A systematic review on the anxiolytic effects of aromatherapy on rodents under experimentally induced anxiety models.
OBJECTIVE
We reviewed studies from 1999 to 2009 on anxiolytic effects of different essential oils toward rodents in anxiety-related behavioral models.


METHODS
Journal papers that evaluated the anxiolytic effects of essential oils for rodents were extracted from available electronic data bases.


RESULTS
The results based on 14 studies showed that different rodent species were recruited including ICR mice and Swiss mice. Most of studies applied the Elevated Plus Maze (EPM) as the animal behavioral model. Lavender oil was the most popular within the 14 studies. Lavender and rose oils were found to be effective in some of the studies. Only one study reported the underlying neurophysiological mechanism in terms of concentrations of emotionally related neuro-transmitters such as dopamine, serotonin, and their derivatives, in various brain regions.


CONCLUSIONS
Some essential oils are found to be effective to induce anxiolytic effect in rodents under different animal anxiety models. However, more standardized experimental procedures and outcome measures are needed in future studies. Translational research to human subjects is also recommended.
Tsang
Hector W H
HW
Neuropsychiatric Rehabilitation Laboratory, Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Honk Kong. rshtsang@inet.polyu.edu.hk
Ho
Timothy Y C
TY
D000818:Animals; D014151:Anti-Anxiety Agents / Q000627:therapeutic use*; D001007:Anxiety / Q000628:therapy*; D019341:Aromatherapy / Q000379:methods*; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D016208:Databases, Factual / Q000706:statistics & numerical data; D004195:Disease Models, Animal; D006801:Humans; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology; D051379:Mice; D018377:Neurotransmitter Agents / Q000378:metabolism; D009822:Oils, Volatile / Q000008:administration & dosage; D051381:Rats; D016896:Treatment Outcome
D014151:Anti-Anxiety Agents; D018377:Neurotransmitter Agents; D009822:Oils, Volatile