Terpenes are nature’s fungicide. Plants produce terpenes to protect them from hostile enemies ranging from grazing animals, insects, microscopic bacteria and fungi, and high temperatures. Terpenes provide the orange color to carrots (beta-carotene) as well as the citrus smell to oranges and lemons (limonene). At last count, scientists had identified more than 15,000 different terpenes created by plants.
Monoterpenes, which are more volatile, repel insects. Sesquiterpenes, which are more bitter, are more abundant on leaves acting against herbivorous animals. Some terpenes can act as a decoy in some plants, attracting either pollinating insects or predatory ones that feed on herbivorous insects, which are beneficial for the plant. As plants sense a temperature rise, they begin synthesising more terpenes and under high temperatures during night or day, more terpenes are released. Terpenes evaporate at high temperatures, producing airflows that cool the plant and lessen transpiration, preventing the plant from drainage.
While these aromatic, organic hydrocarbon compounds are toxic to insects, recent studies have shown that some terpenes, when taken in moderation, produce side benefits for humans. Terpenes, it turns out, are healthy for people as well as plants. A September 2011 report by Dr. Ethan Russo in the British Journal of Pharmacology discussed the wide-ranging therapeutic attributes of terpenes, which are typically lacking in “CBD-only” products.
For example, terpenes such as limonene have shown promise in improving pain tolerance. Beta-Caryophyllene, another terpene found in Cannabis, is a sesquiterpene found in the essential oil of black pepper, oregano, and other edible herbs, as well as in various cannabis strains and in many green, leafy vegetables. It is gastro-protective, good for treating certain ulcers, and offers great promise as a therapeutic compound for inflammatory conditions and auto-immune disorders because it binds directly to the peripheral cannabinoid receptor known as “CB2.” Dr. Russo reported that cannabinoid-terpene interactions “could produce synergy with respect to treatment of pain, inflammation, depression, anxiety, addiction, epilepsy, cancer, fungal and bacterial infections.”
In fact, there are over 140 known terpenes found in Cannabis. Each Cannabis strain can be recognized and identified by its unique “signature” of terpenes contained in the plant in varying concentrations. These terpene concentrations can even vary from plant-to-plant, as there are many factors that influence a plant’s development of terpenes, including climate, weather, age and maturation, fertilizers, soil type, and even the time of day. But while Cannabis plants contain terpenes that provide each strain its signature aroma, there are no known terpenes that are specific to Cannabis. So if terpenes are not unique to Cannabis and are fairly common in the plant kingdom, can isolated terpenes be a prohibited Schedule I drug in Maryland and under federal law? Sadly, the answer is probably that it depends upon the source of the terpenes.
Marylanders, like the residents of so many other states, are still living under the dual “Twilight Zone” existence created by our system of federalism. Maryland, like many other states, has created a state-wide intrastate exemption for the production, distribution, possession, and use of medical Cannabis by its growers, its processors, its dispensers, its patients, and its caregivers. On the other than, the federal government maintains its strict position that cannabis is a Schedule I drug under the Controlled Substances Act of 1970 that has no accepted medical use and carries a high likelihood for abuse.
Under Maryland law, Cannabis is still known as “Marijuana,” which is defined as Marijuana is defined as “all parts of any plant of the genus Cannabis, whether or not the plant is growing . . the seeds of the plant . . . the resin extracted from the plant . . and each compound, manufactured product, salt, derivative, mixture, or preparation of the plant, its seeds, or its resin. Marijuana does not include the mature stalks of the plant . . fiber produced from the mature stalks . . . oil or cake made from the seeds of the plant . . except for resin, any other compound, manufactured product, sale, derivative, mixture, or preparation of the mature stalks, fiber, oil, or cake, or . . the sterilized seed of the plan that is incapable of germination . . . hemp as defined by the Agricultural Article.” (emphasis added).
Under federal law, the Controlled Substances Act defines “Marihuana” as “all parts of the plant Cannabis sativa L., whether growing or not; the seeds thereof; the resin extracted from any part of such plant; and every compound, manufacture, salt, derivative, mixture, or preparation of such plant, its seeds or resin. Such term does not include the mature stalks of such plant, fiber produced from such stalks, oil or cake made from the seeds of such plant, any other compound, manufacture, salt, derivative, mixture, or preparation of such mature stalks (except the resin extracted therefrom), fiber, oil, or cake, or the sterilized seed of such plant which is incapable of germination.” (emphasis added).
Terpenes form in the Cannabis plant’s glandular trichromes of leaves and flowers, which are specialized to produce and accumulate these hydrocarbon molecules. Terpenes accumulate in the exuded resin of the plant, and are secondary metabolites that provide the plant with its organoleptic characteristics (aroma and flavor) and that constitutes most of the essential oil produced by aromatic plants. In the Cannabis plant, terpenes provide the plant with the sticky and viscous quality that will get some insects trapped and immobilized, thus, acting as a protection against insects and high temperatures. The proportion of terpenes in the plant is normally less than 1%, potentially achieving up to 10% of the resin composition.
So are terpenes derived from Cannabis lawful to possess for a non-medicinal patient in Maryland? The definitions of Marijuana in Maryland and Marihuana under federal law would seem to indicate that the answer would be no. Cannabis terpenes are chemical compounds derived from the resin of the plant. This would place Cannabis terpenes as a controlled and dangerous substance in Maryland. Yet the same organic chemicals would be perfectly lawful to possess and use in their distilled form when derived from non-Cannabis sources. These are the same terpenes that humans rely upon every day to provide flavor their food, scent to cleaning products, flavor to tea, and scent to their perfumes.
Sadly, this same “is it or isn’t it” discussion mirrors the controversy surrounding another compound created by the Cannabis plant. Cannabidiol (or CBD) is also a molecule created by Cannabis Plant that is non-psychotropic. Last year in the 2018 Farm Bill, lawmakers removed hemp — defined as cannabis and cannabis derivatives with very low concentrations (no more than 0.3% on a dry weight basis) of THC — from the definition of marijuana in the Controlled Substances Act. However, as the Food and Drug Administration (FDA) continues to reiterate, CBD products are still subject to the same laws and requirements as FDA-regulated products that contain any other substance. But without formal guidance from the FDA, state and local officials from New York to Nebraska have started cracking down on manufacturers and distributors that market CBD as a food additive or supplement.
Despite all we have learned about terpenes (or even CBD), the world will not learn any more about the benefits of these wondrous natural compounds produced by Cannabis plants so long as the federal prohibition continues to exist. Will Cannabis-derived terpenes ever be available as a commercial product to non-medical patients in Maryland? For now, the answer will have to be, “It depends.”