Phytochemical Screening and Microbicidal Activity of Siegesbeckia orientalis Against Human Bacterial Pathogens

Background: Sigesbeckia orientalis, commonly known as the “Chinese herb” has been utilized in traditional medicine for its various therapeutic properties. This plant is part of the Asteraceae family and is known for its anti-inflammatory, analgesic, and antimicrobial effects. The increasing prevalence of antibiotic-resistant pathogens has prompted researchers to explore alternative sources of antimicrobial agents, particularly from natural products. Aim: This study investigated the ability of Sigesbeckia orientalis to inhibit common human pathogens, including Proteus vulgaris, Staphylococcus aureus, Klebsiella sp., Escherichia coli, Pseudomonas aeruginosa, Enterobacter aerogenes, Trichophyton rubrum, and Epidermophyton floccosum. Method: Fifty grams of crushed material were treated with 300 ml each of chloroform, hexane, methanol, and ethanol for 24 hours at 23±2°C. The extracts were filtered through Whatman filter paper into a clean beaker. A second extraction was performed with the same solvents for another 24 hours, followed by filtration. The combined extracts were evaporated using a rotary flash evaporator and stored in sealed containers at 4°C until further use. Results: The ethanol extract showed significant antibacterial activity, particularly against Pseudomonas aeruginosa (15 mm) and Staphylococcus aureus (13 mm). In contrast, the chloroform extract was less effective, with minimal inhibition against several bacteria. Minimum inhibitory concentrations (MICs) were 0.75 mg/ml for S. aureus and 1.0 mg/ml for P. aeruginosa, while other bacterial isolates exceeded 2.0 mg/ml. MIC values for Trichophyton rubrum and Epidermophyton floccosum from the ethanol extract were higher than the standard antifungal agent, ketoconazole. Conclusion: These findings support the antimicrobial potential of phytoconstituents in traditional medicinal plants for developing new treatments for infections. Major Findings: The antimicrobial activity observed in plant extracts may be attributed to the presence of one or more phytoconstituent active compounds, which could be functioning synergistically. According to the current study’s findings, S. orientalis leaf preparations in ethanol contain a variety of pharmacologically potent substances.