NO (Nitric oxide) is a signaling molecule and exhibits a plethora of biological activities.
Three isoforms of NOS (Nitric Oxide Synthase) are involved in NO production viz. iNOS, eNOS and
nNOS. Evidence from research shows that pathological conditions such as arthritis, asthma, cardiovascular
dysfunctions, hypertension, neurodegeneration and septic shock arise due to an imperfect
control of the NO levels.
NOS inhibitors have emerged as the successful solution for control of NO levels. Most of the research
attention and expenditure are focused on the two isoforms, iNOS, and nNOS, due to their involvement
in various pathological conditions. Due to its physiological role, eNOS is excluded as a drug target. Despite innumerable
NOS inhibitors available, selectivity towards a particular isoform, poses a serious challenge in the design of successful inhibitors.
With the help of advancement in the respective fields of synthesis, modeling software, bioassays, molecular biology
and the perception of the far reached functions of NO and role of NOS enzyme; successful efforts have been made by
various groups of scientists to get more selective, potent and less toxic inhibitors. The present review summarizes in and
out of the various approaches used in the designing of non-selective and selective inhibitors in the recent past.