Santosh Jangir

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.

Synthesis of S-(2-thioxo-1,3-dithiolan-4-yl)methyl dialkylcarbamothioate and S-thiiran-2-ylmethyl dialkylcarbamothioate via intermolecular O-S rearrangement in water.

A facile synthesis of S-(2-thioxo-1,3-dithiolan-4-yl)methyl dialkylcarbamothioates (3) and S-thiiran-2-ylmethyl dialkylcarbamothioate (5) has been reported by the reaction of 5-(chloromethyl)-1,3-oxathiolane-2-thione (1) with sodium dialkylcarbamodithioate (2) and dialkylamine (4), respectively, through intermolecular O-S rearrangement in water. A plausible mechanism of formation of the title compounds has also been proposed.

Dithiocarbamate-thiourea hybrids useful as vaginal microbicides also show reverse transcriptase inhibition: design, synthesis, docking and pharmacokinetic studies.

Prophylactic prevention is considered as the most promising strategy to tackle STI/HIV. Twenty-five dithiocarbamate-thiourea hybrids (14-38) were synthesized as woman controlled topical vaginal microbicides to counter Trichomonas vaginalis and sperm along with RT inhibition potential. The four promising compounds (18, 26, 28 and 33) were tested for safety through cytotoxic assay against human cervical cell line (HeLa) and compatibility with vaginal flora, Lactobacillus. Docking study of most promising vaginal microbicide (33) revealed that it docked in a position and orientation similar to known reverse transcriptase inhibitor Nevirapine. The preliminary in vivo pharmacokinetics of compound 33 was performed in NZ-rabbits to evaluate systemic toxicity in comparison to Nonoxynol-9.

A unique dithiocarbamate chemistry during design & synthesis of novel sperm-immobilizing agents.

1-Substituted piperazinecarbodithioates were obtained by an unusual removal of CS2 in benzyl substituted dithiocarbamate derivatives under acid and basic conditions during design and synthesis of 1,4-(disubstituted)piperazinedicarbodithioates as double edged spermicides. A plausible mechanism for CS2 removal has been proposed. All synthesized compounds were subjected to spermicidal, antitrichomonal and antifungal activities. Twenty-one compounds irreversibly immobilized 100% sperm (MEC, 0.06-31.6 mM) while seven compounds exhibited multiple activities. Benzyl 4-(2-(piperidin-1-yl)ethyl) piperazine-1-(carbodithioate) (18) and 1-benzyl 4-(2-(piperidin-1-yl)ethyl)piperazine-1,4-bis(carbodithioate) (24) exhibited appreciable spermicidal (MEC, 0.07 and 0.06 mM), antifungal (MIC, 0.069-0.14 and >0.11 mM) and antitrichomonal (MIC, 1.38 and 0.14 mM) activities. The probable mode of action of these compounds seems to be through sulfhydryl binding which was confirmed by fluorescence labeling of sperm thiols.

Azole-carbodithioate hybrids as vaginal anti-Candida contraceptive agents: design, synthesis and docking studies.

Azole and carbodithioate hybrids were synthesized as alkyl 1H-azole-1-carbodithioates (7-27) and evaluated for spermicidal/microbicidal activities against human sperm, Trichomonas vaginalis and Candida species. Seventeen compounds (7-14, 16-18 and 20-25) showed spermicidal activity at MEC 1.0% (w/v) and permanently immobilized 100% normal human spermatozoa within ∼30 s. Seventeen compounds (7-11, 13-18 and 20-25) exhibited anti-Candida activity (IC50 1.26-47.69 μg/mL). All compounds were devoid of bactericidal activity against four bacterial strains (50.00 μg/mL) and antiprotozoal activity against Trichomonas vaginalis (200.00 μg/mL). Four promising compounds (10, 17, 20 and 22) have better safety profile as compared to Nonoxynol-9 (N-9). Docking study was done to visualize the possible interaction of designed scaffold with prospective receptor (Cyp51) of Candida albicans.

Design and synthesis of substituted morpholin/piperidin-1-yl-carbamodithioates as promising vaginal microbicides with spermicidal potential.

A series of seventeen morpholin/piperidin-1-yl-carbamodithioate (3-19) were synthesized as topical vaginal microbicidal spermicides. The synthesized compounds were evaluated for their anti-Trichomonas activity against MTZ susceptible and resistant strains along with their spermicidal and antifungal potential. All the synthesized compounds were assessed for their safety through cytotoxic assay against human cervical cell line (HeLa) and compatibility with vaginal flora, Lactobacillus. The study identified eleven dually active compounds with apparent safety. The plausible mode of action of these compounds was through sulfhydryl binding, confirmed via reduction in available free thiols on human sperm. The most promising compound 9 significantly inhibited (P<0.001) thiol-sensitive sperm hexokinase. The stability of compound 9 in simulated vaginal fluid (SVF) was performed via HPLC-PDA method, which supported its utility for vaginal administration.