Inhibitory influence of ginsenoside Rb3 on activation of strychnine-sensitive glycine receptors in hippocampal neurons of rat

Optimization of Fermentation Conditions and Product Identification of a Saponin-Producing Endophytic Fungus

BACKGROUND

Some fungal endophytes isolated from P. ginseng may present a new method of obtaining saponins. This experiment aimed to optimize the total saponin yield produced through in vitro fermentation by an endophytic fungus and analyze its saponin species in the fermented extract.

METHODS

Fermentation protocols were optimized with a uniform design and verified through regression analysis to maximize the total saponin yield. The saponin types under optimal fermentation conditions were then identified and analyzed using Liquid Chromatography-Mass Spectrometry.

RESULTS

The Trametes versicolor strain NSJ105 (gene accession number: OR144428) isolated from wild ginseng could produce total saponins. The total saponin yield could be increased more than two-fold through the optimization of fermentation conditions. The concentration of the total saponins achieved by the verified protocol 105-DP was close to the predicted value. The fermentation conditions of the 105-DP protocol were as follows: potato concentration 97.3 mg/mL, glucose concentration 20.6 mg/mL, inoculum volume 2.1%, fermentation broth pH 2.1, fermentation temperature 29.2 °C, and fermentation time 6 d. It was detected and analyzed that the fermented extract of 105-DP contained the ginsenosides Rf and Rb3.

CONCLUSION

The endophytic fungus Trametes versicolor strain NSJ105 has potential application value in saponin production.

Preparative separation of gypenoside XVII, ginsenoside Rd2, and notoginsenosides Fe and Fd from Panax notoginseng leaves by countercurrent chromatography and orthogonality evaluation for their separation

The minor ginsenosides with less polarity may have more potent biological activities. Four minor saponins, i.e., gypenoside XVII, ginsenoside Rd2, notoginsenoside Fe, and notoginsenoside Fd, were successfully separated from Panax notoginseng leaves (PNL) after biotransformation by one-step countercurrent chromatography using the biphasic solvent system consisting of n-butanol-ethyl acetate-water (1:4:5, v/v/v). 30 mg of the refined extract of PNL produced 1 mg of gypenoside XVII, 4 mg of notoginsenoside Fe, 2.5 mg of ginsenoside Rd2, and 8.4 mg of notoginsenoside Fd, with purity of 74.9, 95.2, 87.3, and 97.6%, respectively. Besides, orthogonality evaluation for the separation of the four saponins using countercurrent chromatography and liquid chromatography was discussed. Four minor saponins were successfully separated from each other on a preparative scale by countercurrent chromatography from PNL, which will facilitate to provide ample of these minor saponins for further pharmacological studies.

Quantitative Characterization of Ginsenoside Biotransformation in Panax notoginseng Inflorescences and Leaves by Online Two-Dimensional Liquid Chromatography Coupled to Mass Spectrometry

Panax notoginseng inflorescences (PNI) and leaves (PNL) are commonly used as folk medicine and food supplements. In this study, an online two-dimensional hydrophilic interaction × reversed-phase liquid chromatography coupled to linear trap quadropole mass spectrometry method was developed to determine 24 ginsenosides, including two novel compounds, in PNI and PNL extracted by water and methanol. Our data demonstrated that ginsenosides Rd, Rc, Rb2, Rb3, Rb1, Ra2, Ra1, and Ra3 in both PNI and PNL extracted by water rather than methanol can be transformed to ginsenoside F2, notoginsenoside Fe, ginsenoside Rd2, notoginsenoside Fd, gypenoside XVII, PN02, PN01, and PN03, respectively, by selectively cleaving the β-(1→2)-glucosidic linkage at the C-3 position. Ginsenoside transformation was further verified to be mediated by the proteins isolated from samples. Additionally, the two newly discovered transformed products, namely, PN02 and PN03, were prepared and identified as novel compounds by nuclear magnetic resonance. Our findings provide new insight into the importance of extraction solvents on the component profile of natural products.

Preparative separation of minor saponins from Panax notoginseng leaves using biotransformation, macroporous resins, and preparative high-performance liquid chromatography

Background

Ginsenosides with less sugar moieties may exhibit the better adsorptive capacity and more pharmacological activities.

Methods

An efficient method for the separation of four minor saponins, including gypenoside XVII, notoginsenoside Fe, ginsenoside Rd2, and notoginsenoside Fd, from Panax notoginseng leaves (PNL) was established using biotransformation, macroporous resins, and subsequent preparative high-performance liquid chromatography.

Results

The dried PNL powder was immersed in the distilled water at 50°C for 30 min for converting the major saponins, ginsenosides Rb1, Rc, Rb2, and Rb3, to minor saponins, gypenoside XVII, notoginsenoside Fe, ginsenoside Rd2, and notoginsenoside Fd, respectively, by the enzymes present in PNL. The adsorption characteristics of these minor saponins on five types of macroporous resins, D-101, DA-201, DM-301, X-5, and S-8, were evaluated and compared. Among them, D-101 was selected due to the best adsorption and desorption properties. Under the optimized conditions, the fraction containing the four target saponins was separated by D-101 resin. Subsequently, the target minor saponins were individually separated and purified by preparative high-performance liquid chromatography with a reversed-phase column.

Conclusion

Our study provides a simple and efficient method for the preparation of these four minor saponins from PNL, which will be potential for industrial applications.

Qualitative and quantitative analysis of the saponins in Panax notoginseng leaves using ultra-performance liquid chromatography coupled with time-of-flight tandem mass spectrometry and high performance liquid chromatography coupled with UV detector

Background

Panax notoginseng leaves (PNL) exhibit extensive activities, but few analytical methods have been established to exclusively determine the dammarane triterpene saponins in PNL.

Methods

Ultra-performance liquid chromatography coupled with time-of-flight mass spectrometry (UPLC/Q-TOF MS) and HPLC-UV methods were developed for the qualitative and quantitative analysis of ginsenosides in PNL, respectively.

Results

Extraction conditions, including solvents and extraction methods, were optimized, which showed that ginsenosides Rc and Rb3, the main components of PNL, are transformed to notoginsenosides Fe and Fd, respectively, in the presence of water, by removing a glucose residue from position C-3 via possible enzymatic hydrolysis. A total of 57 saponins were identified in the methanolic extract of PNL by UPLC/Q-TOF MS. Among them, 19 components were unambiguously characterized by their reference substances. Additionally, seven saponins of PNL—ginsenosides Rb1, Rc, Rb2, and Rb3, and notoginsenosides Fc, Fe, and Fd—were quantified using the HPLC-UV method after extraction with methanol. The separation of analytes, particularly the separation of notoginsenoside Fc and ginsenoside Rc, was achieved on a Zorbax ODS C8 column at a temperature of 35°C. This developed HPLC-UV method provides an adequate linearity (r² > 0.999), repeatability (relative standard deviation, RSD < 2.98%), and inter- and intraday variations (RSD < 4.40%) with recovery (98.7–106.1%) of seven saponins concerned. This validated method was also conducted to determine seven components in 10 batches of PNL.

Conclusion

These findings are beneficial to the quality control of PNL and its relevant products.

Ginsenoside Rb3 exerts antidepressant-like effects in several animal models

Total ginsenosides have been shown to have therapeutic actions as antidepressants. We report a major active ingredient of total ginsenosides, the ginsenoside Rb3 (Rb3), which may have antidepressant-like effects. Using the forced swim test, tail suspension test, and learned helplessness procedure, we found that Rb3 had significant anti-immobility effects in mice in the forced swim and tail suspension tests and reduced the number of escape failures in the learned helplessness procedure. In a reserpine-induced syndrome model, Rb3 attenuated hypothermia, palpebral ptosis, and akinesia. In the chronic mild stress model, chronic Rb3 administration reversed the decrease in locomotor activity, novelty-suppressed feeding, and sucrose preference. Furthermore, neurochemical tests were performed to support our hypothesis that biochemical variations (i.e. brain-derived neurotrophic factor and the monoamine neurotransmitters 5-hydroxytryptamine, dopamine, and norepinephrine) are involved in Rb3's antidepressant-like effects. Finally, we found, using whole-cell patch-clamp recordings, that the action potential transmission in neurons within the somatosensory cortex was excited by Rb3 perfusion and blocked with Panax notoginseng total saponins extracted from leaves. This study provides evidence for the mechanism of action of the antidepressant-like effects of Rb3.

The antidepressant effects and mechanism of action of total saponins from the caudexes and leaves of Panax notoginseng in animal models of depression

Total saponins extracted from the caudexes and leaves of Panax notoginseng (SCLPN) have been used in the clinic for improving mental function, treating insomnia, and alleviating anxiety. The present study evaluated the potential antidepressant activity of SCLPN in rodent models of depression and the mechanism of action of SCLPN. Mice were received SCLPN at doses of 10-1000 mg/kg daily for 1, 7, and 14 days and then were subjected to the forced swim test and locomotor activity test. The results showed that SCLPN decreased immobility time in the forced swim test, with little effect on locomotion. In the chronic mild stress model, chronic SCLPN treatment (70 mg/kg) reversed the rats' depression-like behavior. Furthermore, SCLPN exerted its antidepressant-like effect by increasing the levels of 5-hydroxytryptamine, dopamine, and noradrenaline. Additionally, SCLPN treatment reduced intracellular Ca(2+) in cultured neurons. The present study suggests that SCLPN may function as an antidepressant, and the antidepressant-like effects of SCLPN may be mediated by modulation of brain monoamine neurotransmitters and intracellular Ca(2+) concentration.

Metabolite profiling of Panax notoginseng using UPLC-ESI-MS

The metabolite profiling of different parts of Panax notoginseng was carried out using rapid ultra-performance liquid chromatography-electrospray ionization mass spectrometry (UPLC-ESI-MS) and multivariate statistical analysis. Principal component analysis (PCA) of the UPLC-ESI-MS data showed a clear separation of compositions among the flower buds, roots and rhizomes of P. notoginseng. The saponins accounting for such variations were identified through the corresponding loadings weights and were further verified by accurate mass, tandem mass and retention times of available standard saponins using UPLC quadrupole time-of-flight mass spectrometer (UPLC-QtofMS). Finally, the influential factors of different metabolic phenotypes of P. notoginseng was elucidated. The currently proposed UPLC-ESI-MS/MS analytical method coupled with multivariate statistical analysis can be further utilized to evaluate chemical components obtained from different parts of the plant and/or the plant of different geographical locations, thereby classifying the medicinal plant resources and potentially elucidating the mechanism of inherent phytochemical diversity.

Simultaneous determination of ginsenosides in Panax ginseng with different growth ages using high-performance liquid chromatography-mass spectrometry

The contents of ginsenosides in Panax ginseng not only vary in different parts of the root, but also exhibit yearly variation. In this study, an HPLC-MS method was established in order to simultaneously analyse ginsenosides Rb1, Rb2, Rb3, Rc, Rd, Re, Rf, Rg1 and Rg2. The concentration of ginsenosides in the tap root and root fibre were compared and the yearly variations of nine ginsenosides elucidated. The results indicate that the total content of ginsenosides in the main root and the root fibre both attain a maximum level in the fourth year of growth, although the amount in the former is much higher than in the latter. The variation in the content of ginsenosides during a 2-6 year period suggests that cultivated P. Ginseng can be harvested after the fourth year. The current results will provide useful information for the quality control and good agricultural practice farming of ginseng.

Anticonvulsant and neuroprotective effects of ginsenosides in rats

A partially purified extract from American ginseng has been shown to have anticonvulsant activity. To identify the active components in this extract, the activities of the individual ginsenosides (Rb(1), Rb(3) and Rd), mixtures of the purified ginsenosides and a newly prepared Rb fraction were determined. One hour after treatment with vehicle or one of the ginseng products, seizures were induced in adult, Sprague-Dawley rats with kainic acid (KA, 10 mg/kg), pilocarpine (300 mg/kg) or pentylenetetrazole (PTZ, 50mg/kg i.p. or 90 mg/kg s.c.). Time to seizure onset, duration of seizure activity and seizure severity were determined. Weight change and neuronal damage were assessed 24h after administration of KA or pilocarpine. Mixtures of purified Rb(1), Rb(3) with or without Rd had significant anticonvulsant effects in all three models of acutely induced seizures demonstrating that the ginsenosides are the active components in the Rb extract. The individual ginsenosides significantly increased the latency to onset of seizures after administration of kainic acid. Since no one individual ginsenoside accounted for the majority of the activity of the Rb extract, the results suggest that the most effective anticonvulsant product is a combination of ginsenosides. In addition, all of the ginseng products had significant neuroprotective activity beyond the reduction in seizure severity and duration.