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Investigating the Effectiveness of St John's Wort Herb as an Antimicrobial Agent against Mycobacteria
Author(s) -
Mortensen Trent,
Shen Shujie,
Shen FenAnn,
Walsh Marie K.,
Sims Ronald C.,
Miller Charles D.
Publication year - 2012
Publication title -
phytotherapy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 129
eISSN - 1099-1573
pISSN - 0951-418X
DOI - 10.1002/ptr.3716
Subject(s) - hyperforin , hypericum perforatum , hypericin , hypericum , antimicrobial , minimum inhibitory concentration , traditional medicine , herb , microbiology and biotechnology , mycobacterium , chemistry , medicine , biology , bacteria , pharmacology , medicinal herbs , genetics
A persistent need exists for effective treatment agents for mycobacterial infections. This research investigated the effectiveness of the Hypericum perforatum herb (commonly known as St John's wort; SJW) in its growth inhibition of mycobacteria. A SJW extract was effective at inhibiting five nonpathogenic Mycobacterium isolates and Bacillus subtilis , but not Escherichia coli . Quantitative studies of concentration sensitivity to the SJW extract were performed with minimal bactericidal concentrations (MBC) ranging from 0.33 to 2.66 mg extract/mL. The SJW compounds hyperforin (Hfn), hypericin (Hpn), and pseudohypericin (Phn) were quantified in the extract using HPLC. The SJW extract solution of 133 mg extract/mL used in this study contained 2.3 mg Hfn/mL, 0.8 mg Hpn/mL, and 2.1 mg Phn/mL. Purified Hfn, Hpn, and Phn were tested for inhibitory activity against Mycobacterium JLS ( M . JLS) at similar concentrations used in the crude extract. While Hfn was inhibitory at 46 µg/mL, none of the purified SJW constituents were bactericidal at concentrations corresponding to SJW treatments. Scanning electron microscopy (SEM) analysis of SJW‐treated M . JLS cells showed changes in cell surface morphology. Copyright © 2012 John Wiley & Sons, Ltd.