To investigate the insecticidal activity of the essential oil of Cinnamomum cassia
and its main
constituent compound, trans-cinnamaldehyde, against the booklice, Liposcelis bostrychophila
Steam distillation of C. cassis
twigs was carried out using a Clavenger apparatus in order to
obtain the volatile oils. Gas chromatography/mass spectrometric (GC/MS) analyses (HP-5MS column)
of the essential oil were performed and its contact (using impregnated filter paper method) and fumigant
toxicity (sealed space) determined. The bioactive constituent compound, trans-cinnamaldehyde was
isolated and identified from the oil based on bioactivity-directed fractionation.
A total of 35 components, accounting for 97.44 % of the essential oil of C. cassis
identified. The principal compounds in the essential oil were trans-cinnamaldehyde (49.33 %),
acetophenone (6.94 %), trans-cinnamic acid (5.45 %) and cis-cinnamaldehyde (4.44 %) followed by o-methoxycinnamaldehyde
(3.48 %), coumarin (3.42 %) and (E)-cinnamyl alcohol (3.21 %). The essential
oil displayed contact toxicity against adult L. bostrychophila
with a median lethal concentration (LC50
as well as fumigant toxicity (LC50
, 1.33 mg/l air). Trans-cinnamaldehyde exhibited strong
contact and fumigant toxicity with LC50
of 43.40 μg/cm2
and 1.29 mg/l air, respectively.
The findings suggest that the essential oil of C. cassis
and its constituent compound,
trans-cinnamaldehyde, possess potentials for development into natural fumigants/insecticides for the
control of booklice.