title: The effects of Melissa officinalis (lemon balm) pretreatment on the resistance of the heart to myocardial injury.
abstract: BACKGROUND
  The antihyperlipidemic, antiarrhythmic, neuroprotective and hepatoprotective effects of Melissa officinalis L. (Lamiaceae) have been reported. However, no study has examined its effects on the resistance of the heart to stressful conditions.
  
  
  OBJECTIVE
  The objective of this study is to evaluate the effects of aqueous extract of M. officinalis aerial parts on Wistar rat heart with/without cardiac injury.
  
  
  METHODS
  Animals were grouped as control, isoproterenol (ISO), M. officinalis without (M50, M100, and M200) and with isoproterenol (M50 + ISO, M100 + ISO, and M200 + ISO). The aqueous extract of M. officinalis was orally administered at dosages of 50, 100, and 200 mg/kg/d, respectively, for 7 consecutive days. On the 6th and 7th day, ISO, M50 + ISO, M100 + ISO, and M200 + ISO groups received 85 mg/kg of isoproterenol for myocardial injury induction. On day 8, hemodynamic parameters were recorded and samplings were done.
  
  
  RESULTS
  The extract (50, 100, and 200 mg/kg) significantly reduced the heart rate (264 ± 5, 259 ± 5 and 281 ± 3 versus 377 ± 13 in control group, p < 0.01). Blood pressure was significantly decreased in M50 + ISO (75 ± 5) versus M50 (110 ± 6) and M100 + ISO (72 ± 6) versus M100 (105 ± 5 mmHg, p < 0.01). The malondialdehyde levels of the injured hearts were lower in M50 + ISO and M100 + ISO groups than in the ISO group (p < 0.05). Serum cardiac troponin I was higher in the M200 + ISO group (5.1 ± 1.7) than in the ISO group (2.7 ± 0.7 ng/ml, p < 0.05).
  
  
  CONCLUSIONS
  The lower dose of extract, by improving the balance of the redox system and by reducing the heart rate, may increase the heart resistance to injury. However, the higher doses of extract may intensify the injury of ischemic heart.
authors.affiliation: a Physiology Research Center , Institute of Neuropharmacology, Kerman University of Medical Sciences , Kerman , Iran .|b Department of Physiology and Pharmacology , School of Medicine, Kerman University of Medical Sciences , Kerman , Iran .|c Cardiovascular Research Center , Institute of Basic and Clinical Physiology Sciences, Kerman University of Medical Sciences , Kerman , Iran .
authors.forename: Siyavash
authors.initials: S
authors.lastname: Joukar
authors.affiliation: a Physiology Research Center , Institute of Neuropharmacology, Kerman University of Medical Sciences , Kerman , Iran .
authors.forename: Haleh
authors.initials: H
authors.lastname: Asadipour
authors.affiliation: d Kerman Medical Student Research Committee , Kerman University of Medical Sciences , Kerman , Iran , and.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Sheibani
authors.affiliation: b Department of Physiology and Pharmacology , School of Medicine, Kerman University of Medical Sciences , Kerman , Iran .|c Cardiovascular Research Center , Institute of Basic and Clinical Physiology Sciences, Kerman University of Medical Sciences , Kerman , Iran .
authors.forename: Hamid
authors.initials: H
authors.lastname: Najafipour
authors.affiliation: e Department of Pathology , School of Medicine, Kerman University of Medical Sciences , Kerman , Iran.
authors.forename: Shahriar
authors.initials: S
authors.lastname: Dabiri
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects*; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D031334:Melissa / Q000737:chemistry*; D009203:Myocardial Infarction / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000517:prevention & control*; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D010084:Oxidation-Reduction; D035261:Plant Components, Aerial / Q000737:chemistry; D010936:Plant Extracts / Q000008:administration & dosage / Q000302:isolation & purification / Q000627:therapeutic use*; D017208:Rats, Wistar; D019210:Troponin I / Q000378:metabolism; D016277:Ventricular Function, Left / Q000187:drug effects
chemical_list: D010936:Plant Extracts; D019210:Troponin I; D007545:Isoproterenol
keywords: Blood pressure; cardiac contractility; cardiac injury; cardiac troponin I