Desenvolvimento, caracterização e avaliação biológica de nanopartículas de ouro e de prata, obtidas por síntese verde, a partir do extrato de Annona muricata Linnaeus (Annonaceae)

Abstract

Green synthesis is an efficient method and is frequently studied in the area of nanobiotechnology, as it does not use reagents and solvents that present toxicity, expanding its application in the development of metallic nanoparticles. Due to the cytotoxicity of drugs, currently the major challenge is to deliver the therapeutic agent directly to its site of action, promoting better effectiveness with minimal side effects. Many targeted therapies are under development to address resistance to multiple drugs. The objective of the present work was to synthesize and characterize the vectorized AgNPs and AuNPs, from the extract of Annona muricata L. and with potential antitumor activity. AgNPs were obtained by photoreduction, from the extract of the pulp, seed and leaves of A. muricata, with exposure to artificial light and also in its absence. AuNPs were obtained from A. muricata pulp extract. The AgNPs and AuNPs obtained with the aqueous extract of the A. muricata pulp were vectorized with folic acid. In the characterization process, particle size, polydispersity index, zeta potential, as well as morphological aspects were evaluated. In addition, vectorized and non-vectorized AgNPs and AuNPs stability and antimicrobial activity were analyzed. Larvicidal activity was performed with AgNPs prepared with the aqueous extract of the A. muricata pulp. The toxicity of AgNPs and AuNPs, both vectorized and non-vectorized, against Artemia salina and erythrocytes was determined. The aqueous extracts of the pulp, seeds and leaves of A. muricata were efficient for the synthesis of AgNPs. AgNPs showed antimicrobial activity, against strains of gram positive and gram negative bacteria and against yeasts. The preparation of AgNPs, obtained without exposure to artificial light, presented more adequate characteristics, in terms of size, polydispersity index, zeta potential and stability. Gas Chromatography and Mass Analyzer determined the presence of anonymous acetogenins, such as annonacin, with potential antitumor activity. The aqueous extract of A. muricata pulp also demonstrated efficacy in the synthesis of AuNPs. The AuNPs obtained showed adequate size, zeta potential and PDI, in addition to good stability in the evaluated period. AuNPs showed antimicrobial activity against strains of Escherichia coli, Staphylococcus aureus and E. faecalis AgNPs prepared with A. muricata pulp extract showed low mortality compared to Plutella xylostella larvae, proving to be of low toxicity. The vectorization of AgNPs and AuNPs with folic acid was successfully achieved, maintaining stability and showing little change in terms of physicochemical and morphological characteristics, compared to AgNPs and AuNPs without vectorization. The antimicrobial activity of both vectorized nanoparticles was greater compared to nanoparticles without vectoring. The evaluation of the toxicity of AgNPs and AuNPs, with and without folic acid vectoring, against Artemia salina, showed excellent results, favoring its use in biological systems. The hemolytic evaluation showed biocompatibility of AgNPs and AuNPs, vectorized and non-vectorized. Thus, AgNPs and AuNPs, vectored or not, can be used in biological systems, developed with potential antimicrobial.