Bioactivity and chemical composition of the essential oil from the leaves of <i>Guatteria australis</i> A.St.-Hil Alberto Theodoro SiqueiraCarlos Freitas SerainAlessandra Cristina Rheder Fagundes PascoalAislan Luiza AndreazzaNathalia Caramano de LourençoCaroline Lúcia T. Góis RuizAna Ernesto de CarvalhoJoão Cláudia Oliveira de SouzaAna Tonini MesquitaJuliana Gustavo TemponeAndre José SalvadorMarcos 2015 <div><p>Essential oil from the leaves of <i>Guatteria australis</i> was obtained by hydrodistillation, analyzed by Gas Chromatography coupled to Mass Spectromery (GC–MS) and their antiproliferative, antileishmanial, antibacterial, antifungal and antioxidant activities were also evaluated. Twenty-three compounds were identified among which germacrene B (50.66%), germacrene D (22.22%) and (<i>E</i>)-caryophyllene (8.99%) were the main compounds. The highest antiproliferative activity was observed against NCI-ADR/RES (TGI = 31.08 μg/ml) and HT-29 (TGI = 32.81 μg/ml) cell lines. It also showed good antileishmanial activity against <i>Leishmania infantum</i> (IC<sub>50</sub> = 30.71 μg/ml). On the other hand, the oil exhibited a small effect against <i>Staphylococcus aureus</i> ATCC 6538, <i>S. aureus</i> ATCC 14458 and <i>Escherichia coli</i> ATCC 10799 (MIC = 250 μg/ml), as well as small antioxidant activity (457 μmol TE/g) assessed through ORAC<sub>FL</sub> assay. These results represent the first report regarding chemical composition and bioactivity of <i>G. australis</i> essential oil.</p></div>