Siccanin is an inhibitor of mitochondrial complex II (succinate dehydrogenase; IC50s = 0.87 and 9.3 μM for P. aeruginosa and rat mitochondria, respectively). It inhibits the growth of T. mentagrophytes (IC50 = 0.3 μg/ml) via inhibition of succinate oxidation in the mitochondria. It also inhibits the growth of C. albicans strains with IC50 values ranging from 5-40 and 80-90 μg/ml for aerobic and anaerobic conditions, respectively.