Study On The Second Metabolites Of Alternaria Alternata And Fusarium Sp. Hungcl

This paper is divided into three section.Sections one and two mainly discuss the chemical composition and biological activities of secondary metabolites of Alternaria alternata isolated from Camptotheca acuminata's leaves and marine-derived fungus Fusarium sp.Hungcl,respectively.Section three reviews the research progress of secondary metabolites of Alternaria species reported in recent decades.Alternaria alternata is an endophytic fungus of Camptotheca acuminata.Since endophytic fungi acquire the same or similar ability to synthesize secondary metabolites in the process of co-evolution with plants,we expect to isolate secondary metabolites with camptothecin-like antitumor activity from Alternaria alternata.These compounds isolated from the rice ferment of Alternaria alternata were mainly the tricycloalternarene-type meroterpenoids with mevalonate biosynthetic pathway.Among them,three were new meroterpenoids,which were composed of three isoprenyl groups and one ?,? unsaturated cyclohexenone.The novelty of structure is that the isoprenyl side chain moiety and the position of the hydroxyl substitution on the cyclohexenone are different.The absolute configuration of the C-17 hydroxyl group on the isopentenyl side chain of one new compound was determined by Mosher's reaction.Tumor cytotoxicity screening was performed on the isolated new compounds.Three new compounds showed weak cytotoxic activity.Due to the marine environment where marine microorganisms live was in high pressure,high salt,low temperature,no light,low nutrition and other variable factors to survive.Marine microorganisms have the specificity of survival,reproduction and metabolism,and can produce many secondary metabolites with novel structure and diverse biological activities.A total of twenty compounds were isolated from the mangrove soil-derived Fusarium sp.Hungcl including five new ?-pyrones and one new cyclic peptide.The planar structure of fusariumin D reported in the literature is corrected by calculating the carbon spectrum.The absolute configuration of the chiral carbon of the branched portion of the polyketone compound was determined by ECD calculation and comparison of the chemical shift difference of the carbon spectrum.The five new polyketides and one new cyclic peptide were screened for tumor cytotoxicity,screened for PTP1 B inhibitory activity,fursarester B had an inhibition rate of PTP1 B of 56% at 20 ?M.