Studies On The Secondary Metabolites And Bioactivities Of Two Fungi

Microbial secondary metabolites are diverse in structure and rich in bioactivity,which provide a great resource for human to study active compounds.In the previous work,two fungi were isolated from Gaoligong mountain.They were identified as Pestalotiopsis sp.GLGS-5 and Eurotium sp.GLGS-4 based on their ITS sequences respectively.The secondary metabolites of the two fungi were abundant,and the crude extract had certain anti-acetylcholinesterase?AChE?activity.The two strains were screened with different media,and fermentation was carried out with a better medium.Then,we isolated and identified the secondary metabolites of two fungi,and tested the anti-acetylcholinesterase and antibacterial activity of compounds.The results were as follows:Nine compounds were isolated from the strain Pestalotiopsis sp.GLGS-5,and five compounds were identified.They are 6-[1-hydroxy-?1S?-pentyl]-4-methoxy-?6S?-2H,5H-2-p-yranonem?1?,?6S,1'S,2'R?-6-?1',2'-dihydroxypentyl?-4-methoxy-5,6-dihydropyrane-2-one?2?,pestalrone A?3?,methyl linolenate?4?and pestalrone C?8?.Among them,pestalrone C?8?is a new compound.Fourteen compounds were isolated from the strain Eurotium sp.GLGS-4,and eight compoundswereidentified.Theyareflavoglaucin?2?,7-OH-emodin?4?,2,4-dihydroxy-6-methylacetophenone?5?,orcinol?6?,3-acetyl-5-hydroxy-7-methoxy-2-methoxy-1,4-naphthalenedione?7?,physcion?9?,1-?2-hydroxy-4-methoxy-6-methylphenyl?ethanone?11?and1,6-dihydroxy-3-?hydroxymethyl?-8-methoxy-9,10-anthracenedione?14?.All compounds obtained from the two fungi have been assessed for antibacterial activity and AChE inhibition activity.The result shows that:compounds 2 and 8 isolated from the strain Pestalotiopsis sp.GLGS-5 had AChE inhibition activity at the final concentration of100?g/mL,inhibition rate were 46.1%and 27.7%respectively,IC₅₀0 value were 16.43?M and33.90?M respectively;compounds 3,8,11 and 14 isolated from Eurotium sp.GLGS-4 had a certain AChE inhibition activity,the inhibition rate were 57.6%,43.8%,31.7%,46.6%respectively.IC₅₀0 value were 36.88?g/mL,17.48?g/mL,121.61?M and 52.39?M respectively,the rest of the compounds had no obvious acetylcholinesterase inhibition activity.Compounds 4 and 9 isolated from the strain Eurotium sp.GLGS-4 had weak inhibitory activity to Bacillus cereus and B.subtilis,at the concentration of 400?g/mL,the rest of the compounds had no obvious antibacterial activity.