Dendrocoumarin: a new benzocoumarin derivative from the stem of Dendrobium nobile.

A new benzocoumarin derivative, dendrocoumarin (1), along with itolide A were isolated from the stems of Dendrobium nobile. The structure of the new compound 1 elucidated on the basis of NMR and mass spectroscopic data. Compounds 1 and 2 showed broad spectrum antibacterial activity against five terrestrial pathogenic bacteria.