Study on the chirality of betalains

• Grant number: 20/05276-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2020
• End date: November 30, 2022
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Organic Chemistry
• Principal Investigator: Erick Leite Bastos
• Grantee: Arthur Alexandre Falkembach Andreis
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated scholarship(s): 21/10248-6 - Betalains as chiral mediators in photoinduced transfer, BE.EP.IC

Abstract

Betalamic acid is a chiral aldehyde prepared by hydrolysis of betalains or isolated from bacteria transformed to express L-DOPA dioxygenase. Betalains are imines or iminium salts and, therefore, the coupling between betalamic acid and amines or amino acids results in natural or pseudo-natural betalains that can be applied as antioxidants, biological markers, catalysts in the formation of hydrogen from sunlight, among other possibilities. Betalamic acid is, however, unstable and cannot be stored under ambient conditions, which has restricted its study. One of the most overlooked characteristics of betalamic acid and betalains in general is their chirality. The ±-enaminic carbon of betalamic acid is asymmetric and has an absolute configuration S. In aqueous media, the slow formation of its enantiomer called isobetalamic acid and the epimerization of betalains with two asymmetric centers are reported. In this undergraduate research project, the optical properties of model betalains and betalamic acid will be characterized through studies of circular dichroism. In addition, the kinetics of hydrolysis and formation of betalains will be investigated by using circularly polarized light.