Antibacterial Properties of Alchemilla vulgaris and Euphorbia helioscopia: Potential Natural Alternatives for the Treatment of Conjunctivitis

Abstract

The emergence of antibiotic-resistant bacteria necessitates the exploration of alternative therapeutic agents. This study investigates the antibacterial potential of Alchemilla vulgaris and Euphorbia helioscopia extracts against bacterial strains associated with conjunctivitis, including Staphylococcus aureus, Pseudomonas aeruginosa, and Streptococcus spp. Plant extracts were prepared using water, ethanol, hexane, and chloroform as solvents, and their antibacterial efficacy was assessed via agar well diffusion and broth microdilution minimum inhibitory concentration (MIC) assays. Ethanol extracts demonstrated the highest antibacterial activity in agar diffusion, with inhibition zones up to 17 mm for E. helioscopia and 12 mm for A. vulgaris (against Streptococcus spp.). Chloroform extracts showed moderate activity (zones ranging from 9–19 mm across both plants), while hexane extracts exhibited lower activity. Water extracts displayed no antibacterial effects. MIC analysis revealed that the ethanol extracts had the lowest MIC values (approximately 280 mg/mL) among all extracts, notably against S. aureus (for A. vulgaris) and P. aeruginosa (for E. helioscopia). All other solvent extracts showed higher MICs (≥550–750 mg/mL). Statistical analysis confirmed significant differences in the antibacterial activity of the extracts compared to the control antibiotic gentamicin (30 µg) (p < 0.05). These findings highlight the potential of Alchemilla vulgaris and Euphorbia helioscopia as sources of natural antibacterial agents. Future studies should focus on isolating bioactive compounds and evaluating their pharmacological properties to develop alternative treatments for ocular bacterial infections