Highly diastereoselective cascade [5 + 1] double Michael reaction, a route for the synthesis of spiro(thio)oxindoles

Diastereoselective Cascade Double Michael Addition to Access Bridged Coumarins, Oxindoles and Spirooxindoles: A Sustainable Strategy for Synthesis of Anticancer Molecules

An efficient and concise synthesis of highly functionalized bridged coumarins has been developed through a diastereoselective double Michael addition reaction of p-quinols with various 4-hydroxy coumarins under catalyst-free conditions in H2O-DMSO (8 : 2). The method has been applied to oxindoles for the synthesis of a variety of bridged-oxindoles and bridged-spiroxindoles in presence of a DABCO base using H2O-EtOH (8 : 2) as solvent medium. The strategy is simple, highly atom economical as there is no by-product and environmentally benign (E-factor=0.1-0.9). The synthesized compounds were screened against triple-negative breast cancers and found that bridged coumarin (3 a) and oxindole (5 d) compounds exhibit potent anti-cancer activity at 6.6 and 8.8 μM (IC50) concentrations respectively. Further analysis revealed that 3 a and 5 d caused elevated early and total apoptosis by arresting the MDA-MB-468 cells in G2/M phase of the cell cycle. Overall, our results demonstrate that bridged coumarin (3 a) and oxindole (5 d) compounds-based approach attenuates the cancer progression and may pave a path for the translational outcome.

Metabolic Pathways of Leishmania Parasite: Source of Pertinent Drug Targets and Potent Drug Candidates

Leishmaniasis is a tropical disease caused by a protozoan parasite Leishmania that is transmitted via infected female sandflies. At present, leishmaniasis treatment mainly counts on chemotherapy. The currently available drugs against leishmaniasis are costly, toxic, with multiple side effects, and limitations in the administration route. The rapid emergence of drug resistance has severely reduced the potency of anti-leishmanial drugs. As a result, there is a pressing need for the development of novel anti-leishmanial drugs with high potency, low cost, acceptable toxicity, and good pharmacokinetics features. Due to the availability of preclinical data, drug repurposing is a valuable approach for speeding up the development of effective anti-leishmanial through pointing to new drug targets in less time, having low costs and risk. Metabolic pathways of this parasite play a crucial role in the growth and proliferation of Leishmania species during the various stages of their life cycle. Based on available genomics/proteomics information, known pathways-based (sterol biosynthetic pathway, purine salvage pathway, glycolysis, GPI biosynthesis, hypusine, polyamine biosynthesis) Leishmania-specific proteins could be targeted with known drugs that were used in other diseases, resulting in finding new promising anti-leishmanial therapeutics. The present review discusses various metabolic pathways of the Leishmania parasite and some drug candidates targeting these pathways effectively that could be potent drugs against leishmaniasis in the future.