A comprehensive study on Geranium robertianum L. antibacterial potential

Area of Science:

• Phytochemistry
• Microbiology
• Natural Product Chemistry

Background:

• Geranium robertianum is a plant species with potential medicinal properties.
• Secondary metabolites from plants are a source of novel antibacterial agents.
• Antibiotic resistance necessitates the discovery of new antimicrobial strategies.

Purpose of the Study:

• To optimize ultrasound-assisted extraction of secondary metabolites from Geranium robertianum.
• To evaluate the antibacterial activity and phytochemical profile of the optimized extracts.
• To investigate the synergistic effects with antibiotics and mechanisms of action.

Main Methods:

• Ultrasound-assisted extraction optimized using Response Surface Methodology.
• Antibacterial activity assessed by microdilution, checkerboard, and time-kill kinetics.
• Cell membrane permeability and cytotoxicity assays were performed.

Main Results:

• Optimized ethanol and acetone extracts exhibited broad-spectrum antibacterial activity (MICs 1.25–20 mg/mL).
• Extracts showed significant synergy with gentamicin against resistant E. coli and S. aureus (up to 32-fold enhancement).
• Mechanism involves disruption of bacterial cell membrane permeability; key compounds identified as kaempferol, ellagic acid, quercetin, and rutin.

Conclusions:

• Geranium robertianum extracts possess significant antibacterial properties.
• These extracts demonstrate potential as natural antibacterial agents for microbial control.
• Synergistic activity with existing antibiotics offers a promising strategy against resistant strains.