

The effective production and usage of ginsenosides, given their distinct pharmacological effects, are receiving increasing amounts of attention. As the ginsenosides content differs in different parts of Panax ginseng, we wanted to assess and compare the ginsenosides content in the ginseng roots, leave, stems, and berries. To extract the ginsenosides, 70% (v/v) methanol was used. The optimal ultra-performance liquid chromatography-quadrupole time of flight mass spectrometry (UPLC-QTOF/MS) method was used to profile various ginsenosides from the different parts of P. ginseng. The datasets were then subjected to multivariate analysis including principal component analysis (PCA) and hierarchical clustering analysis (HCA). A UPLC-QTOF/MS method with an in-house library was constructed to profile 58 ginsenosides. With this method, a total of 39 ginsenosides were successfully identified and quantified in the ginseng roots, leave, stem, and berries. PCA and HCA characterized the different ginsenosides compositions from the different parts. The quantitative ginsenoside contents were also characterized from each plant part. The results of this study indicate that the UPLC-QTOF/MS method can be an effective tool to characterize various ginsenosides from the different parts of P. ginseng.

Isoform Sequencing Provides a More Comprehensive View of the Panax ginseng Transcriptome.

Korean ginseng (Panax ginseng C.A. Meyer) has been widely used for medicinal purposes and contains potent plant secondary metabolites, including ginsenosides. To obtain transcriptomic data that offers a more comprehensive view of functional genomics in P. ginseng, we generated genome-wide transcriptome data from four different P. ginseng tissues using PacBio isoform sequencing (Iso-Seq) technology. A total of 135,317 assembled transcripts were generated with an average length of 3.2 kb and high assembly completeness. Of those unigenes, 67.5% were predicted to be complete full-length (FL) open reading frames (ORFs) and exhibited a high gene annotation rate. Furthermore, we successfully identified unique full-length genes involved in triterpenoid saponin synthesis and plant hormonal signaling pathways, including auxin and cytokinin. Studies on the functional genomics of P. ginseng seedlings have confirmed the rapid upregulation of negative feed-back loops by auxin and cytokinin signaling cues. The conserved evolutionary mechanisms in the auxin and cytokinin canonical signaling pathways of P. ginseng are more complex than those in Arabidopsis thaliana. Our analysis also revealed a more detailed view of transcriptome-wide alternative isoforms for 88 genes. Finally, transposable elements (TEs) were also identified, suggesting transcriptional activity of TEs in P. ginseng. In conclusion, our results suggest that long-read, full-length or partial-unigene data with high-quality assemblies are invaluable resources as transcriptomic references in P. ginseng and can be used for comparative analyses in closely related medicinal plants.

The complete chloroplast genome sequence of Panax vietnamensis Ha et Grushv (Araliaceae).

The complete chloroplast genome sequence of Panax vietnamensis, a medicinal herb belonging to Araliaceae family, was generated by de novo assembly using whole genome next-generation sequences. The chloroplast genome was a circular form of 155 992 bp long and showed typical chloroplast genome structure consisting of a large single-copy region of 86 177 bp, a small single copy region of 17 935 bp and a pair of inverted repeats of 25 940 bp. The chloroplast genome had 79 protein-coding genes, 29 tRNA genes and 4 rRNA genes. The phylogenetic analysis with the reported chloroplast genomes revealed that four Panax species were grouped in the same clade and P. vietnamensis is more closely related to P. notoginseng than P. ginseng and P. quinquefolius.

De novo transcriptome assembly and the identification of gene-associated single-nucleotide polymorphism markers in Asian and American ginseng roots.

We performed de novo transcriptome sequencing for Panax ginseng and Panax quinquefolius accessions using the 454 GS FLX Titanium System and discovered annotation-based genome-wide single-nucleotide polymorphism (SNPs) using next-generation ginseng transcriptome data without reference genome sequence. The comprehensive transcriptome characterization with the mature roots of four ginseng accessions generated 297,170 reads for 'Cheonryang' cultivar, 305,673 reads for 'Yunpoong' cultivar, 311,861 reads for the G03080 breeding line, and 308,313 reads for P. quinquefolius. In transcriptome assembly, the lengths of the sample read were 156.42 Mb for 'Cheonryang', 161.95 Mb for 'Yunpoong', 165.07 Mb for G03080 breeding line, and 166.48 Mb for P. quinquefolius. A total of 97 primer pairs were designed with the homozygous SNP presented in all four accessions. SNP genotyping using high-resolution melting (HRM) analysis was performed to validate the putative SNP markers of 97 primer pairs. Out of the 73 primer pairs, 73 primer pairs amplified the target sequence and 34 primer pairs showed polymorphic melting curves in samples from 11 P. ginseng cultivars and one P. quinquefolius accession. Among the 34 polymorphic HRM-SNP primers, four primers were useful to distinguish ginseng cultivars. In the present study, we demonstrated that de novo transcriptome assembly and mapping analyses are useful in providing four HRM-SNP primer pairs that reliably show a high degree of polymorphism among ginseng cultivars.

Classification of ginseng berry (Panax ginseng C.A. MEYER) extract using 1H NMR spectroscopy and its inhibition of lipid accumulation in 3 T3-L1 cells.

BACKGROUND: Panax ginseng is a famous traditional medicine in Korea for its beneficial effect on obesity, cardiac and liver associated diseases. The aim of this study was to investigate the metabolite in Panax ginseng (P. ginseng, Aralicaceae) berries depending on the ripen stages and evaluate its potential inhibition on adipocyte differentiation in 3 T3-L1 cells. METHODS: Different ripening stage samples of P. ginseng berry were analyzed through global metabolite profiling by NMR spectroscopy. Lipid accumulation in the cells was analyzed by Oil Red O staining. RESULTS: The PLS-DA clearly distinguished P. ginseng berry extract (PGBE) according to the partial ripe (PR), ripe(R) and fully ripe (FR) stage. Lipid accumulation of PGBE was examined by measuring triglyceride content and Oil-Red O staining. These results suggested that the FR stage of PGBE decrease in lipid accumulation during adipocyte differentiation and the amount of threonine, asparagine, fumarate, tyraine, tyrosine, and phenylalanine increased with longer ripening of ginseng berries. CONCLUSION: Metabolite profiling of P. ginseng was identified by 1H NMR spectra. P. ginseng extract efficiently inhibits adipogenesis in 3 T3-L1 adipocytes concluded that the P. ginseng has the antiobesity properties.

CAPS markers using mitochondrial consensus primers for molecular identification of Panax species and Korean ginseng cultivars (Panax ginseng C. A. Meyer).

Cleaved amplified polymorphic sequence (CAPS) marker system using mitochondrial consensus primers was applied for molecular identification of Korean ginseng cultivars (Panax ginseng). Initially, a total of 34 primers were tested to six Korean ginseng cultivars and two foreign Panax species, P. quinquefolius and P. notoginseng. In the polymerase chain reaction (PCR) amplification results, four primers (mt7, mt11, mt13, and mt18) generated co-dominant polymorphic banding patterns discriminating the Korean ginseng cultivars from P. quinquefolius and P. notoginseng. In the CAPS analysis results, the majority of the cleaved PCR products also yielded additional latent polymorphisms between the Korean ginseng cultivars and two foreign Panax species. Specific latent CAPS polymorphisms for cultivar Gopoong and Chunpoong were detected from internal region amplified with mt9 primer by treating HinfI and Tsp509I endonucleases, respectively. Sequencing analysis revealed that the length of amplified region of Korean ginseng cultivars was 2,179 bp, and those of P. quinquefolius and P. notoginseng were 2,178 and 2,185 bp, respectively. Blast search revealed that the amplified region was a mitochondrial cytochrome oxidase subunit 2 (cox2) gene intron II region. Nineteen single nucleotide polymorphisms (SNP) including each specific SNP for Gopoong and Chunpoong, and three insertion and deletion (InDel) polymorphisms were detected by sequence alignment. The CAPS markers developed in this study, which are specific to Gopoong and Chunpoong, and between the Korean ginseng cultivars and two foreign Panax species, will serve as a practical and reliable tool for their identification, purity maintenance, and selection of candidate lines and cultivars.

Construction of genomic DNA library of Korean ginseng (Panax ginseng C. A. MEYER) and development of sequence-tagged sites.

This study describes an efficient approach for developing sequence tagged sites (STS) for Panax ginseng C.A. MEYER, and their applications for line discrimination. By using the methylation filtering (MF) technique, a genomic library was constructed, in which clone inserts were derived from the hypomethylated regions of ginseng genome. A methylation unfiltered genomic library was also constructed and the clone inserts were compared to those from the MF library in terms of sequence characteristics. Sequence analysis revealed that MF efficiently enriched the protein coding region of P. ginseng, for which the repetitive DNA appeared to be as little as 2.5 fold lower than clones in the unfiltered library, and also indicated that the P. ginseng genome may contain a large fraction of methylated repetitive DNA elements. A total of 99 and 100 highly stringent STS primer sets were designed from the filtered and unfiltered library, respectively. Amplification products were tested for latent polymorphism across six cultivars of P. ginseng and other 2 Panax species using six endonucleases recognizing four-bases. STS primer sets described here will be useful for marker-assisted selection, genome mapping and line discrimination of P. ginseng or its cultivars from other Panax species.

Characterization of a dammarenediol synthase in Centella asiatica (L.) Urban.

To elucidate the exact function of CabAS in Centella asiatica, which was previously reported as a putative beta-amyrin synthase [Plant Cell Rep, 24:304-311, 2005], this gene was functionally expressed in the lanosterol synthase-deficient yeast mutant (erg7). After inducing the CabAS gene with galactose, a peak consistent with the dammarenediol standard was detected in LC/APCIMS analyses and the accumulated product was confirmed as dammarenediol. CabAS should therefore be renamed to C. asiatica dammarenediol synthase (CaDDS). The confirmation of this gene function may allow us to better understand the generation of numerous triterpene carbon skeletons.

Cloning, expression, purification, crystallization and preliminary X-ray diffraction analysis of the central zinc-binding domain of the human Mcm10 DNA-replication factor.

The initiation of eukaryotic DNA replication requires the tightly controlled assembly of a set of replication factors. Mcm10 is a highly conserved nuclear protein that plays a key role in the initiation and elongation processes of DNA replication by providing a physical link between the Mcm2-7 complex and DNA polymerases. The central domain, which contains the CCCH zinc-binding motif, is most conserved within Mcm10 and binds to DNA and several proteins, including proliferative cell nuclear antigen. In this study, the central domain of human Mcm10 was crystallized using the hanging-drop vapour-diffusion method in the presence of PEG 3350. An X-ray diffraction data set was collected to a resolution of 2.6 A on a synchrotron beamline. The crystals formed belonged to space group R3, with unit-cell parameters a = b = 99.5, c = 133.0 A. According to Matthews coefficient calculations, the crystals were predicted to contain six MCM10 central domain molecules in the asymmetric unit.

Enhanced production of asiaticoside from hairy root cultures of Centella asiatica (L.) Urban elicited by methyl jasmonate.

Transformed root ("hairy root") cultures have been shown to be a good model for the study of many secondary metabolites. However, economically important compounds such as asiaticoside and madecassoside are produced in insignificant amounts in the root of Centella asiatica (L.) Urban. To overcome this problem, C. asiatica was transformed using Agrobacterium rhizogenes strain R1000 that harbors pCAMBIA1302 encoding the hygromycin phosphotransferase (hpt) and green fluorescence protein (mgfp5) genes and the hairy culture was coupled with elicitation technique. Hairy roots were obtained at a frequency of up to 14.1% from a tissue junction between the leaf and petiole. Abundant hairy roots were observed when co-cultivation of the plant with A. rhizogenes was done for 7 days (36.1%). Transformation was confirmed by PCR and Southern blot analyses. Five weeks after inoculation, no asiaticoside was detected in the hairy root samples. However, when 0.1 mM methyl jasmonate (MJ) was applied as an elicitor to the culture medium for 3 weeks, a large quantity of asiaticoside was generated (7.12 mg/g, dry wt). In the case of gene expression, 12 h after MJ treatment the expression of the CabAS (C. asiatica putative beta-amyrin synthase) gene in the hairy roots is significantly different from that of the control and this level of transcripts was maintained for 14 days. Our results showed that production of C. asiatica hairy roots could be optimized and the resulting cultures could be elicited with MJ treatment for enhanced production of asiaticoside.