Reticulol is an isocoumarin derivative produced by certain species of Streptomyces that inhibits cAMP phosphodiesterase (IC50 = 41 uM). It also inhibits DNA topoisomerase I when used at a concentration of 45 uM in B16F10 melanoma cells. Reticulol has antifungal activity against T. mentagrophyes with a MIC of 1.8 uM. It is cytotoxic against A427 human lung and B16F10 mouse melanoma cells at concentrations of 25 and 200 uM, respectively, and inhibits lung metastasis in mice.