Dong Young Lee

Identification of ginsenoside markers from dry purified extract of Panax ginseng by a dereplication approach and UPLC–QTOF/MS analysis

A dry purified extract of Panax ginseng (PEG) was prepared using a manufacturing process that includes column chromatography, acid hydrolysis, and an enzyme reaction. During the manufacturing process, the more polar ginsenosides were altered into less polar forms via cleavage of their sugar chains and structural modifications of the aglycones, such as hydroxylation and dehydroxylation. The structural changes of ginsenosides during the intermediate steps from dried ginseng extract (DGE) to PEG were monitored by ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectroscopy (UPLC-QTOF/MS). 22 ginsenosides isolated from PEG were used as the reference standards for determining of unknown ginsenosides and further suggesting of the metabolic markers. The elution order of 22 ginsenosides based on the type of aglycones, and the location and number of sugar chains can be used for the structural elucidation of unknown ginsenosides. This information could be used in a dereplication process for quick and efficient identification of ginsenoside derivatives in ginseng preparations. A dereplication approach helped the identification of the metabolic markers in the UPLC-QTOF/MS chromatograms during the conversion process with multivariate analyses, including principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) plots. These metabolic markers were identified by comparing with the dereplication information of the reference standards of 22 ginsenosides, or they were assigned using the pattern of the MS/MS fragmented ions. Consequently, the developed metabolic profiling approach using UPLC-QTOF/MS and multivariate analysis represents a new method for providing quality control as well as useful criteria for a similarity evaluation of the manufacturing process of ginseng preparations.

Quality control of Pulsatilla koreana based on the simultaneous determination of triterpenoidal saponins by HPLC-ELSD and principal component analysis.

INTRODUCTIONnPulsatilla koreana Nakai, with triterpenoidal saponins as its main pharmacological effective compounds, is known to have several biological activities, including hypoglycaemic, antitumour, cognition-enhancing, neuroprotective, cytotoxic and antiangiogenic activities. However, few analytical methods have been reported on the quality assessment of P. koreana roots.nnnOBJECTIVEnTo establish a high-performance liquid chromatography coupled with evaporative light scattering detection for the simultaneous determination of five triterpenoidal saponins, including pulsatilloside E (1), pulsatilla saponin H (2), anemoside B4 (3), hederacolchiside E (4) and cussosaponin C (5) in P. koreana.nnnMETHODOLOGYnThe chromatographic separation was performed on a Shiseido CapCell PAK C18 analytical column efficiently using gradient elution with acetonitrile and water.nnnRESULTSnAll calibration curves showed excellent linear regressions (R(2) > 0.9996) within the range of tested concentrations. The intra- and inter-day variations were below 4.78% in terms of RSD. The recoveries were 94.82-102.97% with RSD of 0.27-3.92% for spiked P. koreana samples.nnnCONCLUSIONnThe validated method was successfully used for the analysis of five saponins in P. koreana from different locations. Moreover, the different samples were clustered in accordance with contents of triterpenoidal saponins based on aglycon type by a principal component analysis.

Hydrolyzable tannins from the fruits of Terminalia chebula Retz and their α-glucosidase inhibitory activities

Nine hydrolyzable tannins, including three previously unknown and six artifacts, were isolated, together with thirty-nine known ones, from the fruits of Terminalia chebula Retz. (Combretaceae). They were identified as 1,2,3-tri-O-galloyl-6-O-cinnamoyl-β-d-glucose, 1,2,3,6-tetra-O-galloyl-4-O-cinnamoyl-β-d-glucose, 4-O-(2″,4″-di-O-galloyl-α-l-rhamnosyl)ellagic acid, 1-O-methyl neochebulanin, dimethyl neochebulinate, 6-O-methyl neochebulagate, dimethyl neochebulagate, dimethyl 4-epi-neochebulagate, and methyl chebulagate by the spectroscopic interpretation. After evaluation for α-glucosidase inhibition of all isolated compounds, 1,2,3,6-tetra-O-galloyl-4-O-cinnamoyl-β-d-glucose and 4-O-(2″,4″-di-O-galloyl-α-l-rhamnosyl)ellagic acid showed significant inhibitory activities with IC50 values of 2.9 and 6.4xa0μM, respectively. In addition, inhibition kinetic studies showed that both compounds have mixed-type inhibitory activities with the inhibition constants (Ki) of 1.9 and 4.0xa0μM, respectively.

New polyhydroxytriterpenoid derivatives from fruits of Terminalia chebula Retz. and their α-glucosidase and α-amylase inhibitory activity

Three new polyhydroxytriterpenoid derivatives, 23-O-neochebuloylarjungenin 28-O-β-d-glycopyranosyl ester (1), 23-O-4-epi-neochebuloylarjungenin (2), and 23-O-galloylpinfaenoic acid 28-O-β-d-glucopyranosyl ester (17) were isolated from the fruits of Terminalia chebula Retz. along with fourteen known ones. Their structures were elucidated by 1D and 2D NMR spectroscopic data and acid hydrolysis. After evaluating for Bakers yeast α-glucosidase, rat intestinal α-glucosidase, and porcine pancreatic α-amylase inhibitory activities of all the isolated compounds, 23-O-galloylarjunolic acid (11, IC50 21.7μM) and 23-O-galloylarjunolic acid 28-O-β-d-glucopyranosyl ester (12, IC50 64.2μM) showed potent inhibitory activities against Bakers yeast α-glucosidase compared to the positive control, acarbose (IC50 174.0μM). However, all the tested compounds except for the positive control, acarbose, had no or only weak inhibitory activity against rat intestinal α-glucosidase and porcine pancreatic α-amylase.

Rapid Determination of Betulin in Betula platyphylla Outer Bark Using Near-Infrared Spectroscopy

A simple, rapid, and nondestructive method for the determination of betulin in the outer birch bark was developed using near infrared spectroscopy (NIRS). NIRS data of the outer birch bark collected throughout the year was preprocessed and analyzed by principal component analysis, which led to clear discrimination of the samples according to their harvest times. The reference content of betulin, a major constituent of the outer birch bark, was determined using ultra performance liquid chromatography with a diode array detector (UPLC-DAD). The optimized and validated analytical conditions of UPLC-DAD provided better separation and faster analysis time compared to a conventional HPLC method. Betulin content also showed seasonal variation and was higher in the samples collected during the summer season. Partial least squares calibration techniques were employed to estimate the relationship between the NIRS data and betulin contents. The spectral data showed high correlation coefficients (over 0.700) with betulin content. These results indicate that NIRS combined with UPLC can be used to determine the quality and to quantify the betulin content of the outer birch bark.

Authentication of Zanthoxylum Species Based on Integrated Analysis of Complete Chloroplast Genome Sequences and Metabolite Profiles

We performed chloroplast genome sequencing and comparative analysis of two Rutaceae species, Zanthoxylum schinifolium (Korean pepper tree) and Z. piperitum (Japanese pepper tree), which are medicinal and culinary crops in Asia. We identified more than 837 single nucleotide polymorphisms and 103 insertions/deletions (InDels) based on a comparison of the two chloroplast genomes and developed seven DNA markers derived from five tandem repeats and two InDel variations that discriminated between Korean Zanthoxylum species. Metabolite profile analysis pointed to three metabolic groups, one with Korean Z. piperitum samples, one with Korean Z. schinifolium samples, and the last containing all the tested Chinese Zanthoxylum species samples, which are considered to be Z. bungeanum based on our results. Two markers were capable of distinguishing among these three groups. The chloroplast genome sequences identified in this study represent a valuable genomics resource for exploring diversity in Rutaceae, and the molecular markers will be useful for authenticating dried Zanthoxylum berries in the marketplace.

Discrimination between Artemisia princeps and Artemisia capillaris Based on Near Infrared Spectroscopy Combined Multivariate Analysis

ABSTRACT − The Artemisia princeps (Compositae) has been used in traditional Korean medicine for the treatment ofmicrobial infections and inflammatory diseases. Since A. princeps is generally difficult to be discriminated from A. cap-illaris, A. caplillaris has been misused in place of A. princeps. To solve this problem, a rapid and nondestructive methodfor discrimination of A. princeps and A. capillaris samples was developed using near infrared spectroscopy (NIRS) in thepresent study. A principal component analysis (PCA) and a partial least squares discrimination analysis (PLS-DA) were per-formed to discriminate two species. As a result, with the use of PLS-DA, A. princeps and A. capillaris were clusteredaccording to their genus. These outcomes indicated that the NIRS could be useful for the discrimination between Artemisiaprinceps and Artemisia capillaris.Key words − Artemisia princeps, Artemisia capillaris, Near infrared spectroscopy (NIRS), Partial least square dis-crimination method(PLS-DA)

Argininosecologanin, a secoiridoid-derived guanidine alkaloid from the roots of Lonicera insularis

Abstract A new secoiridoid-derived guanidine alkaloid, argininosecologanin (1), along with 12 known iridoids and secoiridoids (2–13), was isolated from the roots of Lonicera insularis. The structures of the isolated compounds were established by the spectroscopic analysis and comparison of their spectral data with previously reported data. Compound 1 was assigned as the first secoiridoid-derived guanidine alkaloid isolated as a natural product. A plausible biogenetic pathway for 1 is suggested based on its structural similarity to (E)-aldosecologanin (4).

Identification of candidate UDP-glycosyltransferases involved in protopanaxadiol-type ginsenoside biosynthesis in Panax ginseng

Ginsenosides are dammarane-type or triterpenoidal saponins that contribute to the various pharmacological activities of the medicinal herb Panax ginseng. The putative biosynthetic pathway for ginsenoside biosynthesis is known in P. ginseng, as are some of the transcripts and enzyme-encoding genes. However, few genes related to the UDP-glycosyltransferases (UGTs), enzymes that mediate glycosylation processes in final saponin biosynthesis, have been identified. Here, we generated three replicated Illumina RNA-Seq datasets from the adventitious roots of P. ginseng cultivar Cheongsun (CS) after 0, 12, 24, and 48u2009h of treatment with methyl jasmonate (MeJA). Using the same CS cultivar, metabolomic data were also generated at 0u2009h and every 12–24u2009h thereafter until 120u2009h of MeJA treatment. Differential gene expression, phylogenetic analysis, and metabolic profiling were used to identify candidate UGTs. Eleven candidate UGTs likely to be involved in ginsenoside glycosylation were identified. Eight of these were considered novel UGTs, newly identified in this study, and three were matched to previously characterized UGTs in P. ginseng. Phylogenetic analysis further asserted their association with ginsenoside biosynthesis. Additionally, metabolomic analysis revealed that the newly identified UGTs might be involved in the elongation of glycosyl chains of ginsenosides, especially of protopanaxadiol (PPD)-type ginsenosides.

Chemical and genomic diversity of six Lonicera species occurring in Korea

Lonicera spp. (Caprifoliaceae) are important not only as a common medicinal herb in East Asia but also as one of the most problematic invasive species in North America. In the present study, we performed a systemic analysis of genomic and chemical diversity among six Lonicera species occurring in Korea, L. japonica, L. maackii, L. insularis, L. sachalinensis, L. praeflorens, and L. vesicaria, using chloroplast DNA whole genome shotgun (WGS) sequencing and LC-MS analyses. The phylogenetic and phylochemical relationships did not coincide with each other, but partial consistency could be found among them. InDel-based cDNA marker for authentication was developed based on the genome sequences. Flavonoids, iridoids, and organic acids were identified in the LC-MS analyses, and their inter-species distribution and localization were also revealed.