The scientists, and the researchers around the globe generate tremendous amount of information
everyday; for instance, so far more than 74 million molecules are registered in Chemical
Abstract Services. According to a recent study, at present we have around 1060 molecules, which are
classified as new drug-like molecules. The library of such molecules is now considered as ‘dark chemical
space’ or ‘dark chemistry.’ Now, in order to explore such hidden molecules scientifically, a good
number of live and updated databases (protein, cell, tissues, structure, drugs, etc.) are available today.
The synchronization of the three different sciences: ‘genomics’, proteomics and ‘in-silico simulation’
will revolutionize the process of drug discovery. The screening of a sizable number of drugs like molecules
is a challenge and it must be treated in an efficient manner. Virtual screening (VS) is an important
computational tool in the drug discovery process; however, experimental verification of the
drugs also equally important for the drug development process. The quantitative structure-activity relationship
(QSAR) analysis is one of the machine learning technique, which is extensively used in VS
techniques. QSAR is well-known for its high and fast throughput screening with a satisfactory hit rate.
The QSAR model building involves (i) chemo-genomics data collection from a database or literature
(ii) Calculation of right descriptors from molecular representation (iii) establishing a relationship
(model) between biological activity and the selected descriptors (iv) application of QSAR model to
predict the biological property for the molecules. All the hits obtained by the VS technique needs to be
experimentally verified. The present mini-review highlights: the web-based machine learning tools, the
role of QSAR in VS techniques, successful applications of QSAR based VS leading to the drug discovery
and advantages and challenges of QSAR.