The paralytic activity is due to the
action of pyrethrins on central and peripheral nervous system
resulting in disruptions of signal transmission along the nerve
axon [31]. However, at low concentration below 0.01%, it led to
mosquito avoidance reaction due to loss of coordination [31]
.
PBO acts as synergist by inhibiting the Mixed Function
Oxidase system also known as the cytochrome P-450 system, a
primary route of detoxification in insects that causes the
oxidative breakdown of pyrethrins thus making it effective
with less active ingredient [33]
. Inspite of this, the reported toxic
effects associated to PBO [33]
and photosensitivity of
phyrethrins [37] makes the formulation less effective as a skin
repellent