Abstract

Molecular descriptors to differentiate four gibberellins and seven anti-gibberellins were studied. DRAGON software and Cambridge Soft ChemOffice were used to calculate 212 descriptors. Of them, 48 showed statistically significant differences between gibberellins and anti-gibberellins which can be summarized as follows. Gibberellins contain as average 14.3 times more 7-membered rings, 14.3 times more 9-membered rings, 7.4 times more ring tertiary carbon (sp3), 6.1 times more terminal tertiary carbon (sp3 ) and 6.0 times more terminal quaternary carbon (sp3 ) than anti-gibberellins. Also gibberellins usually have ring quaternary carbon (sp3 ) and aliphatic secondary carbon (sp2 ) while anti-gibberellins usually do not. On the other hand, anti-gibberellins generally have aromatic ratio, aromatic bonds, nitrogen atoms, chlorine atoms, halogen atoms, benzene-like rings, aromatic carbon (sp2 ), unsubstituted benzene carbon (sp2 ) and substituted benzene carbon (sp2 ) while gibberellins usually do not. A dendrogram was obtained after conducting a hierarchical cluster analysis with data of chemical molecular descriptors with statistical significant differences (48). The dendrogram correctly classified gibberellins and antigibberellins in two independent branches.