Composição química, atividade inseticida e potencial antioxidante dos óleos essenciais das folhas e flores de Plumeria pudica Jacq

Abstract

Agricultural producers usually suffer from the attack of pest insects that cause great damage to plantations, among these insects is Plutella xylostella, popularly known as cruciferous moth, as it usually attacks Brassicas plantations, this pest has already caused a global damage of about of US$ 4 billion. Currently, the control of this pest is carried out with commercial insecticides, but the excessive use of these products tends to cause greater resistance of the pest, in addition to contaminating soil, rural workers and mammals. With that, seeing being studied the use of natural products such as extract and essential oil of plants, as an alternative for the control of these agricultural pests, since these materials have in their chemical composition secondary metabolites with high toxicity to insect pests without causing damage to the environment, workers and consumers. The present work analyzed the chemical composition of the essential oil of the leaves and flowers of Plumeria pudica in order to evaluate its chemical composition and insecticidal and antioxidant properties. The analysis by gas chromatography coupled with mass spectrometry (GC-MS) revealed the presence of 8 and 13 compounds in the essential oil of leaves and flowers, respectively. The major compounds identified were (2E)-hexenal (40.67%) and lauric acid (39.97%) for leaves and flowers, respectively. The toxicity bioassay was carried out through residual contact and direct contact with the oil of P. pudica flowers with concentrations of 10μL/mL and 15μL/mL on P. xylostella, for the test using residual contact the oil did not show toxicity, on the other hand, using direct contact, the concentration of 10μL/mL showed a toxicity of 92% and 15μL/mL of 93.10%. In the antioxidant tests it was found that the two oils were active both in the ABTS and DPPH test. In the antioxidant tests, it was found that the oils from the leaves and flowers were active both in the ABTS test and with DPPH. For the acetylcholinesterase (AChE) inhibition test, the oils from the leaves and flowers of P. pudica were used, both oils showed inhibition, and the flower oil showed the closest inhibition to the positive control with an IC50 of 9 .94 mg/ml. The cytotoxicity assay against Artemia salina was also performed with the oils of leaves and flowers with concentrations between 10-100μg/mL and both showed no toxicity.