SÍNTESE VERDE DE NANOPARTÍCULAS DE PRATA COM Marsypianthes chamaedrys (Vahl) Kuntze E SUAS ATIVIDADES ANTIBACTERIANAS

Abstract

Natural origins products have been used in skin treatments and have shown great potential even against multi-resistant microorganisms. Marsypianthes chamaedrys (VAHL) Kuntze is a Lamiaceae family plant with medicinal use. This species has shown rich chemical composition and anti-inflammatory activity, as well as in vitro antioxidant activity. Silver nanoparticles are composed of nanometric size that have been researched and used in cosmetic formulations and drugs mainly because they have antibacterial activity. This work evaluated the chemical profile and antibacterial activity of Marsypianthes chamaedrys against bacteria Staphylococcus aureus and Pseudomonas aeruginosa and synthesized silver nanoparticles using the green synthesis method. In the first chapter, an integrative review was made on the use of Lamiaceae family plants in the treatment of skin infections caused by microorganisms. The results show that the Lamiaceae family has an important antimicrobial activity in vitro and in randomized clinical studies. Their extracts, fractions, essential oils or isolated constituents demonstrated promising antimicrobial activity. In the second chapter, the synthesis and antibacterial evaluation of silver nanoparticles with M. chamaedrys fractions was made. The ethanolic extract of the aerial part was subjected to partition fractionation with solvents in increasing order of polarity, hexane, dichloromethane, and ethyl acetate. Then the chemical profile, determination of total phenols and flavonoids and mass spectrometry analysis, and antibacterial activity of the extract and M. chamaedrys fractions were obtained. The fractions of greatest polarities presented high levels of phenols and flavonoids. Dichloromethane fraction mass spectrometry analysis revealed the presence of eighteen compounds, fourteen phenolic acids, two flavonoids, and two fatty acids. The fraction in dichloromethane presented the highest concentration of total flavonoids and was the only sample to present antibacterial activity against S. aureus and P. aeruginosa, with minimum inhibitory concentration (CIM) of 200 µg.mL-1 for both. To enhance the antibacterial activity of M. chamaedrys, silver nanoparticles were synthesized. The fraction of M. chamaedrys was used as a reductive agent, producing spherical-shaped particles, crystalline structure, and size less than one hundred nanometers. Silver nanoparticles had a bactericidal effect against both bacteria and low cytotoxicity in raw 264.7 macrophages. The results of this study demonstrate the biosynthetic potential of M. chamaedrys in silver nanoparticles synthesis for therapeutic use, being the most active dichloromethane fraction against bacteria S. aureus (50 µg.mL-1) and P. aeruginosa (CIM 100 µg.mL-1). The green synthesis method is an alternative for the production of low toxicity silver nanoparticles and antibacterial potential, and a promising option can be suggested for the development of skin infections caused by bacteria of clinical interest.