Structure and absolute configuration of acetosellin, a new polyketide from a phytotoxic strain of Cercosporella acetosella

Abstract

A new yellow pigment, designated acetosellin 1, was isolated from the mycelium of Cercosporella acetosella as a reduced azaphilone metabolite. The structure of I was determined by spectroscopic investigations and chemical evidence. Compound I possesses a novel carbon skeleton that of a naphtopyrane derivative, linked to an extensively conjugated chain. The absolute configuration was determined by NOE experiments and CD correlations

Epicoccolides: Antimicrobial and Antifungal Polyketides from an Endophytic Fungus Epicoccum sp. Associated with Theobroma cacao

“…The large‐scale fermentation and chemical investigation of the crude extract from the solid rice substrate of Epicoccum sp. CAFTBO yielded two polysubstituted polyketides, epicolactone ( 1 )7 and epicoccolide A ( 2 ), together with epicoccolide B ( 3 ),8 acetosellin ( 5 ),9 epicoccamide ( 6 ),10 1,3‐dihydro‐4,5,6‐trihydroxy‐7‐methylisobenzofuran ( 8a ),11,12 the monomethyl ether of the latter ( 8b ),11,12 epicoccone ( 9 ),13 and their postulated biosynthetic precursor, flavipin ( 4 ; Figure 1 and Scheme ). In addition, cerebroside C14 was isolated and characterized.…”

Azaphilones: Chemistry and Biology

“…Acetosellin ( 74 ) from Ce. acetosella Ell at 6.4 × 10 –4 M suppressed Lepidium sativum and Zea mais using the root elongation assays, but not any antifungal activity. Trichoflectin ( 104 ) from T.…”

“…Compound 73 represents a new class of natural fluorescent probes and is a cell-permeable long Stokes shift fluorescent stain for live cell imaging and multiplexing applications . Acetosellin ( 74 ), a naphtopyrane derivative with a novel carbon skeleton, is a phytotoxic pigment of the phytopathogenic fungus Cercosporella acetosella Ell . The absolute configuration was determined by CD correlations.…”

Phytotoxic Secondary Metabolites from Fungi

“…Acetosellin ( 37 ) was isolated from the mycelia of Cercosporella acetosella , the pathogen of leaf spots of the cosmopolitan weed ( Rumex acetosella ). It inhibited root elongation of Lepidium sativum and Zea mais at 6.4 × 10 −4 M [ 53 ].…”