Abstract: Chemical constituents of the fermentation broth of endophytic fungi Alternaria sp.TY23 associated with Gastrodia elata were studied.Ten compounds were isolated,and their chemical structures were determined by spectrum analysis as alternariol5Omethyl ether (1),altenusin (2),ACTGtoxin D (3),ACTGtoxin E (4),tricycloalternarene D (5),tricycloalternarene 6b (6),tricycloalternarene 6a (7),tricycloalternarene 1a (8),tricycloalternarene B (9),3methoxy6,8dihydroxy3methyl3,4dihydroisocoumarin (10).All of these compounds were isolated from the endophytic fungi of Gastrodia elata for the first time.

Key words: endophytic fungus, Alternaria sp., chemical constituents, structural determination