Q: Why are Terpenes important and what is the Entourage Effect?
A: This question can be considered in two different ways. The first being why are terpenes important to the plants that produce them, and second why are terpenes important to humans. The later is probably more important to you, but by answering the first we can better understand the second.
First of all terpenes are not unique to cannabis. Terpenes are present in literally thousand of species of plants, and they give plants or more specifically the oils produced by plants their unique aroma and taste. This is why terpenes are called aromatic hydrocarbons, they emit a strong aroma.
To plants, terpene are part of larger metabolic process, often representing intermediate molecules as the plant interacts with its environment, that ultimately are transformed into some final plant compound that plays some important function for the plant. This might be to prevent an herbivore or grazer from eating that particular plant, this is because many terpenes are very bitter so it's not a very attractive meal to a plant eater. This might also be to attract certain beneficial insects like pollinators, or deter certain insects that would otherwise be a pest. Terpenes also function as chemical shields to the harsh environment plants are often found in. This could be by shielding the plant from harmful UV-rays or helping the plant to mediate moisture loss in order to survive a time of drought. There are many other roles terpenes play including being able to ward off harmful fungus, or serve to protect the plant against infection. The versatility and applications of terpenes are many, and as diverse as the number of plants which sport them.
Knowing all of this will help you to understand why terpenes are important to humans. Much like how they are helpful to plants, keeping them healthy in so many ways, they can also be helpful to humans. Humans have been using plants for food for as long as we have existed on this planet, and have used plants and plant extracts for medicine for thousands of years.
Cannabis terpenes specifically, as it turns out, play a very important role in how our bodies make use of cannabinoids, the other primary constituent of cannabis essential oil. The terpenes that the cannabis plant produces including myrcene, caryophyllene, pinene, and linalool to name a few all seem to have synergy with cannabinoids.
Limonene is a potent imunostimulant when inhaled and works in a synergistic fashion when introduced alongside CBD. (Cannabis and the anxiety of...) It is an anxiolytic (Effects of the essential oil from...). Kills breast cancer cells, active against acne, Dermatophytes, and at treating gastroesophageal reflux. (Pharmacological activity reference)
a-Pinene is an anti-inflammatory via PGE-1. (Gil et al 1989) Bronchodilatory in Humans. (Falk et al 1990) Acetylcholinesterase inhibitor, aiding memory. (Perry et al 2000) And is synergistic with THC and CBD.
Myrcene blocks inflammation via PGE-2. (Lorenzetti et al 1991) Is an analgesic. (Rao et al 1990) Is sedating, a muscle relaxant, and hypnotic. (Do Vale et al 1992) Blocks hepatic carcinogenesis by aflatoxin. (de Oliveira et al 1997)
The list goes on and on demonstrating the synergistic effect cannabis terpenes have with cannabinoids. You can read more about the various terpenes and their associated pharmacology Here.
The point is that terpenes have incredible and unique pharmacology and function to modulate how we use cannabinoids within our bodies. This relationship is called the Entourage Effect.
The Entourage effect describes the relationship between cannabinoids and terpenes, and ultimately distinguishes one variety of cannabis from the next.
This is why the presence of terpenes, more aptly a 'strain specific terpene profile' is critical to understanding the pharmacological value of a particular full spectrum oil, and also why being ablate pick and choose which terpene profile you introduce to your cannabinoid rich extract helps to distinguish what particular symptoms that oil will be adept at remedying.