Bioprospecção de 16 espécies de plantas endêmicas para uso na restauração de áreas degradadas e exploração sustentável da caatinga

Abstract

The largest tropical dry forest in the world is located in Brazil, in the Caatinga biome. The Caatinga covers a large part of the Northeastern region of Brazil and is rich in biodiversity. In this study, hydroethanolic extracts were prepared from the leaves and stem bark of 16 plant species used in the BrazilDry project, which aims to restore degraded areas of the Caatinga. The samples were collected in the Assú National Forest, RN, and the extracts were analyzed by UHPLC-DAD and their larvicidal activity was evaluated against Aedes aegypti, with the extracts of Libidibia ferrea, Cochlospermum vitifolium and Combretum leprosum being the most active. The antibacterial activity of the extracts was evaluated against Staphylococcus aureus and Escherichia coli using the agar diffusion method. The extracts of Cenostigma bracteosum, Combretum leprosum and Cochlospermum vitifolium were active against S. aureus and C. bracteosum was the only one active against E. coli. The extract with the highest antibacterial activity (C. bracteosum) was analyzed by HPLCMS/MS, which allowed the annotation of five metabolites observed in the chromatogram, as well as the development and characterization of stable Carbopolbased gel formulations containing 1% and 3% of the extract. It was also possible to obtain and characterize by GC-MS the essential oil of Bauhinia cheilantha, obtained by hydrodistillation (HD) and microwave extraction (MWE). The essential oil of B. cheilantha was active against Aedes aegypti larvae and mosquitoes. A nanoemulsion containing B. cheilantha essential oil was prepared and characterized, which was less stable compared to nanoemulsions containing Syzygium aromaticum and Cinnamomum verum essential oils. A nanoemulsion containing B. cheilantha essential oil was prepared and characterized, which was less stable than nanoemulsions containing Syzygium aromaticum and Cinnamomum verum essential oils. The cytotoxicity of the extracts and essential oil was evaluated using the MTT reduction method on L929-CCL1 and MC3T3-E1 cells, and no cytotoxicity was observed at the concentrations tested (5 - 100 μg/mL). Therefore, the discovery of new plant species with potential activities will be useful for future studies to develop formulations and isolate new molecules, adding socio-economic value and increasing scientific knowledge about the plants used in the BrazilDry project to restore degraded areas in the Caatinga.