A novel technique of classifying liminoids and protolimonoids using ar
tificial neural networks is presented, The difficulties associated wit
h natural product classification are discussed, as well as the relevan
ce of artificial neural networks to the task of automated classificati
on by computer, Data from the C-13 nuclear magnetic resonance spectra
of the compounds is pre-processed using histogram binning, Neural netw
orks are trained on this data correctly to classify the data as belong
ing to a ''limonoid'', ''triterpenoid'' or ''other'' category and to d
iscriminate the protolimonoids from the rest of the triterpenoids in t
he ''triterpenoid'' data set, Finally, neural networks are trained to
recognise each individual limonoid belonging to the ''limonoid'' data
set, The accuracy of the neural networks is typically better than 90%
on unseen or impure data. (C) 1997 John Wiley & Sons, Ltd.