Antibacterial Activity of Isobavachalcone (IBC) Is Associated with Membrane Disruption

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de Assis, Leticia Ribeiro ; Theodoro, Reinaldo dos Santos ; Silva Costa, Maria Beatriz ; Silva Nascentes, Julyanna Andrade ; da Rocha, Miguel Divino ; de Souza Bessa, Meliza Arantes ; Menezes, Ralciane de Paula ; Dilarri, Guilherme ; Hypolito, Giovane Boerner ; dos Santos, Vanessa Rodrigues ; Duque, Cristiane ; Ferreira, Henrique ; Gomes Martins, Carlos Henrique ; Regasini, Luis Octavio

• Document type: Journal article
• Source: MEMBRANES; v. 12, n. 3, p. 12-pg., 2022-03-01.

Abstract

Isobavachalcone (IBC) is a natural prenylated chalcone with a broad spectrum of pharmacological properties. In this work, we newly synthesized and investigated the antibacterial activity of IBC against Gram-positive, Gram-negative and mycobacterial species. IBC was active against Gram-positive bacteria, mainly against Methicillin-Susceptible Staphylococcus aureus (MSSA) and Methicillin-Resistant Staphylococcus aureus (MRSA), with minimum inhibitory concentration (MIC) values of 1.56 and 3.12 mu g/mL, respectively. On the other hand, IBC was not able to act against Gram-negative species (MIC > 400 mu g/mL). IBC displayed activity against mycobacterial species (MIC = 64 mu g/mL), including Mycobacterium tuberculosis, Mycobacterium avium and Mycobacterium kansasii. IBC was able to inhibit more than 50% of MSSA and MRSA biofilm formation at 0.78 mu g/mL. Its antibiofilm activity was similar to vancomycin, which was active at 0.74 mu g/mL. In order to study the mechanism of the action by fluorescence microscopy, the propidium iodide (PI) and SYTO9 fluorophores indicated that IBC disrupted the membrane of Bacillus subtilis. Toxicity assays using human keratinocytes (HaCaT cell line) showed that IBC did not have the capacity to reduce the cell viability. These results suggested that IBC is a promising antibacterial agent with an elucidated mode of action and potential applications as an antibacterial drug and a medical device coating. (AU)

• FAPESP's process: 14/18330-0 - Synthesis and biological evaluation of curcumin-cinnamaldehyde hybrids as bacterial cell division inhibitors
• Grantee: Luis Octávio Regasini
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/15083-2 - Synthesis and biological evaluation of isobavachalcone (IBC) and analogs as potential agents against tuberculosis
• Grantee: Luis Octávio Regasini
• Support Opportunities: Regular Research Grants