Análise morfoanatômica de folhas e caules e análise química e biológica do óleo essencial de Eucalyptus saligna sm.(Myrtaceae)

Abstract

Eucalyptus saligna Sm. is a tree native to southeastern Australia. Its main use is related with the wood. However, morpho-anatomical studies of this species, chemical and biological involving its essential oil are scarce. The objective of the present work was to study the morphology of leaves and stems, as well as to determine the chemical composition, to investigate the antioxidant activity, the antimicrobial effect and the cytotoxic potential of the essential oil of E. saligna. The botanical material was collected on the campus of the State University of Ponta Grossa (Paraná, Brazil). From the usual methods of optical microscopy and scanning electron microscopy, anomocytic stomata were evident on both sides of the leaf of E. saligna, absence of trichomes, isobilateral mesophyll, midrib with a biconvex shape on both sides, idioblasts with calcium oxalate prismatic crystals, secretory cavities containing essential oil, petiole with open arch vascular system. In addition, a rounded-shaped stem, angular collenchyma, secretory cavities, calcium oxalate prismatic crystals and druses were observed. The yield of essential oil extracted by hydrodistillation from leaves and stems was1.03%. The main compounds of essential oil of E. saligna were ρ-cymene and cryptone. The total antioxidant activity of the essential oil, by the phosphomolybdenum method, was superior to that determined for the routine. However, through the free radical DPPH and ABTS methods, the antioxidant potential observed was low. The essential oil of E. saligna showed an antimicrobial activity against Staphylococcus aureus and Candida albicans strains, using both methods of disc diffusion and diffusion in solid-medium by plate-cavities. As for the cytotoxicity assessed by the MTT method, essential oil of E. saligna presented to be cytotoxic for both cells, Calu-3 and 3T3. Considering these results, additional studies can be recommended, in order to use the essential oil of E. saligna as raw material for the pharmaceutical industry.