Banca de DEFESA: RAYANI ALMEIDA DE LIMA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : RAYANI ALMEIDA DE LIMA
DATA : 06/12/2021
HORA: 14:00
LOCAL: https://meet.google.com/bvp-nrpq-mts
TÍTULO:

Semisynthesis, hydrolytic stability, photophysical properties, and antioxidant capacity of a betalain derived from mefenamic acid

PÁGINAS: 92
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Orgânica
ESPECIALIDADE: Físico-Química Orgânica
RESUMO:

Diphenylamine derivatives are used as nonsteroidal anti-inflammatory drugs due to their ability to prevent prostaglandin biosynthesis by inhibiting the activity of cyclooxygenases COX-1 and COX-2. Despite their therapeutic effectiveness, the use of these drugs is limited by their side effects in the gastrointestinal tract, which leads to the search for therapeutic alternatives for a variety of inflammatory diseases. Betalains are non-toxic pigments found in plants and fungi that interfere in the pro-inflammatory signaling cascade, mainly in the nuclear factor kappa B (NF-κB) pathway. This Master's Thesis describes the semisynthesis of a betalain derived from the coupling between betalamic acid and mefenamic acid, a commercial diphenylamine used as a nonsteroidal anti-inflammatory agent. The compound obtained, called MefBeet, had its photophysical characterization, hydrolytic stability, antioxidant capacity and interaction with proteins determined, presenting characteristics that lead the molecule to be a possible candidate for the development of an anti-inflammatory drug. MefBeet is soluble in water and its hydrolysis does not depend on the pH in the range from 3 to 7. Its maximum absorption in water is 502 nm and its excitation at this wavelength produces an emission centered at 567 nm (Stoke shift: 65 nm, 2284 cm^–1). Although the quantum fluorescence yield in the solution is low (Φ_FL = 5.5 × 10^–3), it was observed that its interaction with an excesso of 100 equiv. of bovine serum albumin (BSA) results in an 40-70× increase in the fluorescence quantum yield, which is not pH dependent in the range between 5 and 7. Furthermore, it was observed that MefBeet has a greater antiradical capacity than Trolox and the precursor amine itself (1.6×). The results may contribute to the development of anti-inflammatory drugs with combined action obtained from natural products.

MEMBROS DA BANCA:
Presidente - Interno ao Programa - 250.887.078-19 - ERICK LEITE BASTOS - USP
Membro Titular - Examinador(a) Interno ao Programa - 1939561 - FERNANDO HEERING BARTOLONI
Membro Titular - Examinador(a) Externo à Instituição - CASSIUS VINICIUS STEVANI - USP
Membro Suplente - Examinador(a) Interno ao Programa - 1600860 - ALVARO TAKEO OMORI
Membro Suplente - Examinador(a) Externo à Instituição - LILIANA MARZORATI - USP