Abstract:
Synthetic insecticides are known to cause negative
environmental impact, an outcome which has led to
increased reaseach activity on natural bioresources as
possible substitutes. The objective of this study was to
determine the efficacy of piperine in controlling bedbugs.
Black pepper (Piper nigrum L.) and all the reagents
were obtained from commercial sources and used
without further purification. The optimal conditions for
piperine extraction and its efficacy as an insecticide were
investigated. Piperine (C17
H19
NO3
) was extracted using
Soxhlet extraction method and its properties determined.
Ethanol (C2
H5
OH) gave the highest yield of piperine
compared to dichloromethane (CH2
Cl2
). Due to low
water-solubility of piperine, different solvent mixtures
were used to improve solubility. Toxicity against bedbugs
(Cimex lectularius) was carried out and the optimum
concentration determined to be 1.4 g L
-1
of piperine in an
aliquot of ethanol/water (v/v 1:4). At this concentration,
both mature and young bedbugs took approximately
300-minute post-exposure to die. The extract was also
100% effective in inhibiting hatching of bedbug eggs
while 83.4 % the unsprayed eggs hatched within seven
days. Piperine can, therefore, serve as an insecticide
against bedbugs since it is effective on all developmental
stages of the bugs.
