Isolation, structure elucidation and biological activity of metabolites from Sch-642305-producing endophytic fungus Phomopsis sp. CMU-LMA

• Main Authors: Emilie Adelin, Claudine Servy, Sylvie Cortial, Hélne Lévaique, Marie Thérse Martin, Pascal Retailleau, Géraldine Le Goff, Boonsom Bussaban, Saisamorn Lumyong, Jamal Ouazzani
• Format: Journal
• Published: 2018
• Subjects: Agricultural and Biological Sciences; Biochemistry, Genetics and Molecular Biology
• Online Access: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=80054953379&origin=inward; http://cmuir.cmu.ac.th/jspui/handle/6653943832/49541
• Institution: Chiang Mai University

Eight polyketide compounds were isolated from the cultivation broth of Phomopsis sp. CMU-LMA. We have recently described LMA-P1, a bicyclic 10-membered macrolide, obtained as a bioconversion derivative of Sch-642305, the major compound isolated in this study. Benquinol is the ethyl ester derivative of the 13-dihydroxytetradeca-2,4,8-trienoic acid produced by Valsa ambiens. This compound is concomitantly produced with the 6,13-dihydroxytetradeca-2,4,8- trienoic acid (DHTTA) previously isolated from Mycosphaerella rubella. The absolute configuration of the new compound, (2R,3R,4S,5R)-3-hydroxy-2,4- dimethyl-5-[(S,Z)-3-methylpentenyl]-tetrahydro-pyranone LMA-P2 was confirmed by X-ray crystallography. The δ-lactone 2,3-dihydroxytetradecan-5-olide (DHTO) was previously isolated from Seiridium unicorne. This compound may form through the cyclization of the methyl-2,3,5-trihydroxytridecanoate LMA-P3, a new linear polyketide isolated in this study. Benquoine, a new 14-membered lactone generated from the cyclization of benquinol, is proposed as the key precursor for the biosynthesis of Sch-642305. Antimicrobial activity and cancer cell viability inhibition by the new compounds were investigated. Benquoine exhibits antimicrobial activity against Gram positive bacteria, and cytotoxicity against HCT-116 cancer cell line. © 2011 Elsevier Ltd. All rights reserved.