This paper reports the effect of phenylbut-3-en-2-one, of its analogues, be
aring 3-nitro, 4-nitro, 4-chloro- and 4-dimethylamino substituents at the p
henyl moiety, and of the hydrazide, phenylhydrazide and oxime of 4-nitrophe
nylbut-3-en-2-one on the growth and germ-tube formation of Candida spp., as
well as their ability to interact with ergosterol in water/dimethylformami
de (DMF) solution and their acute toxicity for mice. 3-Nitro-, 4-nitro- and
4-chlorophenylbul-3-en-2-ones inhibit candidial growth in vitro in concent
rations ranging from 0.01 to >0.4 mM and their activity is comparable to th
at of ketoconazole (in mg/l) and lower than that of amphotericin B. The res
t of the compounds are inactive at >0.4 mM. Germ-tube forma tion of C. albi
cans is inhibited at 0.04 mM 4-nitrophenylbut-3-en-2-one and at 0.005 mM of
the 3-nitro isomer. A decrease in the absorption maxima in ergosterol mixt
ures with 4-dimethyl amino, 3-nitrophenylbut-3-en-2-one and the oxime of th
e 4-nitrophenylbut-3-en-2-one was observed, indicative of interaction in wa
ter/DMF solutions, while no changes in the UV spectra of the remaining comp
ounds were detectable. That suggests that the growth inhibiting effect is n
ot in correlation with their ability to interact with ergosterol. despite t
he resemblance to polyenes. LD50 for mice is 367 mg/kg for 4-nitrophenylbut
-3-en-2-one and 395 mg/kg for the 3-nitro isomer.