Studies On The Secondary Metabolites Of Endophytic Fungi Aspergillus Flavipes

There were two chapters in the dissertation.The secondary metabolites of Aspergillus flavipes,derived from Lycoris radiata were systematic studied in the first chapter.The second chapter is a review of natural polyketides from marine-derived fungi and their biological activities,focusing on the period from 2006 to 2016.Previous investigations on fungi concerning the genus Aspergillus flavipes shown that their primary secondary metabolites were aspochalasin,butyrolactone,epicoccine derivatives and other compounds.Cytochalasans is a group of polyketide–amino acid hybrid metabolites,which have a variety of biological activities,such as phytotoxicity,antitumor activity and antibacterial activity.We isolated Aspergillus flavipes from Lycoris radiata.It was then analyzed by means of repeated gel chromatographies,including normal phase chromatographies,Sephadex LH-20,reversed-phase chromatographies,and semi-preparative HPLC.Finally we isolated and identified 10 compounds in this work.We determined the structures of 10 compounds by comparing their physicochemical parameters and NMR data with published literatures,including: aspochalasin P(1),aspochalasin H(2),aspergillin PZ(3),epicoccolide B(4),N-Benzoyl-L-phenylalaninol(5),Methyl acetylsalicylate(6),epicoccine(7),4-Hydroxyphenylacetic acid(8),emodin(9),questin(10).This study enriched people’s understanding of the secondary metabolites of Aspergillus flavus and provided a scientific basis for the further study of the strain resources.