Antimicrobial activity of yellow tabebuia flower extract (Tabebuia aurea) against drug-resistant microbes

Abstract

Antimicrobial resistance is an urgent global challenge in the treatment of infections. Medicinal plants such as Tabebuia aurea, known for its yellow flowers, have potential as therapeutic alternatives. This study evaluated the antimicrobial activity of yellow tabebuia flower extract against drug-resistant microbes in silico and in vitro. Molecular docking was performed between the enzymes Aminoglycosid-2“-phosphotransferase-IIa (APH(2”)-IIa) and aspartic proteinases (Saps) with active compounds from yellow tabebuia. Yellow tabebuia flower extract was obtained by sonication extraction method with 96% ethanol. The antimicrobial activity was tested using agar-well diffusion and agar dilution tests to determine the minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC) against 6 resistant pathogens including Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus mutans, and Candida albicans. All selected active compounds in yellow tabebuia were able to bind to APH(2")-IIa and Saps. Among the bond between active compounds and microbial proteins, stigmast-5-en-3-ol - APH(2")-IIa and rutin – Saps complexes produced the strongest bond, with affinity energy lower than the positive control, streptomycin and pepstatin, respectively. Yellow tabebuia flower extract showed antimicrobial activity against all pathogenic microbes tested, with the greatest zone of inhibition on P. aeruginosa. The MIC values obtained varied, with a bactericidal effect against S. aureus (MBC 500 mg/mL). This study proved the potential of yellow tabebuia flowers as an alternative to overcome antimicrobial resistance.