Abstract: A new depsidone, cetrariastrumin (1), C22H20O10, mp. l63-165℃, has been isolated from the extracts of Cetrariastrum nepalensis Awas. by means of silicagel column chromatography. The structtlre of (l ) was elucidated as 3-formyl- 4-hydrox--3' -hydrokymethyl-2', 6'-diethoxycarbony1- 6-methyl-depsidone by IR, UV, MS, 1H NMR and 18C NMR spectral data of cetrarias- trumin is presented.

Key words: structure, cetrariastrumin, desidone, lichen