Chemical constituents from acid hydrolyzates of Panax quinquefolius total saponins and their inhibition activity to α-glycosidase and protein tyrosine phosphatase 1B / 中草药·英文版

Objective: To investigate the hypoglycemic components from the acid hydrolyzates of Panax quinquefolius total saponins, and screen the active compounds by in vitro inhibitory activities to α-glycosidase enzymes and protein tyrosine phosphatase-1B (PTP1B). Methods: The hydrolyzates were chromatographed repeatedly over silica gel column, and the structures of the compounds were determined by means of NMR. The in vitro bioassay was performed through the inhibitory effects on α-glucosidase or/and PTP1B. Results: Eight compounds were isolated, which identified as 20(S)-panaxadiol (1), (20S,24R)-dammarane-20,24-epoxy-3β,6α,12β,25-tetraol (2), 20(R)-dammarane-3β,12β,20,25-tetraol (3), 20(S)-dammarane-3β,6α,12β,20,25-pentol (4), 20(R)-dammarane-3β,12β,20,25-tetrahydroxy-3β-O-β-D-glucopyranoside (5), β-sitosterol (6), oleanolic acid (7) and 20(S)-protopanaxadiol (8). Compound 5 was ginseng triterpenoid isolated from the acid hydrolysates of total saponins from P. quinquefolius for the first time. In this paper, the possible in vitro inhibitory activities were investigated. Compound 5 exhibited significantly inhibitory activity against α-glucosidase, and the IC50 value [(0.22 ± 0.21) µmol/L] was about 43-fold lower than positive control. For the PTP1B inhibition assay, compound 5 indicated the strongest inhibitory effect with IC50 of (5.91 ± 0.38) µmol/L, followed by compound 4 with IC50 of (6.21 ± 0.21) µmol/L, which were all showed competitive inhibitory pattern by using a Lineweaver-Burk plot. Conclusion: These results supported the potential application of dammaranes from acid hydrolyzates of P. quinquefolius total saponins can be used as ingredients of ancillary anti-diabetic agent or functional factor.

Evaluation and prediction of ecological suitability of medicinal plant American ginseng (panax quinquefolius) / 中草药·英文版

Objective: American ginseng is a medicinal plant with large market demands, however, its producing areas are shrinking because of the continuous cropping obstacles in China. Therefore, it is urgent to establish a suitable model to determine the new producing areas. Here we evaluated and predicted the suitable areas of American ginseng using the maximum entropy model (MaxEnt). Methods: Based on the 37 environmental variables over thirty years from 1970 to 2000 and 226 global distribution points of American ginseng, MaxEnt was used to determine the global ecological suitable areas for American ginseng. The Receiver Operating Curve (ROC) was used to evaluate the model prediction accuracy. Meanwhile, an innovative ecological variable, the precipitation–temperature ratio, was established to indicate the climate characteristic in the American ginseng suitable areas based on the monthly precipitation and temperature. Results: The potential ecological suitable areas of American ginseng were primarily in Appalachian Mountain in America and Changbai Mountain in China, about in the range of 35°N–50°N, 60°W–120°W and 35°N–50°N, 110°E–145°E, respectively, including the United States, Canada, China, North Korea, South Korea, Russia and Japan. South Korea and Japan were the potential producing regions. The precipitation–temperature ratios were stable at (0.22, 0.56) of the vigorous growth period (April–October) in the best suitable areas of American ginseng, serving as characteristic parameters to optimize the prediction model. The model showed that the common soil parameters were pH 4.5–7.2, Base Saturation (BS) above 80%, Cation Exchange Capacity (CEC) 10–20 cmol/kg, organic carbon (OC) < 1.4%, and the soil types were sandy loam or loam. Conclusion: An optimized MaxEnt model was established to predict the producing area for American ginseng that needed to be validated by a field test.

Relationship between occurrence of root-rot and changes of bacterial community structure in rhizosphere soil of Panax quinquefolius / 中草药

Objective In this paper, the changes of bacterial community structure in the rhizosphere soil of healthy and root-rot Panax quinquefolius were investigated to explore the occurrence mechanism of root-rot in P. quinquefolius. Methods The changes of bacterial communities structure in uncultivated soil (group C), rhizosphere soil of 4-year-old healthy ginseng (group N), and 4-year-old root-rot ginseng (group R) were analyzed by using the Illumina MiSeq high-throughput sequencing technology. Results A total of 636 654 effective sequences and 8 422 OTUs were obtained from nine samples based on high-throughput sequencing of the 16S gene. Bacterial species detected in these samples covered 42 phyla, 106 classes, 180 orders, 158 families, and 246 genera. The main phylums were the same in the three groups, including Proteobacteria, Actinobacteria, Acidobacteria, and Chloroflexi with significantly different relative abundance. At the genera level, the composition and relative abundance of the bacterial communities in the three groups are very different. Among them, Rhodoplanes, kaistobacter, and Sphingobium may be the key bacteria causing root rot of P. quinquefolius and should be focused in the further research. Conclusion There are significant differences in the bacterial community composition from the rhizosphere soil of healthy and root-rot P. quinquefolius. This finding plays a theoretical guiding role in exploring the micro-ecological mechanism of root-rot of P. quinquefolius and improving the soil microbial community during the cultivation of P. quinquefolius.

Study on UPLC-UV-ELSD fingerprint for roots of Panax quinquefolius / 中草药

Objective: To establish a method of UPLC-UV-ELSD fingerprint and chemical pattern recognition which could provide a reliable evidence for the scientific evaluation and quality control for the roots of Panax quinquefolius, based on clustering analysis, principal component analysis, and similarity assessment techniques. Methods: The chromatographic separation was achieved on Waters Acquity UPLC system, TUV detector, and ELSD detector, performed on Acquity UPLC™ BEH C18 column (50 mm × 2.1 mm, 1.7 μm) and gradient eluted with acetonitrile-water, and the column temperature was maintained at 30℃; The detection wavelength was set at 203 nm; The temperature of drift tube was maintained at 50℃, sprayer parameter was 50%, and nitrogen pressure was 275.8 kPa The common mode of UPLC fingerprint for the roots of P. quinquefolius was set up. There were 12 common peaks in the fingerprints, with 10 reference substance identified ten common peaks, the PCA analysis showed that ginsenosides Rg1, Re, Rc, Rb2, and Rb3 in the roots of P. quinquefolius in Beijing, Jilin, and Heilongjiang regions distinguish from the United States, Shandong and Shaanxi, while ginsenosides Rg2, Rb1, and Rd conversely. Conclusion: This method has the advantages of high reproducibility and stability, and it can be used to control the quality of the roots in P. quinquefolius.

Cloning of β-amyrin synthase gene from Panax quinquefolius and its bioinformatics analysis / 中草药

Objective: To obtain the full-length cDNA of β-amyrin synthase (bAS) involved in triterpene saponin biosynthesis in Panax quinquefolius and provide the reference for saponin biosynthesis and the regulation of secondary metabolism in P. quinquefolius. Methods: Based on large-scale ESTs sequencing and RACE technology, the full-length cDNA of P. quinquefolius bAS (PqbAS) was obtained. Results: The full-length cDNA of PqbAS (GenBank No. JX185490) was 2 309 bp which included an open reading frame (ORF) code of 631 amino acid peptide. Common conserved domains of oxidosqualene cyclases (OSCs) were found in PqbAS including active sites and conserved sequence. Singal P4.0 analysis showed that PqbAS was a non-secreted protein. Tmhmm 2.0 analysis showed that PqbAS was a non-transmembrane protein. Real-time fluorescence quantitative PCR analysis showed PqbAS gene expressed in various organs, higher in flowers and stems while relatively lower in roots and leaves. Conclusion: The full-length of bAS is first cloned, which could provide the foundation for the investigation on expression characteristics and its role in synthesis of saponin.

Correlation between ginsenoside accumulation and SQS and SQE gene expression in different organs of Panax quinquefolius / 中草药

Objective: To examine the biological accumulation of total ginsenosides and their monomers, and determine their relationships with the expression of squalene synthase (SQS) and squalene epoxidase (SQE) genes that are involved in the ginsenoside biosynthetic pathway in different organs of Panax quinquefolius. Methods: Fourteen organs of four year-old P. quinquefolius were used as materials. Total ginsenosides were extracted using the Soxhlet ginsenoside extraction method, and the contents of total ginsenosides and their monomers Rg1, Re, Rb1, Rc Rb2 and Rd in the organs were determined by the Vanillin-sulfuric Colorimetry and HLPC methods, respectively. The expressions of the SQS and SQE genes in the organs were profiled by real-time quantitative PCR. Results: The biological accumulation of total ginsenosides and each of their monomers varied significantly (P<0.01) in different parts of P. quinquefolius.Except for ginsenoside monomer Rb 2, there were significantly positive correlations between total ginsenoside and monomers Re, Rg1, Rb1 and Rd (P<0.01). The expressions of both SQS and SQE genes were extremely significantly different among the 14 plant parts (P<0.01) and significantly positively correlated with the biological accumulation of total ginsenoside and monomers, Re, Rg 1, Rb1 and Rd (P<0.05). Conclusion: The results indicate that the SQS and SQE genes play the important roles in the biosynthesis of total gingenosides and their monomers.

Studies on the Chemical Constituents in the Fruit of Panax quinquefolius / 中草药

Four compounds were isolated from the fruit of Panax quinquefolius L. , They were iden-tified as 20 (R)-ginsenoside-Rg3( Ⅲ ), ginsenoside-Ra1( Ⅱ ), pseudo ginsenoside-RTs (iⅣ) and a new com-pound named quinquetriose ( Ⅰ ). Its structure was established as β3-D-xylopyranosyl-(1→6)-α-D-glucopy-ranosyl (1→6)-β-D-glucopyranoside, on the basis of chemical and spectroscopic evidences.

Comparison of content of total ginsenoside and ginsenoside Rb_1 in Panax quinquefolius from different origins / 中草药

Object The quality of Panax quinquefolius L from different origins were assessed in accordance with the contents of total ginsenoside and ginsenoide Rb 1 of them Methods The contents of total ginsenoside were determined by UV spectrophotometry, and the contents of ginsenoside Rb 1 were determined by HPLC Results Among the seven commercially available samples, the sample from Canada gave the highest content of total ginsenoside and ginsenoside Rb 1, the second is the samples from Huairou, Beijing, China. Conclusion Contents of total ginsenoside of all the seven samples are more than 4%, while content's of ginsenoside Rb 1 are more than 1%. And the more content of total ginsenoside is, the more content of ginsenoside Rb 1 is

Study on mechanism of forming red-skin and dark-green-skin of Panax quinquefolius / 中草药

Object To study the causes for the occurrence of red skin and dark green skin of Panax quinquefolius L. during processing and its mechanism. Methods To observe the phenomena and analyze the result which simulated the processing condition of P. quinquefolius based on its components. Results The cross section of P. quinquefolius began to appear light red at 40 ℃, lasting 72 h. Whereas the time of browning was shortened with the temperature rising. The cross section of P. quinquefolius turned green while dipping in solution of Fe 3+ ion of 0 01 mol/L for 25 min. The time of turning green was shortened with the increasing concentration of Fe 2+ , Fe 3+ solution. Conclusion The results show that red skin of P. quinquefolius was caused by the Maillard reaction while drying at the excessive higher temperature. Whereas the complex reaction between phenolic substances in P. quinquefolius and metal ions during processing might result in dark green skin of P. quinquefolius. This expounds the mechanism of red skin and dark green skin turning during the P. quinquefolius processing in the theory.