buckaroo bonzai
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The Complex Bouquet of Cannabis, Terpenoid Diversity and Abundance
SEPTEMBER 15, 2014
Cannabis has always been recognized for it’s distinctive and often pungent aroma, which is the result of the production of secondary metabolites known as terpenoids. Although the terpenoid composition of cannabis was studied decades ago in the academic community, there has been a recent surge of interest in terpenoid composition and effect in both the medical and recreational cannabis communities.
marijuana terpenes
Terpenoids are a class of natural compounds that are composed from isoprene units, which is a 5-carbon unit. Terpenes are further classified based on the number of carbons or the number of isoprene units within their chemical structures. Thus compounds with 5 carbons such as isoprene are known as hemiterpenes, those with 10 carbons (or 2 isoprene units) are called monoterpenes, those with 15 carbons (or 3 isoprene units) are called sesquiterpenes, those with 20 carbons (or 4 isoprene units) are diterpenes, those with 30 carbons (or 6 isoprene units) are triterpenes, and so forth. Terpenoids include the terpenes listed above as well as terpenes with additional modifications, such as with oxygen atoms included in the structure. What is truly astounding about terpenoids is that they are the most diverse class of secondary metabolites; these terpenoids composed of the simple isoprene building block can bond and cyclize to produce over 25,000 different structures. For comparison sake, this is more than twice the number of known alkaloids.
the entourage of effect
Although most conifers and angiosperms produce a large variety of terpenoids, Cannabis sativa is unique because varieties within cannabis species produce very diverse terpenoid ratios. For example, pine trees all produce pinene as their major terpenoid and most roses produce geraniol and citronellol as there principle terpenoids, however cannabis varieties have the capacity to produce numerous terpenoids without one single terpenoid structure dominating within the species. For example, many cannabis strains produce myrcene as their major terpenoid while other strains may produce terpinolene or limonene as their major terpenoid product. The diversity of terpenoids produced by cannabis, as well as the particular ratios of the terpenoids within a strain are what lead to the complex bouquet of cannabis. More importantly, the terpenoid content also produces synergistic or entourage effects with medicinal effects of the cannabinoids.
A review by ElSohly in 1980 identified 103 terpenes observed in cannabis, including 58 monoterpenes, 38 sesquiterpenes, 1 diterpene, 2 triterpenes, and 4 miscellaneous compounds. As chemical analysis techniques have evolved even more terpenoids have been observed. A list of some of the more abundant and medicinally important terpenoids found in cannabis include borneol, β-caryophyllene, cineole, citronellol, geraniol, humulene, limonene, linalool, myrcene, nerolidol, ocimene, pinene, terpineol, terpinolene, and valencene. These terpenes have traditionally been isolated from artemisia species (mugwort, wormwood, sagebrush), black pepper, cloves, eucalyptus, rose, hops, citrus, lavender, bay leaf, ginger, jasmine, basil, thyme, pine, tea tree, and cumin. It is intriguing that cannabis produces such a cornucopia of terpenoids; and the diversity as well as the relative abundances explains why various strains of cannabis have such distinct aromas and various medicinal properties.
Plant terpenes observed in nature
The biosynthetic pathways that form some specific terpenes have been studied in various species and many of these pathways are conserved through the plant kingdom. However, there is still much to learn about terpenoid biosynthesis in plants in general. Through careful scientific study, the pathways that form each specific terpenoid can be elucidated. Knowledge of these pathways provide potential for producing strains that produce increased quantities of some rare terpenoids observed in cannabis. Another frontier in science is the detailed study of the entourage effects caused by the synergy between cannabinoids such as TCH with terpenoids. These efforts will prove to invigorate the cannabis science community for decades to come.
http://marijuana.com/news/2014/09/the-complex-bouquet-of-cannabis-terpenoid-diversity-and-abundance/