Evaluation of the Antibacterial Activity of Rheum palmatum Processed by Different Methods Against Staphylococcus aureus using Integrated in vitro and in silico Approaches

Abstract

Introduction Traditional Chinese Medicine (TCM) employs various processing methods to enhance the bioactivity of herbs. Rheum palmatum (R. palmatum) is commonly processed to optimize its medicinal properties, yet its antibacterial activity under different processing techniques remains unclear. Standardizing preparation methods is essential for ensuring consistent therapeutic efficacy. This study examines how different processing methods influence the antibacterial activity of R. palmatum, contributing to the standardization of TCM preparation.Materials and Methods R. palmatum roots underwent 10 different water-based processing methods. Antibacterial activity against S. aureus was assessed using disc diffusion and broth microdilution assays. The most effective extracts were further analyzed via molecular docking to evaluate their binding interactions with bacterial virulence proteins (alpha-hemolysin and Catalase).Results Disc diffusion and MIC results showed that RP-4 (high-pressure steamed with wine) exhibited the largest inhibition zone (11.67 mm) and the lowest MIC (1250 mu g/mL). Compared to other tested microorganisms, selective inhibition was also observed against S. aureus. Molecular docking revealed that Rhein, a major active compound identified in the RP-4 extract, exhibited strong binding affinity to alpha-hemolysin and Catalase, comparable to standard antibiotics.Discussion RP-4, processed through high-pressure steaming with wine, showed the strongest antibacterial activity based on ZOI and MIC results. Wine processing enhances the dissolution of active compounds, while high-pressure steaming reduces anthraquinone derivatives that cause digestive problems. Molecular docking also confirmed interactions between Rhein and the virulent proteins alpha-hemolysin and Catalase, suggesting a potential mechanism for inhibiting S. aureus.Conclusion Processing methods significantly influence the antibacterial properties of R. palmatum. RP-4 demonstrated the strongest activity against S. aureus, making it a promising candidate for future TCM formulation and antibacterial drug development.