Synthesis of new bis-pyrazole linked hydrazides and their in vitro evaluation as antimicrobial and anti-biofilm agents: A mechanistic role on ergosterol biosynthesis inhibition in Candida albicans.

Literature reports suggest that pyrazoles and hydrazides are potential antimicrobial pharmocophores. Considering this fact, a series of nineteen conjugates containing hybrids of bis-pyrazole scaffolds joined through a hydrazide linker were synthesized and further evaluated for their antimicrobial activity against a panel of Gram-positive and Gram-negative bacteria along with Candida albicansMTCC 3017 strain. Although the derivatives exhibited good antibacterial activity, some of the derivatives (13d, 13j, 13l, 13p, and 13r) showed excellent anti-Candida activity with MICs values of 3.9 µg/ml, which was equipotent to that of the standard Miconazole (3.9 µg/ml), which has inspired us to further explore their anti-Candida activity. The same compounds were also tested for anti-biofilm studies against various Candida strains and among them, compounds 13l and 13r efficiently inhibited the formation of fungal biofilms. Field emission scanning electron micrographs revealed that one of the promising compound 13r showed cell damage and in turn cell death of the Candida strain. These potential conjugates (13l and 13r) also demonstrated promising ergosterol biosynthesis inhibition against some of the strains C. albicans, which were further validated through molecular docking studies. In silico computational studies were carried out to predict the binding modes and pharmacokinetic parameters of these conjugates.

Design, Synthesis, and in vitro and in vivo Evaluations of (Z)-3,4,5-Trimethoxystyrylbenzenesulfonamides/sulfonates as Highly Potent Tubulin Polymerization Inhibitors.

Newer therapeutics can be developed in drug discovery by adopting the strategy of scaffold hopping of the privileged scaffolds from known bioactive compounds. This strategy has been widely employed in drug-discovery processes. Structure-based docking studies illustrate the basic underlying concepts and reveal that interactions of the sulfonamide group and hydrophobic interactions are crucial. On the basis of this strategy, over 60 synthetic analogues were synthesized and evaluated for their cytotoxicity against the NCI panel of 60 human cancer cell lines; the majority of these compounds exhibited promising cytotoxicity with GI50 values ranging between 18 and 50 nm. Among these compounds, (Z)-N-[2,3-dimethoxy-5-(3,4,5-trimethoxystyryl)phenyl]-4-methoxybenzenesulfonamide (7 a) and (Z)-N-[2-hydroxy-3-methoxy-6-(3,4,5-trimethoxystyryl)phenyl]-4-methoxybenzenesulfonamide (9 a) were found to be potent. Similar results were obtained against three human cancer cell lines with IC50 values ranging between 0.04 and 3.0 µm. Studies aimed at elucidating the mechanism of action of these new analogues revealed that they inhibited the in vitro polymerization of tubulin and disorganized the assembly of microtubules in HeLa and MCF-7cancer cells. Lead compounds 7 a and 9 a displayed notable in vivo antitumor activity in a HeLa tumor xenograft model. Our studies have resulted in the identification of a scaffold that can target tubulin polymerization, which should have significant potential toward the development of new antitumor drugs.

Access to Imidazo[1,2-a]pyridines via Annulation of α-Keto Vinyl Azides and 2-Aminopyridines.

A novel strategy for the synthesis of imidazo[1,2-a]pyridines via efficient catalyst/metal-free annulations of α-keto vinyl azides and 2-aminopyridines is described. Several imidazo[1,2-a]pyridines were synthesized from readily available vinyl azides and 2-aminopyridines and obtained in highly pure form by simply evaporating the reaction solvent. This remarkably high yielding and atom economical protocol allows the formation of three new C-N bonds through cascade reactions and rearrangements.

Design, synthesis and anticancer properties of novel oxa/azaspiro[4,5]trienones as potent apoptosis inducers through mitochondrial disruption.

A series of twenty seven oxa/azaspiro[4,5]trienone derivatives were synthesized and their anticancer properties have been explored. GI50 values of all these compounds were evaluated against four types of human cancer cell lines, i.e. MCF-7 (breast), DU-145 (prostate), A549 (lung) and HepG2 (liver). Five compounds of the series exhibited good anticancer potential against MCF-7 with GI50 values less than 2 µM. Detailed biological studies of the two representative compounds 9b and 9e revealed that they arrest cell cycle in G0/G1 phase and induce mitochondria mediated apoptosis, that was further confirmed by measurement of mitochondrial membrane potential (ΔΨm), intracellular ROS generation, caspase 9 activity and Annexin V-FITC assay. Furthermore, western blot analysis suggested that these compounds up-regulate the levels of p53, p21, p27 and Bax, and down-regulate the level of Bcl-2 confirming the apoptosis inducing properties.