Cytochalasans from the Endophytic Fungus Phomopsis sp. shj2 and Their Antimigratory Activities.

Cytochalasans from the endophytic fungi featured structure diversity. Our previous study has disclosed that cytochalasans from the endophytic fungus Phomopsis sp. shj2 exhibited an antimigratory effect. Further chemical investigation on Phomopsis sp. shj2 has led to the discovery of seven new cytochalasans (1-7), together with four known ones. Their structures were elucidated through extensive spectroscopic data interpretation and single-crystal X-ray diffraction analysis. Compounds 1-3 and 8-11 exhibited antimigratory effects against MDA-MB-231 in vitro with IC50 values in the range of 1.01-10.42 µM.

Discovery of isopenicin A, a meroterpenoid as a novel inhibitor of tubulin polymerization.

Microtubules are involved in celluar processes of movement, intracellular trafficking and mitosis, thus microtubule-targeting agents have been widely used in cancer therapy. Herein, we report isopenicin A, a novel meroterpenoid isolated from the plant endophytic fungus of Penicillium sp. sh18, as a novel microtubule binding molecule that efficiently depolymerizes microtubule polymerization to evoke G2/M cell cycle arrest and subsequent cell apoptosis, contributing to proliferation inhibition of human tumor cell lines. The discovery of isopenicin A provides a new chemotype for discovery and development of promising microtubule inhibitors.

Ensemble docking-based virtual screening toward identifying inhibitors against Wee1 kinase.

Aim:Wee1 kinase plays a key role in the arrest of G2/M checkpoint that prevents mitotic entry in response to DNA damage. This work is to discover potent Wee1 inhibitors which can be considered valuable. Materials & Methods: Herein, Ensemble docking using multiple crystal structures was considered an effective strategy in the virtual screening. The performance of 17 scoring functions obtained from different docking software was evaluated for molecular docking. Results: Two novel compounds B1 and A2 were identified as Wee1 inhibitors with IC50 values of 10.23 ± 0.505 and 8.72 ± 0.323 µM, respectively. Further cell viability assay demonstrated that the two active compounds exhibited good anticancer activities. Conclusion: This provides a meaningful starting point for further structure optimization to discover more potent Wee1 inhibitors.

Physalis peruviana-Derived 4ß-Hydroxywithanolide E, a Novel Antagonist of Wnt Signaling, Inhibits Colorectal Cancer In Vitro and In Vivo.

Deregulation of the Wnt signaling pathway leads to colorectal cancer progression. Natural dietary compounds serve as promising candidates for development as chemopreventive agents by suppressing the Wnt/ß-catenin signaling pathway. Physalis peruviana-derived 4ßHWE showed a significant inhibitory activity with a calculated IC50 of 0.09 µΜ in a screening of novel inhibitors of Wnt signaling with the dual-luciferase reporter assay. This study investigated the anti-tumor effect of 4ßHWE and the potential Wnt signaling inhibitory mechanism. Both the western blot analysis and immunofluorescence assay showed that 4ßHWE promoted the phosphorylation and degradation of ß-catenin and the subsequent inhibition of its nuclear translocation to attenuate the endogenous Wnt target gene expression in colorectal cancer (CRC) cells. The cell viability assay indicated that 4ßHWE preferentially inhibited the proliferation of CRC compared with CCD-841-CoN, a normal human colonic epithelial cell line. 4ßHWE-mediated G0/G1 cell cycle arrest and apoptosis induction contributed to the suppression of the proliferation of CRC in the cell cycle and Annexin V-FITC/Propidium Iodide apoptosis analysis. Moreover, in vivo, 4ßHWE dramatically inhibited tumor growth in HCT116 xenografts by attenuating the Wnt/ß-catenin signaling pathway. In conclusion, our study suggested that 4ßHWE could be of potential use in anti-tumor agent development as a novel Wnt signaling inhibitor.

Norascyronones A and B, 2,3,4- nor-Polycyclic Polyprenylated Acylphloroglucinols from Hypericum ascyron.

Phytochemical study of Hypericum ascyron led to the characterization of norascyronones A-C (1-3), metabolites derived from bicyclic polyprenylated acylphloroglucinols by losing eight carbons (C-2/3/4 of core and the isoprenyl at C-3). Compounds 1/2 with an unprecedented 6/6/5/6 ring system should be generated via [4 + 2] intramolecular cyclization of 3. Their structures were determined by spectroscopic and X-ray diffraction data. Compounds 1 and 2 showed cytotoxicities against the SK-BR-3 cell line (IC50 4.3 and 7.8 µM).

Isopenicins A-C: Two Types of Antitumor Meroterpenoids from the Plant Endophytic Fungus Penicillium sp. sh18.

Isopenicins A-C (1-3), three novel meroterpenoids possessing two types of unprecedented terpenoid-polyketide hybrid skeletons, were isolated from the cultures of Penicillium sp. sh18. Their structures were determined through synergetic use of extensive spectroscopic analysis, quantum-chemical calculation with ANN-PRA analysis, and X-ray crystallographic analysis. Additionally, the inhibitory activities of these compounds on the Wnt/ß-catenin signaling pathway were evaluated, and 1 was identified as a potent inhibitor of the Wnt signaling pathway.

Enantioselective N-Heterocyclic Carbene-Catalyzed Synthesis of Spirocyclic Oxindole-benzofuroazepinones.

Herein, we report an enantioselective synthesis of azepinones via the N-heterocyclic carbene (NHC) catalyzed [3+4] annulation reaction of isatin-derived enals and aurone-derived azadienes. The corresponding spirocyclic oxindole-benzofuroazepinones were obtained in good yields, with excellent diastereo- and enantioselectivities. The resulted azepinones were evaluated for their in vitro cytotoxic activities against six human tumor cell lines, with two compounds showing significant inhibitory activity comparable with that of cisplatin.

Natural and Semisynthetic Tigliane Diterpenoids with New Carbon Skeletons from Euphorbia dracunculoides as a Wnt Signaling Pathway Inhibitor.

Euphordraculoates A (1) and B (2), featuring tigliane diterpenoids with two new carbon skeletons, were characterized as metabolites of Euphorbia dracunculoides and semisynthetic products, respectively. Their structures were determined by spectroscopic analyses and X-ray crystallography. The respective biosynthetic and chemical formation mechanisms for 1 and 2 from a known tigliane 3 was proposed. The detailed decarbonization mechanism from 3 to 2 was further explored by 18O-labeling experiment. Compound 2 could inhibit Wnt pathway in a dose- and time-dependent manner.

Diffusion Kurtosis Imaging Detects Microstructural Changes in the Brain after Acute Alcohol Intoxication in Rats.

The aim of this study was to test the technical feasibility of diffusion kurtosis imaging (DKI) in the brain after acute alcohol intoxication. Diffusion tensor imaging (DTI) and DKI during 7.0 T MRI were performed in the frontal lobe and thalamus before and 30 min, 2 h, and 6 h after ethyl alcohol administration. Compared with controls, mean kurtosis values of the frontal lobe and thalamus first decreased by 44% and 38% within 30 min (p < 0.01 all) and then increased by 14% and 46% at 2 h (frontal lobe, p > 0.05; thalamus, p < 0.01) and by 29% and 68% at 6 h (frontal lobe, p < 0.05; thalamus, p < 0.01) after acute intake. Mean diffusivity decreased significantly in both the frontal lobe and the thalamus at various stages. However, fractional anisotropy decreased only in the frontal lobe, with no detectable change in the thalamus. This demonstrates that DKI possesses sufficient sensitivity for tracking pathophysiological changes at various stages associated with acute alcohol intoxication and may provide additional information that may be missed by conventional DTI parameters.

Evaluation of mean diffusion and kurtosis MRI mismatch in subacute ischemic stroke: Comparison with NIHSS score.

Neurological deterioration (ND) is a devastating complication following ischemic stroke. This study aimed to identify the differences in lesion characteristics in subacute ischemic stroke patients with and without ND using diffusional kurtosis imaging (DKI), as well as to confirm the responsible lesions that may lead to ND, as assessed by the National Institutes of Health Stroke Scale (NIHSS) score. Seventy-nine patients with subacute cerebral infarction were allocated to the ND (-) and ND (+) groups according to the NIHSS score and lesion number. The mean diffusion (MD) lesions were significantly larger than the mean kurtosis (MK) deficits in the ND (+) group (P<0.05); however, there was no significant difference in the ND (-) group (P>0.05). The MD and MK in the lesion recovered to normal levels over time; however, the recovery trends in the ND (+) group were substantially slower than the ND (-) group. The differences between the two groups were only significant regarding the MK (p<0.05). Furthermore, multiple infarction lesions exhibited good consistency in the ND (-) group, but were non-homogeneous in the ND (+) group. To the best of our knowledge, this is the first study to demonstrate that a significant MD/MK mismatch and heterogeneity of multiple ischemic lesions on MK in subacute ischemic stroke may represent a new expansion of an ischemic lesion or acute reinfarction, which is closely related to ND.

Bisleuconothine A, a bisindole alkaloid, inhibits colorectal cancer cell in vitro and in vivo targeting Wnt signaling.

Wnt signaling pathway is aberrantly activated in a variety of cancers, especially in colorectal cancer and small molecule antagonists of Wnt/ß-catenin signaling are attractive candidates for developing effective therapeutics. In the present study, we identified Bisleuconothine A, a bisindole alkaloid with an eburnane-aspidosperma type skeleton, as a novel and selective Wnt signaling inhibitor by using a cell-based luciferase assay system. Our study found that Bisleuconothine A down-regulated the endogenous Wnt target gene expression through promoting phosphorylation of ß-catenin and the subsequent inhibition of its nuclear translocation in HCT116 and SW480 colorectal cancer cells. In vitro, Bisleuconothine A inhibited cell proliferation through induction of apoptosis by increasing the cleavage of caspases in HCT116 and SW480 colorectal cancer cells. Moreover, in vivo, Bisleuconothine A dramatically suppressed tumor growth in HCT116 Xenograft. And further analysis showed that Bisleuconothine A suppressed the Wnt target gene expression in HCT116 Xenograft, which was associated with up-regulation of ß-catenin phosphorylation and subsequent Wnt signaling inhibition. Taken together, our study indicated that bisindole alkaloids could be included as a new chemotype of small-molecule Wnt signaling inhibitors, and have great potential to be further developed for anti-tumor agents.

Phomopchalasins A and B, Two Cytochalasans with Polycyclic-Fused Skeletons from the Endophytic Fungus Phomopsis sp. shj2.

Phomopchalasins A (1) and B (2), two novel cytochalasans with unprecedented carbon skeletons, and phomopchalasin C (3), containing a rare hydroperoxyl motif, were obtained from the endophytic fungus Phomopsis sp. shj2, which was first isolated from the Isodon eriocalyx var. laxiflora. Their structures were elucidated by extensive spectroscopic analyses, electronic circular dichroism (ECD) calculation, and X-ray crystallographic analysis. Notably, 1 possessed an unprecedented 5/6/5/8-fused tetracyclic ring system, and 2 featured a novel 5/6/6/7/5-fused pentacyclic skeleton. The cytotoxic, anti-inflammatory, and antimigratory activities of 1-3 were evaluated in vitro.

Biflavone Ginkgetin, a Novel Wnt Inhibitor, Suppresses the Growth of Medulloblastoma.

Medulloblastoma (MB) is a form of malignant brain tumor that predominantly arises in infants and children, of which approximately 25 % is due to upregulation of canonical Wnt pathway with mainly mutations in CTNNB1. Therefore, Wnt inhibitors could offer rational therapeutic strategies and chemoprevention for this malignant cancer. In our present study, we undertook a screening for antagonists of Wnt signaling from 600 natural compounds, and identified Ginkgetin, a biflavone isolated from Cephalotaxus fortunei var. alpina. Ginkgetin inhibited Wnt pathway with an IC50 value around 5.92 µM and structure-activity relationship analysis suggested the methoxy group in Ginkgetin as a functional group. Biflavone Ginkgetin showed obvious cytotoxicity in Daoy and D283 MB cells. Cell cycle analysis by flow cytometry showed that Ginkgetin induced efficiently G2/M phase arrest in Daoy cells. Further mechanism studies showed that Ginkgetin reduced the expression of Wnt target genes, including Axin2, cyclinD1 and survivin in MB cells. The phosphorylation level of ß-catenin also decreased in a time- and concentration-dependent manner. Collectively, our data suggest that Ginkgetin is a novel inhibitor of Wnt signaling, and as such warrants further exploration as a promising anti-medulloblastoma candidate.

New cytotoxic and anti-inflammatory compounds isolated from Morus alba L.

Six Diels-Alder adducts (1-6) and nine prenylated flavanones (7-15) were isolated from the root bark of Morus alba L. Among them, soroceal B (1) and sanggenol Q (7) were new compounds. Their structures were elucidated on the basis of extensive spectroscopic methods, including 1D and 2D NMR techniques. Compounds 1-3, 9, 10, 12, 13 and 15 exhibited cytotoxic activity against five human tumour lines and compound 2 inhibited significantly selective cytotoxic activities towards HL-60 and AGS cells with IC50 of 3.4 and 3.6 µM. Compounds 3, 5, 9 and 12 exhibited moderate inhibitory activity against nitric oxide production in LPS-activated RAW264.7.

Cycloartane Glycosides from the Roots of Cimicifuga foetida with Wnt Signaling Pathway Inhibitory Activity.

Four new 9,19-cycloartane triterpenoids, cimilactone E (1), cimilactone F (2), 2'-O-(E)-butenoyl-23-epi-26-deoxyactein (3), and 2',12ß-O-diacetylcimiracemonol-3-O-ß-d-xylopyranoside (4), together with four known constituents (5-8) were isolated from the roots of Cimicifuga foetida. The new structures were elucidated by extensive spectroscopic analysis. In addition, compounds 7 and 8 showed significant Wnt signaling pathway inhibitory activity, with IC50 values of 3.33 and 13.34 µM, respectively, using the luciferase reporter gene assay.

Identification and validation of p50 as the cellular target of eriocalyxin B.

As an ent-kaurene diterpenoid isolated from Isodon eriocalyx var. Laxiflora, Eriocalyxin B (EriB) possesses potent bioactivity of antitumor and anti-autoimmune inflammation, which has been suggested to work through inhibition of NF-kappaB (NF-κB) signaling. However, the direct target of EriB remains elusive. In this study, we showed that EriB induced apoptosis is associated with the inhibition of NF-κB signaling in SMMC-7721 hepatocellular carcinoma cells. With activity-based probe profiling, we identified p50 protein as the direct target of EriB. We showed that cysteine 62 is the critical residue of p50 for EriB binding through the α, ß-unsaturated ketones. As the result, EriB selectively blocks the binding between p50 and the response elements, whereas having no effect on the dimerization or the nuclear translocation of p50 and p65. SiRNA mediated knockdown of p50 attenuated the apoptosis induced by EriB in SMMC-7721 cells. Taken together, our studies illustrated that EriB induces cancer cell apoptosis through interfering with the binding between NF-κB and the response elements by targeting the cysteine 62 of p50, which highlights its potential for the development of p50 targeted cancer therapeutic agents.

Two Natural ent-kauranoids as Novel Wnt Signaling Inhibitors.

Constitutively active Wnt signaling frequently occurs in most colon cancers. Therefore, inhibitors of Wnt signaling pathway could provide rational therapeutic effects for colorectal malignancy. Within this paper, we identified two inhibitors of Wnt signaling pathway, rabdoternin B and maoecrystal I from a natural ent-kauranoid library by a dual-luciferase reporter gene assay. The two compounds inhibited Wnt signaling pathway in a concentration-dependent manner and exhibited selective cytotoxicity toward a number of colon carcinoma cell lines SW480, HCT116, and HT29, with only weak cytotoxicity towards the normal colonic epithelial cell line CCD-841-CoN. Rabdoternin B and maoecrystal I treatment induced G2/M phase arrest efficiently in SW480 cells as revealed by flow cytometry analysis. A further study found that maoecrystal I decreased the expression of Wnt signaling target genes, including c-myc, cyclin D1, survivin and Axin2 in colon cancer cells. Collectively our data suggests that rabdoternin B and maoecrystal I are novel inhibitors of canonical Wnt signaling pathway and may possess potentials for colon cancer therapy.

Bioactive phenolics and terpenoids from Manglietia insignis.

Four new compounds, maninsigins A-D (1-4), including two new neolignans (1-2) and two new sesquiterpenes (3-4), as well as ten known compounds (5-14), were isolated from the leaves and stems of Manglietia insignis. Their structures were established on the basis of extensive spectroscopic analyses. In addition, some compounds were tested for their cytotoxic and neurite outgrowth-promoting activities, as well as their antagonistic activity toward FXR ligand.

Enmein-type diterpenoids from the aerial parts of Isodon rubescens and their cytotoxicity.

Three new enmein-type diterpenoids, jianshirubesins A-C (1-3), together with ten known compounds, were isolated from the aerial parts of Isodon rubescens. Their structures were established by using spectroscopic methods, and the absolute configuration of compound 1 was confirmed by a single-crystal X-ray diffraction analysis. All compounds except 3 were evaluated for their in vitro cytotoxicity by MTT assay, and compounds 5 and 10 exhibited significant inhibitory ability on selected cell lines.

Ternifolide A, a new diterpenoid possessing a rare macrolide motif from Isodon ternifolius.

Ternifolide A (1), a new diterpenoid featuring a unique 10-membered lactone ring formed between C-6 and C-15, along with ternifolide B (2), a nor-diterpenoid, and ternifolide C (3) were isolated from the leaves of Isodon ternifolius. Both H-8 and H-9 being α-orientations in compound 1 were found for the first time. The absolute configurations of 1 and 3 were confirmed by X-ray diffraction study. Compounds 1 and 3 were evaluated for their cytotoxicity.