Cytotoxicity, Pro-apoptotic Activity and in silico Studies of Dithiocarbamates and their Structure Based Design and SAR Studies

Pyrazole derivatives of pyridine and naphthyridine as proapoptotic agents in cervical and breast cancer cells

Cancer is one of the leading causes of death worldwide. The increasing prevalence and resistance to chemotherapy is responsible for driving the search of novel molecules to combat this disease. In search of novel compounds with pro-apoptotic potential, pyrazolo-pyridine and pyrazolo-naphthyridine derivatives were investigated against cervical cancer (HeLa) and breast cancer (MCF-7) cells. The anti-proliferative activity was determined through the MTT assay. Potent compounds were then analyzed for their cytotoxic and apoptotic activity through a lactate dehydrogenase assay and fluorescence microscopy after propidium iodide and DAPI staining. Flow cytometry was used to determine cell cycle arrest in treated cells and pro-apoptotic effect was verified through measurement of mitochondrial membrane potential and activation of caspases. Compounds 5j and 5k were found to be most active against HeLa and MCF-7 cells, respectively. G0/G1 cell cycle arrest was observed in treated cancer cells. Morphological features of apoptosis were also confirmed, and an increased oxidative stress indicated the involvement of reactive oxygen species in apoptosis. The compound-DNA interaction studies demonstrated an intercalative mode of binding and the comet assay confirmed the DNA damaging effects. Finally, potent compounds demonstrated a decrease in mitochondrial membrane potential and increased levels of activated caspase-9 and -3/7 confirmed the induction of apoptosis in treated HeLa and MCF-7 cells. The present work concludes that the active compounds 5j and 5k may be used as lead candidates for the development of lead drug molecules against cervical and breast cancer.

Domino assembly of dithiocarbamates via Cu-catalyzed denitrogenative thiolation of iodotriazole-based diazo precursors

An efficient domino approach to assemble benzoxazoles and anthranilamides bearing dithiocarbamate moieties has been developed. The proposed route represents a Cu-catalyzed three-component reaction between readily available 5-iodo-1,2,3-triazoles, amines, and CS₂. The cascade transformation is based on a denitrogenative coupling of in situ formed dithiocarbamic acids with diazo intermediates, generated via annulation-triggered triazole ring-opening. This method is applicable to nucleophilic secondary amines and features good functional group compatibility.

Dithiocarbamate derivatives inhibit α-glucosidase through an apparent allosteric site on the enzyme

Dithiocarbamate derivatives possess diverse biological activities. This work further expands their activity profile by identifying seven benzylamine-containing dithiocarbamate derivatives with piperazine and piperidine substitutions at the main moiety, and five piperazine-containing dithiocarbamates with various substitutions at the piperazine moiety as new inhibitors of α-glucosidase. Compounds bearing the benzylamine moiety exhibited more potent inhibition of the enzyme than the piperazine derivatives. Majority of the compounds non-competitively inhibited α-glucosidase that led to the identification of a new allosteric site on the enzyme with the help of molecular dynamics and docking studies. These studies suggest that the compounds regulate inhibition of the enzyme by binding to an allosteric site that is located in the vicinity of the active site. This is the first report on the allosteric inhibition of α-glucosidase by dithiocarbamate derivatives that provides insights into the mechanism of inhibition of the enzyme at molecular level. Moreover, it also explores new avenues for drug development of α-glucosidase inhibitors as antidiabetic drugs.

New triorganotin(iv) compounds with aromatic carboxylate ligands: synthesis and evaluation of the pro-apoptotic mechanism

Three new organotin(iv) carboxylate compounds were synthesized and structurally characterized by elemental analysis and FT-IR and multinuclear NMR (1H, 13C, 119Sn) spectroscopy. Single X-ray crystallography reveals that compound C2 has a monoclinic crystal system with space group P21/c having distorted bipyramidal geometry defined by C3SnO2. The synthesized compounds were screened for drug-DNA interactions via UV-Vis spectroscopy and cyclic voltammetry showing good activity with high binding constants. Theoretical investigations also support the reactivity of the compounds as depicted from natural bond orbital (NBO) analysis using Gaussian 09. Synthesized compounds were initially evaluated on two cancer (HeLa and MCF-7) cell lines and cytotoxicity to normal cells was evaluated using a non-cancerous (BHK-21) cell line. All the compounds were found to be active, with IC50 values less than that of the standard drug i.e. cisplatin. The cytotoxic effect of the most potent compound C2 was confirmed by LDH cytotoxicity assay and fluorescence imaging after PI staining. Apoptotic features in compound C2 treated cancer cells were visualized after DAPI staining while regulation of apoptosis was observed by reactive oxygen species generation, binding of C2 with DNA, a change in mitochondrial membrane potential and expression of activated caspase-9 and caspase-3 in cancer cells. Results are indicative of activation of the intrinsic pathway of apoptosis in C2 treated cancer cells.