In order to understand the medicinal value of the cannabis plant, you first need to learn about the many compounds that are found within it. The cannabis plant is made up of over 400 chemical compounds. When you use cannabis, you are taking a mixture of natural compounds that work together to balance each other.
The Latin name of the plant is Cannabis Sativa, in the family called Cannabaceae and Genus Cannabis. Other plants in this family are Humulus (hops) and Celtis (hackberries). These plants share an evolutionary origin but are quite different from one another.
The cannabis plant contains biologically active compounds called phytocannabinoids, terpenoids and flavonoids. These chemicals interact with our brain and body chemistry to give certain effects. Hundreds of different cannabis varieties, or “chemovars,” are grown all over the world, each containing varying amounts of the 400 different compounds, with each chemovar giving different effects.
The term “cannabinoids” is very general and refers to a group of chemical compounds that are usually made up of 21 carbon atoms in a three-ring structure. When we add the prefix “phyto” to the word, we are specifically referring to the cannabinoids that are found almost exclusively in the cannabis plant.
The main two phytocannabinoids are THC (delta-9-tetrahydrocannabinol) and CBD (cannabidiol).
Figure 1: Molecular structures of THC and CBD
Other phytocannabinoids found in the cannabis plant, often referred to as “minor cannabinoids,” include cannabinol (CBN), cannabigerol (CBG), cannabichromene (CBC), cannabicyclol (CBL), cannabidivarin (CBDV), and tetrahydrocannabivarin (THCV). Future research may reveal some of these to be major cannabinoids.
The main effects of THC and CBD are summarized in Table 1.
Table 1: THC and CBD effects
The average THC content of cannabis in 1972 was 1%, increasing to 4% in the 1990s, to a national average of 13% today. California cannabis testing laboratories report a current average of 18 – 20% THC content. Cannabis currently available in California dispensaries has THC content between 15% -28% with a corresponding CBD content of <1%. Concentrated forms of THC-rich cannabis can have contents up to 90%. This increase in THC content has led to a decrease in CBD content and made CBD-rich plants rare, although this is changing.
Until 2012, the potency of cannabis tested by the government and dispensaries was based solely on THC content. Now that CBD is recognized as having significant medicinal effects, testing of various cannabis products routinely reports the potency of both compounds. As you can see in Figure 2, various chemovars (chemical varieties or “strains”) of cannabis are listed with their potencies of THC, CBD, and CBN. (If you are not familiar with cannabis, the plants vary in their compounds and are often given names that may reflect their chemical makeup.) Two are high in THC and quite low in CBD (Blue Dream and Sour OG), one is quite high in CBD and low in THC (AC/DC), and two have varying amounts of both THC and CBD (Cannatonic and Omrita). These plants will vary widely in their effects due to their different phytocannabinoid potencies. CBN stands for cannabinol, one of the minor phytocannabinoids. This compound is present only in trace amounts in freshly cut cannabis flowers and arises from the degradation of THC over time. As you can see in this chart, there is no CBN detected in these samples, which indicates that testing was likely performed on freshly cut flowers.
Figure 2: Cannabinoid potency test results for different cannabis chemovars
The phytocannabinoids are formed and concentrated in a viscous resin in the plant’s glandular trichomes, the tiny, sticky hair-like formations on the cannabis flower.
Close up of the trichome of the cannabis plant
It is inside the trichomes that the phytocannabinoids are formed.
Figure 3: How the cannabis plant synthesizes phytocannabinoids
The majority of cannabis plants are genetically determined to take the pathway that leads to THCA. A small number of plants have the genetics that will lead to a higher amount of CBDA: we call these plants CBD-rich chemovars. This genetic dominance for THC explains why most cannabis is higher in THC potency and lower in CBD potency. The rampant cross-breeding of chemovars over the past three decades has also resulted in higher THC potency.
Not all of the phytocannabinoids have been thoroughly studied, but those that have are found to have their own medicinal effects when isolated from the other phytocannabinoids. When used together as they occur naturally in the whole plant, they balance each other in a synergistic action first called “the entourage effect” by Raphael Mechoulam, PhD. Dr. Mechoulam, an Israeli researcher, was the first to isolate THC and CBD in the early 1960s. The “entourage effect” means that the cannabinoids work better together than when isolated from one another. The synergy can enhance effects or modulate effects beneficially.
Example of synergistic enhancement: both THC and CBD, when given separately, have been found to have pain-relieving properties, but studies show that CBD enhances pain relief when used together with THC, compared to THC used by itself.
Example of opposing effects: CBD can decrease psychoactivity, memory loss and the increased heart rate THC can induce.
Terpenoids (also called terpenes) are the essential oils that occur naturally and exist in all plants, trees and flowers, including the cannabis plant. These oils give cannabis its odor, color, and flavor. About 200 terpenoids occur in the cannabis plant. The unique combination of phytocannabinoids and terpenoids in a specific cannabis plant accounts for the varying effects felt when different types of cannabis plants are used.
Terpenoids are made up of repeating units of isoprene (C5H8) and include monoterpenoids (C10), sesquiterpenoids (C15), diterpenoids (C20), and triterpenoids (C30).
Some important facts about terpenoids:
Phytocannabinoids and terpenoids work synergistically to provide therapeutic effects. Terpenoids are also synergistic with each other, again enhancing medicinal effects.
An example of a very important terpenoid is limonene. It is a monoterpene found in lemon and other citrus fruits and is the second most common terpenoid found in nature. Limonene has potent anti-depressant and anti-anxiety activity, as well as anti-tumor effects. It has been used successfully to decrease the symptoms of gastro-esophageal reflux.
This chart explains four of the most important terpenoids in the cannabis plant.
Some examples of known synergies between phytocannabinoids and terpenoids:
Cannabis plants can be tested for their terpenoid profiles as well as phytocannabinoid content. The terpenoid makeup of the plant is like a “fingerprint” for the chemovar. Different growers may be growing the same varieties but calling them different names, or they may be calling chemovars the same names yet terpenoid testing reveals that they are different. The terpenoid profile allows for detailed comparison of varieties and is very important to patients who find relief with one particular chemovar. If you know which terpenoids and terpenoid combinations are helpful for your condition, you can check terpenoid testing results to see if a certain product will be likely to be effective.
Flavonoids are compounds that give plants their pigmentation, filter ultraviolet rays, attract pollinators, and prevent plant disease. About 20 flavonoid compounds have been found in the cannabis plant. These compounds are classified as aromatic polycyclic phenols and have a 15 carbon skeleton.
Flavonoids have been shown in laboratory studies to have anti-inflammatory and antioxidant properties. They also have anti-fungal, anti-bacterial, anti-viral, anti-cancer and anti-allergic activity. Several studies in humans report the following benefits of flavonoids:
Three of the main flavonoids that have been found in the cannabis plant and their properties:
You may have noticed I have not mentioned the terms “sativa” and “indica” in the discussion of the plant. These terms are used frequently in the cannabis industry to designate the “two” types of cannabis plants that can have different effects. Currently cannabis growers and suppliers continue to use these terms, albeit incorrectly, referring to sativa plants as “uplifting and stimulating” and indica plants as “relaxing and sedating.” Some say sativa plants cause a “brain high” and indica plants cause a “body high.” Most experts agree that due to extensive hybridization over the last three decades, these designations no longer apply.
If one uses the correct scientific nomenclature, Cannabis sativa, variety sativa refers to the hemp (fiber) variety of the plant, meaning that the genetics of this particular plant promote the growth of the fiber with very little THC production. These fiber varieties also carry the gene that allows the plant to synthesize CBD over THC. Cannabis sativa, variety indica scientifically refers to the variety of the plant that carries the genetics to synthesize THC instead of fiber, so called “drug” variety plants.
Aside from their genetics, cannabis plants are living entities that respond to their environment. Growing conditions, harvest time and other factors play an enormous role in the final product. This is why the same chemovar grown in different places by different growers under different conditions can result in different phytocannabinoid and terpenoid content. For instance, a chemovar grown outdoors in Northern California is likely to have a different profile than the same chemovar grown in a greenhouse in Colorado.
The best way to determine the effects of a particular plant or product is to first evaluate the content of CBD and THC, calculate the ratio of CBD to THC, and then look at the dominant terpenoids. This assessment will be much more informative than the simple and often incorrect terms “sativa” and “indica.”
There are numerous products made from industrial hemp that claim to contain CBD for medicinal purposes. It can be very confusing to patients and caregivers who see products available online that claim to be CBD products that are legal in all states.
Martin Lee from Project CBD (ProjectCBD.org) explains that there are two types of cannabis plants: hemp plants that are used for fiber and seed oil, and drug plants that are used for medicine and recreational purposes, what I prefer to call the “medicine” plants. As Lee explains, the main difference between the hemp variety and the drug variety is the content of resin. High-resin plants contain the phytocannabinoids, terpenoids and flavonoids – all the compounds that have proven beneficial medical effects. Industrial hemp is low-resin and therefore typically low in cannabinoid content. Hemp is not an optimal source of CBD or other medicinal compounds.
The US government has defined industrial hemp as containing less than 0.3% THC. The majority of high-resin plants, including CBD-rich plants, contain over 0.3% THC and therefore are still illegal federally and in most states. These high-resin plants are much preferred as medicine when compared to low-resin industrial hemp.
A large number of hemp plants are required in order to obtain a small amount of CBD. This increases the risks of contamination since hemp is a “bioaccumulator”, which means it accumulates toxic substances from the soil. These plants can contain metals, pesticides, gasoline and solvents and, during the CBD extraction process, these contaminants may be concentrated and can be toxic. In fact, there are anecdotal reports of people getting ill from so-called “CBD” products made from industrial hemp.
The Hemp Industries Association in a press release in 2014 stated that:
CBD is not a product or component of hemp seeds, and labeling to that effect is misleading and motivated by the desire to take advantage of the legal gray area of CBD under federal law. Hemp seed oil does not contain any significant quantity of CBD. Hemp fiber and seed cultivars contain relatively minimal CBD and CBD production from such plants should not be considered a primary product. There are high CBD cultivars that may qualify as “hemp” under federal law, however the genetics for such cultivars are closely held by various parties, and generally hemp cultivars available to American farmers are not suitable for producing CBD.
Source: www.thehia.org/HIAhemppressrelease/3346474
In 2015, the FDA tested products obtained through the Internet, which claimed to contain CBD. They found these products to contain either no CBD or tiny amounts of CBD that would not be effective as medicine.
I encourage my patients to avoid products that come from industrial hemp as I have found that the drug (medicine) variety of cannabis is a much more effective product when treating most illnesses. That means patients should use whole plant cannabis that is labeled properly, lab-tested, and safely extracted. There are some products that are labeled as hemp but they contain THC, other cannabinoids and terpenoids. These products may have medicinal value. Unfortunately there is still a fair amount of confusion even within the cannabis industry. Hemp products, such as hemp milk, hemp oil, and hemp seeds, which are available in most grocery stores are a beneficial dietary source of balanced omega-3 and omega-6 fatty acids and should be a part of your diet.