By Frances Watkins, Barbara Pendry, Alberto Sanchez-Medina, Olivia Corcoran
Journal of Ethnopharmacology, Volume 144, Issue 2 (2012)
Three important Anglo-Saxon medical texts from the 10th century contain herbal formulations for over 250 plant species, many of which have yet to be evaluated for their phytochemical and/or pharmacological properties. In this study, three native British plants were selected to determine antimicrobial activity relevant to treating bacterial infections and wounds.
Materials and methods
Several preparations of Agrimonia eupatoria L., Arctium minus (Hill) Bernh. and Potentilla reptans L. were screened for antimicrobial activity against selected Gram-positive and Gram-negative bacteria of relevance in wounds using a 96 well plate microdilution method (200, 40 and 8 μg/mL). Minimum inhibitory concentration (MIC) values were determined for the most potent extracts from 2 to 0.004 mg/mL and HPLC chromatograms examined by multivariate analysis. Principle components analysis (PCA) was used to identify chemical differences between antimicrobial activity of the crude extracts.
The HPLC–PCA score plots attributed HPLC peaks to the antimicrobial activity with all three plants inhibiting growth of Gram-positive Staphylococcus aureus by >50% in four or more extracts. The first two principal components (PC) represented 87% of the dataset variance. The P. reptans 75% ethanol root extract exhibited the greatest range of activity with MIC50 at 31.25 μg/mL to a total MIC that was also the minimum bactericidal concentration (MBC) at 1 mg/mL. Additionally, the root of P. reptans, inhibited growth of Gram-negative bacteria with the 75% ethanol extract having a MIC50 at 1 mg/mL against Pseudomonas aeruginosaand the decoction a MIC50 at 3.9 μg/mL against Escherichia coli.
The results indicate a moderate antimicrobial activity against common wound pathogens for P. reptanssuggesting it may well have been effective for treating wound and bacterial infections. Anglo-Saxon literary heritage may provide a credible basis for researching new antimicrobial formulations. Our approach encompassing advanced analytical technologies and chemometric models paves the way for systematic investigation of Anglo-Saxon medical literature for further therapeutic indications to uncover knowledge of native British plants, some of which are currently lost to modern Western herbal medicine.