Funalenone is phenalenone isolated as a novel inhibitor of collagenase from Aspergillus niger by Omura and co-workers at the Kitasato Institute, Japan in 1999. Funalenone was reported to be devoid of antimicrobial activity (Gram positive and Gram negative, yeast and fungi). However, funalenone was also reported to inhibit bacterial cell wall synthesis enzymes, MraY and MurG. Funalenone has been identified as a potent inhibitor of HIV-1 integrase, showing 50-fold selectivity over mammalian cell toxicity.