<em>An ent</em>-Kaurane-Type Diterpene in <em>Croton antisyphiliticus</em> Mart.

<em>Croton antisyphiliticus </em>is a medicinal plant widely used in the treatment of microbial infections, especially those affecting the genital tract. Crude extract, fractions and pure compound isolated from roots of this species were investigated to validate their antimicrobial activity against <em>Escherichia coli</em> and <em>Staphylococcus aureus</em>. The compound <em>ent</em>-kaur-16-en-18-oic acid was isolated as a major component (0.7% of crude extract), and its MIC value determined against <em>S. aureus</em> (ATCC 6538) was 250 μg/mL. This is the first phytochemical work on the species monitored with antimicrobial assay