Banca de QUALIFICAÇÃO: LAYS NOGUEIRA MIRANDA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : LAYS NOGUEIRA MIRANDA
DATE: 10/05/2021
TIME: 08:30
LOCAL: Webconferência via Plataforma Google Meet
TITLE:

CHEMICAL CHARACTERIZATION AND BIOACTIVITY OF THE ESSENTIAL OILS FROM CROTON TRICOLOR KLOTZSCH EX BAILL (EUPHORBIACEAE)

KEY WORDS:

Essential oil; Biotechnology; Bionsecticide; Tribolium castaneum.

PAGES: 78
BIG AREA: Outra
AREA: Multidisciplinar
SUMMARY:

Essential oils (EO) are secondary metabolites derived from aromatic plants,
composed of complex mixtures of chemical components, such as phenols,
aldehydes, hydrocarbons and others, and, due to their highly volatile nature, are
less likely to leave residues in stored products, representing minimal risk to the
environment and health. With the knowledge about these adaptive processes
present in plants, humanity started to explore these physiological adjustments as
a source of useful bioactive compounds to combat pest insects that cause
considerable losses in agricultural production. Tribolium castaneum Herbst.
(Coleoptera: Tenebrionidae) is one of the stored products pests recognized for
having one of the greatest population growth potentials among these insects.
Thus, this study aims to evaluate the insecticidal and repellent potential of Croton
tricolor Klotzsch ex Baill against Tribolium castaneum. The essential oils of leaves
and branches of C. tricolor were obtained by hydrodistillation in Clevenger
equipment and the chemical characterization will be carried out by gas
chromatography coupled with mass spectrometry (CG-EM). The evaluation of the
repellency potential was developed based on the area preference method and a
contact toxicity bioassay was carried out with concentrations of 1, 2.5, 5, 7.5 and
10% of leaves EO and 1, 5, 10, 15 and 20% of branches EO. The effects of EO
on nutritional indexes and on the metabolism of T. castaneum after exposure to
LD50 were evaluated. The C. tricolor EO showed a yield of 0.20% for branches
and 0.66% for leaves and showed repellency potential (RP) against T. castaneum
at all times of exposure, with a RP class ranging from IV to V, being the essential
oil of C. tricolor leaves (EOCTL) responsible for higher RP, obtaining class V in
30 and 60 minutes after exposure. The contact toxicity tests resulted in an LD50
of 2.193 μg / adult for the essential oil of C. tricolor branches (EOCTB) and 0.923
μg / adult for EOCTL and a reduction in the nutritional index of food conversion
efficiency, associated with a marked reduction in cholesterol levels. Exposure to
EOCTB caused a 79.7% inhibition of reproduction (p <0.05). The partial results
of this study point out that C. tricolor EO are promising alternatives for the control
of the insect pest T. castaneum in stored products and suggest that these EO act
as inhibitors of sterol transport proteins, which may be one mechanisms of action
to promote the insecticidal potential of these oils.

BANKING MEMBERS:
Externo ao Programa - 2089586 - FRANCIS SOARES GOMES
Interno - 1369387 - JOAO XAVIER DE ARAUJO JUNIOR
Presidente - 1653558 - LUCIANO APARECIDO MEIRELES GRILLO
Externo ao Programa - 1488396 - TICIANO GOMES DO NASCIMENTO