A quantum chemical and statistical study of flavonoid compounds with anti-HIV activity

The molecular orbital semi-empirical method PM3 is employed to calculate a set of molecular properties (variables) of 21 flavonoid compounds with anti -HIV activity. Pattern recognition techniques, principal component analysis (PCA) and hierarchical cluster analysis (HCA) were employed in order to re duce dimensionality, and investigate which subset of variables would be mor e effective in classifying the flavonoid compounds according to their degre e of anti-HIV activity. The principal component and hierarchical cluster st udies showed that the variables LUMO (the energy of the lowest unoccupied m olecular orbital), chi (electronegativity), and Q(2), Q(3) and Q(7) (charge s on atoms 2, 3 and 7) are related to the compounds with higher anti-HIV ac tivity. These variables keep the more active flavonoids clustered together and separate them from those less active when principal component analysis and hierarchical cluster analysis are employed. (C) 1999 Elsevier Science B .V. All rights reserved.