An interesting exploration into the similarities and differences between Ginger CO2 extract and Ginger essential oil.
Common to both
Name: Ginger (Zingiber officinale)
Description: Ginger is an erect perennial herb that grows up to 1 meter high, with a thick, spreading, tuberous rhizome root.
History/Folklore: Ginger has a tradition of being used as both a spice and a medicinal remedy for thousands of years. There is lots of evidence that shows that it was used in both cooking and as a medicine, by the ancient Greeks, Romans, Egyptians, Arabians, Hawaiians, and Chinese. Hawaiians scented their clothing with ginger and made shampoos and massage oils from the secretions of ginger flowers.
Method of Extraction
CO2: Carbon dioxide as the `solvent` to extract the viscous liquid from the dried root.
Essential Oil: The unpeeled, dried, ground root is steam distilled to produce the essential oil.
Colour and Appearance
CO2: Brown to dark red-brown viscous liquid. (Burfield)
Essential Oil: Pale Yellow to Brown. Viscous. (Burfield)
CO2: Powerfully warm and spicy ginger aroma, very reminiscent of the fresh herb. (Burfield)
Essential Oil: Spicy, warm, sharp, pleasant. (Burfield)
CO2: Waxes, fatty acids and 30 – 50% essential oil. The essential oil consists of the Major Functional Group Sesquiterpenes: 60 – 65% Sesquiterpenes: 19% Zingiberene, 18% α-Curcumene, 14% β-Sesquiphellandrene, 4.3% α-Farnesene, and 9.1% β-Bisabolene. 4.7% Shogaols and 20.4% Gingerols are also found in the CO2 extract but not in the essential oil.
Essential Oil: Major Functional Group at around 55% Sesquiterpenes: 38 – 41% Zingiberene, 17% Curcumene and 7% B-sesquiphellandrene. Plus Aldehydes (5%); Ketones (2%); Oxides (0.13%); Monoterpenes (20%); Alcohols (10%).
E. Joy Bowles, in her book, The Chemistry of Aromatherapeutic Oils says: The inclusion of components such as waxes, carotenoids, flavonoids, and alkaloids would make the therapeutic properties of supercritical CO2 extracts more like herbal extracts or oleoresins than essential oils.
Properties that have been attributed to some of these chemical constituents include:
Zingiberene and α-Curcumene both have anti-inflammatory effects (Bowles)
β-Sesquiphellandrene – has demonstrated in vitro anti-tumoral activity (Tisserand and Young)
Gingerols and Shogaols – anti-oxidants, anti-bacterial, anti-histamine, anti-inflammatory through COX-2 enzyme inhibition (Kerkhof)
CO2: Can irritate the skin. Be careful with sensitive skin. Don`t use in warm water as the heat will enhance the effect of the CO2 and may lead to redness and irritation. (Kerkhof)
Essential Oil:Hazards: None known. Contraindications: None known. (Tisserand and Young)
Use in low concentrations as this oil can cause skin irritations. According to a report by D.L.J. Opdyke in Food Cosmet. Toxicology, Ginger has a very low phototoxicity potential and they do not consider it to be significant.
Indications for Use
CO2: According to Madeline Kerkhof, based on Indian research and her personal observations, the presence of the gingerols and shogaols in Ginger CO2 total extract, making it a better option for treating nausea than the steam distilled essential oil which does not contain these components. As the CO2 oil is much stronger and more likely to cause skin irritations, I prefer to use it for inhalation methods.
Essential Oil: The steam distilled essential oil is not as hot in character as the CO2 version, and while one should always pay attention to the individual client`s skin, I prefer to use the steam distilled essential oil for topical applications.
While both the CO2 and the essential oil can be effectively used for emotional and spiritual concerns, as I find that the aroma of the CO2 is much more pleasing, as long as I am not applying the blend topically it would be my personal choice for the synergy.
References Tony Burfield, Natural Aromatic Materials – Odours & Origins, 2000E. Joy Bowles, the A to Z of Essential Oils, 2003 E. Joy Bowles, The Chemistry of Aromatherapeutic Oils, 2003 Eden Botanicals Certificate of Analysis for Ginger CO2 Ernst Guenther, The Essential Oil, Vol I-V, 1948 reprinted 1972 Madeline Kerkhof, CO2 Extracts in Aromatherapy, 2018 Tisserand and Young, 2nd Edition Essential Oil Safety, 2014