Those Pungent Smells Oozing Out of Marijuana Buds Are Actually Giving You Clues About What Their Effects Will Be Like
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Scientists are now formally acknowledging something that Cannabis consumers have long taken for granted: aroma is associated with effect.
Plant cannabinoids —21-carbon molecules found only in Cannabis— are odorless. It’s the terpenoids —components of the plant’s “essential oils”— that create the fragrance. Terpenoids contain repeating units of a 5-carbon molecule called isoprene and are prevalent in smelly herbs such as mints and sage, citrus peel, some flowers, aromatic barks and woods.
The aroma of a given plant depends on which terpenoids predominate. They tend to be volatile molecules that readily evaporate, and they’re very potent —all it takes is a few reaching the nose to announce their presence.
Evidence that “phytocannabinoid-terpenoid interactions” enhance the therapeutic effects of cannabis was presented by Ethan Russo, MD, at a conference in Israel in 2010 and published in the August 2011 British Journal of Pharmacology. Russo, a neurologist and ethnobotanist, is senior medical adviser at GW Pharmaceuticals.
Both terpenoids and cannabinoids are secreted inside the Cannabis plant’s glandular trichomes, and they have a parent compound in common (geranyl pyrophosphate). More than 200 terpenoids have been identified in Cannabis. The most common and most studied include limonene, myrcene, alpha-pinene, linalool, beta-caryophyllene, caryophyllene oxide, nerolidol and phytol. Anecdotal evidence suggests that pinene is alerting, limonene “sunshine-y,” and myrcene sedating.
The fact that most terpenoid compounds are common components of the human diet and “generally recognized as safe” by the Food and Drug Administration has made research possible, and scientists employed by flavor and fragrances manufacturers have investigated their properties over the years. But the terpenoids “remain understudied” in terms of therapeutic potential, according to Russo.
His paper mustered all the evidence —proof in some cases, hints in others— that cannabinoids and terpenoids can work in concert to abate symptoms of pain, inflammation, depression, anxiety, addiction, epilepsy, cancer, fungal and bacterial infections, including methicillin-resistant Staphylococcus aureus (MRSA, which kills more Americans nowadays than AIDS) and other illnesses.
Jeffrey Hergenrather, MD, president of the Society of Cannabis Clinicians, who heard Russo’s presentation in Israel, expects its publication to “generate great interest in terpenes among medical cannabis users as well as physicians.” The SCC recently began collecting data on patients’ responses to CBD-rich Cannabis. Future surveys will seek to document which other cannabinoids and which terpenoids are associated with which effects.
The “Entourage Effect”
The conference at which Russo presented his paper was held at Hebrew University, Jerusalem, where Raphael Mechoulam directs a lab, in honor of Mechoulam’s 80th birthday.
In 1999 Mechoulam co-authored a paper with Shimon Ben-Shabat suggesting that cannabinoids made in the body work by means of an “entourage effect.” They had found that the endocannabinoid 2-AG (2-arachidonoylglycerol), when administered with two related compounds, would bind more readily at the cannabinoid receptors and exert more pronounced behavioral effect on mice.
To pharmacologists who customarily designed experiments aimed at finding the active ingredient, this had heavy implications. Mechoulam spelled them out: “Biochemically active natural products, from either plant or animal origin, are in many instances accompanied by chemically related though biologically inactive constituents. Very seldom is the biological activity of the active constituent assayed together with inactive ‘entourage’ compounds. Investigations of the effect of the active component in the presence of its ‘entourage’ compounds may lead to results that differ from those observed with the active component only.”
In 2001 John McPartland and Russo published a paper in the Journal of Cannabis Therapeutics applying the “entourage” concept to the plant itself. “Good evidence shows that secondary compounds in cannabis may enhance the beneficial effects of THC... and reduce THC-induced anxiety, cholinergic deficits, and immunosuppresion,” they wrote. “Cannabis terpenoids and flavonoids may also increase cerebral blood flow, enhance cortical activity, kill respiratory pathogens, and provide anti-inflammatory activity.”