1,4-Naphthoquinone is a potential pharmacophore for inhibition of both MAO (monoamine oxidase) and DNA topoisomerase activities, this latter associated with antitumor activity[1].
[1]. Coelho-Cerqueira E, et al. Beyond topoisomerase inhibition: antitumor 1,4-naphthoquinones as potential inhibitors of human monoamine oxidase. Chem Biol Drug Des. 2014 Apr;83(4):401-10.