• Journal of Ginseng Research
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• v.42 no.4
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• pp.512-523
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• 2018

Background: 20(S)-Protopanaxadiol (20S-PPD) is a fully deglycosylated ginsenoside metabolite and has potent dermal antiaging activity. However, because of its low aqueous solubility and large molecular size, a suitable formulation strategy is required to improve its solubility and skin permeability, thereby enhancing its skin deposition. Thus, we optimized microemulsion (ME)-based hydrogel (MEH) formulations for the topical delivery of 20S-PPD. Methods: MEs and MEHs were formulated and evaluated for their particle size distribution, morphology, drug loading capacity, and stability. Then, the deposition profiles of the selected 20S-PPD-loaded MEH formulation were studied using a hairless mouse skin model and Strat-M membrane as an artificial skin model. Results: A Carbopol-based MEH system of 20S-PPD was successfully prepared with a mean droplet size of 110 nm and narrow size distribution. The formulation was stable for 56 d, and its viscosity was high enough for its topical application. It significantly enhanced the in vitro and in vivo skin deposition of 20S-PPD with no influence on its systemic absorption in hairless mice. Notably, it was found that the Strat-M membrane provided skin deposition data well correlated to those obtained from the in vitro and in vivo mouse skin studies on 20S-PPD (correlation coefficient $r^2=0.929-0.947$). Conclusion: The MEH formulation developed in this study could serve as an effective topical delivery system for poorly soluble ginsenosides and their deglycosylated metabolites, including 20S-PPD.

• Journal of Ginseng Research
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• v.46 no.1
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• pp.167-174
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• 2022

Background: 20(S)-protopanaxadiol (20(S)-PPD), one of the main active metabolites of ginseng, performs a broad spectrum of anti-tumor effects. Our aims are to search out new strategies to enhance anti-tumor effects of natural products, including 20(S)-PPD. In recent years, fasting has been shown to be multi-functional on tumor progression. Here, the effects of fasting combined with 20(S)-PPD on hepatocellular carcinoma growth, apoptosis, migration, invasion and cell cycle were explored. Methods: CCK-8 assay, trypan blue dye exclusion test, imagings photographed by HoloMonitorTM M4, transwell assay and flow cytometry assay were performed for functional analyses on cell proliferation, morphology, migration, invasion, apoptosis, necrosis and cell cycle. The expressions of genes on protein levels were tested by western blot. Tumor-bearing mice were used to evaluate the effects of intermittent fasting combined with 20(S)-PPD. Results: We firstly confirmed that fasting-mimicking increased the anti-proliferation effect of 20(S)-PPD in human HepG2 cells in vitro. In fasting-mimicking culturing medium, the apoptosis and necrosis induced by 20(S)-PPD increased and more cells were arrested at G0-G1 phase. Meanwhile, invasion and migration of cells were decreased by down-regulating the expressions of matrix metalloproteinase (MMP)-2 and MMP-9 in fasting-mimicking medium. Furthermore, the in vivo study confirmed that intermittent fasting enhanced the tumor growth inhibition of 20(S)-PPD in H22 tumor-bearing mice without obvious side effects. Conclusion: Fasting significantly sensitized HCC cells to 20(S)-PPD in vivo and in vitro. These data indicated that dietary restriction can be one of the potential strategies of chinese medicine or its active metabolites against hepatocellular carcinoma.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.18
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• pp.7919-7923
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• 2014

20(S)-Protopanaxadiol (PPD), a ginsenoside isolated from Pananx quinquefolium L., has been shown to inhibit growth and proliferation in several cancer cell lines. The aim of this study was to evaluate its anticancer activity in human breast cancer cells. MCF-7 cells were incubated with different concentrations of 20(S)-PPD and cytotoxicity was evaluated by MTT assay. Occurrence of apoptosis was detected by DAPI and Annexin V-FITC/PI double staining. Mitochondrial membrane potential was measured with Rhodamine 123. The Bcl-2 and Bax expression were determined by Western blot analysis. Caspase activity was measured by colorimetric assay. 20(S)-PPD dose-dependently inhibited cell proliferation in MCF-7 cells, with an $IC_{50}$ value of $33.3{\mu}M$ at 24h. MCF-7 cells treated with 20(S)-PPD presented typical apoptosis, as observed by morphological analysis in cell stained with DAPI. The percentages of annexin V-FITC positive cells were 8.92%, 17.8%, 24.5% and 30.5% in MCF-7 cells treated with 0, 15, 30 and $60{\mu}M$ of 20(S)-PPD, respectively. Moreover, 20(S)-PPD could induce mitochondrial membrane potential loss, up-regulate Bax expression and down-regulate Bcl-2 expression. These events paralleled activation of caspase-9, -3 and PARP cleavage. Apoptosis induced by 20(S)-PPD was blocked by z-VAD-fmk, a pan-caspase inhibitor, suggesting induction of caspase-mediated apoptotic cell death. In conclusion, the 20(S)-PPD investigated is able to inhibit cell proliferation and to induce cancer cell death by a caspase-mediated apoptosis pathway.

• Journal of Ginseng Research
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• v.43 no.4
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• pp.539-549
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• 2019

Background: 20(S)-Protopanaxadiol (PPD), the aglycone part of 20(S)-protopanaxadiol ginsenosides, possesses antidepressant activity among many other pharmacological activities. It is currently undergoing clinical trial in China as an antidepressant. Methods: In this study, an ultra-performance liquid chromatography coupled with triple quadrupole time-of-flight mass tandem mass spectrometry method was established to identify the metabolites of PPD in human plasma and urine following oral administration in phase IIa clinical trial. Results: A total of 40 metabolites in human plasma and urine were identified using this method. Four metabolites identified were isolated from rat feces, and two of them were analyzed by NMR to elucidate the exact structures. The structures of isolated compounds were confirmed as (20S,24S)-epoxydammarane-12,23,25-triol-3-one and (20S,24S)-epoxydammarane-3,12,23,25-tetrol. Both compounds were found as metabolites in human for the first time. Upon comparing our findings with the findings of the in vitro study of PPD metabolism in human liver microsomes and human hepatocytes, metabolites with m/z 475.3783 and phase II metabolites were not found in our study whereas metabolites with m/z 505.3530, 523.3641, and 525.3788 were exclusively detected in our experiments. Conclusion: The metabolites identified using ultra-performance liquid chromatography coupled with triple quadrupole time-of-flight mass spectrometry in our study were mostly hydroxylated metabolites. This indicated that PPD was metabolized in human body mainly through phase I hepatic metabolism. The main metabolites are in 20,24-oxide form with multiple hydroxylation sites. Finally, the metabolic pathways of PPD in vivo (human) were proposed based on structural analysis.

• Journal of Ginseng Research
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• v.41 no.3
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• pp.392-402
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• 2017

Background: Previously, we reported that Korean Red Ginseng inhibited liver fibrosis in mice and reduced the expressions of fibrogenic genes in hepatic stellate cells (HSCs). The present study was undertaken to identify the major ginsenoside responsible for reducing the numbers of HSCs and the underlying mechanism involved. Methods: Using LX-2 cells (a human immortalized HSC line) and primary activated HSCs, MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide) assays were conducted to examine the cytotoxic effects of ginsenosides. $H_2O_2$ productions, glutathione contents, lactate dehydrogenase activities, mitochondrial membrane permeabilities, apoptotic cell subpopulations, caspase-3/-7 activities, transferase dUTP nick end labeling (TUNEL) staining, and immunoblot analysis were performed to elucidate the molecular mechanism responsible for ginsenoside-mediated cytotoxicity. Involvement of the AMP-activated protein kinase (AMPK)-related signaling pathway was examined using a chemical inhibitor and small interfering RNA (siRNA) transfection. Results and conclusion: Of the 11 ginsenosides tested, 20S-protopanaxadiol (PPD) showed the most potent cytotoxic activity in both LX-2 cells and primary activated HSCs. Oxidative stress-mediated apoptosis induced by 20S-PPD was blocked by N-acetyl-$\text\tiny L$-cysteine pretreatment. In addition, 20S-PPD concentration-dependently increased the phosphorylation of AMPK, and compound C prevented 20S-PPD-induced cytotoxicity and mitochondrial dysfunction. Moreover, 20S-PPD increased the phosphorylation of liver kinase B1 (LKB1), an upstream kinase of AMPK. Likewise, transfection of LX-2 cells with LKB1 siRNA reduced the cytotoxic effect of 20S-PPD. Thus, 20S-PPD appears to induce HSC apoptosis by activating LKB1-AMPK and to be a therapeutic candidate for the prevention or treatment of liver fibrosis.

• Journal of Ginseng Research
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• v.45 no.1
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• pp.126-133
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• 2021

Background: 20(S)-protopanaxadiol (20(S)-PPD), one of the aglycone derivatives of major ginsenosides, has been shown to have an anticancer activity toward a variety of cancers. This study was initiated with an attempt to evaluate its anti-cancer activity toward human endometrial cancer by cell and xenograft mouse models. Methods: Human endometrial cancer (HEC)-1A cells were incubated with different 20(S)-PPD concentrations. 20(S)-PPD cytotoxicity was evaluated using MTT assay. Apoptosis was detected using the annexin V binding assay and cell cycle analysis. Cleaved poly (ADP-ribose) polymerase (PARP) and activated caspase-9 were assessed using western blotting. HEC-1A cell tumor xenografts in athymic mice were generated by inoculating HEC-1A cells into the flank of BALB/c female mice and explored to validate 20(S)-PPD anti-endometrial cancer toxicity. Results: 20(S)-PPD inhibited HEC-1A cell proliferation in a dose-dependent manner with an IC50 value of 3.5 μM at 24 h. HEC-1A cells morphologically changed after 20(S)-PPD treatment, bearing resemblance to Taxol-treated cells. Annexin V-positive cell percentages were 0%, 10.8%, and 58.1% in HEC-1A cells when treated with 0, 2.5, and 5 μM of 20(S)-PPD, respectively, for 24 h. 20(S)-PPD subcutaneously injected into the HEC-1A cell xenograft-bearing mice three times a week for 17 days manifested tumor growth inhibition by as much as 18% at a dose of 80 mg/kg, which sharply contrasted to controls that showed an approximately 2.4-fold tumor volume increase. These events paralleled caspase-9 activation and PARP cleavage. Conclusion: 20(S)-PPD inhibits endometrial cancer cell proliferation by inducing cell death via a caspase-mediated apoptosis pathway. Therefore, the 20(S)-PPD-like ginsenosides are endowed with ample structural information that could be utilized to develop other ginsenoside-based anticancer agents.

• Journal of Ginseng Research
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• v.33 no.4
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• pp.316-323
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• 2009

Ginseng saponins have various pharmacological effects on the immune system. 20(S)-protopanaxadiol (PPD) and 20(S)-protopanaxatriol (PPT) are the species of ginseng saponin metabolites that are formed by human intestinal bacteria and detected in circulation. The effects of PPD and PPT on the inflammatory mediator release from the activated mast cells were tested. Histamine release was evaluated in activated guinea pig lung mast cells, and the secretion of interleukin-4 (IL-4), interleukin-8 (IL-8), and the tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) was assessed in an HMC-1 cell after treating it with ginseng saponin metabolites. The results are as follows. PPT, at its maximum concentration of $100\;{\mu}M$, completely abolished the secretion of IL-4 from the PMA-stimulated HMC-1 cell. It also inhibited IL-8 secretion from the same cells by about 40-50% of the PMA-treated DMSO control. PPD, at its maximum concentration of $100\;{\mu}M$, showed a tendency to induce histamine release from the guinea pig lung mast cells. It inhibited the secretion of IL-4 (by 89% of the PMA-treated DMSO control) in the PMA-stimulated HMC-1 cell, but did have a significant effect on the IL-8 release from the same cell. Both PPD and PPT showed no effects, however, on the release of TNF-${\alpha}$ from the PMA-stimulated HMC-1 cell. These results suggest that PPD and PPT are from the ginseng metabolites that are responsible for the immunomodulating activity of ginseng extracts when they are taken orally.

• Journal of Ginseng Research
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• v.47 no.4
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• pp.543-551
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• 2023

Background: Panax ginseng Meyer is a representative Chinese herbal medicine with antioxidant and anti-inflammatory activity. 20(S)-Protopanaxadiol (PPD) has been isolated from ginseng and shown to have promising pharmacological activities. However, effects of PDD on pulmonary fibrosis (PF) have not been reported. We hypothesize that PDD may reverse inflammation-induced PF and be a novel therapeutic strategy. Methods: Adult male C57BL/6 mice were used to establish a model of PF induced by bleomycin (BLM). The pulmonary index was measured, and histological and immunohistochemical examinations were made. Cell cultures of mouse alveolar epithelial cells were analyzed with Western blotting, coimmunoprecipitation, immunofluorescence, immunohistochemistry, siRNA transfection, cellular thermal shift assay and qRT-PCR. Results: The survival rate of PPD-treated mice was higher than that of untreated BLM-challenged mice. Expression of fibrotic hallmarks, including α-SMA, TGF-β1 and collagen I, was reduced by PPD treatment, indicating attenuation of PF. Mice exposed to BLM had higher STING levels in lung tissue, and this was reduced by phosphorylated AMPK after activation by PPD. The role of phosphorylated AMPK in suppressing STING was confirmed in TGF-b1-incubated cells. Both in vivo and in vitro analyses indicated that PPD treatment attenuated BLM-induced PF by modulating the AMPK/STING signaling pathway. Conclusion: PPD ameliorated BLM-induced PF by multi-target regulation. The current study may help develop new therapeutic strategies for preventing PF.

• Journal of Ginseng Research
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• v.44 no.5
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• pp.690-696
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• 2020

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.

• Journal of Ginseng Research
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• v.45 no.2
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• pp.325-333
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• 2021

Background: Alzheimer's disease (AD) is one of the most prevalent neurodegenerative disorders. Enhancing hippocampal neurogenesis by promoting proliferation and differentiation of neural stem cells (NSCs) is a promising therapeutic strategy for AD. 20(S)-protopanaxadiol (PPD) and oleanolic acid (OA) are small, bioactive compounds found in ginseng that can promote NSC proliferation and neural differentiation in vitro. However, it is currently unknown whether PPD or OA can attenuate cognitive deficits by enhancing hippocampal neurogenesis in vivo in a transgenic APP/PS1 AD mouse model. Here, we administered PPD or OA to APP/PS1 mice and monitored the effects on cognition and hippocampal neurogenesis. Methods: We used the Morris water maze, Y maze, and open field tests to compare the cognitive capacities of treated and untreated APP/PS1 mice. We investigated hippocampal neurogenesis using Nissl staining and BrdU/NeuN double labeling. NSC proliferation was quantified by Sox2 labeling of the hippocampal dentate gyrus. We used western blotting to determine the effects of PPD and OA on Wnt/GSK3β/β-catenin pathway activation in the hippocampus. Results: Both PPD and OA significantly ameliorated the cognitive impairments observed in untreated APP/PS1 mice. Furthermore, PPD and OA significantly promoted hippocampal neurogenesis and NSC proliferation. At the mechanistic level, PPD and OA treatments resulted in Wnt/GSK-3β/β-catenin pathway activation in the hippocampus. Conclusion: PPD and OA ameliorate cognitive deficits in APP/PS1 mice by enhancing hippocampal neurogenesis, achieved by stimulating the Wnt/GSK-3β/β-catenin pathway. As such, PPD and OA are promising novel therapeutic agents for the treatment of AD and other neurodegenerative diseases.