Phytochemical Profiling and Antimicrobial Efficacy of Loropetalum Chinense Var. Rubrum Leaf Crude Extracts Against Gram-Positive and Gram-Negative Pathogenic Bacteria

The increasing prevalence of multi-drug-resistant bacteria presents a significant challenge to traditional antibiotic therapies, emphasizing the urgent need to explore alternative antimicrobial sources. Bioactive secondary metabolites derived from plants have long been recognized for their therapeutic potential in traditional medicine and serve as vital raw materials for modern pharmaceuticals. This study investigates the antimicrobial properties of Loropetalum chinense var. rubrum, a species traditionally used in Chinese folk medicine. Qualitative phytochemical analyses of crude leaf extracts revealed the presence of several bioactive compounds, including carbohydrates, glycosides, proteins, amino acids, flavonoids, phenols, and tannins. The antimicrobial activity of these extracts was assessed using disc diffusion assays, demonstrating significant growth inhibition against both gram-positive and gram-negative pathogenic bacterial strains, including Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Enterobacter aerogenes, and Escherichia coli. Inhibition was concentration-dependent, with activity observed at extract concentrations ranging from 62.5 µg/disc to 500 µg/disc. This study underscores the promising antimicrobial potential of Loropetalum chinense var. rubrum, highlighting its potential as a valuable source for developing new antimicrobial agents to combat resistant infections.