Octahedral ruthenium and magnesium naringenin 5-alkoxide complexes: NMR analysis of diastereoisomers and in-vivo antibacterial activity against Xylella fastidiosa

Author(s)

da Silva, Danielle Fernandes ^[1] ; Amaral, Jessica Cristina ^[1] ; Carlos, Rose Maria ^[1] ; Ferreira, Antonio Gilberto ^[1] ; Forim, Moacir Rossi ^[1] ; Fernandes, Joao Batista ^[1] ; das Gracas Fernandes da Silva, Maria Fatima ^[1] ; Della Coletta Filho, Helvecio ^[2] ; de Souza, Alessandra Alves ^[2]

Affiliation

^[1] Univ Fed Sao Carlos, Dept Quim, CP 676, BR-13565905 Sao Carlos, SP - Brazil

^[2] Ctr APTA Citros Sylvio Moreira, Inst Agron, CP 04, BR-13490970 Cordeiropolis, SP - Brazil

• Document type: Journal article
• Source: Talanta; v. 225, APR 1 2021.
• Web of Science Citations: 0

Abstract

Although many copper-based antimicrobial compounds have been developed to control pathogenic bacteria and fungi in plants and applied for crop protection, there is evidence that several plant pathogens have developed resistance to copper-based antimicrobial compounds, including some Xanthomonas species. Xylella is a bacterial genus belonging to the Xanthomonas family; and X. fastidiosa, which is responsible for citrus variegated chlorosis (CVC) in sweet orange, may develop resistance to one or more copper-based antimicrobials. Because of the time required for the development and approval of new antimicrobials for commercial use, the discovery of novel bactericidal compounds is essential before the development of resistance to the antimicrobials currently in use becomes widespread. Here, we explored the antimicrobial potential of two newly synthesized antimicrobials complexes and one natural compound against X. fastidiosa. Several nuclear magnetic resonance (NMR) assays with high resolution and sensitivity were developed to identify new diastereoisomers in the context of octahedral ruthenium - {[}Ru(narin)(phen)(2)]PF6-and magnesium naringenin 5-alkoxide - {[}Mg(narin)(phen)(2)]OAc - complexes, obtained in the present work. The NMR assays proved to be powerful tools for the identification of isomers in metal complexes. Moreover, a protocol for the in-vivo determination of the effects of these complexes against X. fastidiosa was developed. The main trunks of X. fastidiosa infected plants were injected with the two complexes as well as with the limonoid azadirachtin using a syringe; the number of bacterial cells in the plants following treatment was estimated via real-time quantitative PCR (qPCR). Importantly, the administration of both complexes and of azadirachtin drastically reduced the number of X. fastidiosa cells in vivo. (AU)

• FAPESP's process: 14/50918-7 - INCT 2014: for the Biorational Control of Pest-Insect and Phytopathogens
• Grantee: Maria Fátima das Graças Fernandes da Silva
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 14/50249-8 - Green chemistry: sustainable synthetic methods employing benign solvents, safer reagents, and bio-renewable feedstock
• Grantee: Arlene Gonçalves Corrêa
• Support Opportunities: Research Grants - Research Centers in Engineering Program
• FAPESP's process: 12/25299-6 - Integrated studies for leaf cutting control
• Grantee: João Batista Fernandes
• Support Opportunities: Research Projects - Thematic Grants