Anti-proliferative neolignans from Saururus chinensis against human cancer cell lines

TAK1 in the AP-1 pathway is a critical target of Saururus chinensis (Lour.) Baill in its anti-inflammatory action

ETHNOPHARMACOLOGICAL RELEVANCE

Saururus chinensis (Lour.) Baill (Saururaceae), also known as Asian lizard's tail, is a plant commonly found in East Asia. Its leaves have been used in traditional medicine to treat many diseases such as edema, pneumonia, hypertension, leproma, jaundice, gonorrhea, and rheumatoid arthritis.

AIM OF THE STUDY

Based on the efficacies of S. chinensis, the anti-inflammatory effects of this plant and the molecular mechanism were evaluated using the ethanol extract of S. chinensis leaves (Sc-EE).

MATERIALS AND METHODS

The production of pro-inflammatory mediators and cytokines in response to Sc-EE was evaluated using Griess and semi-quantitative reverse transcription-polymerase chain reactions. Furthermore, relevant proteins including c-Jun, c-Fos, p38, JNK, ERK, MEK1/2, MKK3/6, MKK4/7, and TAK1 were detected through immunoblotting.

RESULTS

Sc-EE diminished production of nitric oxide (NO); decreased expression levels of cyclooxygenase (COX)-2, interleukin (IL)-6, inducible NO synthase (iNOS), and IL-1β in LPS-stimulated RAW264.7 cells; and attenuated activator protein 1 (AP-1)-mediated luciferase activities. The extract markedly downregulated the phosphorylation of TAK1, upregulated thermal stability of TAK1, and reduced TAK1/AP-1-mediated luciferase activity in LPS-treated RAW264.7 cells and TAK1-overexpressing HEK293T cells.

CONCLUSIONS

These results demonstrated that Sc-EE suppresses pro-inflammatory gene expression through blockade of the TAK1/AP-1 pathway in LPS-treated RAW264.7 macrophages, implying that inhibition of TAK1/AP-1 signaling by S. chinensis is a key event in its anti-inflammatory activity.

Structure-Based Pharmacophore Screening Coupled with QSAR Analysis Identified Potent Natural-Product-Derived IRAK-4 Inhibitors

Interleukin-1 Receptor-Associated Kinase 4 (IRAK-4) has crucial functions in inflammation, innate immunity, and malignancy. Structure-based pharmacophore modeling integrated with validated QSAR analysis was implemented to discover structurally novel IRAK-4 inhibitors from natural products database. The QSAR model combined molecular descriptors with structure-based pharmacophore capable of explaining bioactivity variation of structurally diverse IRAK-4 inhibitors. Manually built pharmacophore model, validated with receiver operating characteristic curve, and selected using the statistically optimum QSAR equation, was applied as a 3D-search query to mine AnalytiCon Discovery database of natural products. Experimental in vitro testing of highest-ranked hits identified uvaretin, saucerneol, and salvianolic acid B as active IRAK-4 inhibitors with IC₅₀ values in low micromolar range.

Sauchinone Protects Renal Mesangial Cell Dysfunction against Angiotensin II by Improving Renal Fibrosis and Inflammation

Abnormal and excessive growth of mesangial cells is important in the pathophysiologic processes of diabetes-associated interstitial fibrosis and glomerulosclerosis, leading to diabetic nephropathy, which eventually turns into end-stage renal disease. Sauchinone, a biologically-active lignan isolated from aerial parts of Saururus chinensis, has anti-inflammatory and anti-viral activities effects on various cell types. However, there are no studies reporting the effects of sauchinone on diabetic nephropathy. The present study aims to investigate the role of sauchinone in mesangial cell proliferation and fibrosis induced by angiotensin II, as well as the underlying mechanisms of these processes. Human renal mesangial cells were induced by angiotensin II (AngII, 10 μM) in the presence or absence of sauchinone (0.1-1 μM) and incubated for 48 h. In this study, we found that AngII induced mesangial cell proliferation, while treatment with sauchinone inhibited the cell proliferation in a dose-dependent manner. Pre-treatment with sauchinone induced down-regulation of cyclins/CDKs and up-regulation of CDK inhibitor, p21, and p27kip1 expression. In addition, AngII-enhanced expression of fibrosis biomarkers such as fibronectin, collagen IV, and connective tissue growth factor (CTGF), which was markedly attenuated by sauchinone. Sauchinone also decreased AngII-induced TGF-β1 and Smad-2, Smad-3, and Smad-4 expression. This study further revealed that sauchinone ameliorated AngII-induced mesangial inflammation through disturbing activation of inflammatory factors, and NLRP3 inflammasome, which is composed of the NLRP3 protein, procaspase-1, and apoptosis-associated speck-like protein containing a CARD (ASC). Moreover, pretreatment of sauchinone inhibited NF-κB translocation and ROS production in AngII-exposed mesangial cells. These data suggest that sauchinone has a protective effect on renal proliferation, fibrosis and inflammation. Therefore, sauchinone might be a potential pharmacological agent in prevention of AngII-induced renal damage leading to diabetic nephropathy.

Antileishmanial activity and ultrastructural changes of related tetrahydrofuran dineolignans isolated from Saururus cernuus L. (Saururaceae)

Objective

This work describes the isolation of anti-Leishmania amazonensis metabolites from Saururus cernuus (Saururaceae). Additionally, ultrastructural changes in promastigotes were evidenced by electron microscopy.

Methods

The MeOH extract from the leaves of S. cernuus was subjected to bioactivity-guided fractionation. Anti-L. amazonensis activity of purified compounds was performed in vitro against promastigote and amastigote forms.

Key findings

Bioactivity-guided fractionation of the MeOH extract from the leaves of S. cernuus afforded two related tetrahydrofuran dineolignans: threo,threo-manassantin A (1) and threo,erythro-manassantin A (2). Compounds 1 and 2 displayed activity against promastigotes (EC50 of 35.4 ± 7.7 and 17.6 ± 4.2 μm, respectively) and amastigotes (EC50 of 20.4 ± 1.9 and 16.0 ± 1.1 μm, respectively), superior to that determined for the positive control miltefosine (EC50 of 28.7 ± 3.5 μm). Reduced cytotoxicity for host cells was observed for both compounds. Additionally, ultrastructural changes in promastigotes leading to an alteration of structural morphology were observed, as evidenced by electron microscopy. Furthermore, these compounds altered the morphology and physiology of the plasmatic membrane of L. amazonensis.

Conclusions

The obtained results indicated that dineolignans 1 and 2 could be considered as a scaffold for the design of novel and selective drug candidates for the treatment of leishmaniasis.

Tris (1,3-dichloro-2-propyl) phosphate-induced apoptotic signaling pathways in SH-SY5Y neuroblastoma cells

Tris (1, 3-dichloro-2-propyl) phosphate (TDCIPP, also known as TDCPP), an extensively used flame retardant, is frequently detected in the environment and biota. Recent studies have shown that TDCIPP has neurotoxic effects. In this study, we determined the mechanisms of TDCIPP-induced neurotoxicity in human neuroblastoma (SH-SY5Y) cells. By using morphological examination, flow cytometry, and mitochondrial membrane potential (ΔYm) measurement, we confirmed that exposure to TDCIPP caused apoptosis accompanied by the activation of apoptosis-related genes (e.g. Bax and Bcl-2) and caspase 3 protein in SH-SY5Y cells. Increased reactive oxygen species (ROS) formation and intracellular calcium ions ([Ca²⁺]_i) were also observed in TDCIPP-treated SH-SY5Y cells. Exposure to TDCIPP led to the activation of protein markers of endoplasmic reticulum (ER) stress, including eukaryotic translation initiation factor 2a subunit (p-EIF2a), activation transcription factor (ATF4), glucose-regulated protein (GRP78), and the proapoptotic factor C/EBP homologous protein (CHOP). To determine the role of the ER in apoptosis, phenyl butyric acid (PBA), an ER stress inhibitor, was applied. Treatment with PBA effectively attenuated TDCIPP-induced ER stress and protected against apoptotic death in SH-SY5Y cells by inhibition of Bax expression and promotion of Bcl-2 expression. Furthermore, we found that pretreatment of the cells with the ROS scavenger N-acetyl cysteine (NAC) inhibited the ER stress response and prevented apoptosis. The combination of PBA and NAC pretreatment could further prevent TDCIPP induced ER-stress and apoptotic death compared with PBA or NAC pretreatment alone. Thus, in the present study, we demonstrated that TDCIPP induces cytotoxicity through a ROS-dependent mechanism involving ER stress and activation of mitochondrial apoptotic pathways in SH-SY5Y cells.

Anti-inflammatory effects of Saururus chinensis aerial parts in murine macrophages via induction of heme oxygenase-1

Saururus chinensis (Lour.) Baill. is a perennial plant distributed throughout Northeast Asia and its roots have been widely used as a traditional medicine for hepatitis, asthma, pneumonia, and gonorrhea. This study was designed to investigate the anti-inflammatory activity of an extract of S. chinensis of the aerial parts (rather than the root), and the signaling pathway responsible for this effect in lipopolysaccharide-stimulated murine macrophages. The subfraction 4 (SCF4) from the n-hexane layer of the ethanol extract of the aerial parts of S. chinensis exhibited the highest nitrite-inhibitory activity. SCF4 significantly inhibited the production of nitrite and the expression of pro-inflammatory mediators via heme oxygenase-1 upregulation. SCF4 caused significant phosphorylation of p38 MAPK and Akt, which subsequently induced the nuclear translocation of p-p65 nuclear factor-κB and Nrf2. SCF4 also suppressed the phosphorylation of signal transducers and activators of transcription 1 (p-STAT1). The heme oxygenase-1 inhibitor zinc protoporphyrin attenuated the inhibitory effect of SCF4 on lipopolysaccharide-stimulated nitrite production and expression of inflammatory mediators, tumor necrosis factor alpha, and p-STAT1. We identified sauchinone as the active compound in S. chinensis extract and SCF4. Sauchinone was shown to significantly inhibit nitrite production and inflammatory mediators expression via heme oxygenase-1 upregulation. These results suggest that S. chinensis extract, SCF4, and its active compound, sauchinone, could be used as an anti-inflammatory agent.

Saururus chinensis Baill induces apoptosis through endoplasmic reticulum stress in HepG2 hepatocellular carcinoma cells

In this study, we examined the mechanism underlying the effect of Saururus chinensis Baill (saururaceae) on hepatocellular carcinoma HepG2 cells. HepG2 cells and Chang cells were exposed to various concentrations of S. chinensis Baill extract (SC-E) for 24 h. SC-E affected more significantly HepG2 cells than Chang cells in terms of cell viability and ATP production. Therefore, current study examined detailed mechanism how SC-E affected HepG2 cell survival. We found that SC-E (75 and 150 μg/ml) induced apoptosis via oxidative stress. SC-E also caused CCAAT-enhancer-binding protein homologous protein (CHOP) activation by dissociating the binding immunoglobulin protein (BiP) from inositol-requiring 1α (IRE1α) in the endoplasmic reticulum (ER) and induced Bax, cytochrome c release to cytosol, caspase-3 activation, and poly ADP ribose polymerase (PARP) cleavage, resulting in HepG2 cell apoptosis. Furthermore, SC-E caused ER Ca(2+) leakage into the cytosol; ER dilation and mitochondrial membrane damage were observed in transmission electron microscopy (TEM). Taken together, our results demonstrated that SC-E induced cancer cell apoptosis specifically through ER stress.

Inhibitory effects of Saururus chinensis and its components on stomach cancer cells

Saururus chinensis (SC) Baill. (Saururaceae), a perennial herb commonly called Chinese lizard's tail or Sam-baekcho in Korea, has been used in the treatment of edema, gonorrhea, jaundice, and inflammatory diseases. Recently, several reports have been commissioned to examine the anti-cancer activities of this plant. In this study, we evaluated the inhibitory activity and mechanism of action on SC and its components against stomach cancer cells. SC extracts displayed cytotoxic effects on AGS cells in a dose-dependent manner. Moreover, SC increased the number of annexin V-positive apoptotic bodies and phosphorylated JNK and p38 in AGS cells. SC also down-regulated anti-apoptotic (Bcl-2) genes and up-regulated apoptotic (Bax) genes in AGS cells. We further confirmed that caspase activation plays an important role in SC-induced apoptosis in AGS cells. Furthermore, we examined erythro-Austrobailignan-6 and meso-dihydroguaiaretic acid, major active constituents of SC, which induced apoptosis in both the AGS and NCI-N87 stomach cancer cell lines. Taken together, our data provide the evidence that SC and its components induce apoptosis in stomach cancer cells, making it a potential candidate as a chemotherapeutic drug.

Attenuation of inflammatory-mediated neurotoxicity by Saururus chinensis extract in LPS-induced BV-2 microglia cells via regulation of NF-κB signaling and anti-oxidant properties

Background

A Saururus chinensis Baill (SC) has been used by Native Americans, early colonists and practitioners of Korean traditional medicine for treating several diseases including cancer, rheumatoid arthritis and edema. The objective of this study was to evaluate the effects of SC extract in lipopolysaccharide (LPS)-stimulated neuroinflammatory responses in BV-2 microglial cells.

Methods

The effects of SC on the LPS–induced neuroinflammatory responses in BV-2 microglial cells were assessed by Western blotting, RT-PCR and immunofluorescence labeling techniques. DPPH and alkyl radical scavenging assay was performed to evaluate the anti-oxidant effects. Comparisons between groups were analyzed using one-way analysis of variance followed by Dunnett’s multiple comparisons test using GraphPad Prism V5.01 software.

Results

Pre-treatment with SC extract (1, 5 and 10 μg/mL) significantly (p < 0.001 at 10 μg/mL) and concentration dependently inhibited LPS-induced production of nitric oxide (NO), inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2) and suppressed the inflammatory cytokine levels such as tumor necrosis factor-alpha and interleukin (IL)-6 in BV-2 microglial cells (p < 0.001 at 10 μg/mL). Further, SC suppressed the nuclear factor-kappa B (NF-κB) activation by blocking the degradation of IκB-α. SC also exhibited profound anti-oxidant effects by scavenging 1, 1-diphenyl-2-picrylhydrazyl (DPPH) (IC50: 0.055 mg/mL) and alkyl radicals (IC50: 0.349 mg/mL). High performance liquid chromatography finger printing analysis of SC revealed quercetin (QCT) as one of the major constituents compared with reference standard. QCT also inhibited the excessive release of NO, and inhibited the increased expressional levels of IL-6, iNOS and COX-2 in LPS-stimulated BV-2 cells.

Conclusions

Our results indicated that SC inhibited the LPS-stimulated neuroinflammatory responses in BV-2 microglia via regulation of NF-κB signaling. The antioxidant active constituents of SC might be partly involved in delivering such effects. Based on the traditional claims and our present results SC can be potentially used in treating inflammatory-mediated neurodegenerative diseases.

Roles of plant extracts and constituents in cervical cancer therapy

Cervical cancer is a major health problem worldwide and is the most frequent cause of cancer in women in India. Early detection and affordable drugs with clinical efficacy have to go hand-in-hand in order to comprehensibly address this serious health challenge. Plant-based drugs with potent anticancer effects should add to the efforts to find a cheap drug with limited clinical side effects. Keeping this very purpose in mind, an attempt has been made in this review to explore the potential of plant extracts or constituents known to exhibit antitumorigenic activity or exert cytotoxic effect in human cervical carcinoma cells. Alkaloids such as those isolated from C. vincetoxicum and T. Tanakae, naucleaorals A and B, isolated from the roots of N. orientalis, (6aR)-normecambroline, isolated from the bark of N. dealbata appear promising in different human cervical carcinoma cells with the IC50 of 4.0-8 μg/mL. However, other compounds such as rhinacanthone and neolignans isolated from different plants are not far behind and kill cervical cancer cells at a very low concentrations. Among plant extracts or its constituents that enhance the effect of known anticancer drugs, noni, derived from the plant M. citrifolia perhaps is the best candidate. The cytotoxic potency and apoptotic index of cisplatin was found to significantly enhanced in combination with noni in different human cervical carcinoma cells and it therefore holds significance as promising herbal-based anticancer agent. However, efficacy needs to be further investigated in various cervical cell lines and more importantly, in in vivo cervical cancer models for possible use as an alternative and safe anticancer drug.

Gene Expression Profile of the A549 Human Non-Small Cell Lung Carcinoma Cell Line following Treatment with the Seeds of Descurainia sophia, a Potential Anticancer Drug

Descurainia sophia has been traditionally used in Korean medicine for treatment of diverse diseases and their symptoms, such as cough, asthma, and edema. Our previous results showed that ethanol extract of the seeds of D. sophia (EEDS) has a potent cytotoxic effect on human cancer cells. In this study, we reveal the molecular events that are induced by EEDS treatment in A549 human lung cancer cells. The dose-dependent effect of EEDS on gene expression was measured via a microarray analysis. Gene ontology and pathway analyses were performed to identify functional involvement of genes regulated by EEDS. From gene expression analyses, two major dose-dependent patterns were observed after EEDS treatment. One pattern consisted of 1,680 downregulated genes primarily involved in metabolic processes (FDR < 0.01). The second pattern consisted of 1,673 upregulated genes primarily involved in signaling processes (FDR < 0.01). Pathway activity analyses revealed that the metabolism-related pathways and signaling-related pathways were regulated by the EEDS in dose-dependent and reciprocal manners. In conclusion, the identified biphasic regulatory mechanism involving activation of signaling pathways may provide molecular evidence to explain the inhibitory effect of EEDS on A549 cell growth.