ABSTRACT
Abstract Green synthesis is an efficient method, frequently applied in nanobiotechnology, as it does not use toxic reagents or solvents. Biological organisms, including medicinal plants, have been used successfully for manufacturing of different types of metallic nanoparticles. The aim of this work was to synthesize, characterize and evaluate the antimicrobial activity of silver nanoparticles (AgNPs) obtained from the extract of the pulp, seed and leaves of Annona muricata L. The particle size, polydispersity index, zeta potential, as well as morphological aspects of AgNPs were evaluated. With the data obtained from the analyses, we concluded that the nanoparticles were successfully obtained by a simple and green method using the aqueous extract of the pulp, seeds and leaves of A. muricata. AgNPs obtained by A. muricata pulp extract without exposure to artificial light showed lowest average of hydrodynamic diameter and smallest size at field emission scanning electron microscope (FESEM). In addition, these nanoparticles showed the best polydispersity index (PDI), and zeta potential of - 29.6, which indicates good stability. AgNPs obtained from the extract of the pulp, seed and leaves showed antimicrobial activity, against strains of gram positive and gram negative bacteria, and antifungal activity, compared to the pure extract.
ABSTRACT
ABSTRACT Lavandula dentata, popularly known as lavender, is commonly used in traditional medicine for the treatment of digestive and inflammatory disorders. The objective of this study was to analyzed the chemical oil composition, antioxidant and antimicrobial activities of the essential oil and anatomical markers of the leaf and stem of L. dentata cultivated in South Brazil. Essential oil showed an antioxidant activity similar to rutin and gallic acid when analyzed by phosphomolybdenum method. However, by the free radical DPPH and ABTS methods, it showed a slight potential antioxidant. Essential oil presented 1,8-cineol (63%) as major component, antimicrobial activity against Gram-positive, Gram-negative bacteria strains and Candida albicans, by broth microdilution. The anatomical profile provided the following main microscopic markers: hypostomatic leaves; diacytic stomata, thin and striate cuticle; multicellular and branched non-glandular trichomes; capitate glandular trichomes; peltate glandular trichomes; dorsiventral mesophyll; flat-convex shape midrib, truncated on the abaxial side; one collateral vascular bundle in the midrib; square stem shape, angular collenchyma alternated with cortical parenchyma; sclerenchymatic fibers well-developed on the four edges.