Brevianamide J, A New Indole Alkaloid Dimer from FungusAspergillus versicolor

Abstract

Brevianamide J (1), a new indole alkaloid dimer, was isolated together with four new diketopiperazine alkaloids (brevianamide K-N, 2-5) from the solid-state fermented culture of Aspergillus versicolor. Their structures were elucidated on the basis of spectral data. X-ray crystallographic analysis confirmed the structures of 1 and 4.Diketopiperazine alkaloids, a class of important secondary metabolites, are widely found in fungi such as Aspergillus, 1 Penicillium, 2 Pestalotiopsis, 3 and Chromocleista. 4 This class of alkaloids are derived from different amino acids and one or more isoprene units. Most of them are characteristic of diverse ring systems and possess diverse biological activities, 5 which attracted much attention of synthetic chemists. 6 Species of Aspergillus are important medically and commercially. Members of the genus are sources of natural products that can be potentially used to treat human diseases. 7 In the course to investigate the alkaloids from the fungus Aspergillus Versicolor, a new alkaloid dimer (1), together

Oxepinamides: Novel Liver X Receptor Agonists from Aspergillus puniceus

“…Hence, the planar structure of 2 was assigned as shown in Figure 1. Brevianamide L, a structure reported recently, [9] shares the same planar structure of 2, but the configuration of C-12 differed in the two compounds. The relative configuration of brevianamide L was deduced by NOESY correlations between H-11 and H-2Ј/H-6Ј.…”

“…Only six have been described: these are oxepinamide A-C, [8] cinereain, [10] janoxepin, [11] and brevianamide L. [9] All of these, except brevianamide L, have the same skeleton as that of oxepinamide D (1); brevianamide L shares the framework of compounds 2-4. It has been presumed that the biosynthesis of natural products featuring oxepin moieties proceeds through a thermal 6π electrocyclic ring opening of arene oxides.…”

Four New Alkaloids, Brevianamides O – R, from the Fungus Aspergillus versicolor

“…[8], and chromones such as aspergillitine or aspergiones A -F [9]. Our previous study on the alkaloidal metabolites of the fungus A. versicolor led to the identification of five new diketopiperazine alkaloids [10]. The present study disclosed four new diketopiperazine alkaloids, brevianamides O -R (1 -4, resp.…”

“…The molecular formula (C 22 Table 1). The NMR data and the UV maxima at l max 209 (4.10), 248 (3.78), and 339 (3.53) nm suggested that compound 1 was an analog of brevianamide L [10]. The comparison of the NMR data of 1 with those of brevianamide L suggested that one O-bearing C-atom resonates at d(C) 84.5 in 1 instead of d(C) 70.4 in brevianamide L. The OH group must be located at C(3) in view of the key HMBCs of HÀC(17) and HÀC(18) with d(C) 84.5 (C(3)).…”

“…Therefore, a variety of secondary metabolites of A. versicolor were extensively characterized, including xanthones such as sterigmatin [2] and sterigmatocystin [3], anthraquinones such as averantin [4], averufin [5], and versicolorone [6], a terpenoid, versiol [7], lactones [8], and chromones such as aspergillitine or aspergiones A -F [9]. Our previous study on the alkaloidal metabolites of the fungus A. versicolor led to the identification of five new diketopiperazine alkaloids [10]. The present study disclosed four new diketopiperazine alkaloids, brevianamides O -R (1 -4, resp.…”