Saroj Verma

Current Status of Malaria Control

Malaria caused by Plasmodium parasites kills approximately 1-3 million people and causes disease in 300-500 million people annually throughout the world. The current approaches to curtail this disease include vector control, vaccination, immunotherapy and chemotherapy. The vector control is achieved by reducing vector density, interrupting their life cycle, and creating a barrier between the human host and mosquitoes. A number of vaccine candidates are being clinically tried and R&D effort in this direction is coming in a big way. Currently there are only limited safe drugs for the treatment of this disease, however, reports of emerging resistance against existing drugs warrant the introduction of new drugs, which are unlikely to come from pharmaceutical industries because of limited commercial opportunities. One of the most important current approaches to develop new drugs involves the synthesis of chemical libraries and evaluate them against most validated biochemical targets of malarial parasite. Although a number of such targets in antimalarial drug development are known today, yet only validated and selective biochemical targets including mitochondrial transport, glycolic pathway, folate pathway, proteases and heme metabolism, apicoplast metabolism, glycophospatidyl inositol, lipid metabolism (glycerophospholipids), peptidyl deformylase and oxidative stress in parasite-infected erythrocytes have been discussed here. The well known antimalarial drugs and different drug combinations for the treatment of malaria are also briefly reviewed. A survey of the recently discovered new molecules active against malaria has also been narrated. Lastly, the future of malaria chemotherapy and new directions emerging from literature has been elucidated.

Pyridones as NNRTIs against HIV-1 mutants: 3D-QSAR and protein informatics

CoMFA and CoMSIA based 3D-QSAR of HIV-1 RT wild and mutant (K103, Y181C, and Y188L) inhibitory activities of 4-benzyl/benzoyl pyridin-2-ones followed by protein informatics of corresponding non-nucleoside inhibitors’ binding pockets from pdbs 2BAN, 3MED, 1JKH, and 2YNF were analysed to discover consensus features of the compounds for broad-spectrum activity. The CoMFA/CoMSIA models indicated that compounds with groups which lend steric-cum-electropositive fields in the vicinity of C5, hydrophobic field in the vicinity of C3 of pyridone region and steric field in aryl region produce broad-spectrum anti-HIV-1 RT activity. Also, a linker rendering electronegative field between pyridone and aryl moieties is common requirement for the activities. The protein informatics showed considerable alteration in residues 181 and 188 characteristics on mutation. Also, mutants’ isoelectric points shifted in acidic direction. The study offered fresh avenues for broad-spectrum anti-HIV-1 agents through designing new molecules seeded with groups satisfying common molecular fields and concerns of mutating residues.

In Silico Exploration for New Antimalarials: Arylsulfonyloxy Acetimidamides as Prospective Agents.

A strategy is described to identify new antimalarial agents to overcome the drug resistance and/or failure issues through in silico screening of multiple biological targets. As a part of this, three enzymes namely CTPS, CK, and GST were selected, from among 56 drug targets of P. falciparum, and used them in virtual screening of ZINC database entries which led to the design and synthesis of arylsulfonyloxy acetimidamides as their consensus inhibitors. From these, two compounds showed good activity against sensitive (3D7; IC50, 1.10 and 1.45 μM) and resistant (K1; IC50, 2.10 and 2.13 μM) strains of the parasite, and they were further investigated through docking and molecular dynamics simulations. The findings of this study collectively paved the way for arylsulfonyloxy acetimidamides as a new class of antimalarial agents.

Synthesis, Biological Evaluation and Molecular Modeling Studies of New 2,3-Diheteroaryl Thiazolidin-4-Ones as NNRTIs

In a focused exploration, thiazolidin‐4‐ones with different C‐2 and N‐3 substituent groups were synthesized and evaluated as non‐nucleoside reverse transcriptase inhibitors against HIV‐1. This has led to new active compounds sporting heteroaryls at both C‐2 and N‐3 positions prompting to view them in the backdrop of nevirapine. To assign the molecular attributes for the activity, the compounds are investigated by docking them into non‐nucleoside inhibitor‐binding pocket of HIV‐1 reverse transcriptase (RT). The most active compounds of this series (7d and 7f) shared spatial features with nevirapine with added molecular flexibility. Furthermore, in molecular dynamics simulations carried out for up to 10 ns, the compounds 7d and 7f showed consistency in their interactions with non‐nucleoside inhibitor‐binding pocket of HIV‐1 RT and suggested Tyr319 and Val106 as potential residues for H‐bond interaction with these molecules. These results open new avenues for the exploration of 2,3‐diheteroaryl thiazolidin‐4‐ones for prevention of HIV‐1.