What’s In This Hand Sanitizer? Part: III The Science of Terpenes

There has been a lot of discussion around terpenes because of the current renewed interest in cannabis. I have discussed terpenes in previous blogs and bring them up again since they are the key active ingredients in all of the products I formulate for FEED CBD, including an alcohol-free hand sanitizer. It d does not contain CBD as the terpene profiles from specific plants are the active ingredients. I have included the terpenes so you can make your own hand sanitizers. The most important detail here is to be sure you buy therapeutic and organic grade. Perfume and cosmetic grade oils do not act the same way! This is a why a simile of plant fragrance does not have therapeutic qualties. You must use plant based, full spectrum essential oils of specific 'cultivars' or 'chemo-types' which have very specific, efficacious terpene, keytone, alcohol and aldehyde profiles.

But what exactly are terpenes and how do they work?

This is what we know about terpenes

  • They are the aromatic compounds that create a range of effects from cannabis strains. One of the first things people usually do is smell the flower. The nose is incredibly adept at picking out different terpenes (more on this later) whether it’s a lemon/citrus note (limonene), a piney note (Alpha-pinene & Beta-pinene), a spicy peppery note (Caryophyllene), etc
  • Terpenes have certain effects on our bodies such as sedation (myrcene), mood uplift (limonene), pain reduction (linalool), anti-inflammatory (caryophyllene), improving respiratory functions (alpha-pinene & beta-pinene), etc.
  • Terpenes are used in the food industry as flavorings as well as fragrances in the perfume industry. They are recognized as generally safe by the FDA
  • Terpenes are chemicals that plants evolved for defense against microbes (viruses and bacteria), insects, and herbivores. (Plants are amazing. For a great article from the American Plant Society on plant defenses check out this link: https://www.apsnet.org/edcenter/disimpactmngmnt/topc/Pages/OverviewOfPlantDiseases.aspx. You can learn a lot about what Trichomes are).
  • Terpenes are a plant’s second metabolite system which is akin to their immune or defense system (the first metabolite systems are used in growth, development, and reproduction).

What Herbology has known for a long time

  • Plants and essential oils can be utilized to heal the body and also prevent illness before it even begins
  • This process of herbalism is iterative and observable, resulting in the high level of efficacy that we see today and that science is rediscovering

Terpenes and the human body

  • Terpenes were evolved by plants to protect against bacteria and viruses, and humans can also use terpenes in the form of essential oils to protect themselves against the same or similar bacteria and viruses.
  • Terpenes act on receptors in cells as well as neurotransmitters. “they act as serotonin uptake inhibitors (similar to antidepressants like Prozac); they enhance norepinephrine activity (similar to tricyclic antidepressants like Elavil); they increase dopamine activity; and they augment GABA (the “downer” neurotransmitter that counters glutamate, the “upper”). (https://www.medicaljane.com/category/cannabis-classroom/terpenes/)

The Science of Terpenes

  • Modern science has begun to look at terpenes as antivirals and antibiotics (especially since there are a rising number of resistant viruses and bacteria, and terpenes don’t have the number of side-effects that some antimicrobials have)

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  • The above micrographs show bacterium being treated with the terpenes eucalyptol, linalool, and a-terpineol. The cell walls on the bacterium have become perforated with increased membrane fluidity and structural damage. You can see components of the cells leaking out around the cell. The constituents were analyzed as K+ (potassium), nucleic acids, ATP, and enzymes (transaminase). Cell death was observable.

  • There are very few studies on the synergetic combinations of terpenes. Essential oils and plants are composed of dozens (and frequently hundreds) of terpenes. These combinations have been used by herbalists in their original form for tens of thousands of years and are just beginning to be studied and understood by science.

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  • The above combinations of terpenes resulted in additive and synergetic effects, permeating the cell walls of the bacterium with more structural damage and leakage of cellular molecules.
  • Terpenes being hydrocarbons and lipophilic, interact with cell membranes (which are also composed of hydrogen, carbon and lipids), allowing deeper penetration of the studied terpene carvacrol into the bacterium. Terpenes are carrier molecules.

To the Limits of Science

The above study by Hatice Zengin & Ayse Baysal is a well researched experiment and paper, documenting the synergetic combinations of essential oils and their effects on 2 bacterium. The bacterium cell walls were disrupted, resulting in cellular leakage and cell death, but the study wasn’t able to “precisely explain the effects of essential oils and their components on specific intracellular constituents.” (https://www.mdpi.com/1420-3049/19/11/17773/htm).

This is a key point. Science is beginning to document the efficacy of terpenes as antimicrobials; yet there are almost no studies on terpene synergies (which is how plants and essential oils in their whole form have been used by herbalists).

This is the limit of science. Science can see the observable effects of terpenes, but ultimately can not explain why terpenes work. Science as an ‘empirical’ model only bases hypotheses on measurable and observable data. Though the efficacy of plant based medicine has been documented for thousands of years, science has a difficult time accepting the empirical evidence.

In addition, the fulcrum of the scientific method is the experiment. In order to validate an experiment it is important to isolate the single independent variable by minimizing the effects of other variables. This is why individual terpenes are researched in the scientific community vs. synergetic combinations; there are just too many uncontrolled variables in whole plant or essential oils.

This isolation of variables is reductionist in nature, and holistic approaches are not easily hypothesized. In other words, holistic based medical traditions (ie herbalism, aromatherapy, acupuncture, Ayurveda, shamanism, et al), are not easy for the scientific model to prove or disprove. Science focuses on individual pieces because the variables in experiments are easier to control. 

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The Smell That Heals

Just from smelling terpenes, there are a number of physiological effects that cascade through the brain and into the various systems of the body. When you take a big sniff of that bud of flower, or smell the pine trees on a hike, or the herbs in a garden, molecules of terpenes enter the nose, infuse your sinuses, get sorted with olfactory receptors and are then processed in the olfactory bulb, a sophisticated section of the forebrain that makes sense of the world of smells. It is in the olfactory bulb that terpene molecules dock with cells and through a highly complex system, a host of physiological and psychological effects is triggered such as inflammation reduction, anxiety mitigation, seizure abatement, and mood uplift to name just a few. Science is just beginning to tease out the mechanisms of the various effects of terpenes.


What Goes On Our Skin, Goes In

The skin is our largest organ, and it is permeable. Our skin is one of our gatekeepers for what goes into our bodies and what exits. How this action occurs is revealed at the molecular cellular level.

Cell membranes (see the illustration above) are composed of a bi-layer of phospholipids (fats), with cholesterol between the lipid molecules. This creates a hydrophobic or water adverse membrane keeping the cell organelle (nucleus, mitochondria, et al) separated from the surrounding water based environment. The hydrophobic nature of the membrane keeps most water soluble molecules from penetrating the cell. Only non-polar (not electrically charged molecules) or very small molecules like O2 or CO2 can easily pass through.

There are also other specialized cells on the membrane to facilitate larger molecules passing through the cell membrane. One of these protein structures is called a pore. Another protein structure is an ion pump which control the conductivity of the cell. Cells are amazing that they also conduct electricity (think of neurons passing an electric signal, cell by cell down to your arm to move your finger).

Essential oils create many of their effects by modifying the electric signaling of cells. This happens in 2 ways:

  1. Terpenes insert themselves into the lipid membrane of the cell wall. This creates more hydrophobic interactions between the lipophilic (fat loving) chains of phospholipids or cholesterol in the cell wall, which leads to a change in the membrane fluidity or permeability of the cell wall, and changes the structure of the cell and thus its function.
  2. Terpenes also attach to protein receptors on the membrane. Again this leads to more hydrophobic interactions which change the shape of the cell and thus it’s function, for example interference with ion channels. In other words, the docking of a terpene molecule to a protein receptor, interferes with the electric signal of the cell. This is the reason why terpenes can reduce pain or inflammation; the electric signal for pain or inflammation has been interfered with and doesn’t get passed to the other cells.

Terpenes also have direct interactions with select receptors and enzyme proteins in our bodies; like a key into a very specific lock. Hormone and neurotransmitter activation is one of the functions of terpenes bonding with select receptors. We see the evidence of these select interactions, reduction in anxiety, mood uplift, or the release of emotional trauma for example; but science does not completely understand the mechanisms of these interactions, possibly because a comprehensive model of the emotions has not been developed yet.

Pioneers in psychoneuroimmunology such as Candace Pert are beginning to examine the interrelation between psychology, neurobiology, and our immune system. Dr. Pert’s research demonstrates that neuropeptides (a neurotransmitter using peptides) dock with the same receptors as certain viruses. The level of these neuropeptides in our body is proportional to our emotion states (ie being ‘happy’ could interfere with the spread of viruses in our cells. (Pert, 1999, ‘Molecules of Emotion’)).

Understanding terpenes, the receptors they bond with, and their role in hormonal and neurotransmitter signaling could very well lead to new models of emotional health.