Identification and Expression Analysis of R2R3-MYB Transcription Factors Associated with Flavonoid Biosynthesis in Panax quinquefolius.

Panax quinquefolius L. is an important medicinal plant, and flavonoids are among its main secondary metabolites. The R2R3-MYB transcription factor plays an irreplaceable role in plant growth, development, and secondary metabolism. In our study, we identified 159 R2R3-MYBs and analyzed their physical and chemical properties in P. quinquefolius. The protein length of 159 PqMYBs varied from 107 to 1050 amino acids. The molecular weight ranged from 12.21 to 116.44 kDa. The isoelectric point was between 4.57 and 10.34. We constructed a phylogenetic tree of P. quinquefolius and Arabidopsis thaliana R2R3-MYB family members, and PqMYB members were divided into 33 subgroups. Transcriptome data analysis showed that the expression patterns of PqMYBs in root, leaf, and flower were significantly different. Following the MeJA treatment of seedlings, five candidate PqMYB genes demonstrated a response. A correlation analysis of PqMYBs and candidate flavonoid pathway genes showed that PqMYB2, PqMYB46, and PqMYB72 had correlation coefficients that were higher than 0.8 with PqCHS, PqANS4, and PqCCoAMT10, respectively. Furthermore, a transient expression assay confirmed that the three PqMYBs were localized in the nucleus. We speculated that these three PqMYBs were related to flavonoid biosynthesis in P. quinquefolius. These results provided a theoretical basis and a new perspective for further understanding the R2R3-MYB gene family and the biosynthesis mechanism of secondary metabolites in P. quinquefolius.

Genome-Wide Identification and Analysis of the Aux/IAA Gene Family in Panax ginseng: Evidence for the Role of PgIAA02 in Lateral Root Development.

Panax ginseng C. A. Meyer (Ginseng) is one of the most used traditional Chinese herbal medicines, with its roots being used as the main common medicinal parts; its therapeutic potential has garnered significant attention. AUXIN/INDOLE-3-ACETIC ACID (Aux/IAA) is a family of early auxin-responsive genes capable of regulating root development in plants through the auxin signaling pathway. In the present study, 84 Aux/IAA genes were identified from the ginseng genome and their complexity and diversity were determined through their protein domains, phylogenetic relationships, gene structures, and cis-acting element predictions. Phylogenetic analyses classified PgIAA into six subgroups, with members in the same group showing greater sequence similarity. Analyses of interspecific collinearity suggest that segmental duplications likely drove the evolution of PgIAA genes, followed by purifying selection. An analysis of cis-regulatory elements suggested that PgIAA family genes may be involved in the regulation of plant hormones. RNA-seq data show that the expression pattern of Aux/IAA genes in Ginseng is tissue-specific, and PgIAA02 and PgIAA36 are specifically highly expressed in lateral, fibrous, and arm roots, suggesting their potential function in root development. The PgIAA02 overexpression lines exhibited an inhibition of lateral root growth in Ginseng. In addition, yeast two-hybrid and subcellular localization experiments showed that PgIAA02 interacted with PgARF22/PgARF36 (ARF: auxin response factor) in the nucleus and participated in the biological process of root development. The above results lay the foundation for an in-depth study of Aux/IAA and provide preliminary information for further research on the role of the Aux/IAA gene family in the root development of Ginseng.

Application of a three dimensional polyethyleneimine functionalized graphene oxide aerogel as an adsorbent for the determination of phytohormones in ginseng.

Aerogels have attracted considerable attention in sample pretreatment for their outstanding properties, such as the unique porous structure, large surface area and abundant modifiable active sites. The present research reports a three-dimensional interconnected porous network aerogel (PEI-AGO) manufactured based on graphene oxide (GO), polyethyleneimine (PEI) and agar as basic materials through a vacuum freeze-drying treatment. The PEI-AGO aerogel exhibits great potential as a solid phase extraction adsorbent for the selective purification of six endogenous plant hormones in conjunction with high performance liquid chromatography-electrospray ionization tandem mass spectrometry (LC-MS). Several factors affecting the extraction efficiency were investigated. Under the optimized extraction conditions, a wide linear range of 0.5-100 ng mL-1 with a good linearity (r > 0.9934) was observed. Low limits of detection (LODs) and limits of quantification (LOQs) were obtained in the range of 0.032-0.155 ng mL-1 and 0.107-0.518 ng mL-1, respectively. Furthermore, the relative recoveries for spiked ginseng samples exhibited remarkable consistency, ranging from 90.2% to 117.6%, with a relative standard deviation (RSD) of ≤9.4% (n = 3). In summary, PEI-AGO has proven to be an effective adsorbent for the pretreatment and enrichment of phytohormones which can be used for the determination of trace endogenous acidic plant hormones in ginseng leaves.

Discrimination for geographical origin of Panax quinquefolius L. using UPLC Q-Orbitrap MS-based metabolomics approach.

American ginseng, Panax quinquefolius L., is an important medicinal plant with multiple pharmacological effects and high nutritional value. American ginseng from different geographical origins varies in quality and price. However, there was no approach for discriminating American ginseng from different geographical origins to date. In this study, a metabolomic method based on the UPLC-Orbitrap fusion platform was established to comprehensively determine and analyze metabolites of American ginseng from America and Canada, Heilongjiang, Jilin, Liaoning, and Shandong provinces in China. A total of 382 metabolites were detected, including 230 saponins, 30 amino acids and derivatives, 27 organic acids and derivatives, 25 lipids, 17 carbohydrates and derivatives, 10 phenols, 8 nucleotides, and derivatives, as well as 35 other metabolites. Metabolite differences between North America and Asia producing areas were more obvious than within Asia. Twenty metabolites, contributed most to the differentiation of producing areas, were identified as potential markers with prediction accuracy higher than 91%. The results provide new insights into the metabolite composition of American ginseng from different origins, which will help discriminate origins and promote quality control of American ginseng.

Whole-genome identification and expression profiling of growth-regulating factor (GRF) and GRF-interacting factor (GIF) gene families in Panax ginseng.

BACKGROUND: Panax ginseng is a perennial herb and one of the most widely used traditional medicines in China. During its long growth period, it is affected by various environmental factors. Past studies have shown that growth-regulating factors (GRFs) and GRF-interacting factors (GIFs) are involved in regulating plant growth and development, responding to environmental stress, and responding to the induction of exogenous hormones. However, GRF and GIF transcription factors in ginseng have not been reported. RESULTS: In this study, 20 GRF gene members of ginseng were systematically identified and found to be distributed on 13 chromosomes. The ginseng GIF gene family has only ten members, which are distributed on ten chromosomes. Phylogenetic analysis divided these PgGRFs into six clades and PgGIFs into two clades. In total, 18 of the 20 PgGRFs and eight of the ten PgGIFs are segmental duplications. Most PgGRF and PgGIF gene promoters contain some hormone- and stress- related cis-regulatory elements. Based on the available public RNA-Seq data, the expression patterns of PgGRF and PgGIF genes were analysed from 14 different tissues. The responses of the PgGRF gene to different hormones (6-BA, ABA, GA3, IAA) and abiotic stresses (cold, heat, drought, and salt) were studied. The expression of the PgGRF gene was significantly upregulated under GA3 induction and three weeks of heat treatment. The expression level of the PgGIF gene changed only slightly after one week of heat treatment. CONCLUSIONS: The results of this study may be helpful for further study of the function of PgGRF and PgGIF genes and lay a foundation for further study of their role in the growth and development of Panax ginseng.

Application of UPLC-Triple TOF-MS/MS metabolomics strategy to reveal the dynamic changes of triterpenoid saponins during the decocting process of Asian ginseng and American ginseng.

Triterpenoid saponins are the main bioactive components contributed to the nutritional value of ginseng, and different process conditions will affect their content and quality. To study the holistic characterization and dynamic changes of triterpenoid saponins in Asian ginseng (ASG) and American ginseng (AMG) during soaking and decoction, a UPLC-Triple TOF-MS/MS-based metabolomics strategy was used to characterize and discover differential saponin markers. In total, 739 triterpenoid saponins (including 225 potential new saponins) were identified from ASG and AMG in untargeted metabolomics. Based on PCA and OPLS-DA, 51 and 48 saponin markers were screened from soaked and decocted ASG and AMG, respectively. Additionally, targeted metabolomics analysis and HCA of 22 ginsenoside markers suggested that decoction of ASG and AMG for 2 h to 4 h could significantly increase the contents of rare ginsenosides (G), such as G-Rg3, G-Rg5, G-F4. This study provides a scientific insight that high boiling combined with simmering enriches ASG and AMG extracts with rich rare ginsenosides that are more beneficial to human health.

Integrated Transcriptomic and Metabolomic Analyses Reveal the Effects of Grafting on Special Metabolites of Acanthopanax senticosus Leaves.

Acanthopanax senticosus (A. senticosus) is a member of Acanthopanax Miq. and is used in traditional Chinese medicine, and it has been found that grafting technology can be used to alter plant metabolite composition and transcriptome characteristics. In this study, shoots of A. senticosus were grafted onto the rootstocks of the vigorous Acanthopanax sessiliflorus (A. sessiliflorus) to improve its varietal characteristics. In order to investigate the changes in metabolites and transcriptional patterns in grafted A. senticosus leaves (GSCL), fresh leaves were collected from 2-year-old grafted A. senticosus scions, while self-rooted seedling A. senticosus leaves (SCL) were used as controls to analyse the transcriptome and metabolome. Metabolic profiles and gene expression patterns were further identified and correlated in special metabolite target pathways. The content of chlorogenic acid and triterpenoids in the GSCL was higher than in the control, while the quercetin content was lower. All these metabolic changes were associated with changes in the expression pattern of transcripts. Our results revealed the transcriptome and metabolome characteristics of GSCL. This may help to improve leaf quality in A. senticosus cultivation, suggesting that it is feasible to improve the medicinal quality of GSCL through asexual propagation, but the long-term effects need further investigation. In conclusion, this dataset provides a useful resource for future studies on the effects of grafting on medicinal plants.

Molecular analysis of the 14-3-3 genes in Panax ginseng and their responses to heat stress.

Background: Panax Ginseng is a perennial and semi-shady herb with tremendous medicinal value. Due to its unique botanical characteristics, ginseng is vulnerable to various abiotic factors during its growth and development, especially in high temperatures. Proteins encoded by 14-3-3 genes form a highly conserved protein family that widely exists in eukaryotes. The 14-3-3 family regulates the vital movement of cells and plays an essential role in the response of plants to abiotic stresses, including high temperatures. Currently, there is no relevant research on the 14-3-3 genes of ginseng. Methods: The identification of the ginseng 14-3-3 gene family was mainly based on ginseng genomic data and Hidden Markov Models (HMM). We used bioinformatics-related databases and tools to analyze the gene structure, physicochemical properties, cis-acting elements, gene ontology (GO), phylogenetic tree, interacting proteins, and transcription factor regulatory networks. We analyzed the transcriptome data of different ginseng tissues to clarify the expression pattern of the 14-3-3 gene family in ginseng. The expression level and modes of 14-3-3 genes under heat stress were analyzed by quantitative real-time PCR (qRT-PCR) technology to determine the genes in the 14-3-3 gene family responding to high-temperature stress. Results: In this study, 42 14-3-3 genes were identified from the ginseng genome and renamed PgGF14-1 to PgGF14-42. Gene structure and evolutionary relationship research divided PgGF14s into epsilon (ε) and non-epsilon (non-ε) groups, mainly located in four evolutionary branches. The gene structure and motif remained highly consistent within a subgroup. The physicochemical properties and structure of the predicted PgGF14 proteins conformed to the essential characteristics of 14-3-3 proteins. RNA-seq results indicated that the detected PgGF14s existed in different organs and tissues but differed in abundance; their expression was higher in roots, stems, leaves, and fruits but lower in seeds. The analysis of GO, cis-acting elements, interacting proteins, and regulatory networks of transcription factors indicated that PgGF14s might participate in physiological processes, such as response to stress, signal transduction, material synthesis-metabolism, and cell development. The qRT-PCR results indicated PgGF14s had multiple expression patterns under high-temperature stress with different change trends in several treatment times, and 38 of them had an apparent response to high-temperature stress. Furthermore, PgGF14-5 was significantly upregulated, and PgGF14-4 was significantly downregulated in all treatment times. This research lays a foundation for further study on the function of 14-3-3 genes and provides theoretical guidance for investigating abiotic stresses in ginseng.

Platycodin D inhibits HFD/STZ-induced diabetic nephropathy via inflammatory and apoptotic signaling pathways in C57BL/6 mice.

ETHNOPHARMACOLOGICAL RELEVANCE: The dried root of Platycodon grandiflorum (Jacq.) A.DC. (PG) is a traditional herb used in Asian countries and is widely used in formulas for the treatment of diabetes. Platycodin D (PD) is one of the most important components of PG. AIM OF THE STUDY: This study aimed to investigate the improvement effects and regulatory mechanisms of PD on kidney injury in a high-fat diet (HFD) combined with streptozotocin (STZ)-induced diabetic nephropathy (DN). MATERIALS AND METHODS: Model mice were treated with oral gavage of the PD (2.5, 5 mg/kg) for 8 weeks. Determination of serum lipid and renal function-related indexes creatinine (CRE), and blood urea nitrogen (BUN) levels in mice, and histopathological section analysis of kidney. Molecular docking and molecular dynamics were utilized to study the binding ability of PD to target NF-κB and apoptosis signaling pathway-related proteins. Moreover, Western blot was used to test the expressions of NF-κB and apoptosis-related proteins. Vitro experiments were performed to validate the related mechanisms using RAW264.7 cells and HK2 cells cultured by high glucose. RESULTS: In vivo experiments, the administration of PD (2.5 and 5.0 mg/kg) reduced fasting blood glucose (FBG) and homeostasis model assessment of insulin resistance (HOMA-IR) levels in DN mice, while lipid levels and renal function were significantly improved. Furthermore, PD significantly inhibited the development of DN in the model mice by regulating NF-κB and apoptotic signaling pathways, reduced the abnormal elevation of serum inflammatory factors TNF-α and IL-1ß, and repaired renal cell apoptosis. In vitro experiments, NF-κB inhibitor ammonium pyrrolidine dithiocarbamate (PDTC) was used to confirm that PD can alleviate high glucose-induced inflammation in RAW264.7 cells and inhibit the release of inflammatory factors. And in HK2 cell experiments, it was verified that PD can inhibit ROS generation, reduce the loss of JC-1 and suppress HK2 cell injury by regulating NF-κB and apoptotic pathways. CONCLUSIONS: These data suggested that PD has the potential to prevent and treat DN and is a promising natural nephroprotective agent.

Identification of anti-inflammatory components in Panax ginseng of Sijunzi Decoction based on spectrum-effect relationship.

Objective: This study aimed to identify the main medicinal active components of Panax ginseng (P. ginseng) in the compatibility environment of clinical application. For this purpose, the anti-inflammatory ingredients of P. ginseng were investigated based on its therapeutic effect in Sijunzi Decoction (SJD) which is a widely used traditional Chinese formula. Methods: The fingerprints of 10 batches of SJD consisting of different sources of P. ginseng were established by UPLC technique to investigate the chemical components. At the same time, the anti-inflammatory effects of these components were evaluated by dextran sulfate sodium-induced ulcerative colitis mouse model. Grey relational analysis was applied to explore the correlation degree between fingerprints and anti-inflammatory effects in SJD. Lipopolysaccharide-stimulated RAW264.7 murine macrophages were established to evaluate the anti-inflammatory action of the screened effective substances of P. ginseng. Results: According to grey relational analysis, notoginsenoside R1, ginsenoside Rg2 and ginsenoside Rb3 of P. ginseng were the major anti-inflammatory contributions in SJD. They had been proven to be closely associated with the anti-inflammatory process of SJD and displayed a close effect compared with SJD by LPS-stimulated RAW264.7 murine macrophages. Conclusion: Our work provides a general strategy for exploring the pharmacological ingredients of P. ginseng in traditional Chinese formulas which is beneficial for establishing the quality standards of traditional herbs in traditional Chinese medicine prescription based on their clinical therapeutic effect.

Genome-wide analysis of Panax MADS-box genes reveals role of PgMADS41 and PgMADS44 in modulation of root development and ginsenoside synthesis.

Panax root is an important material used in food and medicine. Its cultivation and production usually depend on root shape and ginsenoside content. There is limited understanding about the synergistic regulatory mechanisms underlying root development and ginsenoside accumulation in Panax. MADS-box transcription factors possibly play a significant role in regulation of root growth and secondary metabolites. In this study, we identified MADS-box transcription factors of Panax, and found high expression levels of SVP, ANR1 and SOC1-like clade genes in its roots. We confirmed that two SOC1-like genes, PgMADS41 and PgMADS44, bind to expansion gene promoters (PgEXLB5 and PgEXPA13), which contribute to root growth, and to SE-4, CYP716A52v2-4, and ß-AS-13 promoters, which participate in ginsenoside Ro biosynthesis. These two genes were found to increase lateral root number and main root length in transgenic Arabidopsis thaliana by improving AtEXLA1, AtEXLA3, AtEXPA5, and AtEXPA6 gene expression. As a non-phytohormone regulatory tool, Ro can stimulate adventitious root growth by influencing their expression and ginsenoside accumulation. Our study provides new insights into the coordinated regulatory function of SOC1-like clade genes in Panax root development and triterpenoid accumulation, paving the way towards understanding root formation and genetic improvement in Panax.

Exploring the mechanism of active components from ginseng to manage diabetes mellitus based on network pharmacology and molecular docking.

A large body of literature has shown that ginseng had a role in diabetes mellitus management. Ginsenosides are the main active components of ginseng. But what ginsenosides can manage in diabetic are not systematic. The targets of these ginsenosides are still incomplete. Our aim was to identify which ginsenosides can manage diabetes mellitus through network pharmacology and molecular docking. To identify the targets of these ginsenosides. In this work, we retrieved and screened ginsenosides and corresponding diabetes mellitus targets across multiple databases. PPI networks of the genes were constructed using STRING, and the core targets were screened out through topological analysis. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed by using the R language. Finally, molecular docking was performed after bioinformatics analysis for verification. Our research results showed that 28 ginsenosides in ginseng might be against diabetes mellitus by modulating related proteins such as VEGFA, Caspase 3, and TNF-α. Among the 28 ginsenosides, 20(R)-Protopanaxatriol, 20(R)-Protopanaxadiol, and Ginsenoside Rg1 might play a significant role. Kyoto Encyclopedia of Genes and Genomes and Gene Ontology enrichment analysis showed that the management of diabetes mellitus by ginsenosides may be related to the positive regulation of reactive oxygen metabolic processes, associated with the insulin signaling pathway, TNF signaling pathway, and AMPK signaling pathway. Molecular docking results and molecular dynamics simulation showed that most ginsenosides could stably bind to the core target, mainly hydrogen bonding and hydrophobic bond. This study suggests the management of ginseng on diabetes mellitus. We believe that our results can contribute to the systematic study of the mechanism of ginsenosides for the management of diabetes mellitus. At the same time, it can provide a theoretical basis for subsequent studies on the management of ginsenosides in diabetes mellitus.

Saponins From Platycodon grandiflorum Reduces Cisplatin-Induced Intestinal Toxicity in Mice through Endoplasmic Reticulum Stress-Activated Apoptosis.

Saponins from the roots of Platycodon grandiflorum, an edible medicinal plant, have shown a wide range of beneficial effects on various biological processes. In this study, an animal model was established by a single intraperitoneal injection of cisplatin (20[Formula: see text]mg/kg) for evaluating the protective effects of saponins from the roots of P. grandiflorum (PGS, 15[Formula: see text]mg/kg and 30[Formula: see text]mg/kg) in mice. The results indicated that PGS treatment for 10 days restored the destroyed intestinal mucosal oxidative system, and the loosened junctions of small intestinal villi was significantly improved. In addition, a significant mitigation of apoptotic effects deteriorated by cisplatin exposure in small intestinal villi was observed by immunohischemical staining. Also, western blot showed that PGS could effectively prevent endoplasmic reticulum (ER) stress-induced apoptosis caused by cisplatin in mice by restoring the activity of PERK (an ER kinase)-eIF2[Formula: see text]-ATF4 signal transduction pathway. Furthermore, molecular docking results of main saponins in PGS suggested a better binding ability with target proteins. In summary, the present work revealed the underlying protective mechanisms of PGS on intestinal injury induced by cisplatin in mice.

Integrative SMRT sequencing and ginsenoside profiling analysis provide insights into the biosynthesis of ginsenoside in Panax quinquefolium.

Panax quinquefolium is one of the most common medicinal plants worldwide. Ginsenosides are the major pharmaceutical components in P. quinquefolium. The biosynthesis of ginsenosides in different tissues of P. quinquefolium remained largely unknown. In the current study, an integrative method of transcriptome and metabolome analysis was used to elucidate the ginsenosides biosynthesis pathways in different tissues of P. quinquefolium. Herein, 22 ginsenosides in roots, leaves, and flower buds showed uneven distribution patterns. A comprehensive P. quinquefolium transcriptome was generated through single molecular real-time (SMRT) and second-generation sequencing (NGS) technologies, which revealed the ginsenoside pathway genes and UDP-glycosyltransferases (UGT) family genes explicitly expressed in roots, leaves, and flower buds. The weighted gene co-expression network analysis (WGCNA) of ginsenoside biosynthesis genes, UGT genes and ginsenoside contents indicated that three UGT genes were positively correlated to pseudoginsenoside F11, notoginsenoside R1, notoginsenoside R2 and pseudoginsenoside RT5. These results provide insights into ginsenoside biosynthesis in different tissues ofP. quinquefolium.

Icariin exhibits protective effects on cisplatin-induced cardiotoxicity via ROS-mediated oxidative stress injury in vivo and in vitro.

BACKGROUND: Cisplatin-induced cardiotoxicity severely limits its clinical application as an antitumor drug and increases the risk of cardiovascular disease. Icariin (ICA), the main flavonoid isolated from Epimedii Folium, has been demonstrated to have various beneficial effects on cardiovascular disease. However, the protective effect of ICA against cisplatin-induced cardiotoxicity remains unclear. PURPOSE: In present study, we explored the protective action of ICA against cisplatin-induced cardiotoxicity and its possible molecular mechanisms in vitro and in vivo. METHODS: Mice were intraperitoneally injected with cisplatin 4 mg/kg every other day for 7 times to establish myocardial injury model. ICA (15, 30 mg/kg) was administered to mice by gavage for 21 days. H9c2 cells were treated with ICA (3, 6, 12 µM) in the presence or absence of cisplatin (40 µM), and then cell viability, oxidative stress, apoptosis, and mitochondrial function were evaluated. RESULTS: Biochemical index detection and histopathological staining analysis showed that ICA had a good protective effect on cisplatin-induced cardiotoxicity. Cellular experiments showed that ICA inhibited cisplatin-induced oxidative stress in a dose-dependent manner by regulating the levels of glutathione peroxidase (GSH-Px), catalase (CAT), superoxide dismutase (SOD) and malondialdehyde (MDA). ICA could inhibit the expression of NF-κB and the secretion of inflammatory factors, thereby alleviating the inflammatory injury caused by cisplatin. In addition, ICA could alleviate cisplatin-induced myocardial injury by activating SIRT1 and PI3K/Akt signaling pathways and inhibiting MAPKs signaling pathway. CONCLUSION: These results suggest that ICA could attenuate cisplatin-induced cardiac injury by inhibiting oxidative stress, inflammation and apoptosis, laying a foundation for ICA to reduce chemotherapy-induced cardiotoxicity in clinical practice.

Multiresidue screening of pesticides in Panax Ginseng C. A. Meyer by ultra-high-performance liquid chromatography with quadrupole time-of-flight mass spectrometry.

In this study, an efficient screening method based on a modified quick, easy, cheap, effective, rugged, and safe extraction method combined with ultra-high-performance liquid chromatography coupled to tandem quadrupole time-of-flight mass spectrometry was established for the determination of 90 pesticides residues in Panax Ginseng. The accuracy of the method was then verified by analyzing the false positive rate and the screening detection limit in Ginseng. The results revealed that the screening detection limit of 33 of 90 pesticide residues were 0.01 mg·kg-1 , 22 species were 0.05 mg·kg-1 , 11 species were 0.10 mg·kg-1 , 8 species were 0.20 mg·kg-1 , and another 16 species were greater than 0.20 mg·kg-1 . A total of 73 pesticides were ultimately suitable to be practically applied for rapid analysis of pesticide residues in Ginseng. Finally, the established method was used to analyze the pesticide residues in 35 Ginseng samples available on the market. And the residual of dimethomorph, azoxystrobin, tebuconazole, and pyraclostrobin was relatively severe in Ginseng samples. This work expanded the range of pesticides detected and provided a rapid, effective method for pesticides screening in Ginseng.

Characterization and quantification of ginsenosides from the root of Panax quinquefolius L. by integrating untargeted metabolites and targeted analysis using UPLC-Triple TOF-MS coupled with UFLC-ESI-MS/MS.

The root of Panax quinquefolius L. (RPQ) is considered as an important functional food and rich in bioactive components, ginsenosides. To comprehensively characterize ginsenosides and evaluate the quality of RPQ from different sources, UPLC-Triple TOF-MS coupled with UFLC-ESI-MS/MS was applied to untargeted metabolites and targeted analysis for the first time. In untargeted metabolites analysis, a total of 225 ginsenosides were identified from RPQ using UPLC-Triple TOF-MS combined with SWATH data-independent strategy. Furthermore, the contents of 39 targeted ginsenoside markers in 14 RPQ samples were analyzed by a rapid and sensitive UFLC-ESI-MS/MS method. In addition, the results of chemometric analysis showed the quality of American RPQ was distinguished from that of Chinese RPQ according to the amount of targeted ginsenosides. This newly developed approach provides a powerful tool for enriching the diversity of saponins database and assessing the quality of RPQ, which can be further extended to other ginseng products and functional foods.

Dynamic changes of ginsenosides in Panax quinquefolium fruit at different development stages measured using UHPLC-Orbitrap MS.

RATIONALE: Some studies have shown that Panax quinquefolium fruit (PQF) could also be used as a potential medicinal resource. However, little is known about the composition of ginsenosides and their dynamic changes at different development stages of PQF. Therefore, this study is of great significance for the metabolomics and rational utilization of PQF. METHODS: The samples were analyzed using ultra-high-performance liquid chromatography combined with an Orbitrap mass spectrometer (UHPLC-Orbitrap MS), and the method of metabonomics was applied to profile the dynamic changes of ginsenosides in PQF at different development stages. RESULTS: A total of 109 ginsenosides were identified or tentatively characterized. Samples collected from different development stages were significantly discriminated according to ginsenoside contents. A total of 25 potential chemical markers enabling the differentiation were discovered. CONCLUSIONS: For the first time, the study developed an UHPLC-Orbitrap MS-based approach to detect ginsenoside in PQF at different development stages using a non-targeted mode. This comprehensive phytochemical profile study revealed the structural diversity and discrimination of ginsenosides in PQF at different development stages, which could provide the basis for the metabolomics and rational application of PQF.

Mycorrhizal fungi alleviate acidification-induced phosphorus limitation: Evidence from a decade-long field experiment of simulated acid deposition in a tropical forest in south China.

South China has been experiencing very high rate of acid deposition and severe soil acidification in recent decades, which has been proposed to exacerbate the regional ecosystem phosphorus (P) limitation. We conducted a 10-year field experiment of simulated acid deposition to examine how acidification impacts seasonal changes of different soil P fractions in a tropical forest with highly acidic soils in south China. As expected, acid addition significantly increased occluded P pool but reduced the other more labile P pools in the dry season. In the wet season, however, acid addition did not change microbial P, soluble P and labile organic P pools. Acid addition significantly increased exchangeable Al3+ and Fe3+ and the activation of Fe oxides in both seasons. Different from the decline of microbial abundance in the dry season, acid addition increased ectomycorrhizal fungi and its ratio to arbuscular mycorrhiza fungi in the wet season, which significantly stimulated phosphomonoesterase activities and likely promoted the dissolution of occluded P. Our results suggest that, even in already highly acidic soils, the acidification-induced P limitation could be alleviated by stimulating ectomycorrhizal fungi and phosphomonoesterase activities. The differential responses and microbial controls of seasonal soil P transformation revealed here should be implemented into ecosystem biogeochemical model for predicting plant productivity under future acid deposition scenarios.

Isolation, identification, and quantification of triterpene saponins in the fresh fruits of Panax notoginseng.

This study is to develop a method for isolation, identification, and quantitative determination of dammarane-type triterpene saponins in the Panax notoginseng fruits (PNF). The saponins were isolated by a serious of chromatographic methods, and their structures were elucidated on the basis of spectroscopic evidence and comparison with those of literature reports. Quantitative assay was performed on an ultra-performance liquid chromatography-UV (UPLC-UV) method. As a result, 22 saponins were isolated from the extract of PNF, among them, compound 1 was a new saponin, named as malonylgypenoside IX, compounds 3-10, and 14-18 were isolated from the PNF for the first time. As to quantitative analysis, the calibration curves showed good linearity (r > 0.998) within the concentration range, and the method validation provided good reproducibility and sensitivity for the quantification of eight major saponins with precision and accuracy of less than 3.0%.