Probing the antibacterial mechanism of Aloe vera based on network pharmacology and computational analysis

Bacterial resistance has emerged as a major clinical challenge globally. Natural products, such as Aloe vera, offer promising antimicrobial potential due to their diverse active components. However, the explicit molecular mechanisms remain unknown. In this study, we employed a multidisciplinary approach integrating network pharmacology, molecular docking, and molecular dynamics simulation to explore the antibacterial mechanism of Aloe vera. We screened the eight major active components of Aloe vera and their targets using multi-source bioinformatics platforms, identifying 55 targets closely associated with the antibacterial effects of Aloe vera. Protein-protein interaction network analysis, revealed potential crucial targets, including cysteine-aspartic acid protease-3 (CASP3) and matrix metalloproteinase-9 (MMP-9). Gene ontology functional enrichment analysis revealed that these targets play critical roles in several essential biological processes, such as "response to xenobiotic stimulus", "positive regulation of gene expression", and "collagen catabolism". The Kyoto Encyclopedia of Genes and Genomes signal pathway analysis indicated that these targets are primarily involved in pathways associated with cancer, lipid metabolism, atherosclerosis, and the AGE/RAGE signaling pathway in diabetes. This finding suggests that Aloe vera may exert its antibacterial effects by regulating the host's immune response and metabolism. Molecular docking and molecular dynamics simulations demonstrated that active ingredients of Aloe vera, such as quercetin and aloe-emodin, can form stable complexes with CASP3 and MMP-9, exhibiting vigorous binding affinity to the active sites of the target. Further antibacterial activity assays and reverse transcription quantitative polymerase chain reaction (RT-qPCR) analysis demonstrated that aloe-emodin exerts antibacterial effects against gram-positive bacteria and inhibits the expression of the MMP-9 gene. This study provided insight into the antibacterial mechanisms of Aloe vera, highlighting MMP-9 as a key target. These findings lay a foundation for further studies on natural antibacterial agents.