Two new compounds, a diterpenoid and an anthraquinone, as well as an indane
derivative, which is reported as a natural product for the first time, hav
e been isolated from the cells of the cultured cyanobacterium Nostoc commun
e (EAWAG 122b) by means of bioguided isolation. The structures were determi
ned by spectroscopic methods, mainly NMR, infrared spectroscopy, and mass s
pectrometry. All isolates exhibit antibacterial activity.