A Review of the Potential Use of Pinene and Linalool as Terpene-Based Medicines for Brain Health: Discovering Novel Therapeutics in the Flavours and Fragrances of Cannabis

Archive of "Frontiers in Psychiatry".“”Medicinal cannabis” is defined as the use of cannabis-based products for the treatment of an illness. Investigations of cannabis compounds in psychiatric and neurological illnesses primarily focus on the major cannabinoids, cannabidiol (CBD) and Δ9-tetrahydrocannabinol (Δ9-THC), which are hypothesised to benefit multiple illnesses manifesting cognitive impairment, neurodegeneration and neuro-inflammation, as well as chronic pain, epilepsy and post-traumatic stress disorder, respectively.

The cannabis plant contains >500 compounds, including terpenes responsible for the flavour and fragrance profiles of plants. Recently, research has begun providing evidence on the potential use of certain plant-derived terpenes in modern medicine, demonstrating anti-oxidant, anti-inflammatory, and neuroprotective effects of these compounds.

This review examined the effects of two key terpenes, pinene and linalool, on parameters relevant to neurological and psychiatric disorders, highlighting gaps in the literature and recommendations for future research into terpene therapeutics.

Overall, evidence is mostly limited to preclinical studies and well-designed clinical trials are lacking. Nevertheless, existing data suggests that pinene and linalool are relevant candidates for further investigation as novel medicines for illnesses, including stroke, ischemia, inflammatory and neuropathic pain (including migraine), cognitive impairment (relevant to Alzheimer’s disease and ageing), insomnia, anxiety, and depression.

Linalool and pinene influence multiple neurotransmitter, inflammatory and neurotrophic signals as well as behaviour, demonstrating psycho-activity (albeit non-intoxicating).   Optimising the phytochemical profile of cannabis chemovars to yield therapeutic levels of beneficial terpenes and cannabinoids, such as linalool, pinene and CBD, could present a unique opportunity to discover novel medicines to treat psychiatric and neurological illnesses; however, further research is needed.”

https://pubmed.ncbi.nlm.nih.gov/34512404/

“Overall, it appears that the importance of the terpene profile of plants to humans extends further than mere olfactory and gustatory delight. Rather, these compounds have the potential for use as treatments for serious chronic neurological and psychiatric illnesses.”

https://www.frontiersin.org/articles/10.3389/fpsyt.2021.583211/full

Cannabidiol (CBD).

Cover of StatPearls“Cannabis sativa or Indian hemp (subfamily Cannaboideae of family Moraceae) is an annual herbaceous plant, native to central and western Asia, cultivated for medicinal properties and for hemp, which is a natural textile fiber. The plant contains over 400 chemical compounds, of which approximately 80 biologically active chemical molecules. The most important cannabis compounds are cannabinoids formed by a terpene combined with resorcinol, or, according to a different nomenclature, by a benzopyranic ring system. There are about sixty cannabinoids, of which the most important psychoactive compound is tetrahydrocannabinol (TCH), in particular the isomer delta (Δ9-THC). Other identified compounds are cannabidiol (CBD), cannabigerol (CBG), cannabinol (CBN), cannabichromene (CBC), and olivetol. In addition to cannabinoids, the plant contains terpenoids such as beta-myrcene, beta-caryophyllene, d-limonene, linalool, piperidine, and p-cymene, as well as flavonoids such as quercetin.”

https://www.ncbi.nlm.nih.gov/pubmed/32310508

https://www.ncbi.nlm.nih.gov/books/NBK556048/

Pharmacological Foundations of Cannabis Chemovars.

“An advanced Mendelian Cannabis breeding program has been developed utilizing chemical markers to maximize the yield of phytocannabinoids and terpenoids with the aim to improve therapeutic efficacy and safety.

Cannabis is often divided into several categories based on cannabinoid content. Type I, Δ9-tetrahydrocannabinol-predominant, is the prevalent offering in both medical and recreational marketplaces. In recent years, the therapeutic benefits of cannabidiol have been better recognized, leading to the promotion of additional chemovars: Type II, Cannabis that contains both Δ9-tetrahydrocannabinol and cannabidiol, and cannabidiol-predominant Type III Cannabis.

While high-Δ9-tetrahydrocannabinol and high-myrcene chemovars dominate markets, these may not be optimal for patients who require distinct chemical profiles to achieve symptomatic relief. Type II Cannabis chemovars that display cannabidiol- and terpenoid-rich profiles have the potential to improve both efficacy and minimize adverse events associated with Δ9-tetrahydrocannabinol exposure. Cannabis samples were analyzed for cannabinoid and terpenoid content, and analytical results are presented via PhytoFacts, a patent-pending method of graphically displaying phytocannabinoid and terpenoid content, as well as scent, taste, and subjective therapeutic effect data.

Examples from the breeding program are highlighted and include Type I, II, and III Cannabis chemovars, those highly potent in terpenoids in general, or single components, for example, limonene, pinene, terpinolene, and linalool. Additionally, it is demonstrated how Type I - III chemovars have been developed with conserved terpenoid proportions. Specific chemovars may produce enhanced analgesia, anti-inflammatory, anticonvulsant, antidepressant, and anti-anxiety effects, while simultaneously reducing sequelae of Δ9-tetrahydrocannabinol such as panic, toxic psychosis, and short-term memory impairment.”

https://www.ncbi.nlm.nih.gov/pubmed/29161743

https://www.thieme-connect.de/DOI/DOI?10.1055/s-0043-122240

Taming THC: potential cannabis synergy and phytocannabinoid-terpenoid entourage effects

“The roots of cannabis synergy.”

“Tetrahydrocannabinol (THC) has been the primary focus of cannabis research since 1964, when Raphael Mechoulam isolated and synthesized it. More recently, the synergistic contributions of cannabidiol to cannabis pharmacology and analgesia have been scientifically demonstrated. Other phytocannabinoids, including tetrahydrocannabivarin, cannabigerol and cannabichromene, exert additional effects of therapeutic interest. Innovative conventional plant breeding has yielded cannabis chemotypes expressing high titres of each component for future study. This review will explore another echelon of phytotherapeutic agents, the cannabis terpenoids: limonene, myrcene, α-pinene, linalool, β-caryophyllene, caryophyllene oxide, nerolidol and phytol. Terpenoids share a precursor with phytocannabinoids, and are all flavour and fragrance components common to human diets that have been designated Generally Recognized as Safe by the US Food and Drug Administration and other regulatory agencies. Terpenoids are quite potent, and affect animal and even human behaviour when inhaled from ambient air at serum levels in the single digits ng·mL−1. They display unique therapeutic effects that may contribute meaningfully to the entourage effects of cannabis-based medicinal extracts. Particular focus will be placed on phytocannabinoid-terpenoid interactions that could produce synergy with respect to treatment of pain, inflammation, depression, anxiety, addiction, epilepsy, cancer, fungal and bacterial infections (including methicillin-resistant Staphylococcus aureus). Scientific evidence is presented for non-cannabinoid plant components as putative antidotes to intoxicating effects of THC that could increase its therapeutic index. Methods for investigating entourage effects in future experiments will be proposed. Phytocannabinoid-terpenoid synergy, if proven, increases the likelihood that an extensive pipeline of new therapeutic products is possible from this venerable plant.”

“Cannabis has been a medicinal plant of unparalleled versatility for millennia, but whose mechanisms of action were an unsolved mystery until the discovery of tetrahydrocannabinol (THC), the first cannabinoid receptor, CB1, and the endocannabinoids, anandamide (arachidonoylethanolamide, AEA) and 2-arachidonoylglycerol (2-AG). While a host of phytocannabinoids were discovered in the 1960s: cannabidiol (CBD), cannabigerol (CBG), cannabichromene (CBC) (Gaoni and Mechoulam, cannabidivarin (CBDV) and tetrahydrocannabivarin (THCV), the overwhelming preponderance of research focused on psychoactive THC. Only recently has renewed interest been manifest in THC analogues, while other key components of the activity of cannabis and its extracts, the cannabis terpenoids, remain understudied. The current review will reconsider essential oil (EO) agents, their peculiar pharmacology and possible therapeutic interactions with phytocannabinoids.”

“Should positive outcomes result from such studies, phytopharmaceutical development may follow. The development of zero-cannabinoid cannabis chemotypes has provided extracts that will facilitate discernment of the pharmacological effects and contributions of different fractions. Breeding work has already resulted in chemotypes that produce 97% of monoterpenoid content as myrcene, or 77% as limonene (E. de Meijer, pers. comm.). Selective cross-breeding of high-terpenoid- and high-phytocannabinoid-specific chemotypes has thus become a rational target that may lead to novel approaches to such disorders as treatment-resistant depression, anxiety, drug dependency, dementia and a panoply of dermatological disorders, as well as industrial applications as safer pesticides and antiseptics. A better future via cannabis phytochemistry may be an achievable goal through further research of the entourage effect in this versatile plant that may help it fulfil its promise as a pharmacological treasure trove.”

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3165946/