The metabolites of Talaromycesflavus: Part 2. Biological activity and biosynthetic studies

• Published in: Canadian journal of chemistry 1990-11, Vol.68 (11), p.2095-2101
• Main Authors: Ayer, William A, Racok, Julie S
• Format: Article
• Language: English
• ISSN: 0008-4042; 1480-3291
• DOI: 10.1139/v90-319

The soil fungus Talaromycesflavus (Klöcker) Stolk and Samson is an effective biological control for Verticillium wilt of eggplant (Solanummelongena L.), a disease caused by the fungus Verticilliumdahliae Kleb. The water soluble metabolites isolated from the broth when the fungus is grown in liquid still culture, hydroxymethylmaltol ( 1 ), 5,6-dihydro-3,5-dihydroxy-6-hydroxymethyl-2H-pyran-2-one ( 3 ), and D -glucono-1,4-lactone ( 5 ), do not show antifungal activity against V. dahliae; however, hydrogen peroxide displays this inhibition. This peroxide has been detected in the T. flavus broth and it, together with 5, is the product of the glucose oxidase catalyzed oxidation of D -glucose. The results of the search for this antifungal activity are presented. [1- 13 C] Labelled sodium acetate was utilized as a precursor for studying the biosynthesis of the T. flavus metabolites 4,6-dihydroxy-5-methylphthalide ( 7 ), methyl 4-carboxy-5-hydroxyphthalaldehydate ( 8 ), and talaroflavone ( 9 ). The incorporation of label into these compounds is discussed. Keywords: Talaromycesflavus, fungal metabolites, hydrogen peroxide, biosynthesis, talaroflavone.