Boophiline, an Antimicrobial Sterol Amide from the Cattle Tick <i>Boophilus microplus</i>

Boophiline (<b>1</b>), a new sterol amide was isolated from the cattle tick <i>Boophilus microplus</i> (Ixodidae). The structure was assigned as N-[3-(sulfooxy)-25ξ-cholest-5-en-26-oyl]-L-isoleucine by detailed 2D NMR investigations in conjunction with FAB mass spectrometry and acidic hydrolyses. Complete assignment of the diastereotopic methylene protons of the ring system could be deduced from the NMR data. In agar dilution assays, <b>1</b> exhibited antifungal properties against <i>Cladosporium cucumerinum</i> and antibacterial activity against <i>Bacillus subtilis</i> and <i>Escherichia coli</i>.