Eastern red cedar: Cedarwood oil extraction and bioactivity

Authors: Eller, Fred

Submitted to: Inform
Publication Type: Trade Journal
Publication Acceptance Date: 5/2/2018
Publication Date: 5/2/2018
Citation: Eller, F.J. 2018. Eastern red cedar: Cedarwood oil extraction and bioactivity. Inform. 29(5):18-21.

Interpretive Summary: Eastern red cedar is an abundant natural resource in the United States. It is valuable for its lumber and cedarwood oil derived from the wood. Cedarwood is generally obtained by steam distillation; however, this process has several disadvantages, including relatively low yields and altered oil characteristics. Our laboratory has been investigating several alternative methods for extracting cedarwood oil from Eastern red cedar, including liquid and supercritical fluid carbon dioxide and pressurized solvent extraction. Carbon dioxide extractions have been demonstrated to give high yields of high quality oil. Pressurized hexane also gave high yields of cedarwood oil and pressurized polar solvents like ethanol and methanol gave high yields of polar compounds not extracted by CO2 or hexane as well high yields of flavonoids. The CO2-derived extracts have been tested for a variety of bioactivities. The extracts have been found to impart resistance to wood-decay and termites when they are impregnated into otherwise susceptible wood. The cedarwood oil has also been shown to be repellent to several species of ants, including red imported fire ants and little fire ants. The cedarwood oil is toxic to black-legged ticks, brown dog ticks, lone star ticks, houseflies and several species of mosquitoes. Cedarwood oil is a very safe material towards humans but has great potential for controlling a wide range of economically important pests.

Technical Abstract: Eastern red cedar (ERC), Juniperus virginana L. (Cupressaceae) is a common coniferous evergreen tree and is a very abundant natural resource in the United States. Because of its encroachment onto pastures and rangeland, ERC is considered an invasive species. Eastern red cedar, however, is highly prized for its aromatic wood, which is used for making cedar chests, closet liners and fence posts. Besides its valuable lumber, cedarwood oil (CWO) (CAS 8000-27-9) can be obtained from the heartwood. Cedarwood oil is most often obtained by steam distillation of sawmill wastes; however, this process has several disadvantages, including relatively low yields and altered oil characteristics. Steam distilled CWO generally has a very low cedrol/alpha-cedrene ratio, usually less than 1.0. Solvent-derived CWO, on the other hand, generally as a much higher cedrol/alpha-cedrene ratio, usually between 3-10, and as high as 26. Because cedrol has been reported to be one the most bioactive components of CWO, so it is prudent to preserve (i.e., prevent its degradation to alpha-cedrene) it in the CWO. Because cedrol has been reported to be one the most bioactive components of CWO, so it is prudent to preserve (i.e., prevent its degradation to alpha-cedrene) it in the CWO. Carbon dioxide-derived CWO, did in fact, confer resistance against both wood-decay fungi and termites when it was vacuum-impregnated into pine sapwood. Carbon dioxide-derived CWO has been shown to be repellent to several species of ants, toxic to several species of ticks, mosquitoes, and houseflies. Cedarwood oil holds great promise for managing a wide range of economically important pests as an environmentally friendly natural pest management tool from an under-utilized abundant renewable natural resource in Eastern red cedar.