Benjamin B. Jularbal
ABSTRACT
This study investigated the effects of Morus sp. extracts on the ctxAB gene expression and cholera toxin production in Vibrio cholerae. As antimicrobial resistance continues to challenge cholera management, identifying natural antivirulence agents offers a promising alternative. Clinical and environmental isolates of V. cholerae O1/O139 were treated with methanolic and aqueous Morus sp. extracts at concentrations of 50, 100, and 200 μg/mL. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) using the 2^-ΔΔCt method determined changes in ctxAB transcription, while cholera toxin levels were quantified using GM1-ELISA. Results revealed a dose-dependent downregulation of ctxAB expression, with the methanolic extract producing fold changes of 0.75, 0.50, and 0.28, compared to 0.85, 0.65, and 0.42 for the aqueous extract, indicating progressive low to high suppression. Correspondingly, toxin production declined as optical density decreased across concentrations. Statistical analysis confirmed significant differences (p < 0.05) between treated and control groups, with methanolic extracts showing stronger inhibitory effects. The pronounced efficacy of the methanolic extract is attributed to its higher solubility of bioactive phenolics and flavonoids, which enhance molecular interactions that interfere with virulence regulation. Overall, Morus sp. demonstrated strong antivirulence potential by suppressing ctxAB transcription and toxin synthesis, highlighting its promise as a natural inhibitor of cholera toxin expression and a potential adjunct strategy for reducing cholera pathogenicity while mitigating the risk of antibiotic resistance.
Keywords: Morus sp., Vibrio cholerae, cholera toxin, ctxAB gene expression, methanolic extract, aqueous extract, antivirulence, qRT-PCR, GM1-ELISA, phenolic compounds
https://doi.org/10.57180/netz1575