ABSTRACT: Safranal, a dominant component of saffron, is known to have antitumor, cytotoxic, and antibacterial properties. In this study, we examined safranal and its structural analogs-thymol, carvacrol, damascenone, cuminol, 2,6,6-trimethyl-2-cyclohexene-1,4-dione (TMCHD), 4-isopropylbenzyl bromide (IPBB), and 4-tert-butylphenol (TBP) induced inhibition of Escherichia coli membrane bound F1Fo ATP synthase. Safranal and its analogs inhibited wild-type enzyme to variable degrees. While safranal caused 100% inhibition of wild-type F1Fo ATP synthase, only about 50% inhibition occurred for αR283D mutant ATP synthase. Moreover, safranal, thymol, carvacrol, damascenone, cuminol, TMCHD, IPBB, and TBP all fully abrogated the growth of wild-type E. coli cells and h