Zygosporium masonii

Cytochalasins.—Previous results have shown that the cytochalasins, e.g. cyto-chalasin B (126), are partially polyketide in origin cf. Vol. 7, p. 29 Vol. 6, p. 44). It has now been shown that [2-2H3,2-13C]acetic acid is incorporated into cyto-chalasin B (126) in Phoma exigua and into cytochalasin D in Zygosporium masonii. Labelling of the expected sites by 13C was observed for both metabolites, but, in keeping with results on other acetate metabolites, most of the deuterium was lost, being retained only in the polyketide chain at C-l 1, which is part of the starter acetate unit.102... 

The Ascomycete Exserohilum rostratum (strain CNK-630) and the Deuteromycete Zygosporium masonii (strain CNK-458), from cyanobacterial carpets collected on the Hawaiian islands of Lanao and Maui, respectively, both yield rostratins A-D, which are cyclic disulfides related to diketopiperazine and presenting structural analogies with gliotoxin (vide supra). Rostratins A-D are cytotoxic to the cell line HCT-116 (colon cancer) with IC50 values respectively of 8.5, 1.9, 0.76, and 16.5 pgml (Tan et al, 2004). 

Oh, D.-C., Jensen, P.R., and Fenical, W. (2006) Zygosporamide, a cytotoxic cyclic depsipeptide from the marine-derived frmgus Zygosporium masonii. Tetrahedron Lett., 47, 8625-8628. 

Cytochalasin D = zygosporin A (75,165,18/ ,21 R)-21 -Acetoxy-7,18-dihydroxy-16, 18-dimethyl-10-phenyl-[l Ijcytochalasa-6( 12), 13( ), 19( )-triene-1,17-dione C30H37NO6 6 M. anisopliae, Zygosporium masonii Hayakawa et ai (1968) Aldridge and Turner (1969a,b) Tsukuda et al. (1969) Minato and Matsumoto (1970) Tsukuda and Koyama (1972)... 

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