Banca de DEFESA: RONY LUCAS DA SILVA VIANA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : RONY LUCAS DA SILVA VIANA
DATA : 30/10/2017
HORA: 14:00
LOCAL: Sala Carl Peter von Dietrich
TÍTULO:

Green synthesis of nanoparticles containing silver and xylan from corn cob: physicochemical characterization and evaluation of its antioxidant and antimicrobial activities against protozoa and fungi.

PALAVRAS-CHAVES:

 

Polysacharides; fungi; antiparasitic; agricultural byproduct.

PÁGINAS: 87
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
RESUMO:

 

Corn cob is an agricultural by-product that annually produces a huge amount of waste estimated at thousands of tons, and it is a source of xylan, a bioactive polysaccharide. In this article, silver nanoparticles containing xylan (nanoxylan) were synthesized using an environmentally friendly synthesis method. So for such, we extracted the xylan from corn cob using ultrasound. Proteins or phenolic compounds did not contaminate this xylan. In addition, HPLC analysis showed that it contains xylose: glucose: arabinose: galactose: mannose: glucuronic acid in a molar percentage ratio of 50: 21: 14: 9.0: 2.5: 2.5, respectively. The formation of nanoxylan was analyzed by UV–vis spectroscopy at kmax = 469 nm. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of silver and xylan in nanoxylan. Dynamic Light Dispersion (DLS) and Atomic Force Microscopy (AFM) showed size of ± 102.0 nm and spherical shaped nanoparticles, respectively. DLS also showed nanoxylans were stable for 12 months. Coupled plasma optical emission spectrometry (ICP OES) showed nanoxylan contain 19% of silver. Nanoxylan reduced viability of the promastigotes of Leishmania amazonensis (L. amazonensis) (IC50 25 μg/mL), while xylan was not effective. In addition, nanoxylan showed antifungal activity on Candida albicans (MIC = 7.5 μg/mL) Candida parapsilosis (MIC = 7.5 μg/mL) and Cryptococcus neorformans (MIC = 7.5 μg/mL). The data obtained here lead us to the conclusion that it is possible to synthesize silver nanoparticles with xylan and that these nanoxylans showed an antileishimanial and antifungal activities superior to the polysaccharide used for its synthesis, and that this can be used as a promising antiparasitic agent against these microorganisms.

MEMBROS DA BANCA:
Externo ao Programa - 2524706 - GIULIANNA PAIVA VIANA DE ANDRADE SOUZA
Presidente - 2195251 - HUGO ALEXANDRE DE OLIVEIRA ROCHA
Externo à Instituição - RANIERE FAGUNDES DE MELO SILVEIRA - UFRN