Potentiating Metronidazole Scaffold against Resistant Trichomonas: Design, Synthesis, Biology and 3D-QSAR Analysis

Metronidazole (MTZ), the FDA-approved drug against Trichomonas vaginalis (TV), is being challenged seriously by drug resistance, while its inertness to sperm makes it ineffective as a vaginal contraceptive. Thirteen piperidine dithiocarbamate hybrids of 2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethane (8-20) were designed to potentiate the MTZ framework against drug resistance and sperm. New compounds were 1.2-12.1 times more effective against MTZ-susceptible and -resistant strains of TV. All of the compounds exhibited high safety toward cervical (HeLa) cells and Lactobacillus. Thirty-eight compounds were scrutinized by CoMFA and CoMSIA techniques of 3D quantitative structure-activity relationship. Good predictive r pred (2) values for CoMFA and CoMSIA models reflected the robustness of the predictive ability. This was validated by designing five new analogues (46-50), which were potently microbicidal (3-10 and 10-20 times against MTZ-susceptible and -resistant TV, respectively) and spermicidal. This in vitro study may have significant clinical relevance, which could become evident in due course.