This manuscript discusses the experience of the research group BIOPROS (Molecular Bioprospecting in the Sustainable Use of Biodiversity) from the Federal University of Viçosa in the field of bioprospecting. We describe our experience on the search for antitumor compounds from the collection of extracts of native tree species from the Atlantic Forest biome. Presenting an interdisciplinary approach, integrating knowledge of forestry engineering, bioinformatics and natural products chemistry, the bioprospecting research of the BIOPROS group has innovated in the generation of pharmacochemical knowledge of native species of the Atlantic Forest. For the composition of the extract library a total of 220 plant species distributed in 57 botanical families and 140 genera were identified. 196 extracts from 49 plant species were produced; all of them evaluated for cytotoxic activity. By showing the process of obtaining a promising antitumor activity withanolides compounds from Athenaea velutina, a species hitherto little known to science, this manuscript shows our sequence of methodological steps used to unravel bioactive natural products from fragments of Atlantic Forest. The research follows the premises of the Convention on Biological Diversity, regarding the creation of strategies for the sustainable use of biodiversity.