Synthesis Of Saponins Research Articles

Spatiotemporal expression analysis of jasmonic acid and saponin-related genes uncovers a potential biosynthetic regulation in Panax notoginseng.

Sanqi, the root of Panax notoginseng, has long been recognized for its therapeutic effects on cardiovascular diseases. Saponins, including ginsenosides and notoginsenosides, are the main bioactive components of P. notoginseng. The biosynthesis of saponins is closely related to the defense responses orchestrated by endogenous hormones. To provide new insights into the underlying role of phytohormone jasmonic acid (JA) in the synthesis and regulation of saponins, we performed an ultra-performance liquid chromatography analysis of different tissues of P. notoginseng aged 2-4 years. Moreover, by combined evaluation of saponin content and transcriptome profiling of each tissue, the spatial and temporal distribution of saponins was analyzed. N notoginsenoside R1, ginsenoside Rb1 and ginsenoside Rd accumulated in the underground tissues, including the root, tuqi, fibril and rhizome. In agreement with this data, the corresponding genes of the endogenous hormone JAs, especially coronatine insensitive 1 (COI1) and myelocytomatosis proteins 2 (MYC2), were predominantly expressed in the underground tissues. The tissue- and age-specific distribution of saponins was consistent with the expression of genes involved in JA biosynthetic, metabolic and signaling pathways. The present study has revealed the temporal and spatial effects of endogenous phtohormones in the synthesis and regulation of notoginsenosides, which will provide a significant impact on improving the ecological planting technology, cultivating new high-quality varieties and protecting the rare resources of medicinal P. notoginseng. © 2024 Society of Chemical Industry.

Identification and analysis of UGT genes associated with triterpenoid saponin in soapberry (Sapindus mukorossi Gaertn.)

BackgroundSoapberry (Sapindus mukorossi) is an economically important multifunctional tree species. Triterpenoid saponins have many functions in soapberry. However, the types of uridine diphosphate (UDP) glucosyltransferases (UGTs) involved in the synthesis of triterpenoid saponins in soapberry have not been clarified.ResultsIn this study, 42 SmUGTs were identified in soapberry, which were unevenly distributed on 12 chromosomes and had sequence lengths of 450 bp to 1638 bp, with an average of 1388 bp. The number of amino acids in SmUGTs was 149 to 545, with an average of 462. Most SmUGTs were acidic and hydrophilic unstable proteins, and their secondary structures were mainly α-helices and random coils. All had conserved UDPGT and PSPG-box domains. Phylogenetic analysis divided them into four subclasses, which glycosylated different carbon atoms. Prediction of cis-acting elements suggested roles of SmUGTs in plant development and responses to environmental stresses. The expression patterns of SmUGTs differed according to the developmental stage of fruits, as determined by transcriptomics and RT-qPCR. Co-expression network analysis of SmUGTs and related genes/transcription factors in the triterpenoid saponin synthesis pathway was also performed. The results indicated potential roles for many transcription factors, such as SmERFs, SmGATAs and SmMYBs. A correlation analysis showed that 42 SmUGTs were crucial in saponin synthesis in soapberry.ConclusionsOur findings suggest optimal targets for manipulating glycosylation in soapberry triterpenoid saponin biosynthesis; they also provide a theoretical foundation for further evaluation of the functions of SmUGTs and analyses of their biosynthetic mechanisms.

Genome-Wide Identification, Characterization, and Expression Analysis of the CYP450 Family Associated with Triterpenoid Saponin in Soapberry (Sapindus mukorossi Gaertn.)

Soapberry (Sapindus mukorossi Gaertn.) is a tree species of the family Sapindaceae, the pericarp of which is rich in triterpenoid saponins, which are important in chemical production, biomedicine, and other fields. Cytochrome P450 monooxygenase (CYP450) is involved in the modification of the skeletons of triterpenoid saponins and is linked to their diversity. We previously identified 323 CYP450 genes in the transcriptome of soapberry and screened 40 CYP450 genes related to the synthesis of triterpenoid saponins by gene annotation and conserved structural domain analysis. The genetic structure and phylogeny of the CYP450 genes were analyzed separately. Phylogenetic analysis categorized the CYP450 genes of soapberry into five subfamilies, the members of which had similar conserved cumulative sequences and intron structures. A cis-acting element analysis implicated several genes in the responses to environmental changes and hormones. The expression of several genes during eight periods of fruit development was analyzed by real-time quantitative qRT-PCR; most showed high expression during the first four periods of fruit development, and their expression decreased as the fruits matured. A co-expression network analysis of SmCYP450s and related genes in the triterpenoid saponin synthesis pathway was performed. Correlation analysis showed that 40 SmCYP450s may be involved in saponin synthesis in soapberry. The triterpenoid saponin synthesis-related candidate genes identified in this study provide insight into the synthesis and regulation of triterpenoid saponins in soapberry.

Uncovering the molecular mechanisms behind steroidal saponin accumulation in Liriope muscari (Decne.) Baily through transcriptome sequencing and bioinformatics analysis

The leaves and roots of Liriope muscari (Decne.) Baily were subjected to high-throughput Illumina transcriptome sequencing. Bioinformatics analysis was used to investigate the enzyme genes and key transcription factors involved in regulating the accumulation of steroidal saponins, which are the main active ingredient in L. muscari. These analyses aimed to reveal the molecular mechanism behind steroidal saponin accumulation. The sequencing results of L. muscari revealed 31 enzymes, including AACT, CAS, DXS and DXR, that are involved in the synthesis of steroidal saponins. Among these enzymes, 16 were in the synthesis of terpenoid skeleton, 3 were involved in the synthesis of sesquiterpene and triterpene, and 12 were involved in the synthesis of steroidal compound. Differential gene expression identified 15 metabolic enzymes coded by 34 differentially expressed genes (DEGs) in the leaves and roots, which were associated with steroidal saponin synthesis. Further analysis using gene co-expression patterns showed that 14 metabolic enzymes coded by 31 DEGs were co-expressed. In addition, analysis using gene co-expression analysis and PlantTFDB's transcription factor analysis tool predicted the involvement of 8 transcription factors, including GAI, PIF4, PIL6, ERF8, SVP, LHCA4, NF-YB3 and DOF2.4, in regulating 6 metabolic enzymes such as DXS, DXR, HMGR, DHCR7, DHCR24, and CAS. These eight transcription factors were predicted to play important roles in regulating steroidal saponin accumulation in L. muscari. Promoter analysis of these transcription factors indicated that their main regulatory mechanisms involve processes such as abscisic acid response, drought-induction stress response and light response, especially abscisic acid responsive elements (ABRE) response and MYB binding site involved in drought-inducibility (MBS) response pathway. Furthermore, qRT-PCR analysis of these eight key transcription factors demonstrated their specific differences in the leaves and roots.

Integrated Transcriptomics and Metabolomics Analysis Reveals the Effects of Cutting on the Synthesis of Flavonoids and Saponins in Chinese Herbal Medicine Astragalus mongholious.

Astragali Radix, derived from the roots of Astragalus mongholicus, is a traditional Chinese medicine containing flavonoids and saponins as its key ingredients. With a shortage in the wild sources of the herbal plant, it is especially important to explore a cultivation mode for A. mongholicus for medicinal purposes. Cutting, a physical environmental stress method, was used in this study with the objective of improving the quality of this herbal legume. We found that cutting of the top 1/3 of the aboveground part of A. mongholicus during the fruiting period resulted in a significant increase in the content of flavonoids and saponins, as well as in root growth, including length, diameter, and dry weight. Furthermore, the leaves were sampled and analyzed using a combined transcriptome and metabolome analysis approach at five different time points after the treatment. Sixteen differentially expressed unigenes (DEGs) involved in the biosynthesis of flavonoids were identified; these were found to stimulate the synthesis of flavonoids such as formononetin and calycosin-7-O-β-D-glucoside. Moreover, we identified 10 DEGs that were associated with the biosynthesis of saponins, including astragaloside IV and soyasaponin I, and found that they only regulated the mevalonic acid (MVA) pathway. These findings provide new insights into cultivating high-quality A. mongholicus, which could potentially alleviate the scarcity of this valuable medicinal plant.

Integrated metabolome and transcriptome analysis reveals the regulatory mechanism of low nitrogen-driven biosynthesis of saponins and flavonoids in Panax notoginseng

BackgroundNitrogen (N) is an important macronutrient involved in the biosynthesis of primary and secondary metabolites in plants. However, the metabolic regulatory mechanism of low-N-induced triterpenoid saponin and flavonoid accumulation in rhizomatous medicinal Panax notoginseng (Burk.) F. H. Chen remains unclear. MethodsTo explore the potential regulatory mechanism and metabolic basis controlling the response of P. notoginseng to N deficiency, the transcriptome and metabolome were analysed in the roots. ResultsThe N content was significantly reduced in roots of N0-treated P. notoginseng (0 kg·N·667 m−2). The C/N ratio was enhanced in the N-deficient P. notoginseng. N deficiency promotes the accumulation of amino acids (L-proline, L-leucine, L-isoleucine, L-norleucine, L-arginine, and L-citrulline) and sugar (arabinose, xylose, glucose, fructose, and mannose), thus providing precursor metabolites for the biosynthesis of flavonoids and triterpenoid saponins. Downregulation of key structural genes (PAL, PAL3, ACC1, CHS2, PPO, CHI3, F3H, DFR, and FGT), in particular with the key genes of F3H, involved in the flavonoid biosynthesis pathway possibly induced the decrease in flavonoid content with increased N supply. Notoginsenoside R1, ginsenoside Re, Rg1, Rd, F1, R1 + Rg1 + Rb1 and total triterpenoid saponins were enhanced in the N0 groups than in the N15 (15 kg·N·667 m−2) plants. Higher phosphoenolpyruvate (an intermediate of glycolyticwith pathway metabolism) and serine (an intermediate of photorespiration) levels induced by N deficiency possibly promote saponin biosynthesis through mevalonic acid (MVA) and methylerythritol (MEP) pathways. Genes (MVD2, HMGS, HMGR1, HMGR2, DXR, and HMGR1) encoding the primary enzymes HMGS, HMGR, DXR, and MVD in the MVA and MEP pathways were significantly upregulated in the N0-treated P. notoginseng. The saponin biosynthesis genes DDS, DDS, CYP716A52, CYP716A47, UGT74AE2, and FPS were upregulated in the N-deficient plants. Upregulation of genes involved in saponin biosynthesis promotes the accumulation of triterpenoid saponins in the N0-grown P. notoginseng. ConclusionsN deficiency enhances primary metabolisms, such as amino acids and sugar accumulation, laying the foundation for the synthesis of flavonoids and triterpenoid saponins in P. notoginseng. F3H, DDS, FPS, HMGR, HMGS and UGT74AE2 can be considered as candidates for functional characterisation of the N-regulated accumulation of triterpenoid saponins and flavonoids in future.

Molecular cloning and heterologous expression analysis of 1-Deoxy-D-Xylulose-5-Phosphate Synthase gene in Centella asiatica L.

Many genes involved in triterpenoid saponins in plants control isoprenoid flux and constitute the precursor pool, which is channeled into various downstream pathways leading to the synthesis of triterpenoid saponins in C. asiatica. Full-length 1-Deoxy-D-Xylulose-5-Phosphate-Synthase (CaDXS) gene was isolated for the study from the previously annotated Centella asiatica leaves transcriptomic data. The CaDXS gene sequence was submitted to the NCBI databases with GenBank accession number MZ997832. The full-length CaDXS gene contained a 2244 base pair open reading frame that encoded a 747 amino acid polypeptide. The predicted molecular weight (MW) and theoretical pI of DXS are 76.28 kDa and 6.86, respectively. Multiple amino acid sequence alignment of amino acids and phylogenetic studies suggest that CaDXS shares high similarities with DXS from other plants DXS belonging to different families. A phylogenetic tree was constructed using Molecular Evolutionary Genetic Analysis (MEGA) version 10.1.6. Structural analysis provided fundamental information about the three-dimensional features and physicochemical parameters of the CaDXS protein. Quantitative expression analysis showed that CaDXS transcripts were maximally expressed in leaf, followed by petiole, roots, and node tissues. CaDXS was cloned into the expression vector pET28a, expressed heterologously in DH5α bacteria, confirmed by sequencing, and subsequently characterized by protein expression and functional complementation. The study focused on understanding the protein structure, biological significance, regulatory mechanism, functional analysis, and gene characterization of the centellosides biosynthetic pathway gene DXS for the first time in the plant. It would provide new information about the metabolic pathway and its relative contribution to isoprenoid biosynthesis.

Synthesis and Evaluation of Saponins with All-Nitrogenated Sugars

AbstractSaponins exhibit multiple biological and pharmacological activities, and the sugar moiety of saponins is known to play a crucial role in bioactivity. In this report, we focus on the synthesis and evaluation of saponins with all-nitrogenated sugar (ANS), in which all oxygen atoms are replaced with nitrogen atoms. OSW-1 derivative-, cholesterol-, and diosgenin-ANS glycosides are synthesized by glycosylation with ANS in the presence of TMSOTf. As a result, the OSW-1 mimic, with ANS, exhibits good cytotoxic activity (IC50 = 7.31 μM) and induces apoptosis.

Genome assembly of Polygala tenuifolia provides insights into its karyotype evolution and triterpenoid saponin biosynthesis.

Polygala tenuifolia is a perennial medicinal plant that has been widely used in traditional Chinese medicine for treating mental diseases. However, the lack of genomic resources limits the insight into its evolutionary and biological characterization. In the present work, we reported the P. tenuifolia genome, the first genome assembly of the Polygalaceae family. We sequenced and assembled this genome by a combination of Illumnina, PacBio HiFi, and Hi-C mapping. The assembly includes 19 pseudochromosomes covering ~92.68% of the assembled genome (~769.62Mb). There are 36 463 protein-coding genes annotated in this genome. Detailed comparative genome analysis revealed that P. tenuifolia experienced two rounds of whole genome duplication that occurred ~39-44 and ~18-20 million years ago, respectively. Accordingly, we systematically reconstructed ancestral chromosomes of P. tenuifolia and inferred its chromosome evolution trajectories from the common ancestor of core eudicots to the present species. Based on the transcriptomics data, enzyme genes and transcription factors involved in the synthesis of triterpenoid saponin in P. tenuifolia were identified. Further analysis demonstrated that whole-genome duplications and tandem duplications play critical roles in the expansion of P450 and UGT gene families, which contributed to the synthesis of triterpenoid saponins. The genome and transcriptome data will not only provide valuable resources for comparative and functional genomic researches on Polygalaceae, but also shed light on the synthesis of triterpenoid saponin.

Synthesis of immunostimulatory saponins: A sweet challenge for carbohydrate chemists

Saponins are a large family of natural glycosides showing a wide range of biological activities. Current research efforts on saponins as vaccine adjuvants have been mainly focused on the development of synthetic analogs. By mimicking the immunomodulatory saponins from Quillaja saponaria (QS), less complex and readily accessible analogs have been synthesized to improve the industrial applicability and efficacy of saponins as vaccine adjuvants. Through the exploration of several structural modifications on the skeleton of QS saponins, including changes in the sugar and aglycone compositions as well as in the nature and configuration of the glycosidic bonds, structure-activity relationship (SAR) studies developed by Pr. Gin in the early 2010s were taken as a starting point for the development of a new generation of immunomodulatory candidates. In this review, the recent synthetic strategies and SAR studies of mono- and bidesmosidic QS saponins are discussed. Original concepts of vaccination including self-adjuvanticity and the development of saponin-based glycoconjugates are described. The synthesis and semi-synthesis of saponin alternatives to QS, such as Momordica saponin and onjisaponin derivatives, are also discussed in this review.

Deciphering the network of cholesterol biosynthesis in Paris polyphylla laid a base for efficient diosgenin production in plant chassis

Cholesterol serves as a key precursor for many high-value chemicals such as plant-derived steroidal saponins and steroidal alkaloids, but a plant chassis for effective biosynthesis of high levels of cholesterol has not been established. Plant chassis have significant advantages over microbial chassis in terms of membrane protein expression, precursor supply, product tolerance, and regionalization synthesis. Here, using Agrobacterium tumefaciens-mediated transient expression technology, Nicotiana benthamiana, and a step-by-step screening approach, we identified nine enzymes (SSR1-3, SMO1-3, CPI-5, CYP51G, SMO2-2, C14-R-2, 8,7SI-4, C5-SD1, and 7-DR1-1) from the medicinal plant Paris polyphylla and established detailed biosynthetic routes from cycloartenol to cholesterol. Specfically, we optimized HMGR, a key gene of the mevalonate pathway, and co-expressed it with the PpOSC1 gene to achieve a high level of cycloartenol (28.79 mg/g dry weight, which is a sufficient amount of precursor for cholesterol biosynthesis) synthesis in the leaves of N. benthamiana. Subsequently, using a one-by-one elimination method we found that six of these enzymes (SSR1-3, SMO1-3, CPI-5, CYP51G, SMO2-2, and C5-SD1) were crucial for cholesterol production in N. benthamiana, and we establihed a high-efficiency cholesterol synthesis system with a yield of 5.63 mg/g dry weight. Using this strategy, we also discovered the biosynthetic metabolic network responsible for the synthesis of a common aglycon of steroidal saponin, diosgenin, using cholesterol as a substrate, obtaining a yield of 2.12 mg/g dry weight in N. benthamiana. Our study provides an effective strategy to characterize the metabolic pathways of medicinal plants that lack a system for in vivo functional verification, and also lays a foundation for the synthesis of active steroid saponins in plant chassis.

Arbuscular mycorrhiza and plant growth promoting endophytes facilitates accumulation of saponin under moderate drought stress

ObjectiveParis polyphylla var. yunnanensis, one of the important medicinal plant resources in Yunnan, China, usually takes 6–8 years to be harvested. Therefore, it is urgent to find a method that can not only shorten its growth years, but also improve its quality. In this study, we examined the effects of a combination treatment of arbuscular mycorrhizal fungi (AMF) and plant growth-promoting endophytes (PGPE) and drought stress on the accumulation of saponins in it. MethodsP. polyphylla var. yunnanensis was infected with a mixture of AMF and PGPE under drought stress. The content of saponins, as well as morphological, physiological, and biochemical indicators, were all measured. The UGTs gene related to saponin synthesis was obtained from transcriptome data by homologous comparison, which were used for RT-PCR and phylogenetic analysis. ResultsRegardless of water, AMF treatment could infect the roots of P. polyphylla var. yunnanensis, however double inoculation with AMF and PGPE (AMF + PGPE) would reduce the infection rate of AMF. Plant height, aboveground and underground fresh weight did not differ significantly between the single inoculation AMF and the double inoculation treatment under different water conditions, but the inoculation treatment significantly increased the plant height of P. polyphylla var. yunnanensis compared to the non-inoculation treatment. Single inoculation with AMF considerably increased the net photosynthetic rate, stomatal conductance, and transpiration rate of P. polyphylla var. yunnanensis leaves under various water conditions, but double inoculation with AMF + PGPE greatly increased the intercellular CO2 concentration and chlorophyll fluorescence parameter (Fv/Fm). Under diverse water treatments, single inoculation AMF had the highest proline content, whereas double inoculation AMF + PGPE may greatly improve the amount of abscisic acid (ABA) and indoleacetic acid (IAA) compared to normal water under moderate drought. Double inoculation AMF + PGPE treatment improved the proportion of N, P, and K in the rhizome of P. polyphylla var. yunnanensis under various water conditions. Under moderate drought stress, AMF + PGPE significantly enhanced the contents of P. polyphylla var. yunnanensis saponins I, II, VII, and total saponins as compared to normal water circumstances. Farnesyl diphosphate synthase (FPPS), Geranyl pyrophosphate synthase (GPPS), Cycloartenol synthase (CAS), and Squalene epoxidase (SE1) were the genes that were significantly up-regulated at the same time. The amount of saponins was favorably linked with the expression of CAS, GPPS, and SE1. Saponin VI content and glycosyl transferase (UGT) 010922 gene expression were found to be substantially associated, as was saponin II content and UGT010935 gene expression. ConclusionUnder moderate drought, AMF + PGPE was more conducive to the increase of hormone content, nutrient absorption, and total saponin content in P. polyphylla var. yunnanensis, and AMF + PGPE could up regulate the expression of key genes and UGTs genes in one or more steroidal saponin synthesis pathways to varying degrees, thereby stimulating the synthesis and accumulation of steroidal saponins in the rhizome of P. polyphylla var. yunnanensis. The combination of AMF and PGPE inoculation, as well as adequate soil drought, reduced the buildup of saponins in P. polyphylla var. yunnanensis and increased its quality.

Comprehensive compositional assessment of bioactive compounds in diverse pea accessions

Pea (Pisum sativum L.) is an important legume crop providing a good source of protein, vitamins, minerals and bioactive compounds with health benefits for humans. In this study, an improved method for simultaneous analysis of multiple phytoestrogens among 100 pea accessions was developed. Ipriflavone, (a synthetic isoflavone), was used as an internal standard for the semiquantitative analysis of 17 phytoestrogens including isoflavone aglycones and conjugates, allowing direct analysis of isoflavones in their naturally occurring forms. This comprehensive dataset demonstrated that the isoflavones varied greatly and some accessions tended to have high levels of multiple phytoestrogens among the 100 accessions analyzed. Isoliquiritigenin followed by glycitein were the predominant compounds detected in the accessions and showed the highest correlation with the total phytoestrogens content. Secoisolariciresinol content was consistently higher in yellow cotyledon peas than in green cotyledon peas, whereas the contents of coumestrol, genestein and secoisolariciresinol were significantly correlated with seed coat color. The total phenolics and saponins showed a wide range of variability among the accessions with higher concentrations of total phenolics observed in seeds with pigmented seed coat or yellow cotyledon seeds, suggesting the synthesis of saponins and phenolics are significantly affected by metabolic pathway genes controlling cotyledon color or seed coat color. This study profiled the variability of bioactive compounds of pea seed quality traits in diverse pea accessions and provides an immense resource for continued research, breeding and selection of genotypes for a wide range of applications.

Comparative transcriptomic analysis of genes in the triterpene saponin biosynthesis pathway in leaves and roots of Ardisia kteniophylla A. DC., a plant used in traditional Chinese medicine.

Ardisia kteniophylla (Primulaceae) is highly valued in traditional medicine due to its production of the pharmacologically active secondary metabolites, especially triterpenoid saponins in its roots. Although A. kteniophylla is very important in traditional medicine, the genetic basis for its production of triterpenoid saponins remains largely unknown. Therefore, we sequenced transcriptomes of A. kteniophylla to identify putative genes involved in production of triterpenoid saponins in both leaves and roots, and we used the transcriptomes to compare expression levels of these genes between the two organ systems. The production of triterpenoid saponins in plants is usually induced through hormonal signaling on account of the presence of pests. Thus, we treated plants with the hormones salicylic acid (SA) and methyl jasmonate (MeJA) and used quantitative real‐time PCR (qRT‐PCR) to investigate expression levels of genes involved in triterpenoid saponin biosynthesis. In total, we obtained transcriptomes for leaf and root tissues representing 52,454 unigenes. Compared with the leaf transcriptome, we found that 6092 unigenes were upregulated in the root, especially enzymes involved in the direct synthesis of triterpenoid saponins, while 6001 genes appeared downregulated, including those involved in precursory steps in the triterpenoid saponin biosynthesis pathway. Our results from qRT‐PCR indicate that genes within the upstream parts of the triterpenoid saponin biosynthesis pathway may be upregulated under exposure to the applied hormones, but downstream genes are downregulated. This suggests possible conflicting effects of SA and MeJA in promoting the production of secondary metabolites on the one hand, and, on the other, limiting plant growth processes to devote energy to combating pests. We also performed an analysis of transcription factors (TFs) and found 997 unique transcripts belonging to 16 TF families. Our data may help to facilitate future work on triterpene saponins biosynthesis in A. kteniophylla with potential pharmacological and molecular breeding applications.

The Effect of Methylation Modification of MDD on the Expression of Key Genes in the Process of Saponin Synthesis in Eleutherococcus senticosus

Mevalonate pyrophosphate decarboxylase is a kind of key enzyme in the terpenoid synthesis pathway in Eleutherococcus senticosus. The results of bisulfite sequencing showed that there were three kinds of samples with a low (0.68%), medium (0.72%) and high (0.79%) DNA methylation ratio in the promoter of MDD in E. senticosus, respectively. The transcriptome sequencing results showed that the expression of MDD in E. senticosus was significantly up-regulated in the types with low DNA methylation ratios of MDD (P < 0.05). There was a significant negative correlation between the saponin content in E. senticosus and the DNA methylation ratio of MDD promoter (P < 0.05). The screening results of differentially expressed transcription factors among the three groups with different DNA methylation ratio showed that a total of 4 transcription factors could bind to 6 CpG sites. Protein-protein interaction analysis showed that E. senticosus MDD could interacted with other key enzymes in the process of terpenoid synthesis. In addition, it was found that the DNA methylation of MDD promoter was mainly regulated by DNA methyltransferase. These results demonstrated that under the action of DNA methyltransferase, the changes of DNA methylation of MDD promoter could regulate its own expression level by affecting the combination ability of transcription factors, and then affected the expression of other genes in terpenoid synthesis pathway. The synthesis and accumulation of saponins in E. senticosus was also changed.

GuRhaGT, a highly specific saponin 2''-O-rhamnosyltransferase from Glycyrrhiza uralensis.

A highly regio- and donor-specific 2''-O-rhamnosyltransferase GuRhaGT was characterised from the medicinal plant Glycyrrhiza uralensis. GuRhaGT could efficiently catalyse rhamnosylation at 2''-OH of the C-3 glycosyl moiety of triterpenoid saponins.

A Stereoselective Glycosylation Approach to the Construction of 1,2-trans-β-d-Glycosidic Linkages and Convergent Synthesis of Saponins.

Conventional syntheses of 1,2-trans-β-d- or α-l-glycosidic linkages rely mainly on neighboring group participation in the glycosylation reactions. The requirement for a neighboring participation group (NPG) excludes direct glycosylation with (1→2)-linked glycan donors, thus only allowing stepwise assembly of glycans and glycoconjugates containing this type of common motif. Here, a robust glycosylation protocol for the synthesis of 1,2-trans-β-d- or α-l-glycosidic linkages without resorting to NPG is disclosed; it employs an optimal combination of glycosyl N-phenyltrifluroacetimidates as donors, FeCl3 as promoter, and CH2 Cl2 /nitrile as solvent. A broad substrate scope has been demonstrated by glycosylations with 12 (1→2)-linked di- and trisaccharide donors and 13 alcoholic acceptors including eight complex triterpene derivatives. Most of the glycosylation reactions are high yielding and exclusively 1,2-trans selective. Ten representative, naturally occurring triterpene saponins were thus synthesized in a convergent manner after deprotection of the coupled glycosides. Intensive mechanistic studies indicated that this glycosylation proceeds by SN 2-type substitution of the glycosyl α-nitrilium intermediates. Importantly, FeCl3 dissociates and coordinates with nitrile into [Fe(RCN)n Cl2 ]+ and [FeCl4 ]- , and the ferric cationic species coordinates with the alcoholic acceptor to provide a protic species that activates the imidate, meanwhile the poor nucleophilicity of [FeCl4 ]- ensures an uninterruptive role for the glycosidation.

Genome and transcriptome analysis to understand the role diversification of cytochrome P450 gene under excess nitrogen treatment

BackgroundPanax notoginseng (Burk.) F. H. Chen (P. notoginseng) is a medicinal plant. Cytochrome P450 (CYP450) monooxygenase superfamily is involved in the synthesis of a variety of plant hormones. Studies have shown that CYP450 is involved in the synthesis of saponins, which are the main medicinal component of P. notoginseng. To date, the P. notoginseng CYP450 family has not been systematically studied, and its gene functions remain unclear.ResultsIn this study, a total of 188 PnCYP genes were identified, these genes were divided into 41 subfamilies and clustered into 9 clans. Moreover, we identified 40 paralogous pairs, of which only two had Ka/Ks ratio greater than 1, demonstrating that most PnCYPs underwent purification selection during evolution. In chromosome mapping and gene replication analysis, 8 tandem duplication and 11 segmental duplication events demonstrated that PnCYP genes were continuously replicating during their evolution. Gene ontology (GO) analysis annotated the functions of 188 PnCYPs into 21 functional subclasses, suggesting the functional diversity of these gene families. Functional divergence analyzed the members of the three primitive branches of CYP51, CYP74 and CYP97 at the amino acid level, and found some critical amino acid sites. The expression pattern of PnCYP450 related to nitrogen treatment was studied using transcriptome sequencing data, 10 genes were significantly up-regulated and 37 genes were significantly down-regulated. Combined with transcriptome sequencing analysis, five potential functional genes were screened. Quantitative real-time PCR (qRT-PCR) indicated that these five genes were responded to methyl jasmonate (MEJA) and abscisic acid (ABA) treatment.ConclusionsThese results provide a valuable basis for comprehending the classification and biological functions of PnCYPs, and offer clues to study their biological functions in response to nitrogen treatment.

Synthesis and performance characterization of an efficient environmental-friendly Sapindus mukorossi saponins based hybrid coal dust suppressant

The coal dust produced during coal mining poses a high risk to the safety and health of miners working in coal mines. Water spray with wetting agents is one of the most used ways to control coal dust and most of the wetting agents are composed of chemical surfactants. Further, the extensive use of chemical surfactants is costly as well as exerts damage to environment and human health. Therefore, it is crucial to find and utilize the natural surfactants to develop a greener efficient wetting agent. In this research, Sapindus mukorossi saponins is extracted and blended with various chemical surfactants to prepare a new and efficient saponins-based compounded wetting agent. Surface tension and coal dust wetting time are measured to optimize the best combination of saponins/surfactants compounding and to compare the wetting ability of newly prepared saponins-based compounded wetting agent with pure chemical surfactants as wetting agents. Fourier transform infrared spectroscopy, scanning electron microscope, and surface area analyzer are used to explain the mechanism of wetting agent on the wettability of coal dust. Results show that the critical micelle concentration (CMC) of Sapindus mukorossi saponins extract is 0.51 wt% and the surface tension of CMC is 41.3 mN/m, which indicates a high surface activity. The chemical surfactants dioctyl sodium sulfosuccinate (T) and alkyl polyglucoside (APG) combined with saponins extract as binarily and ternarily have synergically reduced the surface tension and coal dust wetting time. The combination of 0.04 wt% saponins extract, 0.004 wt% APG and 0.02 wt% T at the volume ratio of 1:1:1 is found to be the best saponins-based compounded wetting agent, which can reduce the surface tension to 26.08 mN/m and coal dust wetting time to 9.2 s. The usage of chemical surfactant concentration in the newly developed saponins-based compounded wetting agent is 0.024 wt% while that of current mainstream industrial ones is in the range of 0.1–0.8 wt%. The saponins-based compounded wetting agent reduces the usage of chemical surfactants, exhibits a better wetting ability, and provides a new way for the utilization of Sapindus mukorossi pericarp. When wetting agent is adsorbed to the coal surface, there is 23.81–63.12% increase of oxygen containing groups on coal surface and the formation of hydrogen bonds. As a result, the coal dust becomes more hydrophilic. Therefore, the coal dust particles are easily agglomerated to larger size and rapidly settled by gravity.

A Review on Saponin Biosynthesis and its Transcriptomic Resources in Medicinal Plants

Saponins are naturally occurring glycosides which are produced by various plant species with diverse biological properties. The surface-active properties of saponins differentiates them from other glycosides. They are classified mainly into steroid and triterpenoid glycosides based on the structure of hydrophobic aglycone unit. The synthesis of saponins and the genes involved in its biosynthesis can be identified by transcriptome profiling. Using high-throughput sequencing technologies, the steroid or triterpenoid saponin biosynthesis related genes have been discovered which can help boosting the molecular research in this biosynthetic pathway. This review mainly illustrates the importance of saponins and the transcriptome resources of important medicinal plants for identifying genes related to its biosynthesis. Furthermore, the significance of unexplored plants which are rich sources of saponins in future studies are also discussed in the current review.