Aloin of Aloe vera disrupts pseudomonas aeruginosa biofilm formation: exploring nutritional therapeutics.

Pseudomonas aeruginosa is responsible for several infections due to its remarkable antibiotic resistance, facilitated by its ability to form biofilms. In this study, Aloin, an anthraquinone present in the plant Aloe vera, was tested for antibiofilm activity against P. aeruginosa PAO1. Aloin demonstrated efficient biofilm-inhibiting capacity at a sub-MIC dose of 4.8 mM, along with/without GEN at 0.002 µg/µL (sub-MIC), in an additive manner, determined by the FICI test. Furthermore, it reduced biofilm-associated carbohydrates by 66.9%, proteins by 66.22%, and extracellular DNA by 69.57%. In silico analysis revealed that Aloin interacts with key P. aeruginosa proteins, such as RhlI (Glide Score: -6.035 kcal/mol; Glide e-model score: -60.414 kcal/mol), LasI (Glide Score: -4.407 kcal/mol; Glide e-model score: -35.286 kcal/mol), LasR (chain A) (Glide Score: -3.764 kcal/mol; Glide e-model score: -36.012 kcal/mol), LasR (chain B) (Glide Score: -5.015 kcal/mol; Glide e-model score: -46.672 kcal/mol), PqsR (Glide Score: -4.701 kcal/mol; Glide e-model score: -25.491 kcal/mol), PelA (Glide Score: -6.097 kcal/mol; Glide e-model score: -53.723 kcal/mol), and PelB (Glide Score: -5.043 kcal/mol; Glide e-model score: -53.128 kcal/mol) by forming strong hydrogen bonds. In silico simulation studies also substantiated the Aloin-protein binding results. The production of virulence factors, such as exoprotease and pyocyanin, was reduced by 71% and 74%, respectively. Furthermore, CLSM and SEM analysis showed a decrease in biofilm thickness from 498 μm to 72 μm and a reduced denser structure in the presence of Aloin. These results suggest that Aloin from Aloe vera has the potential to be an effective biofilm inhibitor without toxicity, with broad applicability.