A couple of hits of high-THC herb, by whatever name it’s called, will get you nice and high. But it’s not the amount of THC that accounts for the particular characteristics of each strain. The minuscule amounts of cannabidiol (CBD) or the hundred or so “minor” cannabinoids and terpenes are a significant part of most strains. With few differences, the THC levels are lofty. Together, the other cannabinoids barely register their presence. This is according to labs that test specimens for farmers and dispensaries in states where medicinal marijuana is allowed.
Terpenes and Cannabis’ Unique Effects
If THC levels are regularly high across the board and the other cannabinoids are present only at minimum levels, what makes one strain different than the other? And why does every marijuana strain impart a different psychoactive result? There must be something else in the cannabis plant that affects the character of the cannabis high.
Terpenes, or terpenoids, are the mixtures in cannabis that give the plant its distinguished smell. David Watson is the master creator of the foundational crossbreed Skunk #1. He was among the first to stress the value of aromatic terpenes for their modifying influence on THC.
Terpenes, or terpenoids, are the elements in cannabis that give the plant its uncommon smell. THC and the other cannabinoids have no fragrance, so marijuana’s compelling aroma depends on which terpenes prevail. It’s the mixture of terpenoids and THC that endows each strain with a particular psychoactive zest.
“We Smelled Them”
In 1989, Watson and his business associate, Robert Connell Clarke, created HortaPharm. HortaPharm was a legal research company in Holland specializing in botany and cannabis therapeutics. Located in Amsterdam, these two American expatriates shattered new ground in horticultural pharmacology. They mixed and interbred thousands of cannabis varietals. They discarded most along the way while choosing a relatively small number for additional development. How did they determine which plants made the first cut? “We smelled them,” Watson explains.
He had long assumed that the terpenes present in cannabis resin improve the potency of THC. Ten years after launching HortaPharm, Watson experimented with his hypothesis in a test. This test compared the subjective results of 100 percent THC to minor amounts in terpene-infused cannabis resin. The accord among Watson and several associates: Terpene-infused resin with 50 percent THC was stronger by dry weight than a similar amount of pure THC.
A History of Terpenes
Typically, terpenes are unstable molecules that evaporate quickly and tingle the nostrils. Therein lies the foundation of aromatherapy, a standard alternative-healing modality. Like their odorless cannabinoid relatives, terpenes are oily compounds concealed within the plant’s glandular trichomes. Terpenes and THC share a biochemical ancestor, geranyl pyrophosphate, which grows into the cannabinoids and terpenoids in the plant’s flowers.
But unlike THC and the different plant cannabinoids that exist nowhere else but in marijuana, terpenes are universal throughout the planet. Provided by countless plant species, terpenes are common in herbs, spices, fruits, vegetables, and other botanicals. Terpenes are also basic ingredients in the human diet and have generally been recognized as safe to eat by the US Food and Drug Administration.
Scientists have recognized and identified the molecular structure of some 20,000 terpenes, which make the largest plant chemicals category. These break down notably into monoterpenes, diterpenes, and sesquiterpenes. This chemical structure depends on the number of repeating units of a five-carbon molecule called isoprene. Isoprene is the structural symbol of all terpenoid compounds.
Around 200 terpenes are in cannabis, but only a few of these odiferous oily substances appear in quantities abundant enough to be unique. Also, the terpenoid form can differ considerably from strain to strain. The assortment of flavors revealed by the genus Cannabis is remarkable – no other plant on earth can equal the cacophony of smells and tastes available from the cannabis plant.
The terpenes in the pot plant have given the plant a surviving evolutionary edge. Some of these crucial oils are powerful enough to disgust insects and animal grazers; others stop fungus. To fight plant disease and infestation, organic pot farmers sprinkle the terpene-rich oils of neem and rosemary onto their crops. And terpenes, it turns out, are healthy for people as well.
Popular Cannabis Terpenes
Alpha-pinene (essential pine oil), the most popular terpene in the plant world and one often found in cannabis, is a bronchodilator likely helpful for asthmatics. Pinene also promotes sharpness and memory recollection by inhibiting acetylcholinesterase’s metabolic breakdown, a neurotransmitter in the brain that spurs these cognitive effects.
Limonene, the main terpene in citrus and cannabis, has been used clinically to destroy gallstones, enhance mood and relieve heartburn and gastrointestinal reflux. Limonene’s forceful antimicrobial action can kill pathogenic bacteria.
Myrcene, another terpene available in numerous cannabis varietals, is a tranquilizer, a muscle relaxant, a hypnotic, a painkiller, and an anti-inflammatory mixture. This musky terpene contributes to the infamous Indica experience, “In-da-couch.”
Beta-caryophyllene is a sesquiterpene located in the essential oils of black pepper, oregano, and other tasty herbs and cannabis, and many green leafy vegetables. It is gastro-protective, fit for treating some ulcers. It exhibits excellent promise as a healing compound for inflammatory ailments and autoimmune diseases because of its capability to bind right to the peripheral cannabinoid receptor known as CB2.
Linalool, a terpenoid noticeable in lavender and some cannabis strains, is an anxiolytic compound that combats anxiety and mediates stress. Also, linalool is a potent anticonvulsant, and it also increases serotonin-receptor transmission, conferring an antidepressant result. Linalool can heal acne and skin injuries without scarring.
The CB2 Receptor and Beta-caryophyllene
THC also stimulates the CB2 receptor, which manages immune use and the peripheral nervous system. This is not why people feel high when they smoke marijuana; rather, what causes the stoned feeling is THC merging to the CB1 receptor, which is in the brain and the central nervous system.
The CB2 receptor manages immune function and the peripheral nervous system. Activating the CB2 receptor doesn’t have a psychoactive effect because CB2 receptors are localized predominantly outside the brain and central nervous system. CB2 receptors exist in blood vessels, lymph cells, gut, spleen, liver, heart, kidneys, bones, endocrine glands, and reproductive organs. Marijuana is such a handy medicinal substance because it acts throughout the body, not just in the brain.
In 2008, a Swiss scientist documented beta-caryophyllene’s binding affinity for the CB2 receptor and defined it as a dietary cannabinoid. It is the only terpenoid known to directly stimulate a cannabinoid receptor (which is one example of why green, leafy vegetables are very healthful for people to consume). The twin status of beta-caryophyllene as a terpenoid and a CB2 activator stresses the synergistic interplay between many components of the cannabis plant. Over 400 chemical compounds in marijuana combine cannabinoids, terpenoids, and flavonoids (which give fruit skin color). Each has precise medicinal attributes.
What else do terpenes do?
Particular terpenoids dilate capillaries in the lungs, enabling smoked or vaporized THC to enter the bloodstream more rapidly. Nerolidol, a sedative terpenoid, is a skin penetrant that boosts permeability and possibly facilitates cannabinoid retention when administered topically for pain or skin diseases. Terpenoids and cannabinoids stimulate blood flow, improve cortical activity, and destroy respiratory pathogens.
One of them is MSRA, the antibiotic-resistant bacteria that took the lives of tens of thousands of Americans over the last few years. Dr. Russo’s article describes cannabinoid-terpenoid interactions could produce synergy concerning the treatment of anxiety, addiction, epilepsy, cancer, fungal, pain, inflammation, depression, and bacterial infections.
Cannabinoid terpenoid interactions can expand the beneficial results of cannabis while decreasing THC-induced anxiety.
THC, Psychoactivity, and Terpenes
Marijuana’s bouquet of terpenes plays another critical role: Terpenes buffer THC’s complex psychoactivity. Cannabinoid terpenoid communications can increase the beneficial results of cannabis while decreasing THC-induced anxiety.
Some people can’t manage THC dominant marijuana, while others appreciate the comfortable intensity of the cannabis high. But few would voluntarily choose Marinol, the pure synthetic-THC pill, rather than naturally grown field bud with its tangy, antioxidant-rich blend of cannabinoids, terpenoids, and flavonoids.
Marinol, legally known as a Schedule III substance, comes on like gangbusters and can make even the most experienced stoner feel a bit too delirious. For almost everyone who has tried both, the experience of THC alone relates poorly to that of THC coupled with terpenes and other components of the cannabis plant.
Testing of Terpenes
In the summer of 2011, the Werc Shop in Los Angeles developed as the leading lab to test cannabis strains for terpenes. Since it began administering this service to the medical marijuana society, the Werc Shop has examined more than 2,000 bud samples for terpene properties. Its review has occasionally reported strains with different names but related terpene content.
A terpene is like a fingerprint. It can tell you if it’s the identical strain under various names. We can see strains going by many names that have the exact terpene profile. We now know those strains are similar.
Terpene testing has allowed the Werc Shop to recognize when strains are not correctly labeled. “We’ve seen a dozen of examples of Trainwreck that have a constant terpene profile,” Raber says. “And then we check some bud purporting to be Trainwreck, but with a terpene profile that varies considerably from what we know is Trainwreck. By examining for terpenes, we can often confirm if the strain is what the farmer or distributor says it is.”
Marijuana Family Tree
It may be reasonable, via terpenoid and cannabinoid analysis, to review and verify various strains’ ancestral genealogy. Although the strains would require a significant amount of study, one might even be able to create something akin to a marijuana family tree.
The Werc Shop has also examined multiple cannabis extracts for their terpene profile. But Raber discovered that the oil-extraction manner requires heating the plant material, typically killing the terpenes, which evaporate at much lower temperatures than THC.
Various extraction methods have their pros and cons. Using hexane or another toxic solvent to extract cannabis oil can leave poisonous residues behind. Critical CO2 extraction, while cleaner, requires expensive, sophisticated equipment and technical expertise. In either case, the extract maker may have to add the terpenes back into the oil concentrate to maximize the plant’s therapeutic potential.
In the future, when the herb is legal nationwide, it should be possible to access strain-specific cannabis oils, as well as made-to-order marijuana extracts with a full array of terpenes artfully tailored to meet the needs and desires of individual users.