title: Antimicrobial activity of lavender, tea tree and lemon oils in cosmetic preservative systems.
abstract: OBJECTIVE
  The aim of the study was to verify the antimicrobial activity of commercial essential oils: lavender, tea tree and lemon as the components of a preservative system in oil in water body milks.
  
  
  RESULTS
  The inhibition efficacy of essential oils alone (0.5%), in mixtures (1%) as well as combined with the synthetic preservative 1,3-dimethylol-5,5-dimethylhydantoin and a 3-iodo-2-propynyl butyl carbamate mixture (0.1% and 0.2%) was tested against Staphylococcus aureus ATCC 6538, Pseudomonas aeruginosa ATCC 9027, Candida sp. ŁOCK 0008 and Aspergillus niger ATCC 16404 in compliance with the standards of the European Pharmacopoeia Commission. The in vitro activity of oils determined by an impedimetric method was also compared with their activity in cosmetic preparations. Criterion A for bacteria (reduction in the inoculum by 3 logarithmic units within 7 days with no increase up to the 28th day) and fungi (reduction in the inoculum by 2 logarithmic units within 14 days with no increase up to the 28th day) was fulfilled for cosmetic formulations containing the tested essential oils with 0.2% of the synthetic preservative. The preservative concentration could be decreased to 0.1% (with preserving the same efficacy) in combination with lavender and tea tree oils at a concentration of 0.5% each.
  
  
  CONCLUSIONS
  In all combinations of essential oils with the synthetic preservative, a synergistic effect of the preservative system components was observed, which made it possible to reduce the usable level of the synthetic preservative up to 8.5 times.
  
  
  CONCLUSIONS
  To develop an effective preservative system in cosmetics in which a synthetic chemical preservative is replaced by natural essential oils.
authors.affiliation: Institute of Fermentation Technology and Microbiology, Technical University of Lodz, Lodz, Poland. akunicka@p.lodz.pl
authors.forename: A
authors.initials: A
authors.lastname: Kunicka-Styczyńska
authors.forename: M
authors.initials: M
authors.lastname: Sikora
authors.forename: D
authors.initials: D
authors.lastname: Kalemba
mesh_terms: D000890:Anti-Infective Agents / Q000494:pharmacology*; D001234:Aspergillus niger / Q000187:drug effects; D001419:Bacteria / Q000187:drug effects; D002175:Candida / Q000187:drug effects; D002219:Carbamates / Q000494:pharmacology; D003358:Cosmetics / Q000737:chemistry*; D006827:Hydantoins / Q000494:pharmacology; D027523:Lavandula / Q000737:chemistry*; D009822:Oils, Volatile / Q000494:pharmacology*; D010938:Plant Oils / Q000494:pharmacology*; D011310:Preservatives, Pharmaceutical / Q000494:pharmacology; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects; D020947:Tea Tree Oil / Q000494:pharmacology*
chemical_list: D000890:Anti-Infective Agents; D002219:Carbamates; D003358:Cosmetics; D006827:Hydantoins; D009822:Oils, Volatile; D010938:Plant Oils; D011310:Preservatives, Pharmaceutical; C106572:3-iodo-2-propynylbutylcarbamate; D020947:Tea Tree Oil; C056057:1,3-dimethylol-5,5-dimethylhydantoin; C501365:lemon oil