Potential Antidiabetic Fumiquinazoline Alkaloids from the Marine-Derived Fungus F41-1.

Fumiquinazoline alkaloids have attracted much attention from medicinal and natural product chemists due to their interesting structures and biological potential. In this study, three new and 12 known fumiquinazoline alkaloids were isolated and characterized from the marine fungus F41-1. The structures of the new compounds and their absolute configurations were determined using NMR spectroscopy, ECD, and OR calculations.

Reactive oxygen species altering the metabolite profile of the marine-derived fungus F31-1.

To investigate the influence of reactive oxygen species (ROS) on the secondary metabolites of the marine-derived fungus F31-1, hydrogen peroxide (HO) was added to the GPY culture medium. The HPLC chromatogram of the EtOAc extract of the culture broth was distinct from that of the HO free GPY medium. Further study of the metabolites in the GPY medium with HO resulted in the discovery of eight known compounds.

Polyketides and Alkaloids from the Marine-Derived Fungus F31-1 and the Antiviral Activity of Scequinadoline A against Dengue Virus.

In our continuous chemical investigation on the marine-derived fungus F31-1, two new polyketides dichocetides B-C (, ), two new alkaloids dichotomocejs E-F (, ), and three known fumiquinozalines: scequinadoline A (), quinadoline A (), and scequinadoline E () were discovered from the culture broth and the mycelium in the culture medium, by the addition of l-tryptophan and l-phenylalanine. Their chemical structures were established by one dimensional (1D), two dimensional (2D) nuclear magnetic resonance (NMR) and high resolution mass spectrometry (HR-MS) data. Among them, scequinadoline A () exhibited significant inhibitory activity against dengue virus serotype 2 production by standard plaque assay, equivalent to the positive control andrographlide.

Ab initio MRCI+Q calculations on the low-lying excited states of the MgBr radical including spin-orbit coupling.

Accurate theoretical calculations on the MgBr radical have been carried out by using the high-level relativistic multireference configuration interaction method with Davidson correction (MRCI+Q) using correlation-consistent Quintuple-ζ quality basis set. The potential energy curves (PECs) of the 14 Λ-S states of MgBr have been computed. In order to improve the PECs, the core-valence correlation, scalar relativistic effect, and spin-orbit coupling effect are taken into account in the computations.

Ab initio calculations on potential energy curves and radiative lifetimes for the band systems A(2)Π-X(2)Σ(+) of magnesium monohalides MgX (X=F, Cl, Br, I).

Ab initio calculations on potential energy curves (PECs), spectroscopic constants, transition dipole moments, radiative transition probabilities and lifetimes for the ground state (X(2)Σ(+)) and the first excited state (A(2)Π) of MgX (X=F, Cl, Br, I) molecules are determined by high-level internally contracted multi-reference configuration interaction (ic-MRCI) method. In order to improve the calculation, the Davidson modification (+Q) and scalar relativistic correction are included. The present results show that most of spectroscopic constants are in accordance with the measurements, the equilibrium internuclear distance Re increases while the other spectroscopic constants reduce along with the increasing of the atomic number of the halogen from F to I.