In this study, 3-alkyl and 3-aryl esters of hexahydroquinoline derivatives were screened
for their ability to decrease bacterial resistance to ciprofloxacin (CAS 85721-33-1),
which is extensively used to treat bacterial infections. A group of 3-alkyl and 3-aryl
esters of hexahydroquinoline derivatives in which 2-aryl thiazole is substituted at
4-position were synthesized. The enhancement of the antibacterial activity of ciprofloxacin
by these new synthetic compounds was evaluated against a resistant clinical strain
of Staphylococcus aureus. The agar disk diffusion method was used to determine the antibacterial activity of
different synthetic compounds in the absence and presence of ciprofloxacin. These
results indicate that the antibacterial effect of ciprofloxacin is enhanced by two
3-alkyl esters of hexahydroquinoline derivatives (7b-3 and 7b-4). The enhancing effect
of 7b-4 on the antibacterial activity of ciprofloxacin was greater than that of compound
7b-3. In comparison to the other synthetic compounds, 7b-4 showed a 5.61-fold increase
of the inhibition zone on the ciprofloxacin supplemented plates. The result demonstrated
that compounds 7b (3 and 4) could serve as valuable probes to study the structure-function
relationships of agents that reverse the resistance to ciprofloxacin.
Key words
Antibacterials - CAS 85721-33-1 - Ciprofloxacin, reversal of resistance, synergism
- Hexahydroquinoline derivatives -
Staphylococcus aureus
