Abstract: To study the chemical constituents and their toxic activity from the endophytic fungus Phomopsis sp. KY-12, isolated from Pleioblastus amarus. The compounds were isolated and purified by means of chromatographic techniques and their structures were identified on the basis of spectral features. Cytotoxic activity was performed by the brine shrimp (Artemiasalina) larvae bioassay.13known compounds including 9Cadinanesesquiterpenoids, 1 azaphilone and 3 steroids,named 3,12-dihydroxycalamenene (1), 3,9,12-trihydroxycalamenene (2), indicumolide C (3), agripilol C (4), 2,15-tihydroxycalamenene (5), dysodensiol D (6), bombamalones D (7), 8-formyl-7-hydroxyl-5-isopropyl-2-methoxy-1,4-naphthoquinone (8), strobilol A (9), Pyrenocine J (10), 3β, 5α-Dihydroxy-6β-methoxyergosta-7,22-dien (11), ergosterol (12) and ergosterol peroxide (13),were isolated from the organic extract of fermentation broths of the endophytic fungus, Phomopsis sp. KY-12. Compounds 3-9 were first isolated from the Phomopsis genus.Compounds 1-8 showed moderate active against the brine shrimp larvae,compound 9 indicated significant growth inhibitory activity against the brine shrimp (Artemias alina) larvae.

Key words: Endophytic fungus, Phomopsis sp.KY-12;Cadinane sesquiterpenoids;toxic activity;Pleioblastus amarus