Toxicity studies on western juniper oil (Juniperus occidentalis) and Port-Orford-cedar oil (Chamaecyparis lawsoniana) extracts utilizing local lymph node and acute dermal irritation assays.
The essential oil extracts of western juniper oil (Juniperus occidentalis) and Port-Orford-cedar oil (Chamaecyparis lawsoniana) were evaluated for possible dermal toxic effects on mice and rabbits. Mice were tested for their response to both extracts utilizing a local lymph node assay. Western juniper oil extract at 0.5% and 5% concentrations did not show a stimulation index (SI) greater than normal (3.0); however, a 50% concentration did show a positive response at 3.3. Port-Orford-cedar oil extract did not show a positive response at concentrations of 0.5%, 5% or 50%. An acute dermal irritation study using rabbits had a primary irritation index (PII) of 3.3 with 100% Port-Orford-cedar oil extract. This was reduced to a PII of 0.625 when diluted 1:1 with olive oil. Undiluted western juniper oil extract had a PII score of 2.7. While a 5.0% solution had a PII score of 0.3, a 0.5% solution of western juniper oil was a non-irritant. It would appear that animals bedded on wood shavings have contact with essential oils at concentrations far less than the 2% maximum by weight obtained by steam distillation extraction. These concentrations did not elicit a hypersensitivity response.
Craig
A Morrie
AM
Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, 208 Dryden Hall, 450 SW 30th Street, Corvallis, OR 97331, USA. a.morrie.craig@oregonstate.edu
Karchesy
Joseph J
JJ
Blythe
Linda L
LL
del Pilar González-Hernández
Maria
M
Swan
Laurence R
LR
D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D007509:Irritants / Q000633:toxicity*; D018653:Juniperus; D008198:Lymph Nodes / Q000187:drug effects*; D051379:Mice; D008808:Mice, Inbred CBA; D009822:Oils, Volatile / Q000633:toxicity*; D011817:Rabbits; D012867:Skin / Q000187:drug effects*
D007509:Irritants; D009822:Oils, Volatile; C042023:cedarwood oil