title: Comparison of rosmarinic acid content in commercial tinctures produced from fresh and dried lemon balm (Melissa officinalis).
abstract: OBJECTIVE
  To measure the rosmarinic acid content of eight commercial tinctures derived from fresh (n= 5) and dried (n=3) Melissa officinalis herb.
  
  
  METHODS
  Rosmarinic acid and the internal standard (esculin) were purchased from Aldrich Chemical Co. The column used was a Luna C18, 5 um (150 x 4.6 mm I.D., Phenomenex) maintained at ambient room temperature. The HPLC system consisted of a Shimadzu SCL-6B controller, Shimadzu LC-6A pumps, Shimadzu SPD-6A UV single wavelength spectrophotometric detector set to 320 nm and Shimadzu SIL-6B autosampler. Gradient elution of the samples and standard were performed using ammonium formate (0.02 M; pH 6.25 at 27 oC; eluent A) and methanol (eluent B). The gradient elution initial conditions were 2% of eluent B with linear gradient to 60% at 30 min, followed by linear gradient to 90% of eluent B at 31 min, this proportion being maintained for 4 min. The column was then returned to the initial condition at 36 min and maintained until the end of the run at 43 min. The flow rate was 1 mL/min. The assay was validated for sensitivity, accuracy and reproducibility.
  
  
  RESULTS
  The content of rosmarinic acid in commercial tinctures was significantly higher in the tinctures made from dried plant material (2.96 - 22.18 mg/mL) compared to fresh plant tinctures (</= 0.92 mg/mL).
  
  
  CONCLUSIONS
  These results have implications both for the manufacturers of commercial tinctures and also for herbal practitioners in the choice of tinctures for treating Herpes simplex infection.
authors.affiliation: The Medicines Research Group, School of Health and Bioscience, University of East London, Romford Road, Stratford, London.
authors.forename: Alberto
authors.initials: A
authors.lastname: Sanchez-Medina
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Etheridge
authors.forename: Geoffrey E
authors.initials: GE
authors.lastname: Hawkes
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Hylands
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Pendry
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Hughes
authors.forename: Olivia
authors.initials: O
authors.lastname: Corcoran
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002934:Cinnamates / Q000032:analysis* / Q000737:chemistry; D053630:Depsides / Q000032:analysis* / Q000737:chemistry; D029001:Herbal Medicine / Q000592:standards; D031334:Melissa / Q000737:chemistry; D004364:Pharmaceutical Preparations / Q000032:analysis* / Q000737:chemistry; D010936:Plant Extracts / Q000032:analysis / Q000737:chemistry; D000097123:Rosmarinic Acid
chemical_list: D002934:Cinnamates; D053630:Depsides; D004364:Pharmaceutical Preparations; D010936:Plant Extracts; D000097123:Rosmarinic Acid