Banca de QUALIFICAÇÃO: LEIDIANE BARBOZA DA SILVA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : LEIDIANE BARBOZA DA SILVA
DATE: 14/10/2022
TIME: 09:00
LOCAL: Google meet
TITLE:

AEDICIDAL, ATTRACTIVE AND REPELLENT ACTION FROM AQUEOUS EXTRACT OBTAINED HOT FROM SEEDS OF

Anadenanthera colubrina

KEY WORDS:

Botanical extracts. Lavicidal. repellency. attractiveness. Vector control. Angico

PAGES: 116
BIG AREA: Ciências Biológicas
AREA: Bioquímica
SUBÁREA: Química de Macromoléculas
SPECIALTY: Proteínas
SUMMARY:

Aedes aegypti and Aedes albopictus are important vectors of arboviruses of medical importance (Dengue, Yellow Fever, Zika and Chikungunya). Combating vectors is the most effective way to prevent arbovirus epidemics, with the use of synthetic insecticides being the main method of controlling these mosquitoes, however they have a high financial and environmental cost. In the search for alternative methods, several botanical extracts have been evaluated for their bioinsecticide potential because of their low cost and low environmental toxicity. Thus, in order to contribute with new control tools for these vectors, in this study, a hot aqueous extract of Anadenanthera colubrina seeds was obtained, and its aedicidal potential at different stages of the life cycle, as well as its attractive and repellent action on the oviposition of pregnant female mosquitoes was investigated. For this, a simple and inexpensive extraction method was used that does not use very sophisticated and complex reagents. The fine meal of A. colubrina seeds was extracted in distilled water at a proportion of 1:10 (m/v) for 7 hours at 80 °C. After extraction, the suspension was centrifuged at 10,000 xg for 30 min at 4 °C, and then the supernatant was filtered and named Hot Aqueous Extract of Angico (EAQA). The larvicidal activity of EAQA was initially analyzed at 7 concentrations between 50% and 0.78% (v/v), and larval mortality was evaluated after 24 and 48 h. We observed a larvicidal effect for both species with LC50 of 0.020 mg/mL and LC90 of 0.26 mg/mL for A. aegypti after 48 h and LC50 of 0.064 mg/mL and LC90 of 0.62 mg/mL for A. albopictus at the same exposure time. Pupicidal activity for both insects was detected at concentrations higher than those observed for larval activity. The EAQA at 0.26 mg/mL also showed ovicidal activity, compromising 76.67% of the larval hatching, in addition to reducing the emergence of hatched adults of the surviving larvae to 25.7%. At these same concentrations, the repellency and attractiveness of the extract for oviposition under laboratory conditions were analyzed. EAQA showed positive IRE in the three highest concentrations tested (50% to 12.5%) being repellent in this range and negative IRE in the lowest concentrations (6.25 to 1.56%, v/v) being attractive for oviposition. After this analysis, attractiveness/repellence tests were carried out under field conditions with the extract in LC90 larvicide for A. aegypti (0.26 mg/mL), which showed an attractive effect with higher egg density than that observed in the control. A partial biochemical characterization was also performed: dosage of total sugars, proteins, phenolic compounds, lectins, trypsin inhibitors, to determine the possible biomolecules involved in the aedicidal activity. EAQA has an estimated protein concentration of 2 mg/mL, total carbohydrates equivalent to 15.5 mg/mL and 0.1 mg/mL of total phenolic compounds. Among the bioactive proteins tested, the presence of lectins was not detected. As for the presence of protease inhibitors, 90.94% inhibition was observed for bromelain, 68.93% inhibition for papain, 68.75% inhibition for trypsin and 9% inhibition for chymotrypsins. The biosafety of the extracts was evaluated by cytotoxicity test for which EAQA did not present cytotoxic effects for the two cell lines (3T3 and HepG2). EAQA, when evaluated for its ecotoxicity, showed low toxicity to the microcrustaceans tested at concentrations that showed aedicidal activity. Thus, we hope that extracts of A. colubrina can be evaluated as candidates for an economical and eco-compatible option for the development of formulations to work together with current methods of controlling the mosquito vectors of the arboviruses Aedes aegypti and A. albopictus.

COMMITTEE MEMBERS:
Presidente - 1149356 - ELIZEU ANTUNES DOS SANTOS
Externo à Instituição - GIULIAN CÉSAR DA SILVA SÁ
Externa à Instituição - PATRICIA BATISTA BARRA MEDEIROS BARBOSA - UERN