OPTIMIZATION OF PIPERINE EXTRACTION FROM BLACK PEPPER (PIPER NIGRUM) USING DIFFERENT SOLVENTS FOR CONTROL OF BEDBUGS

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 (C17H19NO3

) 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