Isolation Of A Strain Of Endophytic Fungus Colletotrichumsp And Study On The Metabolites From The Strain Of HCCB03289

Endophytic fungi can produce numerous secondary metabolites withnovel chemical skeletons and varied bioactivities, and they have been one ofthe important sources for searching new lead compounds of drug.In this paper, 304 strains of endophytic fungi were isolated from 61kinds of plants by surface-sterilized method. Predominant endophytic fungifrom three kinds of Asarum heterotropoides were different in types andquantities. 126 and 12 strains out of 134 endophytic fungi showed inhibitionactivities by antitumor and antibacterial screening. The strain HCCB03289from Ludwigia prostrata Roxb. was identified as Colletotrichum sp. bymorphology together with similarity of 18S rDNA internal transcribed spacer(ITS) sequence. The metabolites from the strain of HCCB03289 were isolated and purified by organic solvent extraction, silica gel chromatography,gel chromatography and HPLC preparation, and 12 kinds of compounds wereobtained. The chemical structure of these compounds were identified withESI-MS, 13C-NMR, 1H-NMR, HSQC, HMBC, COSY and NOESY asPyrenocine A, Pyrenocine B, Pyrenocine E, Pyrenocine G, Macommelinoacetate(Pyrenocine L), (2α,3β)-3-hydroxy-2,5-dimethyl-3,4-dihydropyrano[4,3-b]pyran-7(2H)-one(Pyrenocine M) and (2α,3β)-3-hydroxy-2,5-dimethyl-3,4-dihydropyrano[4,3-b]pyran-7(2H)-one(Pyrenocine N), Cathisterol,Ergosterol, 6-Hydroxymellein, indole acetic acid and phenyl acetic acid. Nineof these compounds Pyrenocine A, Pyrenocine B, Pyrenocine E, PyrenocineG, Pyrenocine L, Pyrenocine M, Pyrenocine N, 6-Hydroxymellein andCyathisterol were isolated from Colletotrichum sp. for the first time. The newcompound Pyrenocine L, Pyrenocine M and Pyrenocine N were first found.The antitumor activities of compounds Pyrenocine A, Pyrenocine B,Pyrenocine E, Pyrenocine G, Pyrenocine L, Pyrenocine M, Pyrenocine N,6-Hydroxymellein and Cyathisterol were investigated on the models of MDA,A549 and PANC1, and the results indicated that Pyrenocine A showedsignificant antitumor activity against MDA and IC50 was less than 2.0μg/mL;Pyrenocine B, Pyrenocine E and 6-Hydroxymellein had higher antitumor activities, and IC₅₀ were less than 30μg/mL.