AVALIAÇÃO DA COMPOSIÇÃO QUÍMICA E DO POTENCIAL ANTIMICROBIANO, ANTIOXIDANTE E ANTIPARASITÁRIO DE ÓLEOS ESSENCIAIS E MICROEMULSÕES DE Duguetia stelechantha (Annonaceae) e Pectis brevipedunculata (Asteraceae)

Abstract

Duguetia stelechantha, belonging to the Annonaceae family, is popularly known as ata brava. The species is little explored chemically and biologically, and the composition of its volatiles is being described for the first time in this work. Species of Duguetias already have identified metabolites such as alkaloids, terpenes and flavonoids, which have demonstrated promising results in the biological activities of Duguetias. Another important species investigated here is Pectis brevipedunculata, called field rosemary, belonging to the Asteraceae Family. The leaves of the species contain citral among the main compounds, a chemical marker of the essential oils (OEs) of Pectis species, which has antimicrobial, nematicidal and larvicidal effects. Both species are widely distributed throughout Brazilian territory, however, they are not significantly used. The fruits of the D. stelechantha tree are used for direct consumption, and P. brevipedunculata is consumed in the form of tea. The objective of the work was to obtain OEs from the leaves and bark of D. stelechantha (OE-DU) and the aerial parts of P. brevipedunculata (OE-PB), develop microemulsions (MEs) (ME-DU and ME-PB) for incorporation of OEs and evaluate the biotechnological potential of the species. The chemical characterization by GC/MS of the hydrodistilled OE indicated that the majority of the OE-DU were β-pinene (46.17%), α-pinene (20.2%) and spathulenol (6.68%) while the analysis of OEPB, by GC/MS-Headspace, indicated α-pinene (56.47%), limonene (19.98%), neral (3.78%) and geranial (3.46%). Analysis of MEs by GC/MS-Headspace and infrared confirmed the incorporation of OEs in the formulations. The physicochemical characterization indicated that the particle size, polydispersity index and zeta potential are in accordance with the literature. Regarding antimicrobial potential, ME-DU showed larger inhibition halos for all bacteria tested (Escherichia coli (ATCC 25922), Salmonella spp. (ATCC 14028), Listeria monocytogenes (ATCC 35152), Staphylococcus aureus (ATCC 25923), Bacillus cereus (ATCC 14579) and Clostridium spp.), when compared to OE-DU and larger or similar inhibition halos when compared to the antibiotics penicillin and gentamicin. ME-PB showed inhibition halos above 50.00 mm for all bacteria studied. ME-DU and ME-PB indicated Minimum Inhibitory Concentration values lower than those obtained by the action of OEs and were considered to have strong inhibition against all bacteria tested. ME-DU and ME-PB showed higher antioxidant concentrations than the OEs by DPPH and ABTS. Regarding the test with Leishmania (L.) amazonensis, OE-DU (IC50=138.30 µg/mL) was classified as moderately active; ME-DU (IC50=4.47 µg/mL), OE-PB (IC50=20.00µg/mL) and ME-PB (IC50=0.93 µg/mL) as active samples. After cytotoxicity testing on RAW 264.7 cells, the selectivity index resulted in ME-DU (CC50=8.87 µg/mL) and ME-PB (CC50=1.33µg/mL) being more selective for inhibiting the parasite and less toxic to cells. The total count of mesophilic aerobes showed that ME-DU, OE-PB and ME-PB inhibited the proliferation of microorganisms. It was found that OE-DU was more efficient than ME-DU to combat fungi. While, OE-PB and ME-PB were equally efficient against fungi, extending the shelf life of strawberries. The results show the potential of these species and the incorporation of OEs in MEs optimized the bioavailability of bioactive principles, improving biological activities.