Abstract:
B-biotype
Bemisia tabaci
is a severe insect pest worldwide in many ornament
al,
agricultural, and horticultural crops. Control of t
his insect is obstructed by resistance to
many AcetylCholinEsterase (AChE)-inhibiting insecti
cides, such as organophosphates
and carbamates. In the present work, we evaluated t
he acetylcholinesterase inhibitory
activity of six monoterpenoids namely
α
-pinene, terpineol, linalool, ß-myrcene, nerol and
geraniol
in vitro
and
in vivo
. Inhibition of AChE of
B. tabaci
was measured by colorimetric
method. The results showed that all of the monoterp
enoids produced AChE inhibitory
activity, with
IC
50
values ranging from 0.96 to 26.85 mM. Alpha-pinene
showed the most
potent inhibitory activity (IC
50
= 0.96 mM). Kinetic analysis showed reversible non-
competitive type inhibition, revealing that these c
omponents might bind both the enzyme
alone and the enzyme-substrate. Results demonstrate
the AChE inhibitory activity as
mode of action of these monoterpenoids at relativel
y high concentrations. Thus, this could
be useful for investigation of new ecofriendly natu
ral insecticidal compounds.
Keywords:
Acetylcholinesterase,
Bemisia tabaci
, , IPM, Monoterpenoids, Non-competitive
inhibition
