The cultivation of cannabis by humans extends from before recorded history all the way through the present day, leaving an indelible mark on American history along the way. Our first president, George Washington, even grew hemp. The widespread cultivation of hemp throughout human history is undoubtedly what led Carl Linnaeus (the Swedish naturalist and father of the modern scientific naming and classification system for all living things) to give the name Cannabis sativa for its scientific designation. Cannabis is a Latinized version of one of the plant’s oldest known names, kanab. Sativa is the Latin word meaning “sown” or “cultivated”. Thus, the plant we know today as “marijuana”, “hemp”, or “cannabis” was scientifically named and described as cultivated. Many agriculturally important plants have the name sativa to reflect their importance to society. Other examples include rice (Oryza sativa), alfalfa (Medicago sativa), and garden lettuce (Lactuca sativa). These facts should not be forgotten as we consider the circumstances of the prohibition of hemp in the United States in the 1930’s.
As mentioned above, the medicinal properties of hemp were first described in writing around 2700 B.C. More recently, it was sold as a medicine in the United States throughout the late 1800’s and early 1900’s by several drug companies; some of which still exist today. Cannabis sativa was described in the United States Pharmacopeia from 1851 until 1942 when it was removed after the federal prohibition of hemp was declared. Some of the maladies that were treated by cannabis and its extracts during this time include: restlessness, neuralgia, sciatica, spasmodic pains, and coughs.
Regardless of the reasons behind the push for hemp prohibition in the 1930’s and the fear-mongering used to rally public support for it, no one was going to risk Federal imprisonment to cultivate hemp fiber for making t-shirts. The only people who would still seek to grow and utilize the plant were those looking to use and abuse its medicinal and psychoactive effects.
Thus, over the nearly nine decades of prohibition of hemp, pretty much the only strains that have been selected for and cultivated are those that produce large amounts of the psychoactive agent Δ9-tetrahydrocannabinol (THC). This compound has since been found to have multiple medicinal effects, which will be discussed further in a later section. In the meantime, the modern chemical sciences of spectroscopy, chromatography, and organic synthesis were almost completely barred from investigating this plant. Many drugs that we derive from plants were isolated, identified, and artificially synthesized for further study and mass production during the same time period as hemp prohibition. Yet this one plant was nearly impossible to research.
Recently, the relaxation of hemp prohibition laws in many states has allowed some research on Cannabis sativa to move forward with the benefit of modern technology and a modern understanding of medicinal and natural products chemistry. Before I get into the details of the medicinal effects of cannabis, it will be useful to learn a little bit about what kinds of compounds the plant makes and why.
Brief Introduction to Cannabinoids and Terpenes
In fact, I am going to simplify the above paragraph so that the rest of this document can be read without confusion: Cannabis sativa makes two classes of compounds that are known to be of medicinal importance: the cannabinoids and the terpenes. The two major cannabinoids that are expressed by hemp are THC and CBD.
These two compounds are found in varying amounts in the hemp plant, depending upon the strain. For example, Strain A might express 100 % THC, Strain B might express 100 % CBD, and Strain C might express 50 % THC and 50 % CBD (percent relative to each other). The plant produces these compounds almost exclusively in glands (called trichomes) on its outer surface, especially concentrated around the female flowering tops. People who grow hemp for the cannabinoid content know that it is possible to force the plant to make more by exposing it to large amounts of ultraviolet (UV) light during the flowering stage.
This leaves an interesting question: why does hemp produce THC and CBD on its outer surfaces in response to UV light? Well, research has shown that THC and CBD both absorb light in the UV spectrum. I believe that the plant expresses these compounds on its outer surface to protect the plant’s DNA. In other words, the plant makes its own “sunscreen” in order to protect the newly developing seeds from becoming damaged by the sun’s UV light. This suggests that THC or CBD could be an effective natural sunscreen if properly formulated.
Besides these two major cannabinoids, each different stain of Cannabis sativa makes its own unique set of compounds called terpenes. These terpenes are what give the unique smell, taste, and medicinal properties to each variety of hemp. Furthermore, these terpenes also modify the medicinal effects that THC and CBD have on your body. This is known as the “medicinal entourage effect”.
But what are these terpenes? Should we be worried about them? Hardly. Terpenes are molecules that are made by nearly every flowering plant including lemon, pine tree, lavender, and rose. Each plant makes its own unique set of terpenes. However, most of the terpenes made by a given plant are in common with other plant species. It’s just that each plant makes different terpenes at different levels, giving rise to unique aromas and medicinal effects.
Some of the common terpenes found in Cannabis sativa plants are: d-limonene, linolool, myrcene, and pinene. In fact, there are hundreds of terpenes expressed by Cannabis sativa at low levels, but only a dozen or so that are consistently expressed in relevant amounts.
Interestingly, d-limonene is primarily responsible for the scent of lemons. Linolool is the predominant terpene in lavender and is responsible for its relaxing effect. Pinene is found in pines and other coniferous trees and is primarily responsible for the smell of sap. Each of these terpenes has a characteristic smell and its own medicinal properties. Amazingly, so many of them can be found in a single species of plant, Cannabis sativa.
Hopefully after reading the above information it is clear why there are so many strains of cannabis available to purchase in a medicinal marijuana dispensary. Each strain has its own unique THC and CBD content as well as its own unique set of terpenes. So, each strain has its own unique medicinal properties, smell, taste, and side effects. It is very important for a medical patient to make sure they are using the right strain in the right way. For example, it may be more appropriate to apply THC or CBD topically as a cream or to take it in pill form, depending on the patient and their needs and preferences.
A Quick Look at Modern Medicinal Marijuana
· Multiple Sclerosis
· Spasticity Disorders
· Parkinson’s Disease
· Lou Gehrig’s Disease (ALS)
· Rheumatoid Arthritis
· Spinal Cord Damage
· Intractable Pain
· Crohn’s Disease
· Hepatitis C
· Cachexia (Wasting Syndrome)
· Alzheimer’s Disease
· Huntington’s Disease
· Epilepsy and Other Seizure Disorders
· Post-Traumatic Stress Disorder (PTSD)
Table 1 – List of many of the modern approved uses of Cannabis sativa.
I mentioned before that THC and CBD have similar medicinal properties. This means that they can serve many of the same functions, but each does have its own unique set of effects on the human body. I have already mentioned one: THC will make you “high” but CBD will not. It turns out that CBD is better at preventing certain kinds of seizures in children and adults. In some cases a child can go from dozens of seizures per day to just a few seizures per month. This is the difference between having a functioning childhood and living in a confusing nightmare. However, I think we can all acknowledge that having a child smoke a plant to dose his or her medicine is a ridiculous notion. Therefore, the active compounds in the plant need to be formulated into a form that is more appropriate for a child, such as a pill or a sweetened beverage.
The active compounds in Cannabis sativa need to be extracted from the plant into a concentrated form in order to accurately dose and formulate them into an appropriate form of consumption for the patient (i.e topical, beverage, pill, or other alternative formulation). Scientifically, this extract would be known as a “resin” or “concentrate”. It is a resin because it is not a single isolated compound but is instead composed of many of the plant’s constituents. In the case of Cannabis sativa, the resin is primarily composed of cannabinoids and terpenes. Resins are amorphous or semi-solid. In the case of a cannabis resin, it is hard when frozen, taffy-like at room temperature, and a liquid upon gentle heating.