Plant extracts containing furocoumarins compounds were identified by using melanin producer strains of Nocardiopis sp (DAUFPE-361) and non producer strains of Streptomyces sp (DAUFPE-87). Ethanol, methanol and acetone extracted compounds from conduru (Brosimum gaudichaudii) bark and stem were evaporated and added to tubes containing ISP7 medium (tyrosine agar). This medium was inoculated with spore suspension (10(6)-10(7) CFU) prepared from the different actinomycetes strains. The ethanol fraction (pH 9.0) from both bark and stem induced pigmentation in actinomycetes melanin non producer strains and increased the pigmentation in producer strains indicating presence of furocoumarins in the correspondent plant extracts.