Volatiles, Flavonoids, and Antibacterial Activity of Ethanol-extract from Geranium wilfordii

  Objective  Antibacterial activity and mechanism of the ethanol-extract of Geranium wilfordii Maxim on clinical pathogens were studied for development of a natural antibiotic.

  Method  The chemical compositions of the extract were analyzed by GC-MS and HPC. The filter paper method was used to test the antimicrobial activity of the extract against 12 clinical samples of the resistant bacteria.

  Result  GC-MS detected 18 volatile substances, including aliphatic hydrocarbons, fatty acids, and alkaloids (1.15%). The 3 flavonoid compounds identified were myricitrin, quercetin-3-O-β-D-glucose, and taxifolin. High antibacterial activities against Enterococcus faecalis ATCC 29212 (MIC 1.0 mg·mL⁻¹), methicillin-resistant Staphylococcus aureus (MIC 1.0 mg·mL⁻¹), Escherichia coli ATCC 25922 (MIC 1.0 mg·mL⁻¹), and Acinetobacter baumannii ATCC 29212 (MIC 2.0 mg·mL⁻¹) of the extract were observed.

  Conclusion  In the G. wilfordii ethanol-extract, aliphatic hydrocarbons, fatty acids, and alkaloids were the major volatiles, and myricitrin, quercetin-3-O-β-D-glucose, and taxifolin the 3 substantial flavonoid compounds found. The extract demonstrated a significant antibacterial activity with wide spectrum against the commonly known clinical pathogens.