PubMed Health⌕ Search

Biomedical subjects

Nicola Borbone

Publications and source records attributed to Nicola Borbone.

12 recordsLinked to original sources
PubMed2006

New constituents of sweet Capsicum annuum L. fruits and evaluation of their biological activity.

Four new acyclic diterpene glycosides named capsianosides (1-4), together with 12 known compounds, were isolated from the fresh sweet pepper fruits of Capsicum annuum L., a plant used as a vegetable food, spice, and external medicine. The chemical structures of new natural compounds, as well as their absolute configurations, were established by means of spectroscopic data including infrared, high-resolution mass spectrometry, and one- and two-dimensional nuclear magnetic resonance and by chemical derivatization. The known capsidiol (11) showed bacteriostatic properties in vitro against Helicobacter pylori with a minimum inhibitory concentration (MIC) of 200 microg/mL when compared with the commercial drug metronidazole (MIC, 250 microg/mL). Some purified components were also tested for their antioxidant activities.

Anti-Bacterial Agents↗
PubMed2006

Physico-chemical analysis of G-quadruplex containing bunch-oligonucleotides.

A growing number of evidences suggest that DNA G-quadruplex structures play an important role in many relevant biological processes. The introduction of chemical modifications in quadruplex structures could enhance the in vivo biological activity. The correlation between the physico-chemical properties and chemical modifications represents an essential step toward the de novo design of quadruplex forming oligonucleotides for biomedical applications. We report the physico-chemical characterisation of a quadruplex formed by a bunch of four d(TG4T) oligonucleotides whose 3'-ends are linked together by a tetra-branched linker. The study was performed by circular dichroism, gel electrophoresis and molecular modelling techniques. The data indicate an high stability for this kind of quadruplex and add some information on the role of the tetra-branched linker on the quadruplex stability.

Models, Molecular↗
PubMed2006

Synthesis and characterization of DNA quadruplexes containing T-tetrads formed by bunch-oligonucleotides.

The solid phase syntheses of the bunch oligonucleotides and based on the sequences of the natural oligodeoxynucleotides (ODNs) d(TG2TG2C) and d(CG2TG2T), respectively, attached to a non-nucleotidic tetrabranched linker, are reported. Bunch-ODNs and were shown to form more stable monomolecular parallel G-quadruplexes and when compared with their tetramolecular counterparts [d(TG2TG2C)]4 and [d(CG2TG2T)]4, respectively. The structure and stability of all the synthesized complexes have been investigated by circular dichroism (CD), CD thermal denaturation experiments, and 1H-NMR (nuclear magnetic resonance) experiments at variable temperatures. Particularly, the spectroscopic data confirmed that 1 adopts a T-tetrad containing parallel-stranded quadruplex structure as in the tetramolecular complex.

Circular Dichroism↗
PubMed2005

New sesquiterpene lactones from Laurus nobilis leaves as inhibitors of nitric oxide production.

Two new metabolites 5alphaH,7alphaH-eudesman-4alpha,6alpha,11,12-tetraol (1) and 1beta,15-dihydroxy-5alphaH,7alphaH-eudesma-3,11(13)-dien-12,6alpha-olide ( 2) have been isolated from the methanolic extract of Laurus nobilis L. leaves. Their structures were determined through analysis of their one- and two-dimensional NMR spectral data ((1)H- and (13)C-NMR, DEPT, COSY, HMQC, HMBC and ROESY). The relative stereochemistry is proposed on the basis of combined J-based configuration analysis and ROESY data. In addition, three known sesquiterpene lactones santamarine (3), reynosin (4) and costunolide (5) along with blumenol C (6) were isolated and identified by spectral means. The isolated compounds 1 - 6 were found to inhibit nitric oxide (NO) production in lipopolysaccharide (LPS)-activated murine macrophages. The most active compound 2 potently inhibited NO (2)(-) release with an IC (50) value of 0.8 microM.

Animals↗
PubMed2005

Unusual monomolecular DNA quadruplex structures using bunch-oligonucleotides.

The chemical synthesis of several G-rich bunch-oligonucleotides and the structural characterization of the corresponding monomolecular G-quadruplexes (I-IV) have been reported. The synthetic method allow the achievement of monomolecular DNA quadruplex structures having unusual and predeterminable oligodeoxyribonucleotide (ODN) strand orientation.

DNA↗
PubMed2004

Megastigmane and phenolic components from Laurus nobilis L. leaves and their inhibitory effects on nitric oxide production.

Laurus nobilis L. leaves are widely used in cooking and in folk medicine. Five new megastigmane glucosides (2-4, 7, and 9) named laurosides A-E and a new phenolic glucoside 12 were isolated from the methanolic extract of L. nobilis L. leaves, along with 10 known components: megastigmane (5), megastigmane glucosides (1, 6, 8, 10, and 11), aromatic compounds (13 and 14), and flavonoids (15 and 16). The structures and relative stereochemistry have been elucidated by one- and two-dimensional nuclear magnetic resonance experiments ((1)H and (13)C NMR, DEPT, correlation spectroscopy, heteronuclear multiple quantum correlation, heteronuclear multiple bond correlation, and nuclear Overhauser enhancement spectroscopy) and by chemical derivatization. The effect of isolated compounds on nitric oxide production in lipopolysaccharide-activated murine macrophages were examined.

Animals↗
PubMed2004

New sesquiterpenes with intestinal relaxant effect from Celastrus paniculatus.

The seed oil obtained from Celastrus paniculatus has been used in Ayurvedic medicine for the treatment of several complaints including intestinal disorders. The muscle relaxing activity of C. paniculatus has been studied in vitro on isolated preparations of rat intestine. C. paniculatus seeds extract (0.001 - 100 microg/mL) produced a concentration-related relaxation of the rat ileum [IC (50) (95 % c. l.) 0.24 (0.13 - 0.45) microg/mL]. Among the four fractions ( n-hexane, CCl (4), CHCl (3), n-BuOH) obtained from the methanolic extract of C. paniculatus, only the carbon tetrachloride fraction (0.01 - 10 000 ng/mL) induced a significant relaxation of the intestinal muscle [IC (50) (95 % c. l.): 1.9 (1.38 - 2.87) ng/mL]. Three new sesquiterpene polyol esters have been isolated from the carbon tetrachloride fraction. These new metabolites, characterised as 1alpha,8beta,14-triacetoxy-9beta-furoyloxydihydro-beta-agarofuran ( 1), 1alpha, 6beta,8beta,14-tetraacetoxy-9beta-benzoyloxydihydro-beta-agarofuran ( 2) and 1alpha,8beta-diacetoxy-9beta-benzoyloxydihydro-beta-agarofuran ( 3), at the concentration of 1 microg/mL produced a relaxant effect of 30.6 +/- 12.2 %, 26.9 +/- 4.7 % and 7.27 +/- 1.7 %, respectively.

Animals↗
PubMed2003

Bioactive asterosaponins from the starfish Luidia quinaria and Psilaster cassiope. Isolation and structure characterization by two-dimensional NMR spectroscopy.

An investigation of the polar extracts from two starfish, Luidia quinaria and Psilaster cassiope, led to the isolation of five sulfated "asterosaponins". Two of them, named luidiaquinoside (1) and psilasteroside (2), are new compounds. Luidiaquinoside (1) contains a novel pentasaccharide chain composed of d-glucose, d-quinovose, and d-fucose, with the d-glucose unit being the branching point. Psilasteroside (2) contains a hexasaccharide chain in which an arabinose residue is detectable in the furanose form. Both of these compounds possess a Delta(9(11)),3beta,6alpha-dihydroxysteroidal nucleus with a 20-hydroxy, 23-oxo functionality. The structures of the new asterosaponins were elucidated by a combination of NMR techniques including (1)H-(1)H (COSY, TOCSY, and ROESY) and (1)H-(13)C (HMQC and HMBC) spectroscopy, ESIMS and HRFABMS spectrometry, and GC analyses. The new asterosaponins show marginal in vitro cytotoxicity against RBL-2H3 (rat basophilic leukemia) cell lines.

Animals↗
PubMed2002

Minor steroidal alkaloids from the marine sponge Corticium sp.

Four new steroidal alkaloids, plakinamine G (1), plakinamine H (2), 4alpha-hydroxydemethylplakinamine B (3), and tetrahydroplakinamine A (4), along with three known compounds, were isolated from the marine sponge Corticium sp. The structures of these metabolites were elucidated largely by 1D and 2D NMR methods and accurate mass measurements (HR-EIMS). Compounds 1, 2, and 4 show significant in vitro cytotoxicity.

Alkaloids↗
PubMedDate not supplied

Synthesis and characterization of monomolecular DNA G-quadruplexes formed by tetra-end-linked oligonucleotides.

Guanine-rich DNA sequences are widely dispersed in the eukaryotic genome and are abundant in regions with relevant biological significance. They can form quadruplex structures stabilized by guanine quartets. These structures differ for number and strand polarity, loop composition, and conformation. We report here the syntheses and the structural studies of a set of interconnected d(TG(4)T) fragments which are tethered, with different orientations, to a tetra-end-linker in an attempt to force the formation of specific four-stranded DNA quadruplex structures. Two synthetic strategies have been used to obtain oligodeoxyribonucleotide (ODN) strands linked with their 3'- or 5'-ends to each of the four arms of the linker. The first approach allowed the synthesis of tetra-end-linked ODN (TEL-ODN) containing the four ODN strands with a parallel orientation, while the latter synthetic pathway led to the synthesis of TEL-ODNs each containing antiparallel ODN pairs. The influence of the linker at 3'- or 5'-ODN, on the quadruplex typology and stability, in the presence of sodium or potassium ions, has been investigated by circular dichroism (CD), CD thermal denaturation, (1)H NMR experiments at variable temperature, and molecular modeling. All synthesized TEL-ODNs formed parallel G-quadruplex structures. Particularly, the TEL-ODN containing all parallel ODN tracts formed very stable parallel G-quadruplex complexes, whereas the TEL-ODNs containing antiparallel ODN pairs led to relatively less stable parallel G-quadruplexes. The molecular modeling data suggested that the above antiparallel TEL-ODNs can adopt parallel G-quadruplex structures thanks to a considerable folding of the tetra-end-linker around the whole quadruplex scaffold.

Chromatography, High Pressure Liquid↗