Today we are going to look at a very important topic in the world of essential oils. The topic is chemical variance or chemotypes that show up among the same genius and species of a plant. Much like twins with different colored eyes or vastly different personalities, essential oils distilled from plants with the same genius and species can have vastly different chemical profiles that will create different therapeutic effects. We are going to look at this concept of chemotypes, by taking a look at the New Zealand Manuka oil. (Thank you Shannon McCleary for sparking my interest in Manuka oil based on your comment in our Facebook Group. This is what the group is all about. Having a place to have conversations about essential oils and how they can help support our good health).
Manuka oil (Leptospermum scoparium) is known for its antimicrobial activity, its skin smoothing and skin revitalizing properties, as well as its deeply grounding and centering effects. The main therapeutic components in Manuka oil come from three chemical families, sesquiterpenes, sequiterpenols, and ketones. The exact amount of each chemical component is dependent upon many factors such as the region the Manuka plant was harvested, the season of the year the plant was harvested, and the growing conditions under which the plant developed. Manuka oil can be harvested with a variety of different chemotypes. Chemotypes are a way of describing the variance in chemical components produced by a particular plant. For example, a plant may have the same genus and species however the chemical profile of the essential oil may differ quite distinctly among two plants that appear to look the same.
Often, the chemical variance in the essential oil may be due to the location in which the plant was grown. For example, the chemical profile of Manuka grown in New Zealand may be distinctly different from the chemical profile of Manuka grown in Australia. In some instances, the chemical profile may be vastly different among two plants grown in New Zealand but in differing parts of the island. A study published in Phytochemistry (2004) by Douglas et al., revealed analysis from over 261 individual manuka plants collected from 87 sites throughout New Zealand showed that the high triketone chemotype was localized on the East Cape, and ten further chemotypes were also identified. Such as essential oils with high amounts of the monoterpene: alpha-pinene. Some of the Manuka samples exhibited chemical profiles that were sesquiterpene-rich with high myrcene; sesquiterpene-rich with elevated caryophyllene and humulene; sesquiterpene-rich with an unidentified sesquiterpene hydrocarbon; high geranyl acetate; sesquiterpene-rich with high gamma-ylangene +alpha-copaene and elevated triketones; sesquiterpene-rich with no distinctive components; sesquiterpene-rich with high trans-methyl cinnamate; high linalol; and sesquiterpene-rich with elevated elemene and selinene.
What this reveals is that the location of where the plant is grown plays a large role in determining the chemical makeup of the final oil produced. With such vast chemical variants, it is important to know the chemotype of the essential oil that you are using. Each chemical constituent contributes specific therapeutic qualities. Having some knowledge of the therapeutic qualities of the chemical components in the oil will help in determining how the oil should be used and how it may support certain conditions in the body.