Several series of novel chirality descriptors of chemical organic molecules
have been introduced. The descriptors have been developed on the basis of
conventional topological descriptors of molecular graphs. They include modi
fied molecular connectivity indices, Zagreb group indices, extended connect
ivity, overall connectivity, and topological charge indices. These modified
descriptors make use of an additional term called chirality correction, wh
ich is added to the vertex degrees of asymmetric atoms in a molecular graph
. Chirality descriptors can be real or complex numbers. Advantages and draw
backs of different series of chirality descriptors are discussed. These des
criptors circumvent the inability of conventional topological indices to di
stinguish chiral or enantiomeric isomers, which so far has: been the major
drawback of 2D descriptors as compared to true 3D descriptors (e.g., shape,
molecular fields) of molecular structure. These novel chirality descriptor
s have been implemented in a quantitative structure-activity releationship
(QSAR) study of a set of ecdysteroids with a high content of chiral and ena
ntiomeric compounds using the k nearest neighbor QSAR method (kNN) recently
developed in this laboratory. We show that the results of this study compa
re favorably with those obtained with the comparative molecular field analy
sis (CoMFA) applied to the same dataset. The novel chirality descriptors of
molecular structure should find their applications in QSAR studies and rel
ated investigations of molecular sdatasets.