Spicochalasin A and New Aspochalasins from the Marine‐Derived Fungus Spicaria elegans

Abstract

Different culture conditions directed by the OSMAC (one strain-many compounds) approach drastically modified the metabolites of the fungus Spicaria elegans, which yielded the novel spicochalasin A (1), five new aspochalasins M-Q (2-6), and two known aspochalasins (7 and 8). The gross structures of 1-6 were elucidated by 1D and 2D NMR and MS methods, and their absolute configurations were determined by X-ray

An Overview on Marine Sponge-Symbiotic Bacteria as Unexhausted Sources for Natural Product Discovery

“…'OSMAC' is the term for 'one strain many compounds', which is the ability of a single strain to produce different compounds when grown under differing conditions [156]. The culturing of a marine fungus, Spicaria elegans, which was grown under 10 different culture conditions was shown to produce a range of new compounds including the novel spicochalasin A, five new aspochalasins M-Q, and two known aspochalasins [234]. This method was also used to isolate two new O-glycosylated angucyclines, actinosporins A and B from the broth culture of Actinokineospora sp.…”

Spicarins A–D from acetylated extract of fungus Spicaria elegans KLA03

“…Since the absolute configuration of the perhydroisoindol-1-one moiety of aspochalasin has been presumed to be conserved, which was biosynthetically derived from a Diels-Alder-type reaction. 7 (Table 1) revealed 3 had 12 aromatic quarternary carbons, 2 oxygenated methines, an oxygenated methylene, an acetalic methine, 3 methyls and 6 acetyls. In comparison to the 1D NMR data of 5, 3 showed the presence of two fully substituted benzene rings, indicating that 3 has structure of dimer of 5.…”

“…7 Spicarin A (1) and B (2) is the first example of carbon-carbon bonds substitution at C-19 and C-20 of aspochalasins class, and represented a type of unprecedented skeleton compounds. Although it is uncertain whether the carbon-25 carbon bonds substitution at C-19 and C-20 of aspochalasins formed enzymatically or during the acylation reaction，this study suggested that simple derivatization can be very useful to generate/identify novel skeleton compounds.…”

Three New Cytochalasins from the Marine‐Derived Fungus Spicaria elegans KLA03 by Supplementing the Cultures with L‐ and D‐Tryptophan

“…-Previous studies revealed that the fungus S. elegans produced two types of cytochalasins, one bearing a phenylalanine residue (10-phenylcytochalasins) and the other bearing a leucine residue (aspochalasins) [5] [6] [9]. These biosynthetic pathways could be activated under stationary and shake-culture conditions in different media, respectively.…”

“…Therefore, we further chemically investigated the strain Spicaria elegan by OSMAC method. Five new aspochalasins were obtained from this strain by varying the culture conditions [9], and two new 7-deoxycytochalasins by the addition of metyrapone, an inhibitor of P-450 dependent monooxygenases [10]. Cytochalasin biosynthesis had been revealed by the formation of an acetate-and methionine-derived octa-or nonaketide chain, and the attachment of an amino acid.…”