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

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 overcome TKI resistance in EGFR-mutated lung adenocarcinoma cells via down-regulation of tyrosine phosphatase SHP2 expression

Resistance to tyrosine kinase inhibitors (TKIs) results in tumor relapse and poor prognosis in patients with lung adenocarcinoma. TKI resistance caused by epidermal growth factor receptor (EGFR) mutations at T790M and c-Met amplification occurs through persistent activation of the MEK/ERK and PI3K/AKT signaling pathways. We therefore expected that dual inhibitors of both signaling pathways could overcome TKI resistance in lung adenocarcinoma. Here, dioscin was selected from a product library of Chinese naturally occurring compounds and overcame TKI resistance in EGFR-mutated lung adenocarcinoma cells. Mechanistically, dioscin may down-regulate the expression of SH2 domain-containing phosphatase-2 (SHP2) at the transcription level by increasing p53 binding to the SHP2 promoter due to reactive oxygen species (ROS). Simultaneous inhibition of MEK/ERK and PI3K/AKT activation via decreased SHP2 expression and its interaction with GAB1 may be responsible for dioscin-mediated TKI sensitivity. A higher unfavorable response to TKI therapy occurred more commonly in patients with high SHP2 mRNA expression than in patients with low SHP2 mRNA expression. Therefore, we suggest that dioscin may act as a dual inhibitor of the MEK/ERK and PI3K/AKT signaling pathways to overcome TKI resistance via dysregulation of SHP2 expression in lung adenocarcinoma.

Novel steroidal saponins from Dioscorea esculenta (Togedokoro)

Fifteen steroidal saponins 1-15, which include 4 furostanol glycosides 1-3 and 15, and 11 spirostanol glycosides 4-14, were isolated from the tubers and leaves of lesser yam (Dioscorea esculenta, Togedokoro). Their structures were identified by nuclear magnetic resonance and liquid chromatography mass spectroscopy. Four steroidal saponins 9, 11, 14, and 15 were found to be novel compounds.

Dioscin enhances osteoblastic cell differentiation and proliferation by inhibiting cell autophagy via the ASPP2/NF-κβ pathway

Dioscin, a typical steroid saponin, has been reported to promote osteoblastic cell differentiation. However, the underling mechanisms remain to be elucidated. In the present study, it was identified that dioscin (0.5, 1, 5, 10 and 25 µg/ml) promoted MC3T3‑E1 cell proliferation and differentiation in a dose‑dependent manner. Western blot analysis showed that dioscin regulated autophagy‑associated protein expression in MC3T3‑E1 cells; it promoted the expression of apoptosis stimulated protein of p53‑2 (ASPP2), and inhibited the expression of nuclear factor (NF)‑κβ and microtubule‑associated protein 1 light chain 3β, in a concentration‑dependent manner. Caffeic acid phenethyl ester (CAPE) was used to inhibit the activation of NF‑κB and examine the effect of the ASPP2/NF‑κβ pathway on osteoblastic cell differentiation, proliferation and autophagy. It was identified that CAPE reversed the regulation of dioscin on osteoblastic cell differentiation, proliferation and autophagy. In conclusion, the present study revealed that dioscin promoted osteoblast proliferation and differentiation by inhibiting cell autophagy via the ASPP2/NF‑κβ pathway. These results are the first, to the best of our knowledge, to reveal the involvement of autophagy in the effects of dioscin on the prevention and therapy of osteoporosis.

Dioscin induces prostate cancer cell apoptosis through activation of estrogen receptor-β

Recent researches have shown that estrogen receptor-β (ERβ) activator may be a potent anticancer agent for prostate cancer (PCa), and our previous study also indicated that dioscin can upregulate the expression of ERβ in MC3T3-E1 cell. In the present work, the activity and mechanism of dioscin, a natural product, against PCa were investigated. The results showed that dioscin markedly inhibited cell viability, colony formation, motility and induced apoptosis in PC3 cells. Moreover, dioscin disrupted the formation of PC3 cell-derived mammospheres and reduced aldehyde dehydrogenase (ALDH) level and the CD133⁺/CD44⁺ cells, indicating that dioscin had a potent inhibitory activity on prostate cancer stem cells (PCSCs). In vivo results also showed that dioscin significantly suppressed the tumor growth of PC3 cell xenografts in nude mice. Furthermore, mechanism investigation showed that dioscin markedly upregulated ERβ expression level, subsequently increased prolyl hydroxylase 2 level, decreased the levels of hypoxia-inducible factor-1α, vascular endothelial growth factor A and BMI-1, and thus induced cell apoptosis by regulating the expression levels of caspase-3 and Bcl-2 family proteins. In addition, transfection experiment of ERβ-siRNA further indicated that diosicn showed excellent activity against PCa in vitro and in vivo by increasing ERβ expression level. The co-immunoprecipitation (Co-IP) results further suggested that dioscin promoted the interaction of c-ABL and ERβ, but did not change c-ABL expression. Moreover, the molecular docking assay showed that dioscin processed powerful affinity toward to ERβ mainly through the strong hydrogen bonding and hydrophobic effects, and the actions of dioscin on ERβ activation and tumor cells inhibition were significantly weakened in the mutational (Phe-336, Phe-468) PC3 cells. Collectively, these findings proved that dioscin exerted efficient anti-PCa activity via activation of ERβ, which should be developed as an efficient candidate in clinical for treating this cancer in the future.

Cytotoxic effects of gastrodin extracted from the rhizome of Gastrodia elata Blume in glioblastoma cells, but not in normal astrocytes, via the induction of oxidative stress-associated apoptosis that involved cell cycle arrest and p53 activation

Researches have been conducted to explore the biological effect of gastrodin, a natural compound extracted from the rhizome of Gastrodia elata Blume, in different models. However, the effects of gastrodin on cytotoxicity, cell cycle distribution and oxidative stress in glia cells have not been explored. The aim of this study was to investigate the cytotoxic effect of gastrodin and its mechanisms in DBTRG-05MG human glioblastoma cells and CTX TNA2 rat astrocytes. In DBTRG-05MG cells but not in CTX TNA2 cells, gastrodin (20-30 μM) induced cytotoxicity, G2/M phase cell cycle arrest and apoptosis. Regarding oxidative stress, gastrodin (20-30 μM) elevated intracellular ROS levels but reduced GSH levels. Treatment with the antioxidant NAC (10 μM) partially reversed gastrodin-altered antioxidant enzymes levels. Furthermore, gastrodin induced mitochondria-associated apoptosis. The apoptotic effects evoked by gastrodin were partially inhibited by the antioxidant NAC and the pancaspase inhibitor Z-VAD-FMK. Together, in DBTRG-05MG cells, but not in CTX TNA2 cells, gastrodin activated ROS-associated mitochondrial apoptotic pathways that involved cell cycle arrest. These data provide insight into the molecular mechanisms governing the ability of gastrodin to induce cytotoxicity in human glioblastoma cells and further suggest that gastrodin is a new potential agent for the treatment of human gliblasoma.

Isolation and characterization of Cepa2, a natural alliospiroside A, from shallot (Allium cepa L. Aggregatum group) with anticancer activity

Exploration of new and promising anticancer compounds continues to be one of the main tasks of cancer research because of the drug resistance, high cytotoxicity and limitations of tumor selectivity. Natural products represent a better choice for cancer treatment in comparison with synthetic compounds because of their pharmacokinetic properties and lower side effects. In the current study, we isolated a steroidal saponin, named Cepa2, from the dry roots of shallot (Allium cepa L. Aggregatum group), and determined its structure by using two-dimensional nuclear manganic resonance (2D NMR). The ¹H NMR and ¹³C NMR data revealed that the newly isolated Cepa2 compound is identical to alliospiroside A (C₃₈H₆₀O₁₂) [(25S)-3β-hydroxyspirost-5-en-1β-yl-2-O-(6-deoxy-α-L-mannopyranosyl)-α-L-arabinopyranoside], whose anticancer activity remains elusive. Our in vitro examination of the cytotoxic activity of the identified Cepa2 against P3U1 myeloma cancer cell line showed its high efficiency as an anticancer with 91.13% reduction in P3U1 cell viability 12 h post-treatment. The reduction of cell viability was correlated with the increase in reactive oxygen species levels in Cepa2-treated P3U1 cells, as compared with untreated cells. Moreover, scanning electron microscope results demonstrated apoptosis of the Cepa2-treated P3U1 cells in a time course-dependent manner. The results of our study provide evidence for the anticancer properties of the natural Cepa2/alliospiroside A extracted from shallot plants, and a strong foundation for in-depth investigations to build theoretical bases for cell apoptosis and development of novel anticancer drugs.

Protective effect of naringin against the LPS-induced apoptosis of PC12 cells: Implications for the treatment of neurodegenerative disorders

Several studies have demonstrated that increased apoptosis plays an essential role in neurodegenerative disorders. It has been demonstrated that lipopolysaccharide (LPS) induces apoptosis largely through the production of intracellular reactive oxygen species (ROS) and inflammatory mediators. In this study, we investigated the potential protective mechanisms of naringin (Nar), a pummelo peel extract, on LPS-induced PC12 cell apoptosis. Nar pre-conditioning prior to stimulation with LPS for 18 h was a prerequisite for evaluating PC12 cell viability and the protective mechanisms of Nar. Nar significantly improved cell survival in a time- and concentration-dependent manner. On the one hand, Nar downregulated cytochrome P450 2E1 (CYP2E1), inhibited the release of ROS, mitigated the stimulation of oxidative stress, and rectified the antioxidant protein contents of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), superoxide dismutase (SOD)2 and glutathione synthetase (GSS). On the other hand, Nar down-regulated inflammatory gene and protein expression, including interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, HMGB1, high mobility group box 1 protein (HMGB1), cyclo-oxygenase-2 (COX-2), the Toll-like receptor 4 (TLR4)-myeloid differentiation factor 88 (MyD88)-TNF receptor-associated factor 6 (TRAF6) path way and downstream mitogen activated protein kinase (MAPK) phosphorylation, activator protein transcription factor-1 (AP-1) and nuclear factor (NF)-κB. Moroever, Nar markedly attenuated the cytochrome c shift from the mitochondria to the cytosol and regulated caspase-3-related protein expression. To the best of our knowledge, this is the first study to report the antioxidant, anti-inflammatory and anti-apoptotic effects of Nar in neuronal-like PC12 cells. These results suggest that Nar can be utilized as a potential drug for the treatment of neurodegenerative disorders.

Genotoxicity of Casiopeina III-Ea in mouse bone marrow cells

Casiopeina III-Ea® (Cas III-Ea®) is a chelated copper complex with antineoplastic activity that is capable of reducing tumor size and inducing antiproliferative and apoptotic effects. However, little is known about its in vivo genotoxic effects. Therefore, this study evaluated two cytogenetic and two proliferative parameters 24 h after the administration of Casiopeina III-Ea® to male CD-1 mice. Three doses of Cas III-Ea® were administered by intraperitoneal injections of 1.69, 3.39 and 6.76 mg/kg (corresponding to 1/8, 1/4 and 1/2 of LD₅₀, respectively). A reduction in the mitotic index (MI) and an increased numbers of cells with structural chromosomal aberrations (SCA) were detected. Additionally, a low but significant increase in the frequency of sister chromatid exchange (SCE) was observed at the highest dose. Changes in the DNA replication index (RI) were not observed. These results indicate that Casiopeina III-Ea® shows cytotoxic and clastogenic activity in bone marrow cells from treated mice.

Xiao Yao San against Corticosterone-Induced Stress Injury via Upregulating Glucocorticoid Receptor Reaction Element Transcriptional Activity

Previous studies have revealed that uncontrollable stress can impair the synaptic plasticity and firing property of hippocampal neurons, which influenced various hippocampal-dependent tasks including memory, cognition, behavior, and mood. In this work, we had investigated the effects and mechanisms of the Chinese herbal medicine Xiao Yao San (XYS) against corticosterone-induced stress injury in primary hippocampal neurons (PHN) cells. We found that XYS and RU38486 could increase cell viabilities and decrease cell apoptosis by MTT, immunofluorescence, and flow cytometry assays. In addition, we observed that XYS notably inhibited the nuclear translocation of GR and upregulated the mRNA and protein expressions levels of Caveolin-1, GR, BDNF, TrkB, and FKBP4. However, XYS downregulated the FKBP51 expressions. Furthermore, the results of the electrophoretic mobility shift assay (EMSA) and double luciferase reporter gene detection indicated that FKBP4 promotes the transcriptional activity of GR reaction element (GRE) by binding with GR, and FKBP51 processed the opposite action. The in vivo experiment also proved the functions of XYS. These results suggested that XYS showed an efficient neuroprotection against corticosterone-induced stress injury in PHN cells by upregulating GRE transcriptional activity, which should be developed as a potential candidate for treating stress injury in the future.

Saponins from Chinese Medicines as Anticancer Agents

Saponins are glycosides with triterpenoid or spirostane aglycones that demonstrate various pharmacological effects against mammalian diseases. To promote the research and development of anticancer agents from saponins, this review focuses on the anticancer properties of several typical naturally derived triterpenoid saponins (ginsenosides and saikosaponins) and steroid saponins (dioscin, polyphyllin, and timosaponin) isolated from Chinese medicines. These saponins exhibit in vitro and in vivo anticancer effects, such as anti-proliferation, anti-metastasis, anti-angiogenesis, anti-multidrug resistance, and autophagy regulation actions. In addition, related signaling pathways and target proteins involved in the anticancer effects of saponins are also summarized in this work.

Dioscin inhibits gastric tumor growth through regulating the expression level of lncRNA HOTAIR

Background

As a member of non-coding RNAs family, long non-coding RNAs’ functions in cancer needs to be further investigated. It has been indicated that the functions of Hox transcript antisense intergenic RNA (lncRNA: HOTAIR) include reprogramming chromatin organization and promoting tumor metastasis such as breast and colorectal tumor. The aim of this study is to investigate the functions of Hox in gastric cancer.

Methods

In the present study, the expression level of HOTAIR was determined by quantitative reverse transcription polymerase chain reaction (qRT-PCR), 20 gastric cancer tissues and 20 normal tissues was included. All clinical data were analyzed retrospectively. The CCK-8 and colony formation assay was used to identify if the knockdown of HOTAIR have an influence on gastric cancer cell lines.

Results

Compared with normal tissues, higher expression level of HOTAIR was found in gastric cancer tissues. Dioscin inhibits proliferation of the three gastric cancer cell lines and decrease HOTAIR expression.

Conclusions

The expression of HOTAIR is up regulated in gastric cancer and gastric cancer cell lines, dioscin inhibits the proliferation of three gastric cancer cell lines and the anti-tumor effect of dioscin may partly depend on the down regulation of HOTAIR.

Berberine enhances the anti‑tumor activity of tamoxifen in drug‑sensitive MCF‑7 and drug‑resistant MCF‑7/TAM cells

Berberine, an isoquinoline alkaloid, has been previously demonstrated to possess anti‑breast cancer properties. Tamoxifen is widely used in the prevention and treatment of estrogen receptor-positive breast cancer. Thus, the aim of the present study was to assess whether berberine enhanced the anticancer effect of tamoxifen, and the underlying mechanism involved in this combined effect in tamoxifen-sensitive (MCF-7) and tamoxifen-resistant (MCF-7/TAM) cells using MTS, flow cytometry and western blot assays. The results indicated that berberine demonstrated dose‑ and time‑dependent anti‑proliferative activity in MCF‑7 and MCF‑7/TAM cells. Furthermore, the combination of berberine and tamoxifen induced cell growth inhibition more effectively than tamoxifen alone. The present study also demonstrated that combinational treatment is more effective in inducing G1 phase arrest and activating apoptosis compared tamoxifen alone, which may be due to upregulation of P21 expression and downregulation of the B‑cell CLL/lymphoma 2(Bcl‑2)/Bcl‑2 associated X protein ratio. The results of the present study suggested that berberine may potentially be useful as an adjuvant agent in cancer chemotherapy to enhance the effect of tamoxifen, which will be useful for anti‑tumor therapy and further research.

Dioscin reduces ovariectomy-induced bone loss by enhancing osteoblastogenesis and inhibiting osteoclastogenesis

Our previous studies showed that dioscin can promote osteoblasts proliferation and differentiation in vitro, but its anti-osteoporosis effect in vivo and the underlying mechanisms remain unclear. In the present work, the results showed that dioscin significantly increased the viability of MC3T3-E1 cells, ALP level and alizarin red S staining area, markedly decreased the numbers of RANKL-induced TRAP-positive multinucleated cells and bone resorption pits formation, enhanced the levels of some osteogenic markers including COL1A2, ALP and OC, which suggested that dioscin clearly promoted osteoblasts proliferation and suppressed osteoclasts formation. In vivo experiments demonstrated that dioscin obviously reduced OVX-induced body weight increase, and improved the biochemical indexes including ALP, StrACP, OC, DPD/Cr, HOP/Cr, BMD, biomechanics and microarchitecture. Moreover, H&E, TB, TRAP staining, and fluorescent double labeling tests indicated that dioscin enhanced osteoblastogenesis and inhibited osteoclastogenesis. Further researches demonstrated that dioscin promoted osteoblastogenesis through up-regulating OPG/RANKL ratio, and inhibited osteoclastogenesis through down-regulating the levels of RANKL induced TRAF6 and the downstream signal molecules including MAPKs, Akt, NF-κB, AP-1, cathepsin K and NFATc1. In addition, dioscin also inhibited TLR4/MyD88 pathway to decrease the levels of TRAF6 and the related proteins. These findings provide new insights to elucidate the effects of dioscin against OVX-induced bone loss, which should be developed as a potential candidate for treating postmenopausal osteoporosis in the future.

Saponin 6 derived from Anemone taipaiensis induces U87 human malignant glioblastoma cell apoptosis via regulation of Fas and Bcl‑2 family proteins

Glioblastoma multiforme (GBM) is the most common and aggressive type of brain tumor, and is associated with a poor prognosis. Saponin 6, derived from Anemone taipaiensis, exerts potent cytotoxic effects against the human hepatocellular carcinoma HepG2 cell line and the human promyelocytic leukemia HL‑60 cell line; however, the effects of saponin 6 on glioblastoma remain unknown. The present study aimed to evaluate the effects of saponin 6 on human U87 malignant glioblastoma (U87 MG) cells. The current study revealed that saponin 6 induced U87 MG cell death in a dose‑ and time‑dependent manner, with a half maximal inhibitory concentration (IC50) value of 2.83 µM after treatment for 48 h. However, saponin 6 was needed to be used at a lesser potency in HT‑22 cells, with an IC50 value of 6.24 µM. Cell apoptosis was assessed by flow cytometry using Annexin V‑fluorescein isothiocyanate/propidium iodide double staining. DNA fragmentation and alterations in nuclear morphology were examined by terminal deoxynucleotidyl transferase‑mediated dUTP nick end labeling and transmission electron microscopy, respectively. The present study demonstrated that treatment with saponin 6 induced cell apoptosis in U87 MG cells, and resulted in DNA fragmentation and nuclear morphological alterations typical of apoptosis. In addition, flow cytometric analysis revealed that saponin 6 was able to induce cell cycle arrest. The present study also demonstrated that saponin 6‑induced apoptosis of U87 MG cells was attributed to increases in the protein expression levels of Fas, Fas ligand, and cleaved caspase‑3, ‑8 and ‑9, and decreases in the levels of B‑cell lymphoma 2. The current study indicated that saponin 6 may exhibit selective cytotoxicity toward U87 MG cells by activating apoptosis via the extrinsic and intrinsic pathways. Therefore, saponin 6 derived from A. taipaiensis may possess therapeutic potential for the treatment of GBM.

Potent effects of dioscin against gastric cancer in vitro and in vivo

BACKGROUND

We previously reported the effect of dioscin on human gastric carcinoma SGC-7901 cells, but its effects on other gastric cancers are still unknown.

PURPOSE

The present paper aimed to demonstrate the activity of dioscin against human gastric carcinoma MGC-803 and MKN-45.

STUDY DESIGN

In our study, MGC-803 and MKN-45 cells were used to examine the effects of dioscin on human gastric carcinoma in vitro. The effects of dioscin against human gastric carcinoma in vivo were accomplished by the xenografts of MGC-803 cells in BALB/c nude mice.

METHODS

AO/EB and DAPI staining, TEM, single cell gel electrophoresis and flow cytometry assays were used in cell experiments. Then, an iTRAQ-based proteomics approach, DNA and siRNA transfection experiments were carried out for mechanism investigation.

RESULTS

In MGC-803 cells, dioscin caused DNA damage and mitochondrial change, induced ROS generation, Ca(2+) release and cell apoptosis, and blocked cell cycle at S phase. In vivo results showed that dioscin significantly suppressed the tumor growth of MGC-803 cell xenografts in nude mice. In addition, dioscin markedly inhibited cell migration, caused Cytochrome c release and adjusted mitochondrial signal pathway. Then, an iTRAQ-based proteomics approach was carried out and 121 differentially expressed proteins were found, in which five biomarkers associated with cell cycle, apoptosis and migration were evaluated. Dioscin significantly up-regulated the levels of GALR-2 and RBM-3, and down-regulated CAP-1, Tribbles-2 and CliC-3. Furthermore, overexpressed DNA transfection of CAP-1 enhanced cell migration and invasion, which was decreased by dioscin. SiRNA to Tribbles-2 affected the protein levels of Bcl-2, Bax and MAPKs, suggesting that dioscin decreased Tribbles-2 level leading to cell apoptosis.

CONCLUSION

Our works confirmed the activity of dioscin against gastric cancer. In addition, this work also provided that dioscin is a new potent candidate for treating gastric cancer in the future.

Mitochondrial Dysfunction in Gliomas: Pharmacotherapeutic Potential of Natural Compounds

Gliomas are the most common primary brain tumors either benign or malignant originating from the glial tissue. Glioblastoma multiforme (GBM) is the most prevalent and aggressive form among all gliomas, associated with decimal prognosis due to it`s high invasive nature. GBM is also characterized by high recurrence rate and apoptosis resistance features which make the therapeutic targeting very challenging. Mitochondria are key cellular organelles that are acting as focal points in diverse array of cellular functions such as cellular energy metabolism, regulation of ion homeostasis, redox signaling and cell death. Eventual findings of mitochondrial dysfunction include preference of glycolysis over oxidative phosphorylation, enhanced reactive oxygen species generation and abnormal mitochondria mediated apoptotic machinery are frequently observed in various malignancies including gliomas. In particular, gliomas harbor mitochondrial structure abnormalities, genomic mutations in mtDNA, altered energy metabolism (Warburg effect) along with mutations in isocitrate dehydrogenase (IDH) enzyme. Numerous natural compounds have shown efficacy in the treatment of gliomas by targeting mitochondrial aberrant signaling cascades. Some of the natural compounds directly target the components of mitochondria whereas others act indirectly through modulating metabolic abnormalities that are consequence of the mitochondrial dysfunction. The present review offers a molecular insight into mitochondrial pathology in gliomas and therapeutic mechanisms of some of the promising natural compounds that target mitochondrial dysfunction. This review also sheds light on the challenges and possible ways to overcome the hurdles associated with these natural compounds to enter into the clinical market.

Dioscin ameliorates cerebral ischemia/reperfusion injury through the downregulation of TLR4 signaling via HMGB-1 inhibition

We previously reported the promising effect of dioscin against hepatic ischemia/reperfusion (I/R) injury, but its effect on cerebral I/R injury remains unknown. In this work, an in vitro oxygen-glucose deprivation and reoxygenation (OGD/R) model and an in vivo middle cerebral artery occlusion (MCAO) model were used. The results indicated that dioscin clearly protected PC12 cells and primary cortical neurons against OGD/R insult and significantly prevented cerebral I/R injury. Further research demonstrated that dioscin-induced neuroprotection was accompanied by a significant inhibition in the expression and the nuclear to cytosolic translocation of HMGB-1, reflected by decreased TLR4 expression. Blockade of the TLR4/MyD88/TRAF6 signaling pathway by dioscin inhibited NF-κB and AP-1 transcriptional activities, MAPK and STAT3 phosphorylation, and pro-inflammatory cytokine responses, and upregulated the levels of anti-inflammatory factors. In addition, small interfering RNA (siRNA) and overexpressed genes of HMGB-1 and TLR4 were applied in in vitro experiments, respectively, and the results further confirmed that dioscin showed an efficient neuroprotection because of its inhibiting effects on HMGB-1/TLR4 signaling and subsequent suppressing inflammation. These findings provide new insights that will aid in elucidating the effect of dioscin against cerebral I/R injury and support the development of dioscin as a potential treatment for ischemic stroke.

Effects of the Total Saponins fromDioscorea nipponicaon Immunoregulation in Aplastic Anemia Mice

Dioscorea nipponica Makino, a popular folk medicine, exerts anti-inflammation properties. The present study investigated the therapeutic effect of the total saponins from Dioscorea nipponica Makino (TSDN) on aplastic anemia (AA) and possible immune regulation mechanisms. Using a mouse model of AA, three different doses of TSDN were orally administrated for 14 consecutive days. We first demonstrated that TSDN was found to be effective in alleviating pancytopenia with a hypocellular bone marrow as compared with AA model group. Moreover, gastrogavage administration of a medium dose of TSDN was found to dramatically increase the percentage of CD4+cells in bone marrow nucleated cells (BMNC) and restore the CD4+/CD8+ratio. The pro-inflammatory cytokine concentrations of IL-2 and IFN-γ were significantly decreased, and anti-inflammatory cytokine IL-4 was significantly increased in culture supernatant of BMNC. Further investigations showed that TSDN obviously inhibited Fas–FasL-induced BMNC apoptosis as well as effectively suppressed intracellular apoptosis protein of caspase-3 and -8 expressions. Taken together, these findings suggested that TSDN could alleviate AA by elevating the CD4+/CD8+T-cell ratio, inhibiting inflammatory Th1-cytokines, and exerting anti-apoptosis effects.

Hydrogen peroxide-responsive anticancer hyperbranched polymer micelles for enhanced cell apoptosis

Hydrogen peroxide-responsive nanomicelles from hyperbranched polymers were developed for effective cancer therapy through enhanced apoptotic cell death.

Cyanidin-3-glucoside isolated from mulberry fruit protects pancreatic β-cells against oxidative stress-induced apoptosis

The extract obtained from berries contains high amounts of anthocyanins, and this extract is used as a phytotherapeutic agent for different types of diseases. In this study, we examined the cytoprotective effects of cyanidin-3-glucoside (C3G) isolated from mulberry fruit against pancreatic β-cell apoptosis caused by hydrogen peroxide (H2O2)-induced oxidative stress. The MIN6 pancreatic β-cells were used to investigate the cytoprotective effects of C3G on the oxidative stress-induced apoptosis of cells. Cell viability was examined by MTT assay and lipid peroxidation was assayed by thiobarbituric acid (TBA) reaction. Immunofluorescence staining, flow cytometry and western blot analysis were also used to determine apoptosis and the expression of proteins associated with apoptosis. Our results revealed that H2O2 increased the rate of apoptosis by stimulating various pro-apoptotic processes, such as the generation of intracellular reactive oxygen species (ROS), lipid peroxidation, DNA fragmentation and caspase-3 activation. However, C3G reduced the H2O2-induced cell death in the MIN6N pancreatic β-cells. In addition, we confirmed that H2O2 activated mitogen-activated protein kinases (MAPKs), such as extracellular signal-regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK) and p38 MAPK. C3G inhibited the phosphorylation of ERK and p38 without inducing the phosphorylation of JNK. Furthermore, C3G regulated the intrinsic apoptotic pathway-associated proteins, such as proteins belonging to the Bcl-2 family, cytochrome c and caspase-3. Taken together, our results suggest that C3G isolated from mulberry fruit has potential for use as a phytotherapeutic agent for the prevention of diabetes by preventing oxidative stress-induced β-cell apoptosis.

Evaluation of antibacterial and cytotoxic activity of Artemisia nilagirica and Murraya koenigii leaf extracts against mycobacteria and macrophages

Background

Artemisia nilagirica (Asteraceae) and Murraya koenigii (Rutaceae) are widely distributed in eastern region of India. Leaves of Artemisia nilagirica plant are used to treat cold and cough by the local tribal population in east India. Murraya koenigii is an edible plant previously reported to have an antibacterial activity. Pathogenic strains of mycobacteria are resistant to most of the conventional antibiotics. Therefore, it is imperative to identify novel antimycobacterial molecules to treat mycobacterial infection.

Methods

In this study, ethanol, petroleum ether and water extracts of Artemisia nilagirica and Murraya koenigii were tested for antibacterial activity against Mycobacterium smegmatis and Mycobacterium bovis BCG in synergy with first line anti-tuberculosis (TB) drugs, and for cytotoxic activities on mouse macrophage RAW264.7 cells. Antibacterial activity was determined by colony forming unit (CFU) assay. Intracellular survival assay was performed by infecting RAW264.7 cells with M. smegmatis before and after treatment with plant extracts. Cytotoxity was checked by MTT [3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide] assay. Genotoxicity was studied by DAPI staining and COMET assay using mouse macrophage RAW264.7 cell line. Cell apoptosis was checked by Annexin-V/FITC dual staining method. Reactive oxygen species and nitric oxide production was checked by DCFH staining and Griess reagent, respectively.

Results

Ethanol extracts of A. nilagirica (IC₅₀ 300 μg/ml) and M. koenigii (IC₅₀ 400 μg/ml) were found to be more effective against Mycobacterium smegmatis as compared to petroleum ether and water extracts. M. koenigii extract showed maximum activity against M. bovis BCG in combination with a first line anti-TB drug rifampicin. M. koenigii leaf extract also exerted more cytototoxic (IC₅₀ 20 μg/ml), genotoxic and apoptosis in mouse macrophage RAW 264.7 cell line. Treatment of mouse macrophages with A. nilagirica extract increased intracellular killing of M. smegmatis by inducing production of reactive oxygen species and nitric oxide.

Conclusions

Ethanol extracts of A. nilagirica and M. koenigii were found to be more effective against mycobacteria. As compared to A. nilagirica, M. koenigii ethanol extract exhibited significant synergistic antibacterial activity against M. smegmatis and M. bovis BCG in combination with anti-tuberculosis drug rifampicin, and also showed increased cytotoxicity, DNA damage and apoptosis in mouse macrophages.