Poster presentation
312
A MACHINE LEARNING STUDY OF THE ANABOLIC ACTIVITY
OF ECDYSTEROIDS
S.S. Narzullaev, U.Yu. Yusupova, D.A. Usmanov, N.Sh. Ramazonov
S.Yu. Yunusov Institute of the Chemistry of Plant Substances Academy of sciences of the
Republic of Uzbekistan st. Mirzo-Ulugbek, 77, 100170 Tashkent
In
the last decade, medicinal plants have become an important part of the world
pharmaceutical market. The peculiarity of many drugs is that it is difficult to determine
the level of pharmacological action of their individual components, because often the
therapeutic effect of phytopreparations depends on the combined effect of various
biologically active compounds contained
in plant raw materials
[1]
.
Ecdysteroids are hormones controlling cell proliferation, growth and the
developmental cycles of insects and other invertebrates. Recent studies suggest that the
anabolic effect of ecdysterone, a naturally occurring steroid hormone claimed to
enhance physical
performance, is mediated by estrogen receptor (ER) binding [2].
The dataset for the present study has been collected from a series of 23 ecdysteroid
compounds. AA data (anabolic activity) are taken from our previous study. All original
in vitro
activity values (5mg/kg) have been converted into molar log(AA) response
variables.
A QSAR study has been performed for the set of 23 ecdysteroids to correlate and
predict anabolic activity. QSAR modeling was performed applying such methods as GA
for variable selection among generated and calculated descriptors and MLRA to get a
final model. Molecular mechanics and quantum-chemical calculations have been
applied for structure optimization and quantum-chemical properties calculations.
Three mathematical models for prediction of AA values are proposed. The best
overall performance is achieved
by two-descriptor QSAR model, where
r
2
values for the
training and test sets are 0.89 and 0.90, respectively. The significant molecular
descriptors related to the compounds with AA are: information indices - SIC0, WHIM
descriptor G3p weighted by polarizability. These variables lead to a molecular level
explanation of the potency of AA, based on structural descriptors.
Obtained model
(two-variables Model 1) can be used to estimate the anabolic activity of new
compounds that belong to functionalized ecdysteroids type.
The following equation represents the two-variable model:
Log [AA] = 0.8082 (±0.1754) SIC0 - 0.5817(±0.1925) G3p + 6.4905 (±0.1417) (1)
n
=23;
r
2
= 0.8899;
s
= 0.110;
F
= 64.664; RMSE tr= 0.101;
q
2
= 0.84 (training set);
n
=4;
r
2
ext
= 0.8990;
s
= 0.128 (test set)
According to the obtained data, this model can be used to predict the anabolic
activity of ecdysteroids.
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