Natural Steroidal Saponin Research Articles

Diosgenin Attenuates Lipopolysaccharide-Induced Parkinson's Disease by Inhibiting the TLR/NF-κB Pathway.

Parkinson's disease (PD) is a neurodegenerative disease characterized by loss of dopaminergic neurons in the substantia nigra. Diosgenin is a natural steroid saponin which was shown to play a beneficial role in Alzheimer's disease. This study sought to investigate the potential effect of diosgenin on a rat model of PD. Sprague Dawley rats were subjected to intra-striatal injection of lipopolysaccharide (LPS) and treated with diosgenin. Stepping, Whisker, and Cylinder tests were carried out to determine the motor function, and the expression of tyrosine hydroxylase was detected by immunohistochemistry. The levels of multiple proinflammatory cytokines, oxidative stress related factors and proteins involved in Toll-like receptor (TLR)/nuclear factor kappa B (NF-κB) pathway were measured. The synergistic effect of environment enrichment on diosgenin was also investigated. Intra-striatal injection of LPS caused motor deficits in rats, induced inflammatory response and oxidative stress response, and activated the TLR/NF-κB pathway both in vivo and in vitro. Diosgenin could attenuate the LPS-induced alterations. Enriched environment enhanced the effect of diosgenin to ameliorate the LPS-induced motor deficits in rats and decreased the protein levels of TLR2, TLR4, and nuclear NF-κB in diosgenin treated PD rats. Diosgenin had a beneficial effect in LPS-induced rat PD models, by suppressing the TLR/NF-κB signaling pathway. Environmental enrichment could play a synergistic effect with diosgenin, by enhancing the inhibitory effect of diosgenin on the TLR/ NF-κB signaling pathway.

Dioscin suppresses the viability of ovarian cancer cells by regulating the VEGFR2 and PI3K/AKT/MAPK signaling pathways.

Diosgenin is a natural steroidal saponin that is extracted from a range of sources, including from fenugreek. It is a critical raw material in the synthesis of steroid hormone drugs, exhibiting antitumor, anti-inflammatory, antioxidation and a number of other significant pharmacological actions, possessing high pharmaceutical value. The aim of the present study was to investigate the effects of dioscin suppression on ovarian cancer cell growth and the mechanism of apoptosis induction by dioscin in ovarian cancer cells. The results of the present study demonstrated that dioscin decreased viability and induced apoptosis in SKOV3 human ovarian cancer cells in a dose-dependent manner. Dioscin significantly increased caspase-3 and caspase-9 activity, and increased the protein expression of Bax and cleaved poly(ADP-ribose) polymerase in SKOV3 cells. In addition, dioscin significantly suppressed vascular endothelial growth factor receptor (VEGFR)2, phosphoinositide 3-kinase (PI3K), phosphorylated AKT and phosphorylated p38 mitogen-activated protein kinase (MAPK) protein expression in SKOV3 cells. Taken together, to the best of our knowledge, the present study demonstrated for the first time that dioscin suppresses cell viability in ovarian cancer cells by regulating the VEGFR2 and PI3K/AKT/MAPK signaling pathways.

Dioscin prevents LPS‑induced acute lung injury through inhibiting the TLR4/MyD88 signaling pathway via upregulation of HSP70.

Dioscin, as a type of important natural steroidal saponin, has widespread sources, primarily from the fenugreek plant, which is an important raw material in the production of synthetic steroid hormone drugs. Dioscin has anti‑tumor, anti‑inflammatory, antioxidant and other significant pharmacological effects with high medicinal value. The present work aimed to research the protective effect and underlying mechanisms by which dioscin prevents acute lung injury (ALI). Mice were injected with 5mg/kg LPS to induce lung injury. Mice were treated with dioscin (20, 40 and 60mg/kg) following LPS‑induced lung injury. Treatment with dioscin significantly decreased total number of alveolar macrophages, water content of lung and total protein concentration in ALI mice. Dioscin treatment significantly suppressed the ALI‑induced interleukin (IL)‑1B, IL‑6, tumor necrosis factor‑α, nuclear factor (NF)‑κB, myeloperoxidase, interferon‑γ and intercellular adhesion molecule‑1 activities in ALI rats. Following this, the authors identified that dioscin significantly also suppressed cyclooxygenase‑2, heat shock protein 70, Toll‑like receptor 4, MyD88 and NF‑κB protein expression in ALI rats. The results suggested that dioscin prevents LPS‑induced ALI through inhibiting the TLR4/MyD88 signaling pathway via upregulation of HSP70.

Dioscin inhibits colon cancer cells' growth by reactive oxygen species-mediated mitochondrial dysfunction and p38 and JNK pathways.

Dioscin is a natural steroid saponin derived from several plants that shows potent anticancer effects against a variety of cancer cells. Here, we investigated the antitumor effect of dioscin against human colon cancer cells and evaluated the molecular mechanism involved in this process. The cell cytotoxicity was studied by the MTT assay and BrdU incorporation. The proapoptotic mechanism of dioscin was characterized by flow cytometry analysis. A western blot and an immunofluorescence staining were used to investigate how dioscin induces apoptosis in vitro. In our study, dioscin could significantly inhibit the growth of colon cancer cells in a time-dependent and dose-dependent manner. Dioscin induces apoptosis and reactive oxygen species (ROS) generation, promoting the disruption of mitochondrial membrane potential, Bax translocation to the mitochondria, cytochrome C release to cytosol, activations of caspase-9/3, PARP cleavage, and subsequent apoptosis. Dioscin-induced apoptosis was accompanied by sustained phosphorylation of JNK, p38-MAPK. N-acetyl-L-cysteine, a scavenger of ROS, significantly reversed dioscin-induced cell death and activation of JNK and p38. Collectively, the data indicate that the induction of apoptosis by dioscin is mediated through ROS proteins, which are critical upstream signals for JNK/p38-MAPK activation.

Dioscin Promotes Proliferation of Pancreatic Beta Cells via Wnt/β-Catenin Signaling Pathways.

Dysfunction of pancreatic beta cells is related with type 2 diabetes mellitus. Dioscin, a natural steroid saponin, has many pharmacological effects. The aim of this study was to investigate the effects of dioscin on apoptosis of pancreatic beta cells induced by high glucose. Pancreatic cell line RNAKT-15 was treated with 20 mM glucose with or without different concentrations of dioscin and viability and apoptosis of cells were measured. Western blot assay was used to measure the expression levels of some proteins such as phosphorylated glycogen synthase kinase 3β (GSK-3β) and β-catenin. Enzymelinked immunosorbent assay (ELISA) was used to detect the pro-inflammatory cytokines. High-glucose could significantly increase cell RNAKT-15 apoptosis and reduce cell viability (p < 0.01). Dioscin could improve the cell degeneration (p < 0.05). The results demonstrated that high-glucose could increase the proinflammatory cytokines, such as tumor necrosis factor α (TNF-α), interferon-γ (INF-γ), and transforming growth factor-β (TGF-β), while these effects were reduced when treated with dioscin (p < 0.05). Western blot results demonstrated that high-glucose affects p-GSK 3β and β-catenin expression levels (p < 0.01) and dioscin could significantly reduce these two protein levels (p < 0.05). The effects of dioscin against high-glucose induced apoptosis of pancreatic cells may occur through the Wnt signaling pathway. High-glucose led to increased pancreatic cell apoptosis and dioscin could attenuate these impairments. These findings highlight an important role of dioscin in the treatment potential of type 2 diabetes mellitus (T2DM).

Dioscin inhibits ischemic stroke‑induced inflammation through inhibition of the TLR4/MyD88/NF‑κB signaling pathway in a rat model.

Diosgenin, as an essential natural steroidal saponin, can be extracted from numerous sources, primarily from fenugreek. It is an important raw material for the synthesis of steroid hormone drugs. It exhibits antitumor, anti‑inflammatory, antioxidation and several other significant pharmacologic actions, and is of high pharmaceutical value. In the present study, the activities and underlying mechanisms of dioscin in the inhibition of ischemic stroke in rats were investigated. Inflammatory responses wer analyzed using ELISA kits and caspase‑3 and caspase‑9 activity was analyzed using Caspase‑3 and caspase‑9 activity kits. Western blot analysis was used to measure Toll‑like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), nuclear factor‑κB (NF‑κB), transforming growth factor‑β1 (TGF‑β1), high‑mobility group protein 1 (HMGB‑1), interleukin‑1 receptor‑associated kinase 1 (IRAK1), and tumor necrosis factor receptor‑associated factor 6 (TRAF6) protein expression. Dioscin inhibited infarct volume and neurological scores in the ischemic stroke rat model. The results demonstrated that dioscin reduced inflammatory responses, and suppressed the expression of TLR4, MyD88, NF‑κB, TGF‑β1, HMGB‑1, IRAK1, and TRAF6 in the rat ischemic stroke model. Taken together, these findings suggested that dioscin inhibited ischemic stroke‑induced inflammation through inhibition of the TLR4/MyD88/NF‑kB‑induced inflammation the rat model, which provided novel insights into the mechanisms underlying the effect of dioscin as an anti‑inflammatory candidate for the treatment of ischemic stroke in in the future.

Abstract 4105: Diosgenin and temozolamide: A potential combinatorial chemotherapy to overcome temozolamide resistance in glioblastoma multiforme

Abstract Introduction: Glioblastoma multiforme (GBM) accounts for the most aggressive form of tumor showing poor prognosis. Prevailing treatment modality includes chemotherapy with temozolomide (TMZ) concomitant with surgical resection and/or irradiation. However, it has been observed that a number of patients are developing resistance to TMZ owing to its high dosage regimen. The aim of this study is to examine the effects of diosgenin (DSG), a natural steroidal saponin obtained from fenugreek, in combination with TMZ in human GBM cells and TMZ resistant GBM cells. Methodology: The potential of combinatorial chemotherapy for overcoming TMZ resistance was evaluated through development of TMZ resistant GBM clones. These clones were generated by treatment of GBM cells with sub-lethal dose of TMZ over several cycles. Cellular effects were studied by viability assay, flow cytometry and wound healing assay on both single and combined drug treated GBM cells and TMZ resistant cells, respectively. The morphological study and cellular uptake in combined or individual drug treated cells was assessed by microscopy and immunofluorescence staining. The time dependant effect of drugs on invasive and migratory potential of GBM cells and TMZ resistant cells was analysed through zymography for matrix metalloproteinases (MMPs) activity and western blot for apoptotic proteins, epithelial and mesenchymal (EMT) markers, MMPs and VEGF expression. Further, the drug induced apoptosis was also assessed through chromatin condensation and DNA laddering assay. Results: Our investigation shows that co-administration of DSG and TMZ resulted in a substantial increase in GBM cell apoptosis and marked inhibition of cell growth in vitro. Anti-angiogenic and anti-invasive potential of DSG and TMZ were assessed through in vitro studies. At molecular level, DSG and TMZ synergistically lower XIAP expression and cleavage of intracellular death substrates such as PARP thereby shifting the balance from survival to apoptosis as indicated by the rise in the sub-G1 cell population. This combination also alters EMT markers, downregulates the expression of Bcl-xL, Bcl-2, Mcl1, MMPs and VEGF and induces expression of Bax, AIF, cytochrome C. Conclusion: The results suggested that DSG in combination with TMZ reduced the dose of TMZ, when administered singly, and also inhibited the migration and invasion of GBM and TMZ resistant cells. It induced apoptosis and altered the expression of EMT markers. These findings reveal a new therapeutic potential for overcoming TMZ resistance in GBM therapy. This novel modality may be a promising tool for GBM treatment. Citation Format: Y Rajesh, Angana Biswas, Subhayan Das, Mahitosh Mandal. Diosgenin and temozolamide: A potential combinatorial chemotherapy to overcome temozolamide resistance in glioblastoma multiforme [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4105. doi:10.1158/1538-7445.AM2017-4105

Protective Effects of Dioscin against Lipopolysaccharide-Induced Acute Lung Injury through Inhibition of Oxidative Stress and Inflammation

The protective effects of dioscin, a natural steroidal saponin from some medicinal plants including Dioscorea nipponica Makino, against lipopolysaccharide (LPS)- induced acute liver and renal damages have been reported in our previous works. However, the actions of dioscin against LPS-induced acute lung injury (ALI) is still unknown. In the present study, we investigated the effects and mechanisms of dioscin against LPS-induced ALI in vitro and in vivo. The results showed that dioscin obviously inhibited cell proliferation and markedly decreased reactive oxidative species level in 16HBE cells treated by LPS. In addition, dioscin significantly protected LPS-induced histological changes, inhibited the infiltration of inflammatory cells, as well as decreased the levels of MDA, SOD, NO and iNOS in mice and rats (p < 0.05). Mechanistically, dioscin significantly decreased the protein levels of TLR4, MyD88, TRAF6, TKB1, TRAF3, phosphorylation levels of PI3K, Akt, IκBα, NF-κB, and the mRNA levels of IL-1β, IL-6, and TNF-α against oxidative stress and inflammation (p < 0.05). Dioscin significantly reduced the overexpression of TLR4, and obviously down-regulated the levels of MyD88, TRAF6, TKB1, TRAF3, p-PI3K, p-Akt, p-IκBα, and p-NF-κB. These findings provide new perspectives for the study of ALI. Dioscin has protective effects on LPS-induced ALI via adjusting TLR4/MyD88- mediated oxidative stress and inflammation, which should be a potent drug in the treatment of ALI.

Dioscin relieves endotoxemia induced acute neuro-inflammation and protect neurogenesis via improving 5-HT metabolism

Sepsis, in addition to causing fatality, is an independent risk factor for cognitive impairment among sepsis survivors. The pathologic mechanism of endotoxemia induced acute neuro-inflammation still has not been fully understood. For the first time, we found the disruption of neurotransmitters 5-HT, impaired neurogenesis and activation of astrocytes coupled with concomitant neuro-inflammation were the potential pathogenesis of endotoxemia induced acute neuro-inflammation in sepsis survivors. In addition, dioscin a natural steroidal saponin isolated from Chinese medicinal herbs, enhanced the serotonergic system and produced anti-depressant effect by enhancing 5-HT levels in hippocampus. What is more, this finding was verified by metabolic analyses of hippocampus, indicating 5-HT related metabolic pathway was involved in the pathogenesis of endotoxemia induced acute neuro-inflammation. Moreover, neuro-inflammation and neurogenesis within hippocampus were indexed using quantitative immunofluorescence analysis of GFAP DCX and Ki67, as well as real-time RT-PCR analysis of some gene expression levels in hippocampus. Our in vivo and in vitro studies show dioscin protects hippocampus from endotoxemia induced cascade neuro-inflammation through neurotransmitter 5-HT and HMGB-1/TLR4 signaling pathway, which accounts for the dioscin therapeutic effect in behavioral tests. Therefore, the current findings suggest that dioscin could be a potential approach for the therapy of endotoxemia induced acute neuro-inflammation.

Diosgenin ameliorates development of neuropathic pain in diabetic rats: Involvement of oxidative stress and inflammation.

Neuropathic pain is one of the prevalent complications of diabetes mellitus (DM). Oxidative stress and inflammation are the principal determinants for its development. Pharmacological interventions targeted at alleviating or suppressing these pathways are clinically promising. Diosgenin is a natural steroidal saponin with anti-diabetic and multiple protective properties. This study was designed to study the efficacy of chronic diosgenin administration on alleviation of hyperalgesia in streptozotocin (STZ)-diabetic rats. Rats were allocated to control, diosgenin-treated control, diabetic, and diosgenin-treated-diabetic groups. Diosgenin was daily administered at a dose of 40mg/kg for 5 weeks. Nociceptive behavior was assessed using paw pressure, hot tail immersion, and formalin tests. In addition, some oxidative stress and inflammation markers were measured. Diosgenin treatment of diabetic group increased mechanical and thermal nociceptive thresholds and lowered pain score at late phase of the formalin test, but not at its early phase. Biochemical analysis of serum samples and sciatic nerve and dorsal root ganglion (DRG) lysates showed restoration or improvement of nuclear factor-<kappa>B (NF-κB), malondialdehyde (MDA) level, activity of superoxide dismutase (SOD), catalase, tumor necrosis factor α (TNFα), and interleukin 1β (IL-1β) upon diosgenin treatment of diabetic rats. The obtained results exhibited antinociceptive potential of diosgenin in diabetic rats through lowering oxidative stress and inflammation and improving antioxidant defense system. This suggests possible therapeutic potential of diosgenin for alleviation and management of diabetic neuropathic pain.

Metabolic profile and pharmacokinetics of polyphyllin I, an anticancer candidate, in rats by UPLC-QTOF-MS/MS and LC-TQ-MS/MS.

Polyphyllin I (PPI), a natural steroidal saponin originating from rihzome of Paris polyphylla, is a potential anticancer candidate. Previous pharmacokinetics study showed that the oral bioavailability of PPI was very low, which suggested that certain amount of PPI might be metabolized in vivo. However, to date, information regarding the final metabolic fates of PPI is very limited. In this study, metabolites of PPI and their pharmacokinetics in rats were investigated using UPLC-QTOF-MS/MS and LC-TQ-MS/MS. A total of seven putative metabolites, including six phase I and one phase II metabolites, were detected and identified with three exact structures by comparison with authentic standards for the first time. Oxidation, deglycosylation and glucuronidation were found to be the major metabolic processes of the compound in rats. The pharmacokinetics of prosapogenin A, trillin and diosgenin, three deglycosylation metabolites of PPI with definite anticancer effects, were further studied, which suggested that the metabolites underwent a prolonged absorption and slower elimination after intragastric administration of PPI at the dose of 500 mg/kg. This study provides valuable and new information on the metabolic fate of PPI, which will be helpful in further understanding its mechanism of action.

Dioscin suppresses hepatocellular carcinoma tumor growth by inducing apoptosis and regulation of TP53, BAX, BCL2 and cleaved CASP3

BackgroundHepatocellular carcinoma (HCC) is the most commonly diagnosed malignancy of the liver, occurs frequently in the setting of chronic liver injury. Although multiple therapeutic approaches are available, the prognosis of patients with HCC remains poor. Dioscin is a natural steroid saponin that presents in various plants. The anti-cancer and anti-fibrotic effects have been extensively reported. However, the effect of dioscin on HCC remains unclear. We aimed to investigate the anti-HCC properties of dioscin in vitro and in vivo. MethodsMTT (3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyl-tetrazolium bromide) assay was used to analyze the growth inhibition activity of Dioscin in human cell lines, Bel-7402, HepG2, Lovo, and EAhy926. Antitumor activity through induction of apoptosis was evaluated by flow cytometry using Annexin-V and propidium iodide (PI) staining, laser scanning confocal microscopy (LSCM) analysis with Hochest33342 and PI labeling, and DNA fragmentation analysis. The expression of apoptosis-related proteins tumor protein p53 (TP53), BCL2-associated X protein (BAX), B-Cell CLL/Lymphoma 2 (BCL2) and Caspase 3 (CASP3) was measured by Western blot. Nude mice bearing Bel-7402 were administered intraperitoneally at different doses of dioscin and 5-FU (5-Fluorouracil) treatment was used as a control. Tumor volume and tumor weight of each mouse were then measured. ResultsWe demonstrated that Dioscin inhibited proliferation of HCC cell lines in a dose-dependent manner. Dioscin also significantly induced morphological changes during death by apoptosis and increased DNA damage of Bel-7402 cells. Moreover, we demonstrated that Dioscin displayed anticancer activity via up-regulating expression of TP53, BAX and CASP3 protein, as well as down-regulating BCL2 in Bel-7402 cells. Notably, the in vivo anticancer activity of Dioscin was further assessed and achieved greater inhibition efficiency at the concentration increased to 24mg/kg/day than 5-FU at dose of 10mg/kg/day in nude mice bearing Bel-7402 cells. ConclusionsDioscin inhibited tumor growth via inducing apoptosis, which was accompanied by altered expression of apoptotic pathway proteins, such as TP53, BAX, BCL2 and CASP3. Our findings indicate that further evaluation of dioscin as a novel therapeutic approach for HCC is warranted.

Ginsenoside Rg1 reverses stress-induced depression-like behaviours and brain-derived neurotrophic factor expression within the prefrontal cortex.

Depression is a major neuropsychiatric disorder that exerts deleterious effects upon public health. However, the neuronal mechanisms of depression remain largely uncharacterized, which has retarded the identification and development of effective therapeutic tools for the treatment of this disorder. The aim of this study was to explore the neuronal mechanisms underlying the protective effects of ginsenoside Rg1, a natural steroidal saponin found in ginseng, against chronic stress-induced depression.The results showed that chronic administration of ginsenoside Rg1 (40mg/kg, i.p., 5weeks) significantly ameliorated depression-like behaviours in rats as assessed in the sucrose preference and forced swim tests. Furthermore, chronic stress decreased the phosphorylation levels of the extracellular signal-regulated kinase and cAMP-response element-binding protein in the prefrontal cortex as well as producing a reduction of brain-derived neurotrophic factor expression. Of particular importance, all reductions in these parameters were significantly reversed by pre-treatment with ginsenoside Rg1. Taken together, the results of the present study suggest that the antidepressant-like effect of ginsenoside Rg1 might be mediated, at least in part, by activating the cAMP-response element-binding protein-brain-derived neurotrophic factor system within the prefrontal cortex. These findings not only reveal some of the underlying neuronal mechanisms of depression, but also the therapeutic potential of ginsenoside Rg1 as a preventive agent in the treatment of depression.

Diosgenin Mitigates Streptozotocin Diabetes-induced Vascular Dysfunction of the Rat Aorta: The Involved Mechanisms.

Chronic diabetes mellitus finally leads to serious vascular dysfunction. Diosgenin is a natural steroidal saponin with potential cardiovascular protective effect. In this study, the protective effect of diosgenin was checked on the aorta from streptozotocin-induced diabetic rats. Diabetic rats received diosgenin (40 mg·kg·d) for 7 weeks starting 1 week after intraperitoneal injection of streptozotocin (60 mg/kg). Aortic reactivity of endothelium-intact and -denuded rings to potassium chloride, phenylephrine, acetylcholine, and isosorbide dinitrate were measured and some involved mechanisms were explored. The results showed that diosgenin has a hypoglycemic effect and attenuates maximum contractile response of endothelium-intact and -denuded rings to PE. In addition, endothelium-dependent relaxation to acetylcholine was greater in diosgenin-treated diabetics with no significant change for endothelium-independent relaxation to isosorbide dinitrate and addition of N(G)-nitro-L-arginine methyl ester, as a nitric oxide synthase inhibitor eliminated this beneficial effect. Furthermore, diosgenin significantly attenuated aortic DNA fragmentation as an index of apoptosis and malondialdehyde content, lowered the aortic expression of angiotensin converting enzyme and transcription factor nuclear factor-κB and raised expression of endothelial nitric oxide synthase with no significant effect on the activity of superoxide dismutase. Taken together, our study provides insight into the mechanisms underlying the beneficial effect of diosgenin as a potential therapeutic agent to mitigate vascular dysfunction in diabetes mellitus.

Dioscin-induced apoptosis of human LNCaP prostate carcinoma cells through activation of caspase-3 and modulation of Bcl-2 protein family

Dioscin is a natural steroid saponin derived from several plants, showing potent anti-cancer effect against a variety of tumor cell lines. In the present study, we investigated the anti-cancer activity of dioscin against human LNCaP cells, and evaluated the possible mechanism involved in its antineoplastic action. It was found that dioscin (1, 2 and 4 μmol/L) could significantly inhibit the viability of LNCaP cells in a time- and concentration-dependent manner. Flow cytometry revealed that the apoptosis rate was increased after treatment of LNCaP cells with dioscin for 24 h, indicating that apoptosis was an important mechanism by which dioscin inhibited cancer. Western blotting was employed to detect the expression of caspase-3, Bcl-2 and Bax in LNCaP cells. The expression of cleaved caspase-3 was significantly increased, and meanwhile procaspase-3 was markedly decreased. The expression of anti-apoptotic protein Bcl-2 was down-regulated, whereas the pro-apoptotic protein Bax was up-regulated. Moreover, the Bcl-2/Bax ratio was drastically decreased. These results suggested that dioscin possessed potential anti-tumor activity in human LNCaP cells through the apoptosis pathway, which might be associated with caspase-3 and Bcl-2 protein family.

Dioscin, a natural steroid saponin, induces apoptosis and DNA damage through reactive oxygen species: A potential new drug for treatment of glioblastoma multiforme

Dioscin, a natural product obtained from medicinal plants shows lipid-lowering, anti-cancer and hepatoprotective effects. However, the effect of it on glioblastoma is unclear. In this study, dioscin significantly inhibited proliferation of C6 glioma cells and caused reactive oxygen species (ROS) generation and Ca²⁺ release. ROS accumulation affected levels of malondialdehyde, nitric oxide, glutathione disulfide and glutathione, and caused cell apoptosis. In addition, ROS generation caused mitochondrial damage including structural changes, increased mitochondrial permeability transition and decreased mitochondria membrane potential, which led to the release of cytochrome C, nuclear translation of programmed cell death-5 and increased activities of caspase-3,9. Simultaneously, dioscin down-regulated protein expression of Bcl-2, Bcl-xl, up-regulated expression of Bak, Bax, Bid and cleaved poly (ADP-ribose) polymerase. Also, oxygen stress induced S-phase arrest of cancer cells by way of regulating expression of DNA Topo I, p53, CDK2 and Cyclin A and caused DNA damage. In a rat allograft model, dioscin significantly inhibited tumor size and extended the life cycle of the rats. In conclusion, dioscin shows noteworthy anti-cancer activity on glioblastoma cells by promoting ROS accumulation, inducing DNA damage and activating mitochondrial signal pathways. Ultimately, we believe dioscin has promise as a new therapy for the treatment of glioblastoma.

Anti-cancer effects of dioscin on three kinds of human lung cancer cell lines through inducing DNA damage and activating mitochondrial signal pathway

Dioscin, a natural steroid saponin, has been widely investigated. However, its anti-cancer activities on human lung cancer cells are still unknown. In the present paper, the inhibitory effects of dioscin were investigated, and the results showed that dioscin inhibited the proliferation of human A549, NCI-H446 and NCI-H460 cancer cells. DNA damage and cell apoptosis in dioscin-treated cells were found through single cell gel electrophoresis and in situ terminal deoxynucleotidyl transferase dUTP nick-end labeling assays. Furthermore, dioscin caused mitochondrial structure changes and blocked cell cycle at S phase based on transmission electron microscope and flow cytometry analysis. In addition, dioscin treatment caused the release of cytochrome c from mitochondria into cytosol. The activities of Caspase-3 and -9 in dioscin-treated groups were significantly increased compared with control group. Western blotting analysis showed that dioscin significantly down-regulated the expressions of Bcl-2 and Bcl-xl, and up-regulated the expressions of Bax, Bak and Bid. Our results indicate that dioscin has anticancer activities against human lung cancer cells through inducing cell cycle arrest, DNA damage and activating mitochondrial signal pathway.

Dioscin, a natural steroid saponin, shows remarkable protective effect against acetaminophen-induced liver damage in vitro and in vivo

The aim of the study was to investigate the protective effect of dioscin against APAP-induced hepatotoxicity. In the in vitro tests, HepG2 cells were given APAP pretreatment with or without dioscin. In the in vivo experiments, mice were orally administrated dioscin for five days and then given APAP. Some biochemical and morphology parameters were assayed and the possible mechanism was investigated. Dioscin improved AST release, mitochondrial dysfunction, apoptosis and necrosis of HepG2 cells induced by APAP. Following administration of dioscin, APAP-induced hepatotoxicity in mice was significantly attenuated. Furthermore, the liver cell apoptosis and necrosis, and hepatic mitochondrial edema were also prevented. Fifteen differentially expressed proteins were found by using proteomics, and six of them, Suox, Krt18, Rgn, Prdx1, MDH and PNP were validated. These proteins may be involved in the hepatoprotective effect of dioscin and might cooperate with the levels of Ca2+ in mitochondria, decreased expression of ATP2A2, and decreased mitochondrial cardiolipin. In addition, dioscin inhibited APAP-induced activation and expression of CYP2E1, up-regulated the expression of Bcl-2 and Bid, and inhibited the expression of Bax, Bak and p53. Dioscin showed a remarkable protective effect against APAP-induced hepatotoxicity by adjusting mitochondrial function. These results indicated that dioscin has the capability on the treatment of liver injury.

A 90-day subchronic toxicological assessment of dioscin, a natural steroid saponin, in Sprague–Dawley rats

Dioscin is the major active compound in many traditional Chinese medicines (TCMs), while safety evaluation of this natural product has not yet been investigated. Therefore, the aim of this study was to evaluate the 90-day subchronic toxicity of dioscin in rats. The rats were divided into four groups and dioscin was administered orally at doses of 0, 75, 150 and 300mg/kg/day, respectively. The toxicity of dioscin was evaluated based on clinical observations, ophthalmic examination, body weight, food and water consumption, urinalysis, hematology, clinical biochemistry and pathology. The results showed that dioscin had no subchronic toxicity in female rats and had slight subchronic toxicity in male rats. However, male rats in the 300mg/kg/day group showed slight gastro-intestinal tract distension during the treatment period and hemolytic anemia in the hematology assessment. Compared with the control group, body weight gain was significantly decreased in male rats. Other significant changes were not associated with dioscin in the male and female groups. In conclusion, the no-observed-adverse-effect level (NOAEL) and the lowest-observed-adverse-effect level (LOAEL) of dioscin are estimated to be 300mg/kg/day for female and male rats, respectively. Our work provides useful data for further research and new drug exploration of dioscin.

Diosgenin, a Steroidal Saponin, Exhibits Anticancer Activity by Attenuating Lipid Peroxidation Via Enhancing Antioxidant Defense System During NMU-Induced Breast Carcinoma

Diosgenin, a natural steroidal saponin, has been reported to be found predominantly in fenugreek and has diverse biological properties. N-Methyl-N-nitrosourea (NMU) is a mammary gland-specific carcinogen that closely mimics human breast cancer in many aspects. The aim of this study was to investigate the anticarcinogenic property of diosgenin with reference to lipid peroxidation, status of antioxidants, and activities of marker enzymes against NMU-induced experimental mammary carcinogenesis. Breast cancer was induced in female Sprague Dawley rats by an intraperitoneal administration of a single dose of NMU (a concentration of 50 mg/kg body weight) diluted in 0.9% saline, and the rats were treated with oral diosgenin, 20 mg/kg body weight, for 45 days. The results were interesting, and the diosgenin treatment remarkably downregulated the peroxidation reaction and marker enzymes and extraordinarily enhanced the indigenous antioxidant defense system. The factor for this remarkable restoration might be due to the effect of the intervention strategy on the downregulation of the peroxidation reaction through the strong antioxidant nature, which ultimately reflected in the downregulation of marker enzyme activities. The histopathological study of breast and liver tissues inevitably confirms the biochemical changes. Thus, it can be concluded that diosgenin exhibits anticarcinogenic activity via reducing peroxidation reaction and marker enzymes through enhancing the intrinsic antioxidant defense system.