Novel Secondary Metabolites, Spirosorbicillinols A, B, and C, from a Fungus

Abstract

In our searching program for novel sorbicillin related compounds, three novel compounds, spirosorbicillinols A (1), B (2), and C (3), were isolated from the fermentation broth of the USF-4860 strain isolated from a soil sample. The planar structures of compounds 1-3 were determined from spectroscopic evidence and degradation reaction, and that of 1 was the same as that of 2. The relative stereochemistries of compounds 1-3 were determined by (1)H-(1)H coupling constants, the elucidation of HMBC and NOESY spectra in detail. 1 and 2 were stereoisomers at C8 position, each other. We propose that compounds 1 and 2 were formed by exo and endo intermolecular Diels-Alder reaction between sorbicillinol as a diene and scytolide (proposed precursor-1) as a dienophile, respectively. Similarly, we propose that compound 3 was formed by an endo intermolecular Diels-Alder reaction between sorbicillinol and proposed precursor-2.

Identification of a Polyketide Synthase Involved in Sorbicillin Biosynthesis by Penicillium chrysogenum

“…The yellow pigments sorbicillinoids are a large group of structurally related metabolites produced by many fungi (1,3,5,11,(21)(22)(23)(24). The polyketide origin of these compounds was demonstrated by radiolabeled acetate feeding experiments (11), but the genes involved in the biosynthesis of these secondary metabolites remained unknown.…”

Chemoenzymatic Total Synthesis of Sorbicatechol Structural Analogues and Evaluation of Their Antiviral Potential

“…Further functionalized sorbicillinoids are likewise formed by these transformations, but instead of a simple dimerization, these transformations involve non‐sorbicillinoid nucleophiles or dienophiles. Structurally and biomedically interesting examples of this class of sorbicillinoids include 5 , 6 , and 7 a (Scheme ) …”

“…Compound 5 is active against murine leukemic lymphoblast cell line L5178y, with an IC 50 of 2.2 mg mL −1 , and protects human T cells from HIV‐1 over a concentration range of 0.3 and 3.0 mg mL −1 . Compound 6 shows 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging activity; this property is also typical for dimeric sorbicillinoids, such as 3 . Although currently far less studied, compared with the above‐mentioned compounds, compound 7 a was reported to exhibit promising antiviral activity against H1N1 .…”

Diels–Alder Reactions During the Biosynthesis of Sorbicillinoids

“…Theh ybrid sorbicillinoids 6a/b are considered to derive from dimerization of 2a with 12 (Scheme 1D). [19] To further investigate the role of SorD in the dimerization of 2,scytolide (12)was purified from T. reesei DsorA ( Figure 1B)and fed to A. oryzae strains and then extracted using standard conditions. 12 remained unaltered in the NSAR1 control (Figure 4A).…”