Phytocannabinoids are compounds that are naturally synthesized in plants. The prefix “phyto” simply means “plant.” While a few different plant species produce them, these substances are most famously and abundantly associated with the Cannabis sativa plant. This species produces a vast array of these compounds, which have become the subject of extensive scientific research. The highest concentration of these molecules is found within the glandular trichomes, the small, hair-like outgrowths on the flowering heads of the female cannabis plant.
Common Phytocannabinoids Explained
The cannabis plant produces over 150 different phytocannabinoids, but two are particularly well-known and abundant: delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD). THC is the primary psychoactive component of cannabis, responsible for the “high” sensation. Different strains of cannabis have been cultivated to have varying concentrations of these compounds; for instance, some cannabis contains high levels of THC and low levels of CBD.
In contrast, CBD is a non-psychoactive phytocannabinoid, meaning it does not produce the intoxicating effects associated with THC. Industrial hemp, a variety of the cannabis plant grown for fiber and seeds, is often rich in CBD while containing only negligible amounts of THC. The legal definition of industrial hemp in many regions is based on it having a very low THC concentration.
Beyond the two major phytocannabinoids, numerous minor ones appear in smaller quantities but are also of scientific interest. Cannabigerol (CBG) is a non-psychoactive compound that is the chemical precursor to both THC and CBD. As the cannabis plant matures, enzymes convert CBG into other cannabinoids. Another example is cannabinol (CBN), which is often found in aged cannabis, is formed from the degradation of THC, and is only mildly psychoactive.
Interaction with the Endocannabinoid System
The effects of phytocannabinoids in the human body are mediated through a complex cell-signaling network known as the endocannabinoid system (ECS). This system is part of human physiology, involved in regulating a wide range of functions to maintain internal balance. The ECS consists of three main components: endocannabinoids (cannabinoids produced by the body), receptors that these compounds bind to, and enzymes that create and break them down.
The two primary receptors of the ECS are cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2). CB1 receptors are found predominantly in the brain and central nervous system, while CB2 receptors are more concentrated in the peripheral nervous system and immune cells. Phytocannabinoids from the cannabis plant can interact with these receptors because they are structurally similar to the body’s own endocannabinoids, like anandamide.
The method of interaction differs between phytocannabinoids. THC, for example, has a high affinity for the CB1 receptor and binds to it directly, much like a key fitting into a lock. This direct activation of CB1 receptors in the brain is what produces its psychoactive effects. CBD, on the other hand, does not bind strongly to either receptor. Instead, it influences the ECS in more indirect ways, such as by inhibiting the enzymes that break down the body’s own endocannabinoids, thereby increasing their levels. Research also suggests CBD can interfere with the ability of THC to bind to CB1 receptors, potentially altering its effects.
The Concept of Synergy
The “entourage effect” is the theory that the many compounds in the cannabis plant work together to produce a unique effect, proposing that the therapeutic impact of the whole plant is greater than the sum of its individual parts. Instead of isolated compounds acting alone, the full spectrum of phytocannabinoids, along with other molecules like terpenes (which provide the plant’s aroma), act in concert.
This synergistic relationship can be compared to a musical orchestra. A single violin can produce a beautiful melody, but the sound of the entire orchestra playing together is far richer and more complex. Similarly, the entourage effect suggests that minor phytocannabinoids and terpenes can modulate or enhance the effects of major cannabinoids like THC and CBD.
For instance, certain terpenes may influence how easily THC can cross the blood-brain barrier, affecting the intensity of its psychoactive properties. Other studies explore how CBD might counteract some of the unwanted effects of THC, such as anxiety, by influencing different receptor systems. The entourage effect remains an active area of scientific investigation, as researchers work to map the intricate interactions between these plant-based molecules.
Phytocannabinoids Beyond Cannabis
While cannabis is the most prolific and well-known source, it is not the only plant that produces compounds capable of interacting with the endocannabinoid system. A handful of other plants synthesize molecules that can bind to or influence cannabinoid receptors.
For example, the compound beta-caryophyllene, a terpene found in the essential oils of black pepper, cloves, and rosemary, has been shown to bind directly to the CB2 receptor. This interaction is being investigated for its potential to influence bodily processes without inducing psychoactive effects, as it does not activate CB1 receptors.
Other examples include certain compounds found in the Echinacea plant. These compounds, known as alkylamides, have some structural similarities to endocannabinoids and interact with the CB2 receptor. Additionally, researchers have found that compounds in cacao, the plant source of chocolate, can interact with the enzymes that break down the body’s own endocannabinoids.