Banca de QUALIFICAÇÃO: Alan Kelbis Oliveira Lima

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : Alan Kelbis Oliveira Lima
DATE: 15/12/2022
TIME: 08:30
LOCAL: Videoconferência
TITLE:

Phytosynthesis of silver nanoparticles (AgNPs) using aqueous extract of guaraná (Paullinia cupana) plant parts: study of the reaction parameters, characterization and biological activities in vitro and in vivo

KEY WORDS:

Amazon, Paullinia cupana, Green synthesis, nanobiotechnology, AgNPs.

PAGES: 150
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

Phytosynthesis of silver nanoparticles (AgNPs) using aqueous extract of guaraná (Paullinia cupana) plant parts: study of the reaction parameters, characterization and biological activities in vitro and in vivo Currently, researchers make numerous attempts to find biocompatible/non-toxic methods or "green" approaches for the synthesis of metal nanoparticles, including silver nanoparticles (AgNPs). Several strategies have been developed for the synthesis of AgNPs and one of the ways is the use of biological materials that present compounds capable of reducing and stabilizing silver ions (Ag+) forming colloidal silver (Ag0). The adequacy of production through biosynthetic processes can favor the increase of the production scale and is useful not only for its lower environmental impact, but also because it can be used to control the properties of the biosynthesized AgNPs. The Brazilian Amazon comprises about 5,098,500 million km2 and its biodiversity emerges as a rich source of biomolecules that can be used as raw material in the biosynthesis of AgNPs, configuring a favorable aspect and with good prospects from the sustainable exploitation of its resources. The guaraná plant (Paullinia cupana, Sapindaceae) is associated with a remarkably wide range of pharmacological actions. Generally, the seed of the guaraná is the commercially exploited part due to the large amounts of alkaloid compounds, such as caffeine. However, other parts of the plant, such as the leaves and flowers, can be investigated for their potential, including by combining them with nanobiotechnology. This project is divided into three chapters where a screening is performed to know the potential of the guaraná plant used in the formation of AgNPs. Chapter 1 aims to optimize the preparation of aqueous extracts from leaves and flowers of Paullinia cupana collected in different seasonal periods and subsequent use in the synthesis of AgNPs. Furthermore, characterizations regarding size, morphology, elemental composition and crystal structure are performed for the AgNPs, while the molecular profile of the metabolites found in each aqueous extract of the guarana parts is also investigated. Finally, this chapter characterizes the plant extracts for the content of phenolic compounds and evaluates their antioxidant potentials and also tests the antimicrobial activity of AgNPs. In Chapter 2, optimization of the reaction parameters involved in the biosynthesis of AgNPs using the leaves of the plant are performed, among them the concentration of the plant extract, the concentration of the silver metal salt, the reaction temperature, and the equipment and/or energy source used in the synthesis. These evaluations are important to modulate the physicochemical characteristics of AgNPs just by modifying the reaction conditions. Next, in order to study how changing some parameters can synthesize AgNPs with distinct characteristics and applications, the morphology of the nanostructures and the possible antibacterial, leishmanicidal and cytotoxic activities are investigated. Finally, in Chapter 3, AgNPs are synthesized using leaves collected in the dry and rainy season under the previously optimized reaction conditions and characterized according to spectrophotometric, dimensional, electrical, morphological techniques. Then, several bioactivities are tested, including in vitro tests as antimicrobial, antioxidant, anticancer, hemolytic, leishmanicidal, and catalytic reduction of dyes and in vivo tests during the embryo-larval development of Danio rerio (zebrafish) and against pupae and larvae of Aedes aegypti are also performed. Thus, the biological efficacy of biogenic AgNPs formed from the use of aqueous plant extracts of a plant native to the Amazon region can be known.

BANKING MEMBERS:
Externo à Instituição - LJUBICA TASIC - UNICAMP
Externo à Instituição - LUCIANO PAULINO DA SILVA - EMBRAPA
Interno - 2107993 - LUIS ALEXANDRE MUEHLMANN
Presidente - 2220195 - MONICA PEREIRA GARCIA