Comparative Antibiofilm Activity of Curcumin and Allicin: A Time-Dependent Analysis against Bacterial Biofilm Formation

Bacterial biofilms represent a significant challenge in clinical microbiology, forming protective matrices that enhance antimicrobial resistance and bacterial persistence. Lactobacillus species, while beneficial in many contexts, can form problematic biofilms in certain clinical conditions, necessitating effective antibiofilm strategies. Natural compounds have emerged as promising alternatives to conventional antimicrobials due to their multitargeted mechanisms and reduced resistance development. This study aims to compare the antibiofilm efficacy of allicin and curcumin against Lactobacillus biofilm formation and evaluate their time-dependent inhibitory effects. Lactobacillus cultures were treated with allicin (15 μM) and curcumin (10 μM) over 24 and 48-hour periods. Biofilm formation was quantified using the crystal violet staining method, with absorbance measured at 578 nm following solubilization. Results demonstrated significant antibiofilm activity for both compounds, with allicin exhibiting superior efficacy. Curcumin achieved moderate biofilm inhibition of 11% at 24 hours and 13% at 48 hours. In contrast, allicin demonstrated pronounced time-dependent antibiofilm effects, achieving 42% inhibition at 24 hours and 61% inhibition at 48 hours. The progressive enhancement of allicin's activity suggests concentration-dependent and time-dependent mechanisms involving biofilm matrix disruption and bacterial membrane damage. Allicin demonstrated superior antibiofilm activity compared to curcumin, with significant time-dependent enhancement of inhibitory effects. These findings support allicin's potential as a natural antibiofilm agent for managing Lactobacillus-associated biofilm infections, warranting further investigation into optimal dosing regimens and clinical applications.