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bioRxiv · 10.1101/2025.07.16.665167

Amlodipine as an Adjunct Bacterial Growth Inhibitor in Iron-Overloaded Conditions: In Vitro Effects Against E. Coli

Eke, S. M.·Cua, A. P.
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Abstract

BackgroundIron overload is a frequently underrecognized condition with a rising global prevalence. Excessive accumulation of iron has been considered a risk factor for the exacerbation of bacterial infections. Ca2+ is universally recognized as an indispensable cation for cell signaling. L-type voltage-dependent calcium channels (LVDCCs) facilitate the transport of Ca2+ and Fe2+ ions into the cytoplasm of eukaryotic cells. A non-protein molecule acting as a calcium channel has been found in prokaryotes. This finding has led to the proposal of a variety of signaling mechanisms for Ca2+ in bacteria. By combining research regarding the proliferation of bacteria exposed to iron and the potential role of Amlodipine not only as a mediator of iron overload at the cellular level but also as a growth inhibiting agent, we aim to test whether Amlodipine would have significant effects on the growth of E. Coli in iron-enriched microenvironments. MethodsFerrous sulfate was utilized to simulate an iron overloaded environment in-vitro by creating an agarose gel mixed with ferrous sulfate. E. coli was uniformly inoculated across the plates using standardized dilution protocol. A zone of inhibition test consisted of soaking sterile paper disks in increasing concentrations of Amlodipine (0, 1, 2, 3, 4, 5 mg/mL) and placing them on the agar. Zones of inhibition were measured, and results were statistically analyzed using one-way ANOVA for assessment of statistically significant differences between the means of the 6 groups and post-hoc Tukey HSD testing for comparison of individual groups to one another. ResultsAmlodipine exhibited a statistically significant, dose-dependent inhibition of E. coli growth (p = 6.1594 x 10 {square} {square}). The diameter of the zones of inhibition increased consistently with Amlodipine concentration, with an R2 value of 0.9885, indicating a strong correlation. Higher concentrations of Amlodipine showed the greatest growth inhibiting effect, while the control group lacking Amlodipine exhibited little to no inhibition. ConclusionThis study suggests that Amlodipine may inhibit bacterial growth in iron-overloaded conditions, highlighting its potential as an adjunct therapeutic option for patients with infections who are simultaneously at risk of iron overload. Further in vivo studies are warranted to assess its clinical relevance.

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Eke, S. M., Cua, A. P.. 2025-07-16. Amlodipine as an Adjunct Bacterial Growth Inhibitor in Iron-Overloaded Conditions: In Vitro Effects Against E. Coli. https://doi.org/10.1101/2025.07.16.665167

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