Compound K-induced apoptosis of human hepatocellular carcinoma MHCC97-H cells in vitro

Ginsenosides in cancer: Targeting cell cycle arrest and apoptosis

Despite the existence of extensive clinical research and novel therapeutic treatments, cancer remains undefeated and the significant cause of death worldwide. Cancer is a disease in which growth of cells goes out of control, being also able to invade other parts of the body. Cellular division is strictly controlled by multiple checkpoints like G1/S and G2/M which, when dysregulated, lead to uncontrollable cell division. The current remedies which are being utilized to combat cancer are monoclonal antibodies, chemotherapy, cryoablation, and bone marrow transplant etc. and these have also been greatly disheartening because of their serious adverse effects like hypotension, neuropathy, necrosis, leukemia relapse and many more. Bioactive compounds derived from natural products have marked the history of the development of novel drug therapies against cancer among which ginsenosides have no peer as they target several signaling pathways, which when abnormally regulated, lead to cancer. Substantial research has reported that ginsenosides like Rb1, Rb2, Rb3, Rc, Rd, Rg3, Rh2 etc. can prevent and treat cancer by targeting different pathways and molecules by induction of autophagy, neutralizing ROS, induction of cancerous cell death by controlling the p53 pathway, modulation of miRNAs by decreasing Smad2 expression, regulating Bcl-2 expression by normalizing the NF-Kb pathway, inhibition of inflammatory pathways by decreasing the production of cytokines like IL-8, causing cell cycle arrest by restricting cyclin E1 and CDC2, and induction of apoptosis during malignancy by decreasing β-catenin levels etc. In this review, we have analyzed the anti-cancer therapeutic potential of various ginsenoside compounds in order to consider their possible use in new strategies in the fight against cancer.

Compound K: A systematic review of its anticancer properties and probable mechanisms

Panax ginseng is a common natural product, which is well-known to have a wide range of pharmacological activities in cancer. Its metabolite, compound K (CK), has been reported to have anticancer activity. We aimed to systematically review the literature for evidence of anticancer effects of CK. We conducted a systematic search in eight databases. We included all in vitro and in vivo studies investigating the anticancer effects of CK with no restrictions. Quality assessment was applied by ToxRTool. Fifty-four articles were included in our study. The purity of CK in our included studies was at least 95%. The in vitro studies reported that CK had a potential anticancer activity on several cell lines including human lung cancer cell lines (A549, PC-9), nasopharyngeal carcinoma cell line (Hk-1), liver cancer cell line (BEL 7402), and pediatric acute myeloid leukemia cell lines (Kasumi-1, MV4-11). The in vivo studies reported a significant decrease in tumor volume in mice treated with CK. CK is a potential supplementary treatment in cancer chemotherapies. The safety and further clinical trials of CK should be explored for future drug development.

Functional Mechanism of Ginsenoside Compound K on Tumor Growth and Metastasis

Ginsenosides, as the most important constituents of ginseng, have been extensively investigated in cancer chemoprevention and therapeutics. Among the ginsenosides, Compound K (CK), a rare protopanaxadiol type of ginsenoside, has been most broadly used for cancer treatment due to its high anticancer bioactivity. However, the functional mechanism of CK in cancer is not well known. This review describes the structure, transformation and pharmacological activity of CK and discusses the functional mechanisms of CK and its metabolites, which regulate signaling pathways related to tumor growth and metastasis. CK inhibits tumor growth by inducing tumor apoptosis and tumor cell differentiation, regulates the tumor microenvironment by suppressing tumor angiogenesis-related proteins, and downregulates the roles of immunosuppressive cells, such as myeloid-derived suppressor cells (MDSCs). There is currently much research on the potential development of CK as a new strategy when administered alone or in combination with other compounds.

Anticancer properties and pharmaceutical applications of ginsenoside compound K: A review

Ginsenoside compound K (CK) is the major intestinal bacterial metabolite of ginsenosides that exhibits anticancer potential in various cancer cells both in vitro and in vivo. The anticancer types, mechanisms, and effects of CK in the past decade have been summarized in this review. Briefly, CK exerts anticancer effects via multiple molecular mechanisms, including the inhibition of proliferation, invasion, and migration, the induction of apoptosis and autophagy, and anti‐angiogenesis. Some signaling pathways play a significant role in related processes, such as PI3K/Akt/mTOR, JNK/MAPK pathway, and reactive oxygen species (ROS). Moreover, the effects of CK combined with nanocarriers for anticancer efficiency are discussed in this review. Furthermore, we aimed to review the research progress of CK against cancer in the past decade, which might provide theoretical support and effective reference for further research on the medicinal value of small molecules, such as CK.

Suppression of phosphoinositide 3-kinase/phosphoinositide-dependent kinase-1/serum and glucocorticoid-induced protein kinase pathway

In the current study, the pivotal roles of serum and glucocorticoid-induced protein kinase (SGK1) and NF-kB related signalings known as prognostic biomarkers in cervical cancers were explored in the antitumor effect of a ginseng saponin metabolite compound K (CK) in HeLa and SiHa cervical cancer cells. CK exerted significant cytotoxicity, induced sub-G1 accumulation, and attenuated the expression of proPoly (ADP-ribose) polymerase (pro-PARP) and Pro-cysteine aspartyl-specific protease (pro-caspase3) in HeLa cells more than in SiHa cells. CK inhibited phosphorylation of SGK1 and its upstream genes, phosphoinositide 3-kinases (PI3K), and phosphoinositide-dependent kinase-1 (PDK1) in HeLa cells. In addition, CK suppressed the phosphorylation of SGK1, NF-κB, and inhibitor of kappa B (IκB) and also NF-κB target genes such as X-linked inhibitor of apoptosis protein and B-cell lymphoma 2 (Bcl-2) in HeLa cells. Notably, Immunoprecipitation revealed that SGK1 binds to PI3K or PDK1 and also CK disturbed the binding between SGK1 and PI3K or PDK1 in HeLa cells. Furthermore, PI3K inhibitor LY294002 decreased expression of PI3K, p-PDK1, p-SGK1, and pro-caspase3 and SGK1 inhibitor GSK650394 also reduced expression of NF-κB and pro-caspase3 just like CK in HeLa cells. Overall, these findings suggest that CK induces apoptosis via suppression of PI3K/PDK1/SGK1 and NF-κB signaling axis.

Review of ginsenosides targeting mitochondrial function to treat multiple disorders: Current status and perspectives

Mitochondrial dysfunction contributes to the pathogenesis and prognosis of many common disorders, including neurodegeneration, stroke, myocardial infarction, tumor, and metabolic diseases. Ginsenosides, the major bioactive constituents of Panax ginseng (P. ginseng), have been reported to play beneficial roles in the molecular pathophysiology of these diseases by targeting mitochondrial dysfunction. In this review, we first introduce the types of ginsenosides and basic mitochondrial functions. Then, recent findings are summarized on different ginsenosides targeting mitochondria and their key signaling pathways for the treatment of multiple diseases, including neurological disorders, cancer, heart disease, hyperglycemia, and inflammation are summarized. This review may explain the common targets of ginsenosides against multiple diseases and provide new insights into the underlying mechanisms, facilitating research on the clinical application of P. ginseng.

p53 dependent LGR5 inhibition and caspase 3 activation are critically involved in apoptotic effect of compound K and its combination therapy potential in HCT116 cells

Though ginsenoside metabolite compound K was known to have antitumor effect in several cancers, its underlying apoptotic mechanism still remains unclear so far. Thus, in the present study, the apoptotic mechanism of compound K was explored in colorectal cancer cells (CRCs) in association with leucine rich repeat containing G protein-coupled receptor 5 (LGR5) that was overexpressed in colorectal cancers with poor survival rate. Here compound K significantly reduced viability of HCT116^p53+/+ cells better than that of HCT116^p53-/- cells. Consistently, compound K increased sub G1 population and attenuated the expression of LGR5, c-Myc, procaspase3, Pin1 in HCT116^p53+/+ cells more than in HCT116^p53-/- cells. Conversely, caspase 3 inhibitor Z-DEVD-FMK reversed inhibitory effect of compound K on LGR5, c-Myc and procaspase3 in HCT116 cells. Consistently, inhibition of LGR5 using transfection method enhanced suppression of pro-PARP, Bcl-x_L c-Myc, Snail and Pin1 in compound K treated HCT116^p53+/+ cells. Furthermore, compound K synergistically potentiated antitumor effect of 5-fluorouracil (5-FU) or Doxorubicin to reduce the survival genes and cytotoxicity in HCT116^p53+/+ cells. Overall, our findings provide scientific insight that compound K induces apoptosis in colon cancer cells via caspase and p53 dependent LGR5 inhibition with combination therapy potential with 5-FU or doxorubicin.

Insights into gastrointestinal microbiota-generated ginsenoside metabolites and their bioactivities

The gastrointestinal microbiota and host co-evolve into a complex 'super-organism,' and this relationship plays a vital role in many physiological processes, such as drug metabolism. Ginseng is an important medicinal resource and the main ingredients are ginsenosides, which are less polar, difficult to absorb, and have low bioavailability. However, studies have shown that the biological activity of ginsenosides such as compound K (CK), ginsenoside Rg3 (Rg3), ginsenoside Rh2 (Rh2), 20(S)-protopanaxatriol (20(S)-PPT), and 20(S)-protopanaxadiol (20(S)-PPD) is closely related to the gastrointestinal microbiota. In this paper, the metabolic pathway of gastrointestinal microbiota-generated ginsenosides and the main pharmacological effects of these metabolites are discussed. Furthermore, our study provides a new insight into the discovery of novel drugs. Specifically, in new drug screening process, candidates with low biological activity and bioavailability should not be excluded. Because their metabolites may exhibit good pharmacological effects due to the involvement of the gastrointestinal microbiota. In addition, in further research studies to develop probiotics, a combination of agents could exert greater efficacy than single agents. Moreover, differences in lifestyle and diet lead to differences in the gastrointestinal microbiota in the human body. Therefore, administration of the same drug dose to different individuals could elicit different therapeutic effects, owing to the involvement of the gastrointestinal microbiota. Thus, treatment accuracy could be achieved by detecting the gastrointestinal microbiota before drug treatment.HighlightsGastrointestinal microbiota plays a decisive role in bioactivities of ginsenosides.The metabolic pathway and main pharmacological effects of ginsenoside metabolites are discussed.It provides new insights into novel drug discovery and further research to find probiotic, combinations to exert greater efficacy.Differences in lifestyle and diet, varies the gastrointestinal microbiota in the human body. However, the same dose of a drug producing different therapeutic effects may involve gastrointestinal microbiota.

Genome-scale CRISPR screening for potential targets of ginsenoside compound K

Ginsenosides exhibit a large variety of biological activities in maintaining physical health; however, the molecule underpinnings underlining these biological activities remain to be defined. Here, we took a cellular condition that compound K (CK) induces autophagic cell death in HeLa cells, and setup a high-throughput genetic screening using CRISPR technology. We have identified a number of CK-resistant and CK-sensitive genes, and further validated PMAIP1 as a CK-resistant gene and WASH1 as a CK-sensitive gene. Compound K treatment reduces the expression of WASH1, which further accelerates the autophagic cell death, highlighting WASH1 as an interesting downstream mediator of CK effects. Overall, our study offers an easy-to-adopt platform to study the functional mediators of ginsenosides, and provides a candidate list of genes that are potential targets of CK.

Micelles modified with a chitosan-derived homing peptide for targeted intracellular delivery of ginsenoside compound K to liver cancer cells

Ginsenoside compound K (CK), a major metabolite of protopanaxadiol ginsenosides, exhibits significant anticancer activities against various cancer cells. However, CK has poor water solubility and low bioavailability, which have limited its application. In this study, A54 peptide was utilized to fabricate CK-loaded micelles (APD-CK) for liver targeting, using deoxycholic acid-O-carboxymethyl chitosan as the vehicle. The average particle size of APD-CK micelles was about 171.4 nm by dynamic light scattering in the hydrated state and their morphology were spherical with good dispersion. An in vitro release assay indicated pH-responsive and sustained release behavior through a mechanism of non-Fickian diffusion. Moreover, the in vitro cytotoxicity of the APD-CK micelles against HepG2 and Huh-7 cells was significantly stronger than that of CK up to 20 μg/mL. Enhanced cellular uptake of micelles in both cell types was established using confocal fluorescence scanning microscopy and flow cytometry. In addition, western blot analysis revealed that APD-CK micelles could promote the protein expression levels of caspase-3, caspase-9, and poly (ADP-ribose) polymerase. Therefore, APD-CK micelles are a potential vehicle for delivering hydrophobic drugs in liver cancer therapy, enhancing drug targeting and anticancer activity.

Naturally occurring anti-cancer compounds: shining from Chinese herbal medicine

Numerous natural products originated from Chinese herbal medicine exhibit anti-cancer activities, including anti-proliferative, pro-apoptotic, anti-metastatic, anti-angiogenic effects, as well as regulate autophagy, reverse multidrug resistance, balance immunity, and enhance chemotherapy in vitro and in vivo. To provide new insights into the critical path ahead, we systemically reviewed the most recent advances (reported since 2011) on the key compounds with anti-cancer effects derived from Chinese herbal medicine (curcumin, epigallocatechin gallate, berberine, artemisinin, ginsenoside Rg3, ursolic acid, silibinin, emodin, triptolide, cucurbitacin B, tanshinone I, oridonin, shikonin, gambogic acid, artesunate, wogonin, β-elemene, and cepharanthine) in scientific databases (PubMed, Web of Science, Medline, Scopus, and Clinical Trials). With a broader perspective, we focused on their recently discovered and/or investigated pharmacological effects, novel mechanism of action, relevant clinical studies, and their innovative applications in combined therapy and immunomodulation. In addition, the present review has extended to describe other promising compounds including dihydroartemisinin, ginsenoside Rh2, compound K, cucurbitacins D, E, I, tanshinone IIA and cryptotanshinone in view of their potentials in cancer therapy. Up to now, the evidence about the immunomodulatory effects and clinical trials of natural anti-cancer compounds from Chinese herbal medicine is very limited, and further research is needed to monitor their immunoregulatory effects and explore their mechanisms of action as modulators of immune checkpoints.

AKT1-targeted proapoptotic activity of compound K in human breast cancer cells

Background

Breast cancer is a severe disease and the second leading cause of cancer death in women worldwide. To surmount this, various diagnosis and treatment options for breast cancer have been developed. One of the most effective strategies for cancer treatment is to induce apoptosis using naturally occurring compounds. Compound K (CK) is a ginseng saponin metabolite generated by human intestinal bacteria. CK has been studied for its cardioprotective, antiinflammatory, and liver-protective effects; however, the role of CK in breast cancer is not fully understood.

Methods

To investigate the anticancer effects of CK in SKBR3 and MDA-MB-231 cells, cell viability assays and flow cytometry analysis were used. In addition, the direct targets of CK anticancer activity were identified using immunoblotting analysis and overexpression experiments. Invasion, migration, and clonogenic assays were carried out to determine the effects of CK on cancer metastasis.

Results

CK-induced cell apoptosis in SKBR3 cells as determined through 3-(4-5-dimethylthiazol-2-yl)-2-5-diphenyltetrazolium bromide assays, propidium iodide (PI) and annexin V staining, and morphological changes. CK increased the cleaved forms of caspase-7, caspase-8, and caspase-9, whereas the expression of Bcl-2 was reduced by CK. In assays probing the cell survival pathway, CK activated only AKT1 and not AKT2. Moreover, CK inhibited breast cancer cell invasion, migration, and colony formation. Through regulation of AKT1 activity, CK exerts anticancer effects by inducing apoptosis.

Conclusion

Our results suggest that CK could be used as a therapeutic compound for breast cancer.

Ginseng: A Qualitative Review of Benefits for Palliative Clinicians

Ginseng has been used for centuries to treat various diseases and has been commercially developed and cultivated in the past 300 years. Ginseng products may be fresh, dried (white), or dried and steamed (red). Extracts may be made using water or alcohol. There are over 50 different ginsenosides identified by chromatography. We did an informal systematic qualitative review that centered on fatigue, cancer, dementia, respiratory diseases, and heart failure, and we review 113 studies in 6 tables. There are multiple potential benefits to ginseng in cancer. Ginseng, in certain circumstances, has been shown to improve dementia, chronic obstructive pulmonary disease, and heart failure through randomized trials. Most trials had biases or unknown biases and so most evidence is of low quality. We review the gaps in the evidence and make some recommendations regarding future studies.

Ginsenoside metabolite compound K induces apoptosis and autophagy in non-small cell lung cancer cells via AMPK-mTOR and JNK pathways

Compound K [C-K; 20-O-(β-d-glucopyranosyl)-20(S)-protopanaxadiol], as a metabolite of ginsenoside, has been verified to have antitumor effects in various cancers, including non-small cell lung cancer (NSCLC). However, the detailed mechanisms of C-K in NSCLC remain largely unknown. In this study, we aimed to evaluate the effect of C-K on apoptosis and autophagy in NSCLC cells as well as its related mechanisms. According to the results, C-K suppressed the proliferation, and led to G1 phase arrest and apoptosis in A549 and H1975 cells. Subsequently, C-K promoted autophagy, as confirmed by the enhanced rate of cells staining positive with acridine orange, increased levels of LC3II and Beclin-1, and with decreased levels of p62 in A549 and H1975 cells. Moreover, 3-methyladenine (3-MA; an inhibitor of autophagy) effectively suppressed the inhibition of proliferation and apoptosis that was induced with C-K. Finally, C-K treatment promoted the activation of the AMPK-mTOR and c-Jun N-terminal kinase (JNK) signaling pathways. Treatment with compound C (AMPK inhibitor) or SP600125 (JNK inhibitor) significantly restrained the inhibition of proliferation, apoptosis, and autophagy induced with C-K in A549 and H1975 cells. In conclusion, this study demonstrates that C-K promotes autophagy-mediated apoptosis in NSCLC via AMPK-mTOR and JNK signaling pathways.

Compound K Induces Endoplasmic Reticulum Stress and Apoptosis in Human Liver Cancer Cells by Regulating STAT3

The ginsenoside compound K (20-O-β-d-glucopyranosyl-20(S)-protopanaxadiol; CK) is an intestinal bacterial metabolite of ginseng protopanaxadiol saponin that has been reported to induce apoptosis in many cancer cells; however, the precise mechanisms of its activity in human hepatocellular carcinoma (HCC) cells remain unclear. Herein, we demonstrated that CK inhibited the growth and colony formation of HepG2 and SMMC-7721 cells, phenotypes that were mediated by inducing apoptosis. Meanwhile, CK showed lower toxicity in normal hepatoma cells. After treating HepG2 and SMMC-7721 cells with CK, p-STAT3 levels decreased, the three branches of the unfolded protein response were activated, and levels of endoplasmic reticulum stress (ERS)-related proteins were increased. We also revealed that CK decreased the DNA-binding capacity of STAT3. Moreover, silencing STAT3 with CRISPR/Cas9 technology enhanced CK-induced ERS and apoptosis. Finally, we showed that CK inhibited the growth of liver cancer xenografts with little toxicity. Mice bearing human HCC xenografts that were treated with CK showed increased GRP78 expression and decreased p-STAT3 levels. Taken together, these data showed that CK induced ERS and apoptosis by inhibiting p-STAT3 in human liver cancer cells; thus, CK might be a potential therapeutic candidate for human HCC.

Targeted delivery of ginsenoside compound K using TPGS/PEG-PCL mixed micelles for effective treatment of lung cancer

Ginsenoside compound K (CK) is one of the effective ingredients in antitumor composition of ginsenoside. However, the poor water solubility and significant efflux have limited the widespread clinical use of CK. In this study, preparation of novel CK-loaded d-alpha-tocopheryl polyethylene glycol 1,000 succinate/poly(ethylene glycol)-poly(ε-caprolactone) mixed micelles (CK-M) is discussed to solve the above problems. Particle size, zeta potential, and morphology were characterized using dynamic light scattering and transmission electron microscopy. CK-M are spherical shaped with an average particle size of 53.07±1.31 nm with high drug loading of 11.19%±0.87% and entrapment efficiency of 94.60%±1.45%. Water solubility of CK was improved to 3.78±0.09 mg/mL, which was ~107.35 times higher than free CK. A549 and PC-9 cells were used to evaluate in vitro cytotoxicity and cellular uptake. IC₅₀ values of CK-M in A549 and PC-9 cells (24 h) were 25.43±2.18 and 18.35±1.90 μg/mL, respectively. Enhanced cellular uptake of CK-M was observed in both cells. Moreover, CK-M promoted tumor cell apoptosis, inhibited tumor cell invasion, metastasis, and efflux through regulation of Bax, Bcl-2, matrix metalloproteinase-2, Caspase-3, and P-glycoprotein. In vivo imaging indicated that CK-M has excellent tumor targeting effect within 24 h, and the relative tumor inhibition rate of CK-M was 52.04%±4.62% compared with control group (P<0.01). Thus, CK-M could be an appropriate delivery agent for enhanced solubility and antitumor effect of CK.

Synthesis and Biological Evaluation of Ginsenoside Compound K Derivatives as a Novel Class of LXRα Activator

Compound K is one of the active metabolites of Panaxnotoginseng saponins, which could attenuate the formation of atherosclerosis in mice modelsvia activating LXRα. We synthesized and evaluated a series of ginsenoside compound K derivatives modified with short chain fatty acids. All of the structures of this class of ginsenoside compound K derivative exhibited comparable or better biological activity than ginsenoside compound K. Especially structure 1 exhibited the best potency (cholesteryl ester content: 41.51%; expression of ABCA1 mRNA: 319%) and low cytotoxicity.

The ginsenoside metabolite compound K inhibits growth, migration and stemness of glioblastoma cells

Glioblastoma (GBM) is the most aggressive and malignant form of primary brain cancer. Despite recent advances in cancer treatment, it remains a substantially incurable disease. Accordingly, more effective GBM therapeutic options are urgently required. In the present study, we investigated the anticancer effect of a ginsenoside metabolite, compound K (CK), against GBM cells. CK significantly inhibited not only growth, but also metastatic ability of U87MG and U373MG cells. CK arrested cell cycle progression at the G0/G1 phase with a decrease in the expression levels of cyclin D1 and cyclin D3 in both cell types. CK also induced apoptosis in GBM cells through nuclear condensation, an increase in ROS generation, mitochondrial membrane potential depolarization, and activation of caspase-3, caspase-9 and poly(ADP-ribose) polymerase (PARP). Furthermore, CK inhibited phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling pathway, contributing to the antiproliferative and apoptotic effects. Moreover, CK suppressed the self-renewal capacity as well as the invasiveness of U87MG and U373MG GBM stem-like cells (GSCs) by inducing a reduction in the expression of GSC markers, such as CD133, Nanog, Oct4 and Sox2. Taken together, our findings suggest that CK may potentially be useful for GBM treatment.

Effects of microRNA-126 on cell proliferation, apoptosis and tumor angiogenesis via the down-regulating ERK signaling pathway by targeting EGFL7 in hepatocellular carcinoma

This study intends to explore the effects of microRNA-126 (miR-126) on cell proliferation, apoptosis, and tumor angiogenesis in hepatocellular carcinoma (HCC) by regulating epidermal growth factor-like domain 7 (EGFL7) through extracellular signal-regulated kinase (ERK) signaling. HCC tissues and adjacent normal tissues were obtained from 184 HCC patients. HCC cells were separately transfected with recombinant plasmids. Western blotting and qRT-PCR were applied to detect miR-126 and EGFL7, ERK, Fas/FasL, Bcl-2, Caspase mRNA and protein levels. CCK8 and TUNEL were performed to determinate cell proliferation and apoptosis. Flow cytometry was used to analyze cell cycle distribution. Rats model of HCC was constructed, and tumor weight and the number of new blood vessels were recorded after 3 weeks of tumor transplantation. Compared with the adjacent normal tissues, HCC tissues exhibited lower miR-126 expression, and higher EGFL7, and ERK mRNA and protein levels. Overexpression of miR-126 in HCC cell lines suppressed EGFL7, ERK, Bcl-2, and P-ERK, and increased apoptotic-associated proteins Fas/FasL and Caspase-3, and it inhibited cell proliferation and induced cell apoptosis. Overexpression of miR-126 in nude mice resulted in reduced tumor weight and less new blood vessels in tumors. The inhibition of miR-126 decreased cell apoptosis, and enhanced cell proliferation and tumor angiogenesis. This study demonstrates that miR-126 might decrease cell proliferation, induce apoptosis, and inhibit tumor angiogenesis in HCC by inhibiting EGFL7 via down-regulating the ERK signaling pathway.

Ginseng for Liver Injury: Friend or Foe?

Panax sp., including Panax ginseng Meyer, Panax quiquifolius L., or Panax notoginseng (Burk.) FH Chen, have been used as functional foods or for traditional Chinese medicine for diabetes, inflammation, stress, aging, hepatic injury, and cancer. In recent decades, a number of both in vitro and in vivo experiments as well as human studies have been conducted to investigate the efficacy and safety of various types of ginseng samples and their components. Of these, the hepatoprotective and hepatotoxic effects of ginseng and their ginsenosides and polysaccharides are reviewed and summarized.

General and Genetic Toxicology of Enzyme-Treated Ginseng Extract: Toxicology of Ginseng Rh2

OBJECTIVES

Ginseng Rh2+ is enzyme-treated ginseng extract containing high amounts of converted ginsenosides, such as compound k, Rh2, Rg3, which have potent anticancer activity. We conducted general and genetic toxicity tests to evaluate the safety of ginseng Rh2+.

METHODS

An acute oral toxicity test was performed at a high-level dose of 4,000 mg/kg/day in Sprague-Dawley (SD) rats. A 14-day range-finding study was also conducted to set dose levels for the 90-day study. A subchronic 90-day toxicity study was performed at dose levels of 1,000 and 2,000 mg/kg/day to investigate the no-observed-adverse-effect level (NOAEL) of ginseng Rh2+ and target organs. To identify the mutagenic potential of ginseng Rh2+, we conducted a bacterial reverse mutation test (Ames test) using amino-acid-requiring strains of Salmonella typhimurium and Escherichia coli (E. coli), a chromosome aberration test with Chinese hamster lung (CHL) cells, and an in vivo micronucleus test using ICR mice bone marrow as recommended by the Korean Ministry of Food and Drug Safety.

RESULTS

According to the results of the acute oral toxicity study, the approximate lethal dose (ALD) of ginseng Rh2+ was estimated to be higher than 4,000 mg/kg. For the 90-day study, no toxicological effect of ginseng Rh2+ was observed in body-weight changes, food consumption, clinical signs, organ weights, histopathology, ophthalmology, and clinical pathology. The NOAEL of ginseng Rh2+ was established to be 2,000 mg/kg/day, and no target organ was found in this test. In addition, no evidence of mutagenicity was found either on the in vitro genotoxicity tests, including the Ames test and the chromosome aberration test, or on the in vivo in mice bone marrow micronucleus test.

CONCLUSION

On the basis of our findings, ginseng Rh2+ is a non-toxic material with no genotoxicity. We expect that ginseng Rh2+ may be used as a novel adjuvant anticancer agent that is safe for long-term administration.

Compound K Attenuates the Development of Atherosclerosis in ApoE(-/-) Mice via LXRα Activation

Background: Atherosclerosis is a fundamental pathological process responded to some serious cardiovascular events. Although the cholesterol-lowering drugs are widely prescribed for atherosclerosis therapy, it is still the leading cause of death in the developed world. Here we measured the effects of compound K in atherosclerosis formation and investigated the probably mechanisms of the anti-antherosclerosis roles of compound K. Methods: We treated the atherosclerotic model animals (apoE^−/− mice on western diet) with compound K and measured the size of atherosclerotic lesions, inflammatory cytokine levels and serum lipid profile. Peritoneal macrophages were collected in vitro for the foam cell and inflammasome experiments. Results: Our results show that treatment with compound K dose-dependently attenuates the formation of atherosclerotic plaques by 55% through activation of reverse cholesterol transport pathway, reduction of systemic inflammatory cytokines and inhibition of local inflammasome activity. Compound K increases the cholesterol efflux of macrophage-derived foam cells, and reduces the inflammasome activity in cholesterol crystal stimulated macrophages. The activation of LXRα may contribute to the athero-protective effects of compound K. Conclusion: These observations provide evidence for an athero-protective effect of compound K via LXRα activation, and support its further evaluation as a potential effective modulator for the prevention and treatment of atherosclerosis.

Could the gut microbiota reconcile the oral bioavailability conundrum of traditional herbs?

ETHNOPHARMACOLOGICAL RELEVANCE

A wealth of information is emerging about the impact of gut microbiota on human health and diseases such as cardiovascular diseases, obesity and diabetes. As we learn more, we find out the gut microbiota has the potential as new territory for drug targeting. Some novel therapeutic approaches could be developed through reshaping the commensal microbial structure using combinations of different agents. The gut microbiota also affects drug metabolism, directly and indirectly, particularly towards the orally administered drugs. Herbal products have become the basis of traditional medicines such as traditional Chinese medicine and also been being considered valuable materials in modern drug discovery. Of note, low oral bioavailability but high bioactivity is a conundrum not yet solved for some herbs. Since most of herbal products are orally administered, the herbs' constituents are inevitably exposed to the intestinal microbiota and the interplays between herbal constituents and gut microbiota are expected. Emerging explorations of herb-microbiota interactions have an opportunity to revolutionize the way we view herbal therapeutics. The present review aims to provide information regarding the health promotion and/or disease prevention by the interplay between traditional herbs with low bioavailability and gut microbiota through gut microbiota via two different types of mechanisms: (1) influencing the composition of gut microbiota by herbs and (2) metabolic reactions of herbal constituents by gut microbiota.

MATERIALS AND METHODS

The major data bases (PubMed and Web of Science) were searched using "gut microbiota", "intestinal microbiota", "gut flora", "intestinal flora", "gut microflora", "intestinal microflora", "herb", "Chinese medicine", "traditional medicine", or "herbal medicine" as keywords to find out studies regarding herb-microbiota interactions. The Chinese Pharmacopoeia (2010 edition, Volume I) was also used to collect the data of commonly used medicinal herbs and their quality control approaches.

RESULTS

Among the 474 monographs of herbs usually used in the Chinese Pharmacopoeia, the quality control approach of 284 monographs is recommended to use high-performance liquid chromatography approach. Notably, the major marker compounds (>60%) for quality control are polyphenols, polysaccharides and saponins, with significant oral bioavailability conundrum. Results from preclinical and clinical studies on herb-microbiota interactions showed that traditional herbs could exert heath promotion and disease prevention roles via influencing the gut microbiota structure. On the other hand, herb constituents such as ginsenoside C-K, hesperidin, baicalin, daidzin and glycyrrhizin could exert their therapeutic effects through gut microbiota-mediated bioconversion.

CONCLUSIONS

Herb-microbiota interaction studies provide novel mechanistic understanding of the traditional herbs that exhibit poor oral bioavailability. "Microbiota availability" could be taken consideration into describing biological measurements in the therapeutic assessment of herbal medicine. Our review should be of value in stimulating discussions among the scientific community on this relevant theme and prompting more efforts to complement herb-microbiota interactions studies.

Cell-based assays in combination with ultra-high performance liquid chromatography-quadrupole time of flight tandem mass spectrometry for screening bioactive capilliposide C metabolites generated by rat intestinal microflora

Many plant-derived glycosides are used as medications. It is common that these glycosides show poor intestinal absorption but their metabolites generated by intestinal microflora demonstrate strong bioactivity. Hence, it is crucial to develop a method for the identification and characterization of the metabolites, and consequently reveal the pathway in which the glycosides are processed in gut. In this study, cell-based assays in combination with ultra-high performance liquid chromatography-quadrupole time of flight tandem mass spectrometry (UHPLC-QTOF-MS/MS) were developed for rapid discovery and evaluation of the metabolites of a glycoside compound, capilliposide C (LC-C). 92.7% of LC-C was biotransformed by rat intestinal microflora after 36-h incubation at 37°C. Human cancer cell lines HepG2, PC-3 and A549 was treated with metabolites pool, respectively, which was followed by cell viability assays and characterization of metabolites using UHPLC-QTOF-MS/MS. As a result, significant cytotoxicity was observed for the metabolites pool, from which six metabolites were identified. Based on the metabolites identified, deglycosylation and esterolysis were proposed as the major metabolic pathways of LC-C in rat intestinal microflora. In addition, M4, an esterolysis product of LC-C, was obtained and evaluated for its bioactivity in vitro. As a result, M4 exhibited a reduction in cell viability in HepG2 with an IC50 value of 17.46±1.55μg/mL.

Effects of ginsenoside compound K combined with cisplatin on the proliferation, apoptosis and epithelial mesenchymal transition in MCF-7 cells of human breast cancer

CONTEXT

Breast cancer seriously harms the health of women and there are currently few therapeutic options for patients with breast cancer.

OBJECTIVE

Effects of ginsenoside compound K (CK) in combination with cisplatin (DDP) on the proliferation, apoptosis, and epithelial mesenchymal transition (EMT) of MCF-7 cells were studied.

MATERIALS AND METHODS

MCF-7 cells were divided into CK (50 μmol/L) group, DDP (10 mg/L) group, CK (50 μmol/L) +DDP (10 mg/L) group, and control (CON) group. The cells in the CON group were not treated with any drugs. Proliferation, apoptosis, expression of E-cadherin, N-cadherin, vimentin, protein kinase B (Akt), phosphorylated Akt (p-Akt), and level of fibronectin (FN) in MCF-7 cells were detected by methyl thiazolyl tetrazolium (MTT), flow cytometry, western blotting, and enzyme-linked immuno sorbent assay (ELISA), respectively.

RESULTS

The proliferation inhibition rates in CK, DDP, and CK + DDP groups at 48 h were 19.18 ± 2.25, 21.34 ± 2.84, and 43.37 ± 5.62, respectively. The apoptosis rates were 2.85 ± 0.56, 13.37 ± 2.28, 20.04 ± 2.92, and 30.78 ± 4.64 at 24 h and 3.14 ± 0.72, 20.36 ± 3.28, 27.58 ± 4.09, and 41.62 ± 5.83 at 48 h in CON, CK, DDP, and CK + DDP groups, respectively. CK or DDP alone and their combination all could reduce the levels of N-cadherin, vimentin, p-Akt/Akt, and FN and elevate level of E-cadherin.

DISCUSSION AND CONCLUSION

Both CK and DDP can inhibit the proliferation, EMT, and induce the apoptosis in MCF-7 cells, which may be related to the PI3K/Akt pathway. In addition, the combination of CK with DDP can produce a better effect.

Ginsenoside metabolite compound K enhances the efficacy of cisplatin in lung cancer cells

OBJECTIVE

To evaluate the potential of ginsenoside metabolite compound K (CK) in enhancing the anti-tumor effects of cisplatin against lung cancer cells, including cell proliferation and apoptosis, and the underlying mechanism.

METHODS

Western blotting and p53 reporter assay were used to assess p53 expression and activity. MTT assay and TUNEL staining were employed to investigate the drug effects on cell growth and apoptosis, respectively. Combination index (CI) was calculated to determine synergism.

RESULTS

We found that CK could significantly enhance cisplatin-induced p53 expression and activity in two lung cancer cell lines, H460 and A549. Consequently, synergistic inhibition of cell growth was observed when the cells were co-treated with CK and cisplatin compared to single treatment. In addition, the ability of cisplatin in apoptosis induction was similarly synergized by CK. Furthermore, by using p53-null lung cancer cells, we demonstrate that the synergy was p53 dependent.

CONCLUSIONS

Conventional chemotherapies are often accompanied by development of drug resistance and severe side effects. Novel discoveries of low toxicity compounds to improve the outcome or enhance the efficacy of chemotherapies are of great interest. In the present study, our data provide the first evidence that CK could be potentially used as an agent to synergize the efficacy of cisplatin in lung cancer.

Selected ginsenosides of the protopanaxdiol series are novel positive allosteric modulators of P2X7 receptors

BACKGROUND AND PURPOSE

The P2X7 receptor is an ATP-gated ion channel predominantly expressed in immune cells and plays a key role in inflammatory processes. Ginseng is a well-known Chinese herb with both pro- and anti-inflammatory properties and many of its actions have been ascribed to constituent ginsenosides. We screened a number of ginsenoside compounds for pharmacological activity at P2X7 receptors, that might contribute to the reported immunomodulatory actions of ginseng.

EXPERIMENTAL APPROACH

We used several assays to measure responses of P2X7 receptors, ATP-mediated dye uptake, intracellular calcium measurement and whole-cell patch-clamp recordings. HEK-293 cells stably expressing human P2X7 receptors were used in addition to mouse macrophages endogenously expressing P2X7 receptors.

KEY RESULTS

Four ginsenosides of the protopanaxdiol series, Rb1, Rh2, Rd and the metabolite compound K (CK) potentiated the dye uptake responses of P2X7 receptors, whereas other ginsenosides tested were ineffective (1-10 μM). The potentiation was rapid in onset, required a threshold concentration of ATP (>50 μM) and had an EC50 of 1.08 μM. CK markedly enhanced ATP-activated P2X7 currents, probably via an extracellular site of action. One of the consequences of this potentiation effect is a sustained rise in intracellular Ca(2+) that could account for the decrease in cell viability in mouse macrophages after a combination of 500 μM ATP and 10 μM CK that are non-toxic when applied alone.

CONCLUSIONS AND IMPLICATIONS

This study identifies selected ginsenosides as novel potent allosteric modulators of P2X7 channels that may account for some of the reported immune modulatory actions of protopanaxdiol ginsenosides in vivo.