Fusagerins A–F, New Alkaloids from the Fungus Fusarium sp.

Abstract

Fusagerins A–F (1–6), six new alkaloids including a unique one with the rare a-(N-formyl)carboxamide moiety (1), a hydantoin (imidazolidin-2,4-dione) derivative (2), and four fungerin analogues (3–6), were isolated from the crude extract of the fungus Fusarium sp., together with the known compound fungerin (7). Compound 2 was isolated as a racemate and further separated into two enantiomers on a chiral HPLC column. The structures of 1–6 were determined mainly by NMR experiments, and the absolute configuration of 1 and 2 was assigned by electronic circular dichroism (ECD) calculations. Compound 7 showed antibacterial activity against Staphylococcus aureus and Streptococcus pneumoniae, and weak cytotoxicity against the T24 cells.Graphical AbstractElectronic supplementary materialThe online version of this article (doi:10.1007/s13659-015-0067-1) contains supplementary material, which is available to authorized users.

Preparation, Spectral and Biological Studies of Azo Ligand Derived from Proline with Cu(II), Ag(I) and Au(III) Metal Ion

“…So light shift occur when complex formation. Moreover a singlet signal observed in the region δ (2.5) ppm for MBP which was attributed to (-NH) proton of proline [19], there is no shift was seemed in the position in the spectra of the complexes. Furthermore another signal peaks were appeared in the spectra of the prepared ligand (MBP) and its complexes which were described in Table(5 3.5Thermal Analysis: Figure (18) have been represented the thermogravimetric analysis (TG and DTGA) curves temperature up to (900) C 0 under helium as inert gas and differential scanning calorimetric (DSC) curves.…”

“…(14-17) and peak assignments are illustrated in Table (3 -18). A singlet peak was appeared at δ(15.75) ppm in the spectra for ligand (MBP) which was due to one proton of free carboxyl moiety in proline [19]. This signal peak don't affect in coordination but stay almost without any chemical shift.…”

Synthesis, NMR analysis and applications of isotope-labelled hydantoins

“…Crucially, these measurements provided the first experimental evidence to demonstrate that PucI is a medium-affinity transporter of allantoin. The Mhp1 substrates L-5-benzylhydantoin (4) and L-5-indolylmethylhydantoin (5) have been synthesised containing both 13 C and 14 C labels ( Figure 5) for use in solid-state NMR measurements of ligand binding (unpublished) and in whole cell transport assays, respectively, with the Mhp1 protein [60,62]. These compounds were prepared from the appropriate L-α-amino acid (phenylalanine or tryptophan) by reaction with potassium cyanate under acidic conditions to give the Lcarbamoyl-L-α-amino acid, which was then cyclised to give the 5-substituted L-hydantoin ( Figure 5, Scheme 8).…”

“…Allantoin is also present in a number of toothpastes, mouth washes, shampoos and cosmetic products and is used in medications that treat skin conditions including acne, impetigo, eczema and psoriasis. Other natural products that contain the hydantoin ring as part of their chemical structure have been isolated from marine sponges [1,2], from a Mediterranean Sea anemone [3] and from the fungus Fusarium sp [4]. A fulvic acid polymer isolated from a coastal pond in Antarctica is also suggested to contain a hydantoin ring based on a solid-state NMR 15 N and 13 C{ 14 N} chemical shift investigation [5].…”

“…This mechanism enables the bacterium to scavenge low concentrations of hydantoin compounds from its environment. The principal transported substrates of Mhp1 are L-5-benzylhydantoin (4) and L-5-indolylmethylhydantoin (5) ( Figure 2B). [62].…”