Thomas Buxton1, Shiori Takahashi1, Akpe-Mary Eddy Doh2, Joshua Baffoe-Ansah3, Ebenezer Oduro Owusu3, Chul-Sa Kim1. 1. Faculty of Agriculture, Laboratory of Natural Product Chemistry, Kochi University, Nankoku City, Japan. 2. Oil Palm Research Centre, Council for Scientific and Industrial Research, Ghana. 3. Department of Animal Biology and Conservation Sciences, University of Ghana, Legon, Ghana.
Abstract
BACKGROUND: Pest management using botanicals has been widely practiced in sub-Saharan Africa and other parts of the world in recent times. The natural compounds present in these botanicals are known to be responsible for the protection they offer against insect pests. Some of these compounds may act as single compounds to produce an effect or they may be synergistically effective. In the present study using a bioassay guided approach, two cinnamic acid derivatives, methyl cinnamate and sitosterol cinnamate, were isolated from the leaves of Ocimum gratissimum and Vitellaria paradoxa, respectively. RESULTS: The two cinnamic acid derivatives were found to show higher levels of insecticidal, larvicidal and larval growth inhibition activities against Tribolium castaneum. The LC50 of methyl cinnamate was determined to be 26.92 mg mL-1 (95% CL: 1.18.66-38.84 mg mL-1 ; slope ± SE: 2.84 ± 0.81) for the adult 8.31 mg mL-1 (95% CL: 2.39-28.83 mg mL-1 ; slope ± SE: 0.66 ± 0.28) for the larvae while the LC50 of sitosterol cinnamate was determined to be 6.92 mg mL-1 (95% CL: 3.97-12.06 mg mL-1 ; slope ± SE: 1.59 ± 0.12) the adult and 3.91 mg mL-1 (95% CL: 2.21-6.93 mg mL-1 ; slope ± SE: 1.52 ± 0.13) for the larvae. CONCLUSION: Generally, the susceptibility of adult T. castaneum to these cinnamic acid esters can be directly associated with the concentration as well as time of exposure to the compounds. The isolated compounds support the use of O. gratissimum and V. paradoxa as important botanicals for the management of storage pests.
BACKGROUND: Pest management using botanicals has been widely practiced in sub-Saharan Africa and other parts of the world in recent times. The natural compounds present in these botanicals are known to be responsible for the protection they offer against insect pests. Some of these compounds may act as single compounds to produce an effect or they may be synergistically effective. In the present study using a bioassay guided approach, two cinnamic acid derivatives, methyl cinnamate and sitosterol cinnamate, were isolated from the leaves of Ocimum gratissimum and Vitellaria paradoxa, respectively. RESULTS: The two cinnamic acid derivatives were found to show higher levels of insecticidal, larvicidal and larval growth inhibition activities against Tribolium castaneum. The LC50 of methyl cinnamate was determined to be 26.92 mg mL-1 (95% CL: 1.18.66-38.84 mg mL-1 ; slope ± SE: 2.84 ± 0.81) for the adult 8.31 mg mL-1 (95% CL: 2.39-28.83 mg mL-1 ; slope ± SE: 0.66 ± 0.28) for the larvae while the LC50 of sitosterol cinnamate was determined to be 6.92 mg mL-1 (95% CL: 3.97-12.06 mg mL-1 ; slope ± SE: 1.59 ± 0.12) the adult and 3.91 mg mL-1 (95% CL: 2.21-6.93 mg mL-1 ; slope ± SE: 1.52 ± 0.13) for the larvae. CONCLUSION: Generally, the susceptibility of adult T. castaneum to these cinnamic acid esters can be directly associated with the concentration as well as time of exposure to the compounds. The isolated compounds support the use of O. gratissimum and V. paradoxa as important botanicals for the management of storage pests.
Authors: Shimaa M A Sayed; Saleh Alseekh; Karsten Siems; Alisdair R Fernie; Walter Luyten; Christian Schmitz-Linneweber; Nadine Saul Journal: Nutrients Date: 2022-10-09 Impact factor: 6.706