Table 1.

Selected Descriptors by GA-PLS and Stepwise Regression from DRAGON Software

Number	Symbol	Definition	Class
1	De	Total accessibility index / weighted by atomic Sanderson electronegativities	WHIM descriptors
2	MATS8e	Moran autocorrelation - lag 8 / weighted by atomic Sanderson electronegativities	2D autocorrelations
3	Mor32m	3D-MoRSE - signal 32 / weighted by atomic masses	3D-MoRSE descriptors
4	SPH	Spherosity index	Geometrical descriptors
5	BELv1	Lowest eigenvalue n. 1 of Burden matrix / weighted by atomic van der Waals volumes	BCUT descriptors
6	MATS7v	Moran autocorrelation - lag 7 / weighted by atomic van der Waalsvolumes	2D autocorrelations
7	R1v+	Maximal autocorrelation of lag 1 / weighted by atomic van der Waalsvolumes	GETAWAY descriptors
8	TIE	E-state topological parameter	Topological descriptors
9	BEHe8	Highest eigenvalue n. 8 of Burden matrix / weighted by atomic Sanderson electronegativities	BCUT descriptors
10	GGI10	Topological charge index of order 10	Galvez topological charge indices
11	GATS6e	Geary autocorrelation - lag 6 / weighted by atomic Sanderson electronegativities	2D autocorrelations

A correlation matrix shows that there is no inter-correlation (R < 0.6) between the selected descriptors (Table 2) and reveals that the selected descriptors are linearly independent and hence can be used together in the development of QSAR models.