Kinetic study for the optimization of ginsenoside Rg3 production by heat treatment of ginsenoside Rb1

Rare ginsenosides: A unique perspective of ginseng research

BACKGROUND

Rare ginsenosides (Rg3, Rh2, C-K, etc.) refer to a group of dammarane triterpenoids that exist in low natural abundance, mostly produced by deglycosylation or side chain modification via physicochemical processing or metabolic transformation in gut, and last but not least, exhibited potent biological activity comparing to the primary ginsenosides, which lead to a high concern in both the research and development of ginseng and ginsenoside-related nutraceutical and natural products. Nevertheless, a comprehensive review on these promising compounds is not available yet.

AIM OF REVIEW

In this review, recent advances of Rare ginsenosides (RGs) were summarized dealing with the structurally diverse characteristics, traditional usage, drug discovery situation, clinical application, pharmacological effects and the underlying mechanisms, structure-activity relationship, toxicity, the stereochemistry properties, and production strategies.

KEY SCIENTIFIC CONCEPTS OF REVIEW

A total of 144 RGs with diverse skeletons and bioactivities were isolated from Panax species. RGs acted as natural ligands on some specific receptors, such as bile acid receptors, steroid hormone receptors, and adenosine diphosphate (ADP) receptors. The RGs showed promising bioactivities including immunoregulatory and adaptogen-like effect, anti-aging effect, anti-tumor effect, as well as their effects on cardiovascular and cerebrovascular system, central nervous system, obesity and diabetes, and interaction with gut microbiota. Clinical trials indicated the potential of RGs, while high quality data remains inadequate, and no obvious side effects was found. The stereochemistry properties induced by deglycosylation at C (20) were also addressed including pharmacodynamics behaviors, together with the state-of-art analytical strategies for the identification of saponin stereoisomers. Finally, the batch preparation of targeted RGs by designated strategies including heating or acid/ alkaline-assisted processes, and enzymatic biotransformation and biosynthesis were discussed. Hopefully, the present review can provide more clues for the extensive understanding and future in-depth research and development of RGs, originated from the worldwide well recognized ginseng plants.

Ginsenoside Rg3 has effects comparable to those of ginsenoside re on diabetic kidney disease prevention in db/db mice by regulating inflammation, fibrosis and PPARγ

Ginsenoside Rg3 (Rg3) is an adjuvant antitumor drug, while ginsenoside Re (Re) is an adjuvant antidiabetic drug. Our previous studies demonstrated that Rg3 and Re both have hepatoprotective effects in db/db mice. The present study aimed to observe the renoprotective effects of Rg3 on db/db mice, with Re as the control. The db/db mice were randomly assigned to receive daily oral treatment with Rg3, Re or vehicle for 8 weeks. Body weight and blood glucose were examined weekly. Blood lipids, creatinine, and BUN were examined by biochemical assay. Hematoxylin and eosin and Masson staining were used for pathological examination. The expression of peroxisome proliferator‑activated receptor gamma (PPARγ) and inflammation and fibrosis biomarkers was examined by immunohistochemical and reverse transcription‑quantitative PCR. Although neither had a significant effect on body weight, blood glucose or lipids, Rg3 and Re were both able to decrease the creatinine and blood urea nitrogen levels of db/db mice to levels similar to those of wild type mice and inhibit pathological changes. The expression of PPARγ was upregulated and biomarkers of inflammation and fibrosis were downregulated by Rg3 and Re. The results showed that the potential of Rg3 as a preventive treatment of diabetic kidney disease was similar to that of Re.

Effect of citric acid and heat treatment on the content of less-polar ginsenosides in flower buds of Panax ginseng

Ginseng flower bud (GFB), as an inexpensive part of Panax ginseng, attracted significant attention as a beneficial functional food with medicinal potentials due to its high content of ginsenosides. A few studies focused on the utilization of heat treatment and citric acid treatment to process ginseng flowers, converting its polar ginsenosides into rare ginsenosides to improve its biological activities. Thus, in this study, we compared the changes of ginsenosides in GFB after citric acid and heat treatment by HPLC method. The results revealed that less-polar ginsenoside, Rg₆ and F₄, increased to 1.01 and 0.27% by heat treatment, respectively. Further, ginsenoside F₂ increased to 1.13% with 1 M citric acid treatment. Furthermore, based on the combination of these two processing methods for the first time, the conversion rate of less-polar ginsenosides surged to 80%. The content of ginsenoside Rg3(s) and Rg₅ increased to 1.509 and 1.871%, respectively, by simultaneous heat and citric acid treatment. Therefore, a processing approach that simultaneously performs heat and citric acid treatments has been proposed, and this considerably inexpensive and convenient processing method could be applied to the processing of GFBs and produce less-polar ginsenosides.

Highly efficient production of diverse rare ginsenosides using combinatorial biotechnology

The rare ginsenosides are recognized as the functionalized molecules after the oral administration of Panax ginseng and its products. The sources of rare ginsenosides are extremely limited because of low ginsenoside contents in wild plants, hindering their application in functional foods and drugs. We developed an effective combinatorial biotechnology approach including tissue culture, immobilization, and hydrolyzation methods. Rh2 and nine other rare ginsenosides were produced by methyl jasmonate-induced culture of adventitious roots in a 10 L bioreactor associated with enzymatic hydrolysis using six β-glycosidases and their combination with yields ranging from 5.54 to 32.66 mg L^-1 . The yield of Rh2 was furthermore increased by 7% by using immobilized BglPm and Bgp1 in optimized pH and temperature conditions, with the highest yield reaching 51.17 mg L^-1 (17.06% of protopanaxadiol-type ginsenosides mixture). Our combinatorial biotechnology method provides a highly efficient approach to acquiring diverse rare ginsenosides, replacing direct extraction from Panax plants, and can also be used to supplement yeast cell factories.

Stem-leaves of Panax as a rich and sustainable source of less-polar ginsenosides: comparison of ginsenosides from Panax ginseng, American ginseng and Panax notoginseng prepared by heating and acid treatment

Background

Ginsenosides, which have strong biological activities, can be divided into polar or less-polar ginsenosides.

Methods

This study evaluated the phytochemical diversity of the saponins in Panax ginseng (PG) root, American ginseng (AG) root, and Panax notoginseng (NG) root; the stem-leaves from Panax ginseng (SPG) root, American ginseng (SAG) root, and Panax notoginseng (SNG) root as well as the saponins obtained following heating and acidification [transformed Panax ginseng (TPG), transformed American ginseng (TAG), transformed Panax notoginseng (TNG), transformed stem-leaves from Panax ginseng (TSPG), transformed stem-leaves from American ginseng (TSAG), and transformed stem-leaves from Panax notoginseng (TSNG)]. The diversity was determined through the simultaneous quantification of the 16 major ginsenosides.

Results

The content of ginsenosides in NG was found to be higher than those in AG and PG, and the content in SPG was greater than those in SNG and SAG. After transformation, the contents of polar ginsenosides in the raw saponins decreased, and contents of less-polar compounds increased. TNG had the highest levels of ginsenosides, which is consistent with the transformation of ginseng root. The contents of saponins in the stem-leaves were higher than those in the roots. The transformation rate of SNG was higher than those of the other samples, and the loss ratios of total ginsenosides from NG (6%) and SNG (4%) were the lowest among the tested materials. In addition to the conversion temperature, time, and pH, the crude protein content also affects the conversion to rare saponins. The proteins in Panax notoginseng allowed the highest conversion rate.

Conclusion

Thus, the industrial preparation of less-polar ginsenosides from SNG is more efficient and cheaper.

Ginsenoside Rg3 Attenuates Angiotensin II-Mediated Renal Injury in Rats and Mice by Upregulating Angiotensin-Converting Enzyme 2 in the Renal Tissue

Angiotensin II- (Ang II-) mediated renal injury represents a major pathogenetic mechanism in most chronic kidney diseases. Our previous research demonstrated that ginsenoside Rg3 (Rg3) attenuates Ang II elevation in the myocardium in spontaneously hypertensive rats (SHR). It is possible that Rg3 has similar effects in the renal tissue. In this research, we first demonstrated that Rg3 could attenuate Ang II increase in the kidney of SHR and reduce hypertensive nephropathy progression. Then, we found that Rg3 attenuated Ang II increase by upregulating angiotensin-converting enzyme 2 (ACE2) in the renal tissue. We confirmed this finding in an exogenous Ang II-infused mice model of renal injury, and two models showed consistent results. In conclusion, Rg3 attenuates Ang II-mediated renal injury in rats and mice by upregulating ACE2 in the renal tissue. This research is the first to demonstrate that Rg3 increases tissue ACE2 levels in vivo.

Computational and experimental characterization of estrogenic activities of 20(S, R)-protopanaxadiol and 20(S, R)-protopanaxatriol

Background

As the main metabolites of ginsenosides, 20(S, R)-protopanaxadiol [PPD(S, R)] and 20(S, R)-protopanaxatriol [PPT(S, R)] are the structural basis response to a series of pharmacological effects of their parent components. Although the estrogenicity of several ginsenosides has been confirmed, however, the underlying mechanisms of their estrogenic effects are still largely unclear. In this work, PPD(S, R) and PPT(S, R) were assessed for their ability to bind and activate human estrogen receptor α (hERα) by a combination of in vitro and in silico analysis.

Methods

The recombinant hERα ligand-binding domain (hERα-LBD) was expressed in E. coli strain. The direct binding interactions of ginsenosides with hERα-LBD and their ERα agonistic potency were investigated by fluorescence polarization and reporter gene assays, respectively. Then, molecular dynamics simulations were carried out to simulate the binding modes between ginsenosides and hERα-LBD to reveal the structural basis for their agonist activities toward receptor.

Results

Fluorescence polarization assay revealed that PPD(S, R) and PPT(S, R) could bind to hERα-LBD with moderate affinities. In the dual luciferase reporter assay using transiently transfected MCF-7 cells, PPD(S, R) and PPT(S, R) acted as agonists of hERα. Molecular docking results showed that these ginsenosides adopted an agonist conformation in the flexible hydrophobic ligand-binding pocket. The stereostructure of C-20 hydroxyl group and the presence of C-6 hydroxyl group exerted significant influence on the hydrogen bond network and steric hindrance, respectively.

Conclusion

This work may provide insight into the chemical and pharmacological screening of novel therapeutic agents from ginsenosides.

Determination of the transformation of ginsenosides in Ginseng Radix et Rhizoma during decoction with water using ultra-fast liquid chromatography coupled with tandem mass spectrometry

This study was conducted to determine the variations of ginsenosides in Ginseng Radix et Rhizoma when using different preparation solvents and explore the major factors for changes. With an established ultra-fast liquid chromatography coupled with tandem mass spectrometry method which could quantify 52 ginsenosides, the extraction differences were characterized and compared using different solvents (water, 70% aqueous ethanol, and ethanol). Subsequently, a series of aqueous solutions with different pH were prepared to test the influence of pH to the changes of ginsenosides. Meanwhile, acetic acid and aspartic acid were used to verify whether the reaction had a relationship with the kind of acids. After refluxing with water, not only highly polar ginsenosides were extracted, some less polar ginsenosides such as ginsenoside Rg₃ , Rg₅ , Rk₁ , and Rh₂ occurred or increased rapidly. Further experiments indicated that less polar ginsenosides were easier to generate at low pH values, and the reaction was only related to pH other than what kind of acids were used. It is the first time to elaborate the contents variation of 52 ginsenosides when using different extraction methods. The results indicated that decoction with water could enhance the transformation of highly polar ginsenosides to less polar ginsenosides and the process was pH dependent.

Ginsenoside Rg3 induces ginsenoside Rb1-comparable cardioprotective effects independent of reducing blood pressure in spontaneously hypertensive rats

Ginsenoside Rg3 (Rg3) is a rare type of ginsenoside used as an anti-tumor medicine in China. Ginsenoside Rb1 (Rb1), which exhibits protective effects on the cardiovascular system, is similar to Rg3 in chemical structure. In the present study, Rb1 and Rg3 were administered for 6 weeks to spontaneously hypertensive rats (SHR) and their cardioprotective effects were assessed. According to echocardiography and histopathological examinations, the decrease in cardiac function and ventricular remodeling that occurred in SHR rats were attenuated by Rb1 and Rg3. However, tail-cuff blood pressure measurements indicated that Rb1 and Rg3 did not reduce blood pressure in SHR rats. The cardioprotective effects of Rb1 and Rg3 occurred independently of blood pressure reduction. Furthermore, immunohistochemistry (IHC) revealed that renin angiotensin system (RAS) activity in the myocardium of SHR was significantly attenuated by Rb1 and Rg3, whereas ELISA identified no significant changes of RAS activity in the serum. The results of IHC and reverse transcription-quantitative polymerase chain reaction demonstrated that levels of transforming growth factor β1, tumor necrosis factor-α, interleukin-6, interleukin-1 and endothelian-1 in the myocardium of SHR rats were reduced following Rb1 and Rg3 treatment. This may be due to the attenuation of RAS activity in the myocardium and the mechanisms of the cardioprotective effects of Rb1 and Rg3.

AKT-targeted anti-inflammatory activity of Panax ginseng calyx ethanolic extract

Background

Korean ginseng (Panax ginseng) plays an anti-inflammatory role in a variety of inflammatory diseases such as gastritis, hepatitis, and colitis. However, inflammation-regulatory activity of the calyx of the P. ginseng berry has not been thoroughly evaluated. To understand whether the calyx portion of the P. ginseng berry is able to ameliorate inflammatory processes, an ethanolic extract of P. ginseng berry calyx (Pg-C-EE) was prepared, and lipopolysaccharide-activated macrophages and HEK293 cells transfected with inflammation-regulatory proteins were used to test the anti-inflammatory action of Pg-C-EE.

Methods

The ginsenoside contents of Pg-C-EE were analyzed by HPLC. Suppressive activity of Pg-C-EE on NO production, inflammatory gene expression, transcriptional activation, and inflammation signaling events were examined using the Griess assay, reverse transcription-polymerization chain reaction, luciferase activity reporter gene assay, and immunoblotting analysis.

Results

Pg-C-EE reduced NO production and diminished mRNA expression of inflammatory genes such as cyclooxygenase-2, inducible NO synthase, and tumor necrosis factor-α in a dose-dependent manner. This extract suppressed luciferase activity induced only by nuclear factor-κB. Interestingly, immunoblotting analysis results demonstrated that Pg-C-EE reduced the activities of protein kinase B (AKT)1 and AKT2.

Conclusion

These results suggest that Pg-C-EE may have nuclear-factor-κB-targeted anti-inflammatory properties through suppression of AKT. The calyx of the P. ginseng berry is an underused part of the ginseng plant, and development of calyx-derived extracts may be useful for treatment of inflammatory diseases.

Anti-adipogenic Effects and Mechanisms of Ginsenoside Rg3 in Pre-adipocytes and Obese Mice

Red or black ginseng has been reported more powerful than white/fresh ginseng in dealing with various diseases/conditions including obesity. The major reason is that heating/steaming, the process of making red or black ginseng, produces large amount of bioactive compounds including ginsenoside Rg3 (Rg3), which are trace in fresh or white ginseng. In the present study, Rg3 was applied both in pre-adipocytes and obese mice to investigate the anti-adipogenic effects and relevant mechanisms. Our results show that Rg3 dose-dependently inhibited cell differentiation both in 3T3-L1 cells (30, 50, and 100 μM) and human primary pre-adipocytes (10, 20, and 30 μM). This inhibitory effect is accompanied by the attenuation of the expressions of adipogenic markers including peroxisome proliferator-activated receptor gamma (PPAR-γ), CCAAT/enhancer binding protein alpha (C/EBP-α), fatty acid synthase (FAS), fatty acid binding protein 4 (FABP4) and perilipin. Although dietary intake of Rg3 (0.1 mg Rg3/kg diet, 8 weeks) did not significantly affect body weight gain, fat pads and food intake as well as of PPAR-γ expression in fat tissues, we found that hepatic PPAR-γ and C/EBP-α protein expressions and hepatic glutathione reductase and glutathione S-transferase, two major antioxidants molecules were significantly reduced by Rg3. These results suggest that ginsenoside Rg3 may be a potential agent in reducing/preventing obesity.

Chemical Constituents Identified from Fruit Body of Cordyceps bassiana and Their Anti-Inflammatory Activity

Cordyceps bassiana is one of Cordyceps species with anti-oxidative, anti-cancer, anti-inflammatory, anti-diabetic, anti-obesity, anti-angiogenic, and anti-nociceptive activities. This mushroom has recently demonstrated to have an ability to reduce 2,4-dinitrofluorobenzene-induced atopic dermatitis symptoms in NC/Nga mice. In this study, we further examined phytochemical properties of this mushroom by column chromatography and HPLC analysis. By chromatographic separation and spectroscopic analysis, 8 compounds, such as 1,9-dimethylguanine (1), adenosine (2), uridine (3), nicotinamide (4), 3-methyluracil (5), 1,7-dimethylxanthine (6), nudifloric acid (7), and mannitol (8) were identified from 6 different fractions and 4 more subfractions. Through evaluation of their anti-inflammatory activities using reporter gene assay and mRNA analysis, compound 1 was found to block luciferase activity induced by NF-κB and AP-1, suppress the mRNA levels of cyclooxygenase (COX)-2 and tumor necrosis factor (TNF)-α. Therefore, our data strongly suggests that compound 1 acts as one of major principles in Cordyceps bassiana with anti-inflammatory and anti-atopic dermatitis activities.

Anti-Inflammatory Effects of Ginsenoside Rg3 via NF-κB Pathway in A549 Cells and Human Asthmatic Lung Tissue

Objective. There is limited information of the anti-inflammatory effects of Rg3 on inflamed lung cells and tissues. Therefore, we confirmed the anti-inflammatory mechanism of ginsenoside Rg3 in inflamed human airway epithelial cells (A549) and tissues whether Rg3 regulates nuclear factor kappa B (NF-κB) activity. Methods. To induce the inflammation, IL-1β (10 ng/ml) was treated to A549 cells for 4 h. The effects of Rg3 on NF-κB activity and COX-2 expression were evaluated by western blotting analysis in both IL-1β-induced inflamed A549 cell and human asthmatic airway epithelial tissues. Using multiplex cytokines assay, the secretion levels of NF-κB-mediated cytokines/chemokines were measured. Result. Rg3 showed the significant inhibition of NF-κB activity thereby reduced COX-2 expression was determined in both IL-1β-induced inflamed A549 cell and human asthmatic airway epithelial tissues. In addition, among NF-κB-mediated cytokines, the secretion levels of IL-4, TNF-α, and eotaxin were significantly decreased by Rg3 in asthma tissues. Even though there was no significant difference, IL-6, IL-9, and IL-13 secretion showed a lower tendency compared to saline-treated human asthmatic airway epithelial tissues. Conclusion. The results from this study demonstrate the potential of Rg3 as an anti-inflammatory agent through regulating NF-κB activity and reducing the secretion of NF-κB-mediated cytokines/chemokines.

Chemical transformation of ginsenoside Re by a heteropoly acid investigated using HPLC-MSn/HRMS

The mechanism and pathway of heteropoly acid-derived chemical transformation of ginsenoside Re are investigated using multistage tandem mass spectrometry and high-resolution mass spectrometry.