Hyperhubeins A-I, Bioactive Sesquiterpenes with Diverse Skeletons from Hypericum hubeiense.

Nine new sesquiterpenes, hyperhubeins A-I (1-9), and 14 known analogues (10-23) were isolated from the aerial portions of Hypericum hubeiense. Their structures and absolute configurations were determined unambiguously via spectroscopic analysis, single-crystal X-ray diffraction, and electronic circular dichroism calculations. Compounds 1-3 possess an unprecedented sesquiterpene carbon skeleton. Further, a plausible biosynthetic pathway from farnesyl diphosphate (FPP) is proposed. The isolated phytochemicals were evaluated for neuroprotective and anti-neuroinflammatory properties in vitro. Compounds 1, 2, 5-8, 14, and 21 displayed notable neuroprotective activity against hydrogen peroxide (H2O2)-induced lesions in PC-12 cells at 10 µM. Additionally, compounds 1, 2, 12, and 13 exhibited inhibition of lipopolysaccharide (LPS)-induced nitric oxide (NO) production in BV-2 microglial cells, with their IC50 values ranging from 4.92 to 6.81 µM. Possible interactions between these bioactive compounds and inducible nitric oxide synthase (iNOS) were predicted via molecular docking. Moreover, Western blotting indicated that compound 12 exerted anti-neuroinflammatory activity by suppressing LPS-stimulated expression of toll-like receptor-4 (TLR-4) and inhibiting consequent activation of nuclear factor-kappa-B (NF-κB) signaling.

Cytotoxic Diterpenoids from Euphorbia fischeriana.

Five new diterpenoids, named euphorfischerins A-E, were isolated from the roots of Euphorbia fischeriana. Their chemical structures and absolute configurations were determined by interpretation of NMR, HR-ESI-MS, ECD and X-ray diffraction data. Euphorfischerin A showed cytotoxicity against the human cancer cell lines HeLa, H460 and Namalwa with IC50 values of 4.6, 11.5 and 16.4 µM, respectively, while euphorfischerin B gave comparable IC50 values of 9.5, 17.4 and 13.3 µM against the three cancer cell lines, respectively.

Meroterpene-Like α-Glucosidase Inhibitors Based on Biomimetic Reactions Starting from ß-Caryophyllene.

BACKGROUND: Natural meroterpenes derived from phloroglucinols and ß-caryophyllene have shown high inhibitory activity against α-glucosidase or cancer cells, however, the chemical diversity of this type of skeletons in Nature is limited. METHODS: To expand the chemical space and explore their inhibitory activities against α-glucosidase (EC 3.2.1.20), we employed ß-caryophyllene and some natural moieties (4-hydroxycoumarins, lawsone or syncarpic acid) to synthesize new types of meroterpene-like skeletons. All the products (including side products) were isolated and characterized by NMR, HR-MS, and ECD. RESULTS: In total, 17 products (representing seven scaffolds) were generated through a one-pot procedure. Most products (12 compounds) showed more potential activity (IC50 < 25 µM) than the positive controls (acarbose and genistein, IC50 58.19, and 54.74 µM, respectively). Compound 7 exhibited the most potent inhibition of α-glucosidase (IC50 3.56 µM) in a mixed-type manner. The CD analysis indicated that compound 7 could bind to α-glucosidase and influence the enzyme's secondary structure. CONCLUSIONS: Compound 7 could serve as a new type of template compound to develop α-glucosidase inhibitors. Full investigation of a biomimic reaction can be used as a concise strategy to explore diverse natural-like skeletons and search for novel lead compounds.

Structure-antifungal relationships and preventive effects of 1-(2,4-dihydroxyphenyl)-2-methylpropan-1-one derivatives as potential inhibitors of class-II fructose-1,6-bisphosphate aldolase.

Emerging fungal phytodiseases are a food security threat and novel fungicides are in an urgent need. Herein, a series of isobutyrophenone derivatives were designed and synthesized. The derivatives exhibited excellent fungicidal activities against seven fungi. The structure-activity relationship (SAR) study indicated that the introduction of a bromo group at the position 3 or 5 of the phenyl ring, as well as esterification of the 4-hydroxy with a chloroacetyl group, could substantially increase the antifungal activity and spectrum of the compounds. Among all 23 compounds, 2-bromo-3-hydroxy-4-isobutyryl-6-methylphenyl 2-chloroacetate (12b) showed the highest fungicidal activity against all seven tested fungal pathogens with EC50 values ranging from 1.22 to 39.94 µg/mL and exhibited the most potent inhibition against class II fructose-1,6-bisphosphate aldolase with an IC50 of 3.63 µM. The lead compounds were proven to be safe to NIH3T3/293 T cells and silkworm larvae, and relatively stable under different harsh conditions. Detached fruit tests showed the practical potential of lead compounds for fruit (or plant) protection. Taken together, our results indicated that the isobutyrophenone derivatives could be further optimized and developed as advanced leads for new fungicides.

Natural products as sources of new fungicides (V): Design and synthesis of acetophenone derivatives against phytopathogenic fungi in vitro and in vivo.

A series of acetophenone derivatives (10a-10i, 11, 12a-12g, 13a-13g, 14a-14d and 15a-15l) were designed, synthesized and evaluated for antifungal activities in vitro and in vivo. The antifungal activities of 53 compounds were tested against several plant pathogens, and their structure-activity relationship was summarized. Compounds 10a-10f displayed better antifungal effects than two reference fungicides. Interestingly, the most potent compound 10d exhibited antifungal properties against Cytospora sp., Botrytis cinerea, Magnaporthe grisea, with IC50 values of 6.0-22.6 µg/mL, especially Cytospora sp. (IC50 = 6.0 µg/mL). In the in vivo antifungal assays, 10d displayed the significant protective efficacy of 55.3% to Botrytis cinerea and 73.1% to Cytospora sp. The findings indicated that 10d may act as a potential pesticide lead compound that merits further investigation.

Natural products as sources of new fungicides (IV): Synthesis and biological evaluation of isobutyrophenone analogs as potential inhibitors of class-II fructose-1,6-bisphosphate aldolase.

Several recently identified antifungal compounds share the backbone structure of acetophenones. The aim of the present study was to develop new isobutyrophenone analogs as new antifungal agents. A series of new 2,4-dihydroxy-5-methyl isobutyrophenone derivatives were prepared and characterized by 1H, 13C NMR and MS spectroscopic data. These products were evaluated for in vitro antifungal activities against seven plant fungal pathogens by the mycelial growth inhibitory rate assay. Compounds 3, 4a, 5a, 5b, 5e, 5f and 5g showed a broad-spectrum high antifungal activity. On the other hand, for the first time, these compounds were also assayed as potential inhibitors against Class II fructose-1,6-bisphosphate aldolase (Fba) from the rice blast fungus, Magnaporthe grisea. Compounds 5e and 5g were found to exhibit the inhibition constants (Ki) for 15.12 and 14.27 µM, respectively, as the strongest competitive inhibitors against Fba activity. The possible binding-modes of compounds 5e and 5g were further analyzed by molecular docking algorithms. The results strongly suggested that compound 5g could be a promising lead for the discovery of new fungicides via targeting Class II Fba.

Synthesis, Antifungal Activities and Molecular Docking Studies of Benzoxazole and Benzothiazole Derivatives.

Based on benzoxazole and benzothiazole scaffold as an important pharmacophore, two series of 2-(aryloxymethyl) benzoxazole and benzothiazole derivatives were synthesized and their antifungal effects against eight phytopathogenic fungi were evaluated. Compounds 5a, 5b, 5h, and 5i exhibited significant antifungal activities against most of the pathogens tested. Especially 5a, 5b, 5h, 5i, 5j, and 6h inhibited the growth of F. solani with IC50 of 4.34⁻17.61 µg/mL, which were stronger than that of the positive control, hymexazol (IC50 of 38.92 µg/mL). 5h was the most potent inhibitor (IC50 of 4.34 µg/mL) against F. Solani, which was about nine times more potent than hymexazol. Most of the test compounds displayed significant antifungal effects against B. cinerea (IC50 of 19.92⁻77.41 µg/mL), among them, 5a was the best one (IC50 of 19.92 µg/mL). The structure-activity relationships (SARs) were compared and analyzed. The result indicates that the electron-drawing ability and position of the substituents have a significant impact on biological activities. Furthermore, docking studies were carried out on the lipid transfer protein sec14p from S. cerevisiae, and preliminarily verified the antifungal activities. Taken together, these results provide 2-(phenoxymethyl)benzo[d]oxazole as an encouraging framework that could lead to the development of potent novel antifungal agents.

Natural products as sources of new fungicides (III): Antifungal activity of 2,4-dihydroxy-5-methylacetophenone derivatives.

A series of new 2,4-dihydroxy-5-methylacetophenone 2 derivatives were synthesized, and characterized by (1)H, (13)C NMR and ESI-MS. Their antifungal activities were evaluated in vitro against five important plant fungal pathogens including Cytospora sp., Glomerella cingulate, Pyricularia oryzaecar, Botrytis cinerea and Alternaria solani by the mycelial growth inhibitory rate assay. Compounds 2b-d, 2g and 2h displayed a broad-spectrum activity. The logP value of these active compounds is ranging from 1.71 to 2.54. Especially, isopropyl ketone 2g (logP 2.27) was found to be the most active to the tested organisms with IC50 values of 17.28-32.32 µg/mL. The results suggest that compound 2g might be a promising candidate in the development of new agrochemical antifungal agents. Preliminary structure-activity relationship (SAR) studies of the acetophenone derivatives are also discussed.

[DZNep raises miR-200c expression to delay the invasion and migration of MGC-803 gastric carcinoma cells].

The aim of the present study was to investigate the regulatory effects of histone methylation modifications on the expression of miR-200c, as well as invasion and migration of gastric carcinoma cells. Gastric carcinoma cell line, MGC-803, were treated by 2.5 µmol/L histone methyltransferase inhibitor, DZNep. The expression of miR-200c was detected by real-time quantitative PCR (qRT-PCR). The epithelial-mesenchymal transition (EMT) indicators (ZEB1/2 and E/N-cadherin), EZH2, EED, SUZ12 and H3K27me3 expressions were detected by Western blot. Cell migration and invasion abilities were detected by Transwell and scratch tests. The result showed that, compared with DMSO (control) group, DZNep significantly increased the expression of miR-200c to about 2.1 times, inhibited ZEB1, ZEB2, and N-cadherin expressions, and activated E-cadherin expression; Also, DZNep decreased the protein expressions of EZH2, EED, SUZ12 and H3K27me3; Moreover, DZNep could inhibit MGC-803 cell invasive and migrative abilities, as well as MMP9 expression. These results suggest DZNep raises miR-200c expression to delay the invasion and migration of gastric carcinoma cells, and the underlying mechanisms involve the regulations of EMT-related proteins and polycomb repressive complex 2.

2-Chloro-N-methyl-N-[2-(methyl-amino)-phen-yl]acetamide.

The title compound, C(10)H(13)ClN(2)O, was obtained as a by-product in the reaction of 2-chloro-methyl-1H-benzimidazole, dimethyl sulfate and toluene to synthesise 2-chloro-methyl-1-methyl-benzimidazole. The dihedral angle between the benzene ring and the acetamide group is 89.72  (6)° while that between the aromatic ring and the chloracetyl group is 84.40 (4)°. In the crystal, adjacent mol-ecules are linked by pairs of N-H⋯O hydrogen bonds into inversion dimers.

Secoscabronine M, a novel diterpenoid from the Chinese bitter mushroom Sarcodon scabrosus.

Secoscabronine M (1) is a hemiacetal cyathane diterpenoid that was isolated from the fruiting bodies of the basidiomycete Sarcodon scabrosus (Fr.) Karst. Compound 1 possesses a novel structure with a bond cleavage between C-3 and C-4. The structure of the new compound was elucidated by means of spectroscopic methods, including two-dimensional nuclear magnetic resonance experiments. The absolute configuration of 1 was established by analysis of circular dichroism spectroscopy and also by employing time-dependent density functional theory calculations. In addition, compound 1 was confirmed to be an equilibrium mixture of two epimers (15S and 15R) at position C-15 in polar solvents by one-dimensional nuclear magnetic resonance analysis.

[Preliminary study on aberrant expression of miRNAs related to the formation of the distinction between pediatric and adult types of brainstem gliomas].

OBJECTIVES: To study the different expression of miRNA between pediatric and adult types of brainstem gliomas, and to provide the target miRNAs for explore the mechanism and miRNA interference of the malignant progression of pediatric BSG. METHODS: miRNA expression profiles in orthotopic models which could simulate the BSG heterogeneity were examined by microarray and analyzed to obtain the aberrantly expressed miRNAs. The two types of human BSG tissue were utilized to verify the microarray data by qRT-PCR and in situ hybridization for the putative causative miRNAs. RESULTS: There were 216 miRNAs detected in both the pediatric BSG group and the adult BSG group, 39 miRNAs to be differential expressed in the pediatric BSG group versus adult group, including 10 up-regulated and 29 down-regulated. qRT-PCR and in situ hybridization indicated good consistency with that of the microarray method. CONCLUSIONS: Aberrantly expressed miRNA may serve as putative causative involvement of malignant progression of pediatric BSG, thereby might be potentially novel targets for therapy.

RETRACTED: Sannastatin, a novel toxic macrolactam polyketide glycoside produced by actinomycete Streptomyces sannanensis.

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. One of the co-authors, Hartmut Laatsch, informed the journal that this paper was submitted and published without his consent. This is a violation of the journal's policy that all authors of a paper should approve submission of a manuscript. Apologies are offered to readers of the journal that this was not detected during the submission and evaluation process.

MiR-221 and miR-222 target PUMA to induce cell survival in glioblastoma.

BACKGROUND: MiR-221 and miR-222 (miR-221/222) are frequently up-regulated in various types of human malignancy including glioblastoma. Recent studies have reported that miR-221/222 regulate cell growth and cell cycle progression by targeting p27 and p57. However the underlying mechanism involved in cell survival modulation of miR-221/222 remains elusive. RESULTS: Here we showed that miR-221/222 inhibited cell apoptosis by targeting pro-apoptotic gene PUMA in human glioma cells. Enforced expression of miR-22/222 induced cell survival whereas knockdown of miR-221/222 rendered cells to apoptosis. Further, miR-221/222 reduced PUMA protein levels by targeting PUMA-3'UTR. Introducing PUMA cDNA without 3'UTR abrogated miR-221/222-induced cell survival. Notably, knockdown of miR-221/222 induces PUMA expression and cell apoptosis and considerably decreases tumor growth in xenograft model. Finally, there was an inverse relationship between PUMA and miR-221/222 expression in glioma tissues. CONCLUSION: To our knowledge, these data indicate for the first time that miR-221/222 directly regulate apoptosis by targeting PUMA in glioblastoma and that miR-221/222 could be potential therapeutic targets for glioblastoma intervention.

Structure and absolute configuration of toxic polyketide pigments from the fruiting bodies of the fungus Cortinarius rufo-olivaceus.

Two new polyketide-derived pigments, named rufoolivacins B (), and D (), with a 4',10-coupled aryl linkage between polysubstituted 1-naphthol and 1,4- or 1,2-anthraquinone, together with nine known metabolites including rufoolivacins A () and C (), have been isolated from the fruiting bodies of the Chinese toadstool Cortinarius rufo-olivaceus (basidiomycetes). Their structures were characterized on the basis of spectroscopic methods, including 2D-NMR experiments (COSY, NOESY, HSQC, and HMBC). The axial chirality of and was assigned through analysis of their CD spectra and ZINDO and TDDFT calculations. Compounds and were found to be unusual natural products incorporating an ortho-anthraquinone chromophore. All the metabolites were shown to be toxic toward the brine shrimp.

1-[4-(3,5-Difluoro-benz-yloxy)-2-hy-droxy-phen-yl]ethanone.

The title compound, C(15)H(12)F(2)O(3), has been obtained by the reaction of 2,4-dihy-droxy-lacetonephenone, potassium carbonate and 3,5-difluoro-benzyl bromide. The hy-droxy group is involved in an intra-molecular O-H⋯O hydrogen bond in each of the two independent mol-ecules in the asymmetric unit. The dihedral angle between the aromatic rings is 0.5 (2)° in one molecule and 1.9 (2)° in the other. In the crystal, weak C-H⋯O inter-actions link the mol-ecules into tetra-meric units aligned perpendicular to b.

2,4-Dichloro-6-[2-meth-oxy-4-(prop-2-en-1-yl)phen-oxy]-1,3,5-triazine.

The title compound, C(13)H(11)Cl(2)N(3)O(2), was obtained by the reaction of eugenol and cyanuric chloride. The dihedral angle between the benzene and triazine rings is 87.56 (4)°. Two C atoms of the allyl group are disordered over two sites in a 0.72 (2):0.28 (2) ratio.

Bioactive metabolites produced by Chaetomium globosum, an endophytic fungus isolated from Ginkgo biloba.

A novel cytotoxic chlorinated azaphilone derivative named chaetomugilin D (1), together with three known metabolites, chaetomugilin A (2), chaetoglobosins A (3) and C (4), has been isolated by a bioassay-guided fractionation from the EtOAc extract of the cultures of Chaetomium globosum, an endophytic fungus found in the leaves of Ginkgo biloba. Structure of 1 was established by analyses of spectroscopic methods, including 2D-NMR experiments (COSY, NOESY, HMQC, and HMBC). Compounds 1-4 displayed significant growth inhibitory activity against the brine shrimp (Artemia salina) and Mucor miehei.

[Inhibitory effect of knocking down microRNA-221 and microRNA-222 on glioma cell growth in vitro and in vivo].

OBJECTIVE: To study the inhibitory effect of knocking down microRNA(miR)-221 and miR-222 on human glioma cell growth and its possible mechanism. METHODS: miRNA-221/222 antisense oligonucleotides (antisense miR221/222) were transfected into human glioma U251 cells by lipofectamine. Northern blot analysis was conducted to detect the mRNA expression of miR-221/222 in the control and transfected cell groups. The proliferation activity of cells was determined by MTT assay. Cell invasion ability was examined by transwell assay, and cell cycle kinetics and apoptosis were detected with flow cytometry. The expression of relevant proteins was analyzed by Western blotting. The therapeutic efficacy of antisense miR221/222 on the growth of xenograft tumors in nude mice were also observed. RESULTS: In the antisense miR-221/222-transfected cells, the expression of miR-221/222 was significantly reduced; the cell invasion ability was suppressed, cell cycle was blocked at G(0)/G(1) phase, and apoptotic cells were increased. The growth of xenograft tumors treated with antisense miR-221/222 was also inhibited. In antisense miR-221/222 treated tumor cells, the expression of bcl-2 was down-regulated while connexin43, p27, PUMA, caspase-3, PTEN, TIMP3 and Bax up-regulated, and p53 expression not changed. CONCLUSION: There is a significant inhibitory effect of antisense miR-221/222 on the growth of human glioma U251 cells. miR-221/222 may be considered as a candidate target for gene therapy of human gliomas.