Banca de DEFESA: MARINA LOBO DA ROCHA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : MARINA LOBO DA ROCHA
DATE: 28/08/2025
TIME: 14:00
LOCAL: Sala da Pós Graduação PPGReN
TITLE:

Evaluation and Standardization of Tests of Amazonian Oils with Repellent Activity against the Main Vector of Malaria in the Northern Region of Brazil (Anopheles darlingi).

KEY WORDS:

natural repellents; prevention; malaria. 

PAGES: 92
BIG AREA: Ciências Biológicas
AREA: Parasitologia
SUBÁREA: Entomologia e Malacologia de Parasitos e Vetores
SUMMARY:

Anopheles darlingi is the primary vector of malaria in the Amazon region, a hematophagous mosquito, highly anthropophilic, and susceptible to human Plasmodium species. Malaria is a disease that affects millions of people worldwide and can lead to high morbidity and mortality rates, especially in endemic areas. Therefore, strategies to aid in control and prevention are essential. The use of repellents is one of the main forms of protection against mosquito bites; however, synthetic repellents have been shown to be toxic to humans and cause ecological damage. In this context, the Amazon biodiversity offers significant biotechnological potential for the development of natural repellents. This study evaluated the repellent action of two Amazonian oils, Carapa guianensis (andiroba) and Copaifera multijuga (copaiba), against An. darlingi mosquitoes, determining their effective concentration and protection time. The mosquitoes used were obtained from the Malaria Vector Production and Infection Platform (PIVEM) of Fiocruz-RO, and the oils were sourced from an agro-extractive reserve in the Amazon region. Irritation tests conducted using the “Hen’s Egg Test Chorionallantoic Membrane” method indicated that the oils did not show any irritant effects. The repellency bioassays revealed that both andiroba and copaiba oils exhibited 100% repellent activity in their almost pure forms. The andiroba oil had an effective dose of ED50 of 0.54 mg/mL (54%) and ED99 of 0.89 mg/mL (89%), while copaiba oil showed an ED50 of 0.60 mg/mL (60%) and ED99 of 0.75 mg/mL (75%). In terms of protection time, although short, andiroba oil stood out by providing 120 minutes of protection, while copaiba oil offered 60 minutes. After the repellency bioassays, chitosan nanoparticles loaded with andiroba oil were developed with the aim of extending the repellent protection time. The production of these chitosan nanoparticles was carried out using a two-step method, first an oil-in-water emulsion, followed by ionic gelation with sodium tripolyphosphate. The resulting nanoparticles showed an encapsulation efficiency of 66.08% and 75.91% at concentrations of 0,12 mg/mL and 0,25 mg/mL, respectively, with an average diameter ranging from 12.50 nm to 378.50 nm and a zeta potential between +38.40 mV and +65.70 mV. The Amazonian oils demonstrated potential as natural repellents and can be a sustainable alternative to synthetic repellents. However, there is still a need to develop formulations that enhance their efficacy, aiming for long-lasting, safe, and environmentally friendly repellents. The standardization of repellency tests with oils from the Amazon is still under development for data presentation.

COMMITTEE MEMBERS:
Presidente - ***.785.002-** - MAISA DA SILVA ARAÚJO - UNIR
Interna - 1222125 - MARIA AUREA PINHEIRO DE ALMEIDA SILVEIRA
Interno - 1530806 - ALEXANDRE DE ALMEIDA E SILVA
Externa à Instituição - NATHÁLIA KELLY DE ARAÚJO
Externa à Instituição - MINELLY AZEVEDO DA SILVA