Chemical composition and antimicrobial activity of Cordiera myrciifolia leaves against pathogenic bacteria and fungi: Drug potentiation ability and inhibition of virulence

Abstract

Cordiera myrciifolia is an abundant species in Northeast Brazil that presents metabolites of biological/therapeutic interest. From this perspective, the present study aimed to investigate the chemical constituents and evaluate the in vitro antimicrobial activity of hexane (HECM) and ethanolic (EECM) extracts of C. myrciifolia leaves. The extracts were analyzed by chromatographic techniques (GC and UPLC) coupled with mass spectrometry. The antimicrobial activity of the extracts and the extracts combined with conventional drugs was evaluated by microdilution. The in vitro effect of the treatments on Candida's morphological transition was verified through cultivation in humid chambers. In HECM, 11 constituents including fatty acids, and triterpenes, including phytosterols, alkanes, tocols, and primary alcohols were identified. Triterpenes represented >40% of the identified constituents, with Lupeol being the most representative. In EECM, 13 constituents were identified, of which eight belonged to the class of flavonoids. High antibacterial activity of HECM was detected against Escherichia coli and Staphylococcus aureus, with Minimum Inhibitory Concentrations of 8 and 16 μg/mL, respectively. The combined activity was more effective when combined with Norfloxacin and Imipenem. In anti-Candida activity, the IC50 of the extracts ranged from 36.6 to 129.1 μg/mL. There was potentiating effect when associated with Fluconazole. Both extracts inhibited the filamentous growth of C. tropicalis at a concentration of 512 μg/mL. C. myrciifolia extracts prove to be candidates for the development of new therapeutic formulations to treat bacterial and fungal infections.