Metabolites of the marine fungus <Emphasis Type="Italic">Humicola fuscoatra</Emphasis> KMM 4629

A new sesquiterpene of the caryophyllene series, fuscoatrol A (1), and known compounds, 11-epiterpestacin (2) and -nitropropionic acid (3), were isolated from the marine fungus Humicola fuscoatra (Traaen) KMM 4629 associated with the Kuril colonial ascidium. The structure of 1 was established on the basis of X-ray diffraction data and 2D NMR spectroscopy. The antimicrobial and cytotoxic activities of compounds 1–3 were studied.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2534–2537, November, 2004.     

Mass spectrometry of kaurene derivatives—I. The mass spectra of some (−)-kauran-16-ols

The mass spectra of nine compounds belonging to the group of (?)-kauran-16-ols are reported. These compounds differ either by stereochemistry at C₁₆ (I, II) or by the nature of the substituent at C₄ (III to VIII). In all cases the most characteristic ions correspond to a process in which ring D is split off and lost as a C₃H₆O fragment. The nature of the substituent R₁ at C₄ can be deduced from such typical ions as [M ? R₁]+ or [M ? R₁ ? H₂O]+. Kauranols epimeric at C₁₆ show little difference in their mass spectra; the assignment of configuration at this centre may be reliable only when the spectra of both epimers are compared.     

Structural characterization of gentiobiosyl diglycerides fromBacillus pumilus associated with ascidiaHalocynthia aurantium

A mixture of 1(3),2-di-O-acyl-3(1)-O-β-gentiobiosylglycerols was isolated from a sea isolate ofBacillus pumilus. The components of the mixture were structurally characterized by mass spectrometry and¹H and¹³C NMR spectroscopy data for the native compounds and their derivatives. The predominant component contains two C₁₅ acyl groups, while the second component contains C₁₅ and C₁₇ fatty acids. Six minor components differ in residues of fatty acids and/or their combinations. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 166–170, January, 2000.     

Mott effect and J/\psi dissociation at the quark-hadron phase transition

We investigate the in-medium modification of pseudoscalar and vector mesons in a QCD-motivated chiral quark model by solving the Dyson-Schwinger equations for quarks and mesons at finite temperature for a wide mass range of meson masses, from light ( , ) to open-charm (D, D ^*) states. At the chiral/deconfinement phase transition, the quark-antiquark bound states enter the continuum of unbound states and become broad resonances (hadronic Mott effect). We calculate the in-medium cross-sections for charmonium dissociation due to collisions with light hadrons in a chiral Lagrangian approach, and show that the D- and D ^*-meson spectral broadening lowers the threshold for charmonium dissociation by - and -mesons. This leads to a step-like enhancement in the reaction rate. We suggest that this mechanism for enhanced charmonium dissociation may be the physical mechanism underlying the anomalous suppression observed by NA50.Received: 30 September 2002, Published online: 22 October 2003PACS: 05.20.Dd Kinetic theory - 12.38.Mh Quark-gluon plasma - 14.40.-n Mesons - 25.75.Nq Quark deconfinement, quark-gluon plasma production, and phase transitions     

Two new steroidal saponins, hylodoside A and novaeguinoside Y, from the starfish Leptasterias hylodes reticulata and Culcita novaeguineae (juvenile)

New steroid glycosides, hylodoside A (1) and novaeguinoside Y (2), along with previously known polyhydroxylated steroids (3-7) were isolated from the ethanolic extracts of the starfish Leptasterias hylodes reticulata and Culcita novaeguineae (juvenile). The structures have been elucidated using 1D and 2D NMR spectra (1H, 13C, DEPT, COSY-45, 1D-TOCSY, HSQCGP, ROESY, HSQC and HMBCGP) and mass spectrometry. Compound 3 was shown to inhibit the growth of Staphylococcus aureus up to 10% from the control at a concentration of 1 mg/mL. Steroids 1, 2 and 5 showed moderate hemolytic activity in the mouse erythrocytes assay. Compounds 3, 4 and 6 displayed pH-depended hemolytic properties.     

4-Methoxy-3-methylgoniothalamin from marine-derived fungi of the genus Penicillium

The new styrylpyrone derivative, viz. 4-methoxy-3-methylgoniothalamin (1), and the known compound sulochrin were isolated from the marine-derived fungi Penicillium glabrum and P. implicatum. The structure of compound 1 was determined by X-ray diffraction, 2D NMR spectroscopy, and high-resolution mass spectrometry. It was shown for the first time that sulochrin increases expression of the protein Hsp70.     

The mass spectrometry of kaurene derivatives—II: Kaurenolides and related systems

The mass spectra of a number of natural (II, IV, XII) and modified kaurenolides (I, III, V to XI) are reported. The major fragmentations of these compounds occur by rupture of the ring B to give fragments B and C, both of which contain the ring A. In the case of the 7-hydroxycompounds (II and III) their mass spectra are markedly different due to the difference in configuration at C₇.     

New diterpene glycosides of the fungus Acremonium striatisporum isolated from a sea cucumber

Three new diterpene glycosides, virescenosides V (1), W (2), and X (3) have been isolated from a marine strain of Acremonium striatisporum KMM 4401 associated with the holothurian Eupentacta fraudatrix. Their structures have been elucidated on the basis of high resolution mass spectrometry, 1D and 2D NMR (1H, 13C, DEPT, COSY 45, COSY RCT, HSQC, HMBC, and NOESY spectra) as 19-O-beta-D-altropyranosyl-7-oxo-isopimara-8(14),15-diene-2alpha,3beta-diol (1), 19-O-beta-D-altropyranosyl-isopimara-7,15-diene-2 alpha,3 beta,6 alpha-triol (2), and 19-O-beta-D-altropyranosyl-isopimara-8,15-diene-2 alpha,3 beta,7 alpha-triol (3).