What Are Terpenes and What Is Their Effect?

The distinctive flavors and smells are one of the most striking qualities of marijuana, and it varies between strains. The flavors and smells are produced by terpenes, which are small molecules with repeating units of the organic compound isoprene. Terpenes are manufactured inside specialized hairs, called trichomes, located on the surface of the leaves and stems of the plant, and they account for 5-10 percent of the total essential oils produced by trichomes; in fact, terpenes are found in all plants to varying degrees.

More than 100 different terpenes have been identified in marijuana, and these terpene profiles can vary from strain to strain. Terpene profiling -- the process of determining the types and quantities of terpenes present in a plant -- is thought to be one of the most accurate ways to distinguish between marijuana strains. Various factors influence the ratio of terpenes present in marijuana, including strain, environment, cultivation and degree of plant degradation.

The Role of Terpenes

Terpenes are functionally diverse, and many are integral to marijuana's growth and survival. They attract pollinators, repel harmful insects, deter herbivores, protect against bacteria and fungi, and act as precursors for more complex molecules, such as cannabinoids. Many terpenes interact with other types of terpenes, and some assist or inhibit the formation of different compounds within the marijuana plant.

Primary Terpenes

Terpenes can be classified as primary or secondary, depending on their role: Primary terpenes are essential for plant growth and development, while secondary terpenes are involved in plant defenses. Following are some of the primary terpenes found in marijuana:

• Pinene gives marijuana its earthy, pine-like flavor and spicy, herbal notes. This terpene crosses the blood-brain barrier and promotes memory retention and alertness by inhibiting the breakdown of acetylcholinesterase, which is a chemical found in the brain. It also acts as both a bronchodilator and an anti-inflammatory.
• Caryophyllene has a peppery flavor and a spicy, earthy aroma with citrus notes. It is the only terpene known to act on the endocannabinoid system, which regulates a variety of physiological processes, including pain sensation and inflammation. Activation of the CB2 receptors by caryophyllene is instrumental in enhancing marijuana's anti-inflammatory and analgesic effects.
• Humulene gives marijuana its robust, woody flavor and spicy, herbal notes. This terpene possesses anti-inflammatory properties and acts as an appetite suppressant.
• Linalool has a floral flavor reminiscent of lavender, with the addition of spicy overtones. It exhibits powerful analgesic and anti-seizure properties and is partly responsible for the sedative effects of certain marijuana strains. It also has strong antibacterial, anti-cancer and antifungal effects.
• Myrcene is the most common terpene found in marijuana, and it is also present in bay, thyme, hops and lemongrass. This musky terpene is a potent analgesic, antibiotic and anti-inflammatory, and its concentration determines whether a strain has an energizing or sedative effect. Strains containing more than 0.5 percent of myrcene have a sedative effect, while strains containing less than 0.5 percent myrcene produce an energizing effect.
• Terpinolene has a woody flavor and is responsible for many of the floral notes characteristic of Jack Herer varieties of marijuana. It has been shown to exhibit antioxidant, anti-cancer and sedative properties.
• Limonene is most often found in sativa strains of marijuana and has a citrus flavor reminiscent of oranges. It has antioxidant, anti-inflammatory and anti-cancer properties, and it is known to activate enzymes that stimulate the liver and increase bile flow, which in turn aids digestion. Studies show that limonene can also help treat anxiety and depression.

Secondary Terpenes

Following are some of the secondary terpenes found in marijuana:

• Sabinene has a woody flavor with spicy, peppery notes. It has been shown to aid digestion, relieve arthritis and soothe skin conditions.
• Phellandrene is known for its peppermint flavor, with slight citrus notes. It possesses antidepressant.
• Borneol has a minty aroma and is found in high concentrations in herbs such as rosemary and mint. It has both anti-inflammatory and analgesic effects.
• Isoborneol has a sweet and musty flavor; also found in mugwort, isoborneol exhibits antioxidant, anti-inflammatory and antimicrobial properties, and it inhibits the herpes simplex type 1 virus, which causes cold sores.
• Phytol results from the breakdown of a green pigment called chlorophyll. It has a floral, balsamic flavor and demonstrates sedative and anti-anxiety effects through inhibiting the activity of an enzyme that degrades GABA, which is a chemical found in the brain.

The Entourage Effect

The medicinal effects of terpenes are due in part to their interactions with cannabinoids, such as cannabidiol (CBD) and tetrahydrocannabinol (THC). Research conducted by Ethan Russo, MD and published in the British Journal of Pharmacology in August 2011, reveals that terpenes mediate the physiological and psychoactive effects of cannabinoids: a phenomenon termed the entourage effect. This may help to explain why the effects of synthetic cannabinoids -- chemicals made to mimic the effects of naturally occurring cannabinoids -- differ from those of smoking or ingesting the whole marijuana plant and why different strains of the marijuana plant differ in their effects.

The primary and secondary terpenes in marijuana exhibit a variety of aromas, flavors and medicinal benefits. Understanding the differences between the different types of terpenes make choosing a suitable strain of marijuana easier.

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