title: Investigating the effectiveness of St John's wort herb as an antimicrobial agent against mycobacteria.
abstract: 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.
authors.affiliation: Department of Biological Engineering, Utah State University, 4105 Old Main Hill, Logan, UT 84322-4105, USA.
authors.forename: Trent
authors.initials: T
authors.lastname: Mortensen
authors.forename: Shujie
authors.initials: S
authors.lastname: Shen
authors.forename: Fenann
authors.initials: F
authors.lastname: Shen
authors.forename: Marie K
authors.initials: MK
authors.lastname: Walsh
authors.forename: Ronald C
authors.initials: RC
authors.lastname: Sims
authors.forename: Charles D
authors.initials: CD
authors.lastname: Miller
mesh_terms: D000873:Anthracenes; D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D020902:Hypericum / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D008855:Microscopy, Electron, Scanning; D009161:Mycobacterium / Q000187:drug effects* / Q000254:growth & development / Q000648:ultrastructure; D010569:Perylene / Q000031:analogs & derivatives / Q000494:pharmacology; D010696:Phloroglucinol / Q000031:analogs & derivatives / Q000494:pharmacology; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D013729:Terpenes / Q000494:pharmacology
chemical_list: D000873:Anthracenes; D000900:Anti-Bacterial Agents; D010936:Plant Extracts; D013729:Terpenes; D010569:Perylene; C004965:hypericin; D010696:Phloroglucinol; C056602:pseudohypericin; C001654:hyperforin