Banca de DEFESA: ADDISON RIBEIRO DE ALMEIDA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : ADDISON RIBEIRO DE ALMEIDA
DATE: 16/04/2025
TIME: 08:30
LOCAL: Auditório do Química III
TITLE:

Bioprospection of extracts and essential oils from 16 endemic plant species of the caatinga: antibacterial activity, for the control of Aedes aegypti, cytotoxicity and formulation development.

KEY WORDS:

Caatinga; Extracts; Essential oil; Aedes aegypti; Antibacterial

PAGES: 135
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Orgânica
SPECIALTY: Química dos Produtos Naturais
SUMMARY:

The largest tropical dry forest in the world is located in Brazil, in the Caatinga biome, an originally semi-arid region that occupies an area of 11% of the Brazilian territory. It covers a large part of the northeastern region of Brazil and contains a number of plant species that have been reported to have popular medicinal uses and that contain bioactive molecules in their phytochemical composition. Extracts were prepared from leaves and stem bark of 16 plant species collected in the Assu National Forest, RN. Methods for analysis of the extracts were developed using UHPLC-DAD. The cytotoxicity of the extracts was evaluated using the MTT reduction method on L929-CCL1 fibroblast and MC3T3-E1 pre-osteoblast cells, and the antibacterial activity on S. aureus and E. coli using the agar diffusion method, and a gel-based formulation was developed for the most active extract ( Cenostigma bracteosum). The activity of the extracts was also evaluated against Aedes aegypti larvae. In addition to the extracts, it was possible to obtain and characterize by GC-MS the essential oil of one of the collected species (Bauhinia cheilantha), in addition to evaluating its activity against Aedes aegypti larvae, female mosquitoes and the cytotoxic effect on L929 and MC3T3 cells. From the essential oil, nanoemulsions were prepared and characterized in comparison with nanoemulsions containing clove and cinnamon essential oils. Antibacterial activity was observed on S. aureus for the extracts of C. bracteosum, Combretum leprosum and Cochlospermum vitifolium and on E. coli for the extract of C. bracteosum, the latter being the most active. It was possible to produce stable gels containing C. bracteosum extract at 1% and 3%. Hexane and ethyl acetate extracts of Libidibia ferrea, C. vitifolium and C. leprosum were active against Ae. aegypti larvae. The essential oil (EO) of B. cheilantha (mororó) was obtained by hydrodistillation and microwave extraction (MWE), with MWE showing a much higher yield. The EO was characterized by GC-MS and its activity against Ae. aegypti larvae and mosquitoes was confirmed. A nanoemulsion containing mororó EO was prepared, which was much less stable than the nanoemulsions containing clove and cinnamon EOs. No cytotoxic effect of the extracts (up to 100 μg/mL) or of the mororó EO (up to 50 μg/mL) was observed in the strains tested. Therefore, the discovery of the potential activities of the EO and leaf extracts of these species will be useful for the subsequent stages of fractionation, isolation and development of formulations, adding value and increasing scientific knowledge about the plants used in the project for the restoration of degraded areas in the caatinga.

COMMITTEE MEMBERS:
Externo ao Programa - 1639820 - ARNOBIO ANTONIO DA SILVA JUNIOR - nullExterna à Instituição - LAILA SALMÉN ESPINDOLA - UnB
Presidente - 2276354 - LEANDRO DE SANTIS FERREIRA
Externo à Instituição - NORBERTO PEPORINE LOPES - USP
Interna - 1569526 - RENATA MENDONÇA ARAUJO