Antiviral biflavonoids from Radix Wikstroemiae (Liaogewanggen)

<p>Abstract</p> <p>Background</p> <p><it>Radix Wikstroemiae </it>is a common Chinese herbal medicine. The ethyl acetate fraction of the ethanolic extract of <it>W. indica </it>possesses potent <it>in vitro </it>antiviral activity against respiratory syncytial virus (RSV). This study aims to identify the antiviral components of the active fraction.</p> <p>Methods</p> <p>The active fraction of the <it>Radix Wikstroemiae </it>extract was isolated with chromatographic methods such as silica gel, Sephadex LH-20 and semi-preparative high performance liquid chromatography (HPLC) columns. The structures of the isolated compounds were determined based on spectroscopic analyses. The <it>in vitro </it>antiviral activity of the compounds against RSV was tested with the cytopathic effect (CPE) reduction assay and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method.</p> <p>Results</p> <p>Four biflavonoids, namely neochamaejasmin B, genkwanol B, genkwanol C and stelleranol, were isolated and characterized. Genkwanol B, genkwanol C and stelleranol, which are stereo isomers of spirobiflavonoids, showed potent anti-RSV activity whereas neochamaejasmin B did not.</p> <p>Conclusion</p> <p>Neochamaejasmin B, genkwanol B, genkwanol C and stelleranol were isolated from <it>Radix Wikstroemiae </it>and the complete absolute configurations of five chiral carbons in stelleranol were substantiated for the first time. Furthermore, the anti-RSV activity of genkwanol B, genkwanol C and stelleranol was reported for the first time.</p

2β-(Isobutyryloxy)florilenalin, a Sesquiterpene Lactone Isolated from the Medicinal Plant Centipeda minima, Induces Apoptosis in Human Nasopharyngeal Carcinoma CNE Cells

Centipeda minima is a medicinal plant reputed in China as a remedy for nasopharyngeal carcinoma (NPC). In this study, bioactivity-guided fractionation of the anti-NPC compound(s) from C. minima led to the isolation of 2β-(isobutyryloxy)florilenalin (IF), a sesquiterpene lactone. IF showed significant dose- and time- dependent inhibition on the growth of the human nasopharyngeal carcinoma epithelia cells (CNE). It induced apoptosis in CNE cells, as shown by the accumulation of sub-G1 cell population, DNA fragmentation and nuclear condensation, caspase-3 activation and PARP cleavage. Such induction was associated with the depletion of mitochondrial membrane potential (ΔΨm) and the release of cytochrome c to cytosol to regulate the expression of Bcl-2 family proteins. These activities led to the cleavage of caspases and the trigger of cell death process. Overall, IF in C. minima showed potent antiproliferative effect of C. minima on NPC cells, suggesting that the plant deserves more extensive investigation for its potential medicinal application

Brevilin A, a Sesquiterpene Lactone, Inhibits the Replication of Influenza A Virus In Vitro and In Vivo

With the emergence of drug-resistant strains of influenza A viruses (IAV), new antivirals are needed to supplement the existing counter measures against IAV infection. We have previously shown that brevilin A, a sesquiterpene lactone isolated from C. minima, suppresses the infection of influenza A/PR/8/34 (H1N1) in vitro. Here, we further investigate the antiviral activity and mode of action of brevilin A against different IAV subtypes. Brevilin A inhibited the replication of influenza A H1N1, H3N2, and H9N2 viruses in vitro. The suppression effect of brevilin A was observed as early as 4&ndash;8 hours post infection (hpi). Furthermore, we determined that brevilin A inhibited viral replication in three aspects, including viral RNA (vRNA) synthesis, expression of viral mRNA, and protein encoded from the M and NS segments, and nuclear export of viral ribonucleoproteins (vRNPs). The anti-IAV activity of brevilin A was further confirmed in mice. A delayed time-to-death with 50% surviving up to 14 days post infection was obtained with brevilin A (at a dose of 25 mg/kg) treated animals compared to the control cohorts. Together, these results are encouraging for the exploration of sesquiterpene lactones with similar structure to brevilin A as potential anti-influenza therapies

Penduliflaworosin, a Diterpenoid from Croton crassifolius, Exerts Anti-Angiogenic Effect via VEGF Receptor-2 Signaling Pathway

Anti-angiogenesis targeting vascular endothelial growth factor receptor-2 (VEGFR-2) has been considered as an important strategy for cancer therapy. Penduliflaworosin is a diterpenoid isolated from the plant Croton crassifolius. Our previous study showed that this diterpenoid possesses strong anti-angiogenic activity by inhibiting vessel formation in zebrafish. This study was conducted to further investigate the anti-angiogenic activity and mechanism of penduliflaworosin. Results revealed that penduliflaworosin significantly inhibited VEGF-induced angiogenesis processes including proliferation, invasion, migration, and tube formation of human umbilical vein endothelial cells (HUVECs). Moreover, it notably inhibited VEGF-induced sprout formation of aortic rings and blocked VEGF-induced vessel formation in mice. Western blotting studies showed that penduliflaworosin inhibited phosphorylation of the VEGF receptor-2 and its downstream signaling mediators in HUVECs, suggesting that the anti-angiogenic activity was due to an interference with the VEGF/VEGF receptor-2 pathway. In addition, molecular docking simulation indicated that penduliflaworosin could form hydrogen bonds within the ATP-binding region of the VEGF receptor-2 kinase unit. Finally, cytotoxicity assay showed that penduliflaworosin possessed little toxicity toward both cancer and normal cells. Taken together, our findings demonstrate that penduliflaworosin exerts its anti-angiogenic effect via the VEGF receptor-2 signaling pathway. The anti-angiogenic property and low cytotoxicity of penduliflaworosin suggest that it may be useful in cancer treatments

EM23, A Natural Sesquiterpene Lactone from Elephantopus mollis, Induces Apoptosis in Human Myeloid Leukemia Cells through Thioredoxin- and Reactive Oxygen Species-Mediated Signaling Pathways

Elephantopus mollis H.B.K. (EM) is a traditional herbal medicine with multiple pharmacological activities. However, the efficacy of EM in treating human leukemia is currently unknown. In the current study, we report that EM23, a natural sesquiterpene lactone isolated from EM, inhibits the proliferation of human chronic myeloid leukemia K562 cells and acute myeloid leukemia HL-60 cells by inducing apoptosis. Translocation of membrane-associated phospholipid phosphatidylserines, changes in cell morphology, activation of caspases and cleavage of PARP were concomitant with this inhibition. The involvement of the mitochondrial pathway in EM23-mediated apoptosis was suggested by observed disruptions in mitochondrial membrane potential (MMP). Mechanistic studies indicated that EM23 caused a marked increase in the level of reactive oxygen species (ROS). Pretreatment with N-acetyl-L-cysteine (NAC), a ROS scavenger, almost fully reversed EM23-mediated apoptosis. In EM23-treated cells, the expression levels of thioredoxin (Trx) and thioredoxinreductase (TrxR), two components of the Trx system involved in maintaining cellular redox homeostasis, were significantly down-regulated. Concomitantly, Trx regulated the activation of apoptosis signal-regulating kinase 1 (ASK1) and its downstream regulatory targets, the p38, JNK, and ERK MAPKs. EM23-mediated activation of ASK1/MAPKs was significantly inhibited in the presence of NAC. Furthermore, tumor necrosis factor alpha (TNF-α)-mediated activation of nuclear factor-κB (NF-κB) was suppressed by EM23, as suggested by the observed blockage of p65 nuclear translocation, phosphorylation and reversion of IκBα degradation following EM23 treatment. Taken together, these results provide important insights into the anticancer activities of the EM component EM23 against human chronic myeloid leukemia K562 cells and acute myeloid leukemia HL-60 cells

A Novel Aniline Derivative from <i>Peganum harmala</i> L. Promoted Apoptosis via Activating PI3K/AKT/mTOR-Mediated Autophagy in Non-Small Cell Lung Cancer Cells

Non-small cell lung cancer (NSCLC) is a common clinical malignant tumor with limited therapeutic drugs. Leading by cytotoxicity against NSCLC cell lines (A549 and PC9), bioactivity-guided isolation of components from Peganum harmala seeds led to the isolation of pegaharoline A (PA). PA was elucidated as a structurally novel aniline derivative, originating from tryptamine with a pyrrole ring cleaved and the degradation of carbon. Biological studies showed that PA significantly inhibited NSCLC cell proliferation, suppressed DNA synthesis, arrested the cell cycle, suppressed colony formation and HUVEC angiogenesis, and blocked cell invasion and migration. Molecular docking and surface plasmon resonance (SPR) demonstrated PA could bind with CD133, correspondingly decreased CD133 expression to activate autophagy via inhibiting the PI3K/AKT/mTOR pathway, and increased ROS levels, Bax, and cleaved caspase-3 to promote apoptosis. PA could also decrease p-cyclinD1 and p-Erk1/2 and block the EMT pathway to inhibit NSCLC cell growth, invasion, and migration. According to these results, PA could inhibit NSCLC cell growth by blocking PI3K/AKT/mTOR and EMT pathways. This study provides evidence that PA has a promising future as a candidate for developing drugs for treating NSCLC

Intregrating metallic wiring with three-dimensional polystyrene colloidal crystals using electron-beam lithography and three-dimensional laser lithography

We demonstrate a method to fabricate narrow, down to a few micron wide metallic leads on top of a three-dimensional colloidal crystal self-assembled from polystyrene (PS) nanospheres of diameter 260 nm, using electron-beam lithography. This fabrication is not straightforward due to the fact that PS nanospheres cannot usually survive the harsh chemical treatments required in the development and lift-off steps of electron-beam lithography. We solve this problem by increasing the chemical resistance of the PS nanospheres using an additional electron-beam irradiation step, which allows the spheres to retain their shape and their self-assembled structure, even after baking to a temperature of 160 degrees C, the exposure to the resist developer and the exposure to acetone, all of which are required for the electron-beam lithography step. Moreover, we show that by depositing an aluminum oxide capping layer on top of the colloidal crystal after the e-beam irradiation, the surface is smooth enough so that continuous metal wiring can be deposited by the electron-beam lithography. Finally, we also demonstrate a way to self-assemble PS colloidal crystals into a microscale container, which was fabricated using direct-write three-dimensional laser-lithography. Metallic wiring was also successfully integrated with the combination of a container structure and a PS colloidal crystal. Our goal is to make a device for studies of thermal transport in 3D phononic crystals, but other phononic or photonic crystal applications could also be envisioned. Keywords: self-assembly, colloidal crystal, cross-linking, electron-beam lithography, three-dimensional lithography, phononic crystal, photonic crystal.peerReviewe