Antioxidant Activity of Secondary Metabolites from the Endophytic Fungus Isolated and Identified from Noni（Morinda Citrifolia Linn.）

Key words: 
• Morinda Citrifolia Linn. /
• endophytic fungi /
• isolation and identification /
• antioxidant activity

Abstract: Fruits and leaves of noni（ Morinda citrifolia Linn.） were collected in Wanning,Danzhou,Qionghai,Sanya,Lingao and Haikou,Hainan Province,from which 32 strains of endophytic fungi were isolated,cultured at 25 ℃ and then identified by using 26 S r DNA D1/D2 and ITS r DNA sequencing. The results showed that these 32 strains belonged to the phylum Basidiomycota and the phylum Ascomycota. Of the 32 strains 13 belonged to 3 genera,i. e. Aureobasidium,Rhodotorula and Cryptococcus,and 5 species,and 19 belonged to 7 genera,i. e. Colletotrichum,Diaporthe,Hypoxylon,Cladosporium,Fusarium,Phyllosticta and Gibberella,and 10 species. The secondary metabolites were extracted with ethyl acetate as solvent from 15 fermented solutions of noni endophytic fungi,and their antioxidant activity was evaluated with ABTS⁺ ·-free radical scavenging assay.The total polyphenols content（ TPC） and total flavonoid content（ TFC） of the secondary metabolites were determined by using Folin-reagent method and Al Cl₃ colorimetric method. The antioxidant assay showed that ethyl acetate extract from 15 solutions of endophytic fungi was full of antioxidant activity,and that the antioxidant activity of M48 and J22 was significantly different. Noni endophytic fungi had abundant diversity and the potential to produce antioxidant substances which have important application value and broad prospect in healthcare and medical sector.