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

Multi-layered effects of Panax notoginseng on immune system

Recent research has demonstrated the immunomodulatory potential of Panax notoginseng in the treatment of chronic inflammatory diseases and cerebral hemorrhage, suggesting its significance in clinical practice. Nevertheless, the complex immune activity of various components has hindered a comprehensive understanding of the immune-regulating properties of Panax notoginseng, impeding its broader utilization. This review evaluates the effect of Panax notoginseng to various types of white blood cells, elucidates the underlying mechanisms, and compares the immunomodulatory effects of different Panax notoginseng active fractions, aiming to provide the theory basis for future immunomodulatory investigation.

Neuroprotection and mechanisms of ginsenosides in nervous system diseases: Progress and perspectives

Ginsenosides are the primary component discernible from ginseng, including Rb1, Rb2, Rd, Rg1, Rg2, and compound K, and so forth. They have been shown to have multiple pharmacological activities. In recent years, more and more studies have been devoted to the neuroprotection of various ginsenosides against neurological diseases and their potential mechanisms. This paper comprehensively summarizes and reviews the neuroprotective effects of various ginsenosides on neurological diseases, especially acute and chronic neurodegenerative diseases, and their mechanisms, as well as their potential therapeutic applications to promote neuroprotection in disease prevention, treatment, and prognosis. Briefly, ginsenosides exert effective neuroprotective effects on neurological conditions, including stroke, Alzheimer's disease, Parkinson's disease, and brain/spinal cord injuries through a variety of molecular mechanisms, including anti-inflammatory, antioxidant, and anti-apoptotic. Among them, some signaling pathways play important roles in related processes, such as PI3K/Akt, TLR4/NF-κB, ROS/TXNIP/NLRP3, HO-1/Nrf2, Wnt/β-catenin, and Ca2+ pathway. In conclusion, the present study reviews the research progress on the neuroprotective effects of ginsenosides in the last decade, with the aim of furnishing essential theoretical underpinning and effective references for further research and exploration of the multiple medicinal values of Chinese herbal medicines and their small molecule compounds, including ginseng and panax ginseng. Because there is less evidence in the existing clinical studies, future research should be focused on clinical trials in order to truly reflect the clinical value of various ginsenosides for the benefit of patients.

Supplementing Glucose Intake Reverses the Inflammation Induced by a High-Fat Diet by Increasing the Expression of Siglec-E Ligands on Erythrocytes

Siglec-9/E is a cell surface receptor expressed on immune cells and can be activated by sialoglycan ligands to play an immunosuppressive role. Our previous study showed that increasing the expression of Siglec-9 (the human paralog of mouse Siglec-E) ligands maintains functionally quiescent immune cells in the bloodstream, but the biological effects of Siglec-9 ligand alteration on atherogenesis were not further explored. In the present study, we demonstrated that the atherosclerosis risk factor ox-LDL or a high-fat diet could decrease the expression of Siglec-9/E ligands on erythrocytes. Increased expression of Siglec-E ligands on erythrocytes caused by dietary supplementation with glucose (20% glucose) had anti-inflammatory effects, and the mechanism was associated with glucose intake. In high-fat diet-fed apoE-/- mice, glucose supplementation decreased the area of atherosclerotic lesions and peripheral inflammation. These data suggested that increased systemic inflammation is attenuated by increasing the expression of Siglec-9/E ligands on erythrocytes. Therefore, Siglec-9/E ligands might be valuable targets for atherosclerosis therapy.

Bioconversion, Pharmacokinetics, and Therapeutic Mechanisms of Ginsenoside Compound K and Its Analogues for Treating Metabolic Diseases

Rare ginsenoside compound K (CK) is an intestinal microbial metabolite with a low natural abundance that is primarily produced by physicochemical processing, side chain modification, or metabolic transformation in the gut. Moreover, CK exhibits potent biological activity compared to primary ginsenosides, which has raised concerns in the field of ginseng research and development, as well as ginsenoside-related dietary supplements and natural products. Ginsenosides Rb1, Rb2, and Rc are generally used as a substrate to generate CK via several bioconversion processes. Current research shows that CK has a wide range of pharmacological actions, including boosting osteogenesis, lipid and glucose metabolism, lipid oxidation, insulin resistance, and anti-inflammatory and anti-apoptosis properties. Further research on the bioavailability and toxicology of CK can advance its medicinal application. The purpose of this review is to lay the groundwork for future clinical studies and the development of CK as a therapy for metabolic disorders. Furthermore, the toxicology and pharmacology of CK are investigated as well in this review. The findings indicate that CK primarily modulates signaling pathways associated with AMPK, SIRT1, PPARs, WNTs, and NF-kB. It also demonstrates a positive therapeutic effect of CK on non-alcoholic fatty liver disease (NAFLD), obesity, hyperlipidemia, diabetes, and its complications, as well as osteoporosis. Additionally, the analogues of CK showed more bioavailability, less toxicity, and more efficacy against disease states. Enhancing bioavailability and regulating hazardous variables are crucial for its use in clinical trials.

Saponins as therapeutic candidates for atherosclerosis

Drug development for atherosclerosis, the underlying pathological state of ischemic cardiovascular diseases, has posed a longstanding challenge. Saponins, classified as steroid or triterpenoid glycosides, have shown promising therapeutic potential in the treatment of atherosclerosis. Through an exhaustive examination of scientific literature spanning from May 2013 to May 2023, we identified 82 references evaluating 37 types of saponins in terms of their prospective impacts on atherosclerosis. These studies suggest that saponins have the potential to ameliorate atherosclerosis by regulating lipid metabolism, inhibiting inflammation, suppressing apoptosis, reducing oxidative stress, and modulating smooth muscle cell proliferation and migration, as well as regulating gut microbiota, autophagy, endothelial senescence, and angiogenesis. Notably, ginsenosides exhibit significant potential and manifest essential pharmacological attributes, including lipid-lowering, anti-inflammatory, anti-apoptotic, and anti-oxidative stress effects. This review provides a comprehensive examination of the pharmacological attributes of saponins in atherosclerosis, with particular emphasis on their role in the regulation of lipid metabolism regulation and anti-inflammatory effects. Thus, saponins may warrant further investigation as a potential therapy for atherosclerosis. However, due to various reasons such as low oral bioavailability, the clinical application of saponins in the treatment of atherosclerosis still needs further exploration.

Compound K Production: Achievements and Perspectives

Compound K (CK) is one of the major metabolites found in mammalian blood and organs following oral administration of Panax plants. CK, also known as minor ginsenoside, can be absorbed in the systemic circulation. It has garnered significant attention in healthcare and medical products due to its pharmacological activities, such as antioxidation, anticancer, antiproliferation, antidiabetics, neuroprotection, and anti-atherogenic activities. However, CK is not found in natural ginseng plants but in traditional chemical synthesis, which uses toxic solvents and leads to environmental pollution during the harvest process. Moreover, enzymatic reactions are impractical for industrial CK production due to low yield and high costs. Although CK could be generated from major ginsenosides, most ginsenosides, including protopanaxatriol-oleanane and ocotillol-type, are not converted into CK by catalyzing β-glucosidase. Therefore, microbial cell systems have been used as a promising solution, providing a safe and efficient approach to CK production. This review provides a summary of various approaches for the production of CK, including chemical and enzymatic reactions, biotransformation by the human intestinal bacteria and endophytes as well as engineered microbes. Moreover, the approaches for CK production have been discussed to improve the productivity of target compounds.

A novel dammarane triterpenoid alleviates atherosclerosis by activating the LXRα pathway

BACKGROUND

We have previously demonstrated that ginsenoside compound K can attenuate the formation of atherosclerotic lesions. Therefore, ginsenoside compound K has potential for atherosclerosis therapy. How to improve the druggability and enhance the antiatherosclerotic activity of ginsenoside compound K are the core problems in the prevention and treatment of atherosclerosis. CKN is a ginsenoside compound K derivative that was previously reported to have excellent antiatherosclerotic activity in vitro, and we have applied for international patents for it.

METHODS

Male C57BL/6 ApoE^-/- mice were fed a high-fat and high-choline diet to induce atherosclerosis and were subjected to in vivo studies. In vitro, the CCK-8 method was applied to evaluate cytotoxicity in macrophages. Foam cells were utilized, and cellular lipid determination was performed for in vitro studies. The area of atherosclerotic plaque and fatty infiltration of the liver were measured by image analysis. Serum lipid and liver function were determined by a seralyzer. Immunofluorescence and western blot analysis were conducted to explore the alterations in the expression levels of lipid efflux-related proteins. Molecular docking, reporter gene experiments and cellular thermal shift assays were used to verify the interaction between CKN and LXRα.

RESULTS

After confirming the therapeutic effects of CKN, molecular docking, reporter gene experiments and cellular thermal shift assays were used to predict and investigate the antiatherosclerotic mechanisms of CKN. CKN exhibited the greatest potency, with a 60.9% and 48.1% reduction in en face atherosclerotic lesions on the thoracic aorta and brachiocephalic trunk, reduced plasma lipid levels and decreased foam cell levels in the vascular plaque content in HHD-fed ApoE^-/- mice. Moreover, CKN in the present study may exert its antiatherosclerotic effects through activated ABCA1 by promoting LXRα nuclear translocation and reducing the adverse effects of LXRα activation.

CONCLUSIONS

Our results revealed that CKN prevented the formation of atherosclerosis in ApoE^-/- mice by activating the LXRα pathway.

Advances in the Bioactivities of Phytochemical Saponins in the Prevention and Treatment of Atherosclerosis

Atherosclerosis (AS) is a chronic inflammatory disease characterized by hardening and narrowing of arteries. AS leads to a number of arteriosclerotic vascular diseases including cardiovascular diseases, cerebrovascular disease and peripheral artery disease, which pose a big threat to human health. Phytochemicals are a variety of intermediate or terminal low molecular weight secondary metabolites produced during plant energy metabolism. Phytochemicals from plant foods (vegetables, fruits, whole grains) and traditional herb plants have been shown to exhibit multiple bioactivities which are beneficial for prevention and treatment against AS. Many types of phytochemicals including polyphenols, saponins, carotenoids, terpenoids, organic sulfur compounds, phytoestrogens, phytic acids and plant sterols have already been identified, among which saponins are a family of glycosidic compounds consisting of a hydrophobic aglycone (sapogenin) linked to hydrophilic sugar moieties. In recent years, studies have shown that saponins exhibit a number of biological activities such as anti-inflammation, anti-oxidation, cholesterol-lowering, immunomodulation, anti-platelet aggregation, etc., which are helpful in the prevention and treatment of AS. This review aims to summarize the recent advances in the anti-atherosclerotic bioactivities of saponins such as ginsenoside, soyasaponin, astra-galoside, glycyrrhizin, gypenoside, dioscin, saikosaponin, etc.

Ginsenosides Rg1 and CK Control Temozolomide Resistance in Glioblastoma Cells by Modulating Cholesterol Efflux and Lipid Raft Distribution

Background

Cholesterol efflux and lipid raft redistribution contribute to attenuating temozolomide resistance of glioblastoma. Ginsenosides are demonstrated to modify cholesterol metabolism and lipid raft distribution, and the brain distribution and central nervous effects of whose isoforms Rb1, Rg1, Rg3, and CK have been identified. This study aimed to reveal the role of Rb1, Rg1, Rg3, and CK in the drug resistance of glioblastoma.

Methods

The effects of ginsenosides on cholesterol metabolism in temozolomide-resistant U251 glioblastoma cells were evaluated by cholesterol content and efflux assay, confocal laser, qRT-PCR, and Western blot. The roles of cholesterol and ginsenosides in temozolomide resistance were studied by CCK-8, flow cytometry, and Western blot, and the mechanism of ginsenosides attenuating resistance was confirmed by inhibitors.

Results

Cholesterol protected the survival of resistant U251 cells from temozolomide stress and upregulated multidrug resistance protein (MDR)1, which localizes in lipid rafts. Resistant cells tended to store cholesterol intracellularly, with limited cholesterol efflux and LXRα expression to maintain the distribution of lipid rafts. Ginsenosides Rb1, Rg1, Rg3, and CK reduced intracellular cholesterol and promoted cholesterol efflux in resistant cells, causing lipid rafts to accumulate in specific regions of the membrane. Rg1 and CK also upregulated LXRα expression and increased the cytotoxicity of temozolomide in the presence of cholesterol. We further found that cholesterol efflux induction, lipid raft redistribution, and temozolomide sensitization by Rg1 and CK were induced by stimulating LXRα.

Conclusions

Ginsenosides Rg1 and CK controlled temozolomide resistance in glioblastoma cells by regulating cholesterol metabolism, which are potential synergists for temozolomide therapy.

Insight on structural modification, biological activity, structure-activity relationship of PPD-type ginsenoside derivatives

Ginsenosides, characterized by triterpenoid, are one of the active components of ginseng. Among them, PPD-type ginsenosides have potent and diverse pharmacological activities, while the effective applications and clinical studies are limited by the poor stability, water solubility and oral bioavailability. In this review, we have attempted to demonstrate the structural-activity relationship of chemical modifications on the dammarane-type skeleton and the C-17 side chain, noting that certain structurally modified derivatives exhibit satisfactory pharmacological activity. This review will provide ideas for the design and synthesis of novel PPD derivatives, and valuable help for the further study of PPD derivatives to make it realize clinical application.

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.

Ginsenoside Compound K Assisted G-Quadruplex Folding and Regulated G-Quadruplex-Containing Transcription

Ginsenoside compound K (CK) is one of the major metabolites of the bioactive ingredients in Panax ginseng, which presents excellent bioactivity and regulates the expression of important proteins. In this work, the effects of CK on G-quadruplexes (G4s) were quantitatively analyzed in the presence and absence of their complementary sequences. CK was demonstrated to facilitate the formation of G4s, and increase the quantity of G4s in the competition with duplex. Thermodynamic experiments suggested that the electrostatic interactions were important for G4 stabilization by CK. CK was further found to regulate the transcription of G4-containing templates, reduce full-length transcripts, and decrease the transcription efficiency. Our results provide new evidence for the pharmacological study of ginsenosides at the gene level.

Chemotherapy-Induced Cognitive Impairment and Hippocampal Neurogenesis: A Review of Physiological Mechanisms and Interventions

A wide range of cognitive deficits, including memory loss associated with hippocampal dysfunction, have been widely reported in cancer survivors who received chemotherapy. Changes in both white matter and gray matter volume have been observed following chemotherapy treatment, with reduced volume in the medial temporal lobe thought to be due in part to reductions in hippocampal neurogenesis. Pre-clinical rodent models confirm that common chemotherapeutic agents used to treat various forms of non-CNS cancers reduce rates of hippocampal neurogenesis and impair performance on hippocampally-mediated learning and memory tasks. We review the pre-clinical rodent literature to identify how various chemotherapeutic drugs affect hippocampal neurogenesis and induce cognitive impairment. We also review factors such as physical exercise and environmental stimulation that may protect against chemotherapy-induced neurogenic suppression and hippocampal neurotoxicity. Finally, we review pharmacological interventions that target the hippocampus and are designed to prevent or reduce the cognitive and neurotoxic side effects of chemotherapy.

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.

Functional roles and mechanisms of ginsenosides from Panax ginseng in atherosclerosis

Atherosclerosis (AS) is a leading cause of cardiovascular diseases (CVDs) and it results in a high rate of death worldwide, with an increased prevalence with age despite advances in lifestyle management and drug therapy. Atherosclerosis is a chronic progressive inflammatory process, and it mainly presents with lipid accumulation, foam cell proliferation, inflammatory response, atherosclerotic plaque formation and rupture, thrombosis, and vascular calcification. Therefore, there is a great need for reliable therapeutic drugs or remedies to cure or alleviate atherosclerosis and reduce the societal burden. Ginsenosides are natural steroid glycosides and triterpene saponins obtained mainly from the plant ginseng. Several recent studies have reported that ginsenosides have a variety of pharmacological activities against several diseases including inflammation, cancer and cardiovascular diseases. This review focuses on describing the different pharmacological functions and underlying mechanisms of various active ginsenosides (Rb1,-Rd, -F, -Rg1, -Rg2, and -Rg3, and compound K) for atherosclerosis, which could provide useful insights for developing novel and effective anti-cardiovascular drugs.

Ginsenoside Compound K: Insights into Recent Studies on Pharmacokinetics and Health-Promoting Activities

Ginseng (Panax ginseng) is an herb popular for its medicinal and health properties. Compound K (CK) is a secondary ginsenoside biotransformed from major ginsenosides. Compound K is more bioavailable and soluble than its parent ginsenosides and hence of immense importance. The review summarizes health-promoting in vitro and in vivo studies of CK between 2015 and 2020, including hepatoprotective, anti-inflammatory, anti-atherosclerosis, anti-diabetic, anti-cancer, neuroprotective, anti-aging/skin protective, and others. Clinical trial data are minimal and are primarily based on CK-rich fermented ginseng. Besides, numerous preclinical and clinical studies indicating the pharmacokinetic behavior of CK, its parent compound (Rb1), and processed ginseng extracts are also summarized. With the limited evidence available from animal and clinical studies, it can be stated that CK is safe and well-tolerated. However, lower water solubility, membrane permeability, and efflux significantly diminish the efficacy of CK and restrict its clinical application. We found that the use of nanocarriers and cyclodextrin for CK delivery could overcome these limitations as well as improve the health benefits associated with them. However, these derivatives have not been clinically evaluated, thus requiring a safety assessment for human therapy application. Future studies should be aimed at investigating clinical evidence of CK.

The Advances on the Protective Effects of Ginsenosides on Myocardial Ischemia and Ischemia-Reperfusion Injury

Ginseng is a traditional medicine with a complex chemical composition, wide bioactivity and unique pharmacological action. Many studies have confirmed that ginsenosides are the active ingredients of ginseng, and ginsenosides have always been the focus of different researchers. With the development of modern separation and analysis technology, more than 150 kinds of ginsenosides have been isolated. The ginsenosides Rb1, Rb2, Rc, Rg1 and Re account for more than 80% of total ginsenosides, and other saponins, such as Rd, Rg3 and Rh2, which are minor constituents, accounting for only a small portion of the total amount. In recent years, ginsenosides have been found to possess strong pharmacological activities, such as antioxidation, clearing of oxygen free radicals, reducing calcium overload and anti-apoptosis. Ginsenosides play a protective role in ischemia-reperfusion injury. This paper reviews the protective effects of ginsenosides on myocardial ischemia and ischemiareperfusion injury.

Functional Regulation of Ginsenosides on Myeloid Immunosuppressive Cells in the Tumor Microenvironment

Ginsenosides, the key components isolated from ginseng, have been extensively studied in antitumor treatment. Numerous studies have shown that ginsenosides have direct function in tumor cells through the induction of cancer cell apoptosis and the inhibition of cancer cell growth and enhance the antitumor immunity through the activation of cytotoxic T lymphocytes and natural killer cells. However, little is known about the function of ginsenosides on myeloid immunosuppressive cells including dendritic cells in tumor, tumor-associated macrophages, and myeloid-derived suppressor cells in the tumor microenvironments. Those myeloid immunosuppressive cells play important roles in promoting tumor angiogenesis, invasion, and metastasis. In the review, we summarize the regulatory functions of ginsenosides on myeloid immunosuppressive cells in tumor microenvironment, providing the novel therapeutic methods for clinical cancer treatment.

Compound K attenuated hepatectomy-induced post-operative cognitive dysfunction in aged mice via LXRα activation

AIMS

Post-operative cognitive dysfunction (POCD) occurs after major surgery in elderly patients and affects the quality of patients' lives. The present study aims to explore the protective effects and possible mechanisms of compound K in old mice with POCD caused by partial hepatectomy.

METHODS

Sixteen month-old mice were administered different doses of compound K from the 8th day to 14th day after partial hepatectomy. Cognitive function was subsequently measured with a Morris water-maze (MWM) test. Serum inflammatory cytokine levels were measured by magnetic bead panel; levels of cytokines in the hippocampus were analyzed using immunohistochemistry and immunoblotting. The mRNA levels of target genes were measured using real-time PCR.

RESULTS

Compared with the model group, MWM scores were significantly attenuated at days 10 and 14 post-surgery in mice receiving compound K (10, 30 mg/kg) in a dose-dependent manner. Both systemic and local cytokine levels were reduced after treatment of compound K. The alterations in serum lipids were independent of the attenuation of POCD syndrome. An inhibitor of liver X receptor-α (LXRα), GGPP, reversed the effects of compound K.

CONCLUSIONS

The results provide evidence for an alleviation of POCD by compound K via local inflammation inhibition in hippocampus tissue; furthermore, the data suggests the mechanism involves the LXRα pathway. The present study supports further evaluation of compound K as a potential effective modulator for POCD.